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Title: Linking radial growth patterns and moderate-severity disturbance dynamics in boreal old-growth forests driven by recurrent insect outbreaks: a tale of opportunities, successes, and failuresAuthors: Maxence Martin1,2,3*, Cornélia Krause1,3, and Hubert Morin1,31 Département des Sciences fondamentales, Université du Québec à Chicoutimi, 555 boul. de l’Université, Chicoutimi, Québec G7H 2B1, Canada; cornelia_krause@uqac.ca (C.K.); Hubert_Morin@uqac.ca (H.M.)2 Institut de recherche sur les forêts (IRF), Université du Québec en Abitibi-Témiscamingue, 445 boul. de l’Université, Rouyn-Noranda, QC J9X 5E4, Canada3 Centre d’étude de la forêt, Université du Québec à Montréal, P.O. Box 8888, Centre-ville Station, Montréal, Québec H3C 3P8, Canada* Corresponding author: maxence.martin1@uqac.ca; Tel.: +1-581-882-8651AbstractIn boreal landscapes, emphasis is currently placed on close-to-nature management strategies, which aim to maintain the biodiversity and ecosystem services related to old-growth forests. The success of these strategies, however, depends on an accurate understanding of the dynamics within these forests. While moderate-severity disturbances have recently been recognized as important drivers of boreal forests, little is known about their effects on stand structure and growth. This study therefore aims to reconstruct the disturbance and post-disturbance dynamics in boreal old-growth forests that are driven by recurrent moderate-severity disturbances. We studied eight primary old-growth forests in Québec, Canada, that have recorded recurrent and moderately severe spruce budworm (Choristoneura fumiferana [Clem.]) outbreaks over the 20th century. We applied an innovative dendrochronological approach based on the combined study of growth patterns and releases to reconstruct stand disturbance and post-disturbance dynamics. We identified nine growth patterns; they represented trees differing in age, size, and canopy layer. These patterns highlighted the ability of suppressed trees to rapidly fill gaps created by moderate-severity disturbances through a single and significant increase in radial growth and height. Trees that are unable to attain the canopy following the disturbance tend to remain in the lower canopy layers. This combination of a low stand height typical of boreal forests, periodic disturbances, and rapid canopy closure often resulted in stands constituted mainly of dominant and codominant trees, similar to even-aged forests. Overall, this study underscored the resistance of boreal old-growth forests owing to their capacity to withstand repeated moderate-severity disturbances. Moreover, the combined study of growth patterns and growth release demonstrated the efficacy of such an approach for improving the understanding of the fine-scale dynamics of natural forests. The results of this research will thus help develop silvicultural practices that approximate the moderate-severity disturbance dynamics observed in primary and old-growth boreal forests.RésuméDans les paysages boréaux, l'accent est désormais mis sur des stratégies de gestion proches de la nature afin de maintenir la biodiversité et les services écosystémiques liés aux vieilles forêts. Le succès de ces stratégies dépend toutefois d'une compréhension fine de la dynamique de ces forêts. Les perturbations de sévérité modérée ont ainsi été récemment reconnues comme étant d’importants moteurs de la dynamique des forêts boréales, mais l’on sait encore peu de choses de leur influence sur la structure et la croissance des peuplements. Par conséquent, l'objectif de cette étude est de reconstruire les dynamiques de perturbation et post-perturbation dans les vieilles forêts boréales causées par des perturbations récurrentes de sévérité modérée. Nous avons étudié huit vieilles forêts primaires au Québec, Canada, ayant enregistré des épidémies de tordeuse des bourgeons de l'épinette (Choristoneura fumiferana [Clem.]) récurrentes et de sévérité modérée au cours du 20ème siècle. Nous avons utilisé une approche dendrochronologique innovante combinant l’étude des patrons et des reprises de croissance pour reconstruire la dynamique de perturbation et post-perturbation de ces forêts. Nous avons identifié neuf patrons de croissance, observés dans des arbres d'?ge, de taille ou de strate de canopée différents, indiquant des dynamiques particulières. Ces patrons ont mis en évidence la capacité des arbres opprimés à rapidement combler les trouées dans la canopée en un unique et significatif accroissement de circonférence et de hauteur. En revanche, les arbres déjà situés dans la canopée ont eu peu d'influence sur la fermeture de ces trouées. En conséquence, les arbres dominants et codominants étaient les plus fréquents dans la canopée. Les résultats de cette étude soulignent la résistance des vieilles forêts boréales aux perturbations récurrentes et de sévérité modérée, car les arbres du sous-étage peuvent rapidement combler les trouées qui en résultent. Cependant, les arbres incapables d’atteindre le sommet de la canopée à la suite d’une perturbation resteront ensuite souvent dans les strates inférieures de la canopée. La combinaison de la faible hauteur des arbres typique des forêts boréales, des perturbations périodiques et de la rapide fermeture des trouées forme des peuplements avec une structure verticale ressemblant à celle des forêts équiennes. Globalement, cette étude souligne la résistance des vieilles forêts boréales en raison de leur capacité à supporter des perturbations répétées de sévérité modérée. De plus, l’étude combinée des patrons et des reprises de croissance démontre l’efficacité de cette approche pour reconstruire la dynamique à échelle fine des forêts naturelles. Les résultats de cette recherche contribueront ainsi à développer des pratiques sylvicoles analogues à la dynamique de perturbation de sévérité modérée observée dans les vieilles forêts primaires des paysages boréaux.Keywords: spruce budworm (Choristoneura fumiferana [Clem.]); old-growth forest; natural disturbance; ecosystem-based management; radial growth pattern; moderate-severity disturbance; forest dynamics; dendroecologyIntroductionAnthropogenic activities over the last centuries have increased pressure on forest ecosystems, causing a significant loss of natural forest areas ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Achard","given":"Frédéric","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Eva","given":"Hugh","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Mollicone","given":"Danillo","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Popatov","given":"Peter","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Stibig","given":"Hans-Jürgen","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Turubanova","given":"Svetlana","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Yaroshenko","given":"Alexey","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Old-growth forests: Function, fate and value","edition":"Ecological","editor":[{"dropping-particle":"","family":"Wirth","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gleixner","given":"Gerd","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Heimann","given":"Martin","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-1","issued":{"date-parts":[["2009"]]},"page":"411-428","publisher":"Springer-Verlag","publisher-place":"Berlin","title":"Detecting intact forests from space: hot spots of loss, deforestation and the UNFCCC","type":"chapter"},"uris":[""]},{"id":"ITEM-2","itemData":{"ISBN":"9785885871440","author":[{"dropping-particle":"","family":"Aksenov","given":"Dmitry","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Karpachevskiy","given":"Mikhail","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Lloyd","given":"Sarah","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Yaroshenko","given":"Alexei","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-2","issue":"December","issued":{"date-parts":[["1999"]]},"number-of-pages":"67","title":"The last of the last: the old-growth forests of boreal Europe","type":"book"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1038/d41586-018-07183-6","ISSN":"14764687","abstract":"Global conservation policy must stop the disappearance of Earth’s few intact ecosystems, warn James E. M. Watson, James R. Allan and colleagues.","author":[{"dropping-particle":"","family":"Watson","given":"James E.M.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Venter","given":"Oscar","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Lee","given":"Jasmine","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Jones","given":"Kendall R.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Robinson","given":"John G.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Possingham","given":"Hugh P.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Allan","given":"James R.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Nature","id":"ITEM-3","issue":"7729","issued":{"date-parts":[["2018"]]},"page":"27-30","title":"Protect the last of the wild","type":"article-journal","volume":"563"},"uris":[""]}],"mendeley":{"formattedCitation":"(Aksenov et al. 1999; Achard et al. 2009; Watson et al. 2018)","plainTextFormattedCitation":"(Aksenov et al. 1999; Achard et al. 2009; Watson et al. 2018)","previouslyFormattedCitation":"(Aksenov et al. 1999; Achard et al. 2009; Watson et al. 2018)"},"properties":{"noteIndex":0},"schema":""}(Aksenov et al. 1999; Achard et al. 2009; Watson et al. 2018). Forest artificialization, fragmentation, and deforestation threaten numerous species and ecosystem services, including carbon sequestration and water supply ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1007/s12199-008-0069-2","ISSN":"1342078X","abstract":"This review aims to contribute to the ongoing discussion about human health, global change, and biodiversity by concentrating on the relationships between forests and human health. This review gives a short overview of the most important health benefits that forests provide to humans, and the risks that forests may pose to human health. Furthermore, it discusses the future challenges for the research on the links between forests and human health, and for delivering health through forests in practice. Forests provide enormous possibilities to improve human health conditions. The results of a vast amount of research show that forest visits promote both physical and mental health by reducing stress. Forests represent rich natural pharmacies by virtue of being enormous sources of plant and microbial material with known or potential medicinal or nutritional value. Forest food offers a safety net for the most vulnerable population groups in developing countries, and healthy forest ecosystems may also help in regulation of infectious diseases. Utilizing forests effectively in health promotion could reduce public health care budgets and create new sources of income. Main challenges to delivering health through forests are due to ecosystem and biodiversity degradation, deforestation, and climate change. In addition, major implementation of research results into practice is still lacking. Inadequate implementation is partly caused by insufficient evidence base and partly due to the lack of policy-makers' and practitioners' awareness of the potential of forests for improving human health. This calls for strong cooperation among researchers, policy-makers, and practitioners as well as between different sectors, especially between health and environmental professionals. ? 2009 The Japanese Society for Hygiene.","author":[{"dropping-particle":"","family":"Karjalainen","given":"Eeva","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Sarjala","given":"Tytti","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Raitio","given":"Hannu","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Environmental Health and Preventive Medicine","id":"ITEM-1","issue":"1","issued":{"date-parts":[["2010"]]},"page":"1-8","title":"Promoting human health through forests: Overview and major challenges","type":"article-journal","volume":"15"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1038/d41586-018-07183-6","ISSN":"14764687","abstract":"Global conservation policy must stop the disappearance of Earth’s few intact ecosystems, warn James E. 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Allan and colleagues.","author":[{"dropping-particle":"","family":"Watson","given":"James E.M.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Venter","given":"Oscar","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Lee","given":"Jasmine","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Jones","given":"Kendall R.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Robinson","given":"John G.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Possingham","given":"Hugh P.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Allan","given":"James R.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Nature","id":"ITEM-2","issue":"7729","issued":{"date-parts":[["2018"]]},"page":"27-30","title":"Protect the last of the wild","type":"article-journal","volume":"563"},"uris":[""]}],"mendeley":{"formattedCitation":"(Karjalainen et al. 2010; Watson et al. 2018)","plainTextFormattedCitation":"(Karjalainen et al. 2010; Watson et al. 2018)","previouslyFormattedCitation":"(Karjalainen et al. 2010; Watson et al. 2018)"},"properties":{"noteIndex":0},"schema":""}(Karjalainen et al. 2010; Watson et al. 2018). Climate change is expected to increase the frequency and severity of natural disturbances and extreme weather conditions, thereby further stressing forest ecosystems ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1126/science.aac6759","ISBN":"9788578110796","ISSN":"1095-9203","PMID":"26293952","abstract":"Humans rely on healthy forests to supply energy, building materials, and food and to provide services such as storing carbon, hosting biodiversity, and regulating climate. Defining forest health integrates utilitarian and ecosystem measures of forest condition and function, implemented across a range of spatial scales. Although native forests are adapted to some level of disturbance, all forests now face novel stresses in the form of climate change, air pollution, and invasive pests. Detecting how intensification of these stresses will affect the trajectory of forests is a major scientific challenge that requires developing systems to assess the health of global forests. It is particularly critical to identify thresholds for rapid forest decline, because it can take many decades for forests to restore the services that they provide.","author":[{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bernier","given":"Pierre","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kuuluvainen","given":"Timo","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Shvidenko","given":"A. Z.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Schepaschenko","given":"D. G.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Science","id":"ITEM-1","issue":"6250","issued":{"date-parts":[["2015"]]},"page":"819-822","title":"Boreal forest health and global change","type":"article-journal","volume":"349"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1038/nclimate3303","ISSN":"17586798","abstract":"Forest disturbances are sensitive to climate. However, our understanding of disturbance dynamics in response to climatic changes remains incomplete, particularly regarding large-scale patterns, interaction effects and dampening feedbacks. Here we provide a global synthesis of climate change effects on important abiotic (fire, drought, wind, snow and ice) and biotic (insects and pathogens) disturbance agents. Warmer and drier conditions particularly facilitate fire, drought and insect disturbances, while warmer and wetter conditions increase disturbances from wind and pathogens. Widespread interactions between agents are likely to amplify disturbances, while indirect climate effects such as vegetation changes can dampen long-term disturbance sensitivities to climate. Future changes in disturbance are likely to be most pronounced in coniferous forests and the boreal biome. We conclude that both ecosystems and society should be prepared for an increasingly disturbed future of forests.","author":[{"dropping-particle":"","family":"Seidl","given":"Rupert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Thom","given":"Dominik","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kautz","given":"Markus","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Martin-Benito","given":"Dario","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Peltoniemi","given":"Mikko","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Vacchiano","given":"Giorgio","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Wild","given":"Jan","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Ascoli","given":"Davide","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Petr","given":"Michal","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Honkaniemi","given":"Juha","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Lexer","given":"Manfred J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Trotsiuk","given":"Volodymyr","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Mairota","given":"Paola","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Svoboda","given":"Miroslav","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fabrika","given":"Marek","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Nagel","given":"Thomas A.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Reyer","given":"Christopher P.O.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Nature Climate Change","id":"ITEM-2","issue":"6","issued":{"date-parts":[["2017"]]},"page":"395-402","publisher":"Nature Publishing Group","title":"Forest disturbances under climate change","type":"article-journal","volume":"7"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1007/s13595-019-0827-x","ISBN":"1359501908","ISSN":"1297966X","abstract":"Key message: Climate change is posing a considerable challenge to foresters. The intensity of required adaptive measures and the relevance of old-growth forests as benchmark for managed forests are debated. Forest managers need to make decisions on stand treatment that are based on climatological and biological parameters with high uncertainties. We provided the conceptual basis for adaptive forest management and provide a number of case studies that reflect the options and limitations of ways of coping with climate change. The examples are derived from the experience of the authors. We conclude that only few forest types are either not strongly affected by climate change or do not require immediate adaptations of forest management. Many productive forests have stand properties that are decisively shaped by past management decisions, such as tree species composition, age distribution, rotation period, and stand structure. Maintaining these properties under the influence of climate change requires continuous and even increasing efforts of forest managers.","author":[{"dropping-particle":"","family":"Jandl","given":"Robert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Spathelf","given":"Peter","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bolte","given":"Andreas","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Prescott","given":"Cindy E.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Annals of Forest Science","id":"ITEM-3","issue":"2","issued":{"date-parts":[["2019"]]},"page":"1-13","publisher":"Annals of Forest Science","title":"Forest adaptation to climate change—is non-management an option?","type":"article-journal","volume":"76"},"uris":[""]}],"mendeley":{"formattedCitation":"(Gauthier et al. 2015; Seidl et al. 2017; Jandl et al. 2019)","plainTextFormattedCitation":"(Gauthier et al. 2015; Seidl et al. 2017; Jandl et al. 2019)","previouslyFormattedCitation":"(Gauthier et al. 2015; Seidl et al. 2017; Jandl et al. 2019)"},"properties":{"noteIndex":0},"schema":""}(Gauthier et al. 2015; Seidl et al. 2017; Jandl et al. 2019). To address these issues, researchers have emphasized forest management strategies that aim to mimic natural forest structures and dynamics ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1016/j.landusepol.2020.104918","author":[{"dropping-particle":"","family":"Eyvindson","given":"Kyle","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Du","given":"Rémi","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Trivi?o","given":"María","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Blattert","given":"Clemens","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Potterf","given":"Mária","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Land Use Policy","id":"ITEM-1","issue":"December 2019","issued":{"date-parts":[["2021"]]},"title":"High boreal forest multifunctionality requires continuous cover forestry as a dominant management","type":"article-journal","volume":"100"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1002/ecs2.2632","ISSN":"21508925","abstract":"Retention harvesting, or the approach of leaving live mature trees behind during forest harvest, is used in natural disturbance-based management to mitigate the effects of logging on biodiversity. However, responses of many boreal vertebrates to variable retention harvesting are unknown. We investigated the influence of different retention levels in forest harvests on stand use by wildlife 15–18?yr post-harvest using a combination of surveys of wildlife signs (scats, middens) and camera trapping. Site-level measures of forest structure, including canopy cover, horizontal cover, tree height, tree diameter, basal area, cover of downed coarse woody material, and understory plant cover, were used to describe post-harvest differences in habitats used by common wildlife species in northwest Alberta's boreal forest. Stand use of six species (black bear, coyote, fisher, red squirrel, wolverine, woodland caribou) increased with level of retention, while stand use of two species (grouse, snowshoe hare) declined with retention level. Retention level did not significantly affect stand use of five species (American marten, Canada lynx, deer, gray wolf, moose). Higher levels of retention characterized by greater canopy cover, basal area, and abundance of deadwood were associated with use of forest habitats by late-seral species. Woodland caribou, a species of conservation concern, was detected only in harvested stands with at least 20% retention. Greater understory and horizontal cover characterized lower levels of retention being attractive for early-seral species. These findings demonstrate the value of retention harvesting for conservation of wildlife species in boreal forest, while highlighting the challenge of managing forests for multiple species with different habitat preferences.","author":[{"dropping-particle":"","family":"Franklin","given":"Caroline M.A.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Macdonald","given":"S. Ellen","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Nielsen","given":"Scott E.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecosphere","id":"ITEM-2","issue":"3","issued":{"date-parts":[["2019"]]},"title":"Can retention harvests help conserve wildlife? Evidence for vertebrates in the boreal forest","type":"article-journal","volume":"10"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1186/s40663-018-0142-2","ISSN":"21975620","abstract":"The circumboreal forest encompasses diverse landscape structures, dynamics and forest age distributions determined by their physical setting, and historical and current disturbance regimes. However, due to intensifying forest utilisation, and in certain areas due to increasing natural disturbances, boreal forest age-class structures have changed rapidly, so that the proportion of old forest has substantially declined, while that of young post-harvest and post-natural-disturbance forest proportions have increased. In the future, with a warming climate in certain boreal regions, this trend may further be enhanced due to an increase in natural disturbances and large-scale use of forest biomass to replace fossil-based fuels and products. The major drivers of change of forest age class distributions and structures include the use of clearcut short-rotation harvesting, more frequent and severe natural disturbances due to climate warming in certain regions. The decline in old forest area, and increase in managed young forest lacking natural post-disturbance structural legacies, represent a major transformation in the ecological conditions of the boreal forest beyond historical limits of variability. This may introduce a threat to biodiversity, ecosystem resilience and long-term adaptive capacity of the forest ecosystem. To safeguard boreal forest biodiversity and ecosystem functioning, and to maintain the multiple services provided to societies by this forest biome, it is pivotal to maintain an adequate share and the ecological qualities of young post-disturbance stages, along with mature forest stages with old-growth characteristics. This requires management for natural post-disturbance legacy structures, and innovative use of diverse uneven-aged and continuous cover management approaches to maintain critical late-successional forest structures in landscapes.","author":[{"dropping-particle":"","family":"Kuuluvainen","given":"Timo","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecosystems","id":"ITEM-3","issue":"1","issued":{"date-parts":[["2018"]]},"page":"15","publisher":"Forest Ecosystems","title":"Young and old forest in the boreal: critical stages of ecosystem dynamics and management under global change","type":"article-journal","volume":"5"},"uris":[""]}],"mendeley":{"formattedCitation":"(Kuuluvainen and Gauthier 2018; Franklin et al. 2019; Eyvindson et al. 2021)","plainTextFormattedCitation":"(Kuuluvainen and Gauthier 2018; Franklin et al. 2019; Eyvindson et al. 2021)","previouslyFormattedCitation":"(Kuuluvainen and Gauthier 2018; Franklin et al. 2019; Eyvindson et al. 2021)"},"properties":{"noteIndex":0},"schema":""}(Kuuluvainen and Gauthier 2018; Franklin et al. 2019; Eyvindson et al. 2021). Reducing the difference between managed and natural forests is expected to offset the loss of biodiversity and ecosystem services while increasing the resistance and the resilience of forest ecosystems to climate change ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"ISBN":"9781597261456","author":[{"dropping-particle":"","family":"Puettmann","given":"Klaus J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Coates","given":"K. David","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Messier","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-1","issued":{"date-parts":[["2009"]]},"number-of-pages":"189","publisher":"Island Press","publisher-place":"Washington D.C.","title":"A Critique of Silviculture: Managing for Complexity","type":"book"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1080/07352689.2014.858956","ISSN":"15497836","abstract":"Considerable uncertainties remain about magnitude and character, if not general direction of anthropogenic climate change. Global mean temperature could increase by 1.5-4.5°C or more over historic levels, and extreme weather events-drought, storms, and flooding-are likely to increase greatly in frequency. Although ecologists and foresters agree that the practice of forestry will be transformed under climate change, these uncertainties compound the challenge of achieving sustainable, adaptive forest management. In this aritcle, we (i) present a multidisciplinary synthesis of current knowledge of responses of temperate and boreal tree species and forest communities to climate change, and (ii) outline silvicultural strategies for adapting temperate and boreal forests to confront climate change. Our knowledge synthesis proceeds through critical appraisals of efforts to model future tree distributions and responses to climate change, and reviews physiological, phenological, acclimation, and epigenetic responses to climate. As is the case of climate change itself, there are numerous uncertainties about tree species and provenance responses to climate change. For example, acclimation of respiration and epigenetic conditioning of seed embryos has the potential to buffer species against limited warming. Provenances within species also display idiosyncratic responses to altered climates, implying that soemm varieties will be more resilient or resistant to climate change than others. Genetically determined limits to climatic tolerance, and the limits of tree community resistance and resilience (speed of recovery from disturbance) in the face of climate-related disturbances are largely unknown. These unknowns require managers to adopt a portfolio of silvicultural strategies, which may range from minor modifications of current practices to design of novel multi-species stands that may have no historical analogue. Forest managers must be prepared to respond nimbly as they develop, incorporate new insights about climate change and species responses to warming into their practices. Marshalling all strategies and sources of knowledge should enable forest managers to mount (at least) a partially successful response to the challenges of climate change. ? 2014 Copyright Taylor & Francis Group, LLC.","author":[{"dropping-particle":"","family":"Park","given":"Andrew","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Puettmann","given":"Klaus","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Wilson","given":"Edward","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Messier","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kames","given":"Susanne","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Dhar","given":"Amalesh","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Critical Reviews in Plant Sciences","id":"ITEM-2","issue":"4","issued":{"date-parts":[["2014"]]},"page":"251-285","title":"Can boreal and temperate forest management be adapted to the uncertainties of 21st century climate change?","type":"article-journal","volume":"33"},"uris":[""]}],"mendeley":{"formattedCitation":"(Puettmann et al. 2009; Park et al. 2014)","plainTextFormattedCitation":"(Puettmann et al. 2009; Park et al. 2014)","previouslyFormattedCitation":"(Puettmann et al. 2009; Park et al. 2014)"},"properties":{"noteIndex":0},"schema":""}(Puettmann et al. 2009; Park et al. 2014).The desire to reduce differences between managed and natural forests has led to a heightened focus on old-growth forests—forests in the final stage of forest succession, driven by secondary disturbances ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Oliver","given":"C. D.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Larson","given":"B. C.","non-dropping-particle":"","parse-names":false,"suffix":""}],"edition":"4th","id":"ITEM-1","issued":{"date-parts":[["1996"]]},"number-of-pages":"520","publisher":"John Wiley & Sons, Inc.","publisher-place":"New York","title":"Forest Stand Dynamics","type":"book"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1007/978","author":[{"dropping-particle":"","family":"Wirth","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Messier","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Frank","given":"Dorothea","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Old-growth forests: Function, fate and value","edition":"Ecological","editor":[{"dropping-particle":"","family":"Wirth","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gleixner","given":"Gerd","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Helmann","given":"Martin","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-2","issued":{"date-parts":[["2009"]]},"page":"11-33","publisher":"Springer","title":"Old-growth forest definitions : a pragmatic view","type":"chapter"},"uris":[""]}],"mendeley":{"formattedCitation":"(Oliver and Larson 1996; Wirth et al. 2009)","plainTextFormattedCitation":"(Oliver and Larson 1996; Wirth et al. 2009)","previouslyFormattedCitation":"(Oliver and Larson 1996; Wirth et al. 2009)"},"properties":{"noteIndex":0},"schema":""}(Oliver and Larson 1996; Wirth et al. 2009). These forests are often the most threatened by human activities, their area greatly reduced through deforestation and intensive forest management ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1126/sciadv.1600821","ISSN":"23752548","abstract":"An intact forest landscape (IFL) is a seamless mosaic of forest and naturally treeless ecosystems with no remotely detected signs of human activity and a minimum area of 500 km2. IFLs are critical for stabilizing terrestrial carbon storage, harboring biodiversity, regulating hydrological regimes, and providing other ecosystem functions. Although the remaining IFLs comprise only 20% of tropical forest area, they account for 40% of the total aboveground tropical forest carbon. We show that global IFL extent has been reduced by 7.2% since the year 2000. An increasing rate of global IFL area reduction was found, largely driven by the tripling of IFL tropical forest loss in 2011–2013 compared to that in 2001–2003. Industrial logging, agricultural expansion, fire, and mining/resource extraction were the primary causes of IFL area reduction. Protected areas (International Union for Conservation of Nature categories I to III) were found to have a positive effect in slowing the reduction of IFL area from timber harvesting but were less effective in limiting agricultural expansion. The certification of logging concessions under responsible management had a negligible impact on slowing IFL fragmentation in the Congo Basin. Fragmentation of IFLs by logging and establishment of roads and other infrastructure initiates a cascade of changes that lead to landscape transformation and loss of conservation values. Given that only 12% of the global IFL area is protected, our results illustrate the need for planning and investment in carbon sequestration and biodiversity conservation efforts that target the most valuable remaining forests, as identified using the IFL approach.","author":[{"dropping-particle":"","family":"Potapov","given":"Peter","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Hansen","given":"Matthew C.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Laestadius","given":"Lars","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Turubanova","given":"Svetlana","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Yaroshenko","given":"Alexey","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Thies","given":"Christoph","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Smith","given":"Wynet","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Zhuravleva","given":"Ilona","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Komarova","given":"Anna","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Minnemeyer","given":"Susan","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Esipova","given":"Elena","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Science Advances","id":"ITEM-1","issue":"1","issued":{"date-parts":[["2017"]]},"page":"1-14","title":"The last frontiers of wilderness: Tracking loss of intact forest landscapes from 2000 to 2013","type":"article-journal","volume":"3"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1186/s40663-018-0148-9","ISBN":"2197-5620","ISSN":"2197-5620","author":[{"dropping-particle":"","family":"Grondin","given":"Pierre","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Poirier","given":"Véronique","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Tardif","given":"Patrice","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Boucher","given":"Yan","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecosystems","id":"ITEM-2","issue":"1","issued":{"date-parts":[["2018"]]},"page":"30","publisher":"Forest Ecosystems","title":"Have some landscapes in the eastern Canadian boreal forest moved beyond their natural range of variability?","type":"article-journal","volume":"5"},"uris":[""]},{"id":"ITEM-3","itemData":{"author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Boucher","given":"Yan","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Marchand","given":"Philippe","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-3","issued":{"date-parts":[["2020"]]},"page":"1-10","title":"Forest management has reduced the structural diversity of residual boreal old-growth forest landscapes in Eastern Canada","type":"article-journal","volume":"458"},"uris":[""]}],"mendeley":{"formattedCitation":"(Potapov et al. 2017; Grondin et al. 2018; Martin, Boucher, et al. 2020)","manualFormatting":"(Potapov et al. 2017; Grondin et al. 2018; Martin et al. 2020a)","plainTextFormattedCitation":"(Potapov et al. 2017; Grondin et al. 2018; Martin, Boucher, et al. 2020)","previouslyFormattedCitation":"(Potapov et al. 2017; Grondin et al. 2018; Martin, Boucher, et al. 2020)"},"properties":{"noteIndex":0},"schema":""}(Potapov et al. 2017; Grondin et al. 2018; Martin et al. 2020a). Many of the structural attributes that generally define these ecosystems, such as structural and compositional complexity, large trees, and high deadwood volume, are rare, if not absent, in younger or managed forests ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1007/978","author":[{"dropping-particle":"","family":"Wirth","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Messier","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Frank","given":"Dorothea","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Old-growth forests: Function, fate and value","edition":"Ecological","editor":[{"dropping-particle":"","family":"Wirth","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gleixner","given":"Gerd","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Helmann","given":"Martin","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-1","issued":{"date-parts":[["2009"]]},"page":"11-33","publisher":"Springer","title":"Old-growth forest definitions : a pragmatic view","type":"chapter"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1016/j.foreco.2015.02.037","ISSN":"03781127","abstract":"Over the past centuries in Western Europe, the long history of forest management has shaped both landscape- and local-scale forest structures. In France, a network of strict forest reserves was created in the 1950s to serve as a reference for nature conservation and forest dynamics. However, few studies to date have quantitatively compared the structural characteristics between managed stands and the reserves, where management has been (more or less recently) abandoned. In addition, the time needed for old-growth characteristics to restore themselves in strict forest reserves remains poorly known.We analysed the differences in stand characteristics between managed and unmanaged stands in 17 French forests (233 plots) located in both lowland and in mountainous regions. We quantitatively showed that overall basal area, very large trees and deadwood features were significantly higher in unmanaged forests, though this pattern was mainly found in the lowland forests while in mountainous regions, managed and unmanaged forests showed far fewer differences. In addition, most structural characteristics that were higher in unmanaged forests also increased with the time since last pared to the remaining old-growth forests elsewhere in Europe, the strict forest reserves in France often appear less mature, since they are still recovering from centuries of intensive management. Our results also show lower levels than those observed in other European studies on the restoration of old-growth characteristics over time; this indicates that it will take French reserves a very long time to reach values comparable to old-growth references in Europe. Our study constitutes one of the first references on unmanaged forests in France and may serve practitioners in their everyday management.","author":[{"dropping-particle":"","family":"Paillet","given":"Yoan","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Pernot","given":"Coryse","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Boulanger","given":"Vincent","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Debaive","given":"Nicolas","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fuhr","given":"Marc","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gilg","given":"Olivier","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gosselin","given":"Frédéric","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-2","issued":{"date-parts":[["2015"]]},"page":"51-64","publisher":"Elsevier B.V.","title":"Quantifying the recovery of old-growth attributes in forest reserves: A first reference for France","type":"article-journal","volume":"346"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1016/j.foreco.2018.04.007","ISSN":"03781127","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-3","issue":"April","issued":{"date-parts":[["2018"]]},"page":"125-136","publisher":"Elsevier","title":"Structural diversity and dynamics of boreal old-growth forests case study in Eastern Canada","type":"article-journal","volume":"422"},"uris":[""]}],"mendeley":{"formattedCitation":"(Wirth et al. 2009; Paillet et al. 2015; Martin et al. 2018)","plainTextFormattedCitation":"(Wirth et al. 2009; Paillet et al. 2015; Martin et al. 2018)","previouslyFormattedCitation":"(Wirth et al. 2009; Paillet et al. 2015; Martin et al. 2018)"},"properties":{"noteIndex":0},"schema":""}(Wirth et al. 2009; Paillet et al. 2015; Martin et al. 2018). These structural features provide essential habitats for many species ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1016/j.foreco.2007.10.029","ISSN":"03781127","author":[{"dropping-particle":"","family":"Winter","given":"Susanne","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"M?ller","given":"Georg Christian","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-1","issue":"3-4","issued":{"date-parts":[["2008","3"]]},"page":"1251-1261","title":"Microhabitats in lowland beech forests as monitoring tool for nature conservation","type":"article-journal","volume":"255"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1139/cjfr-2017-0352","ISSN":"0045-5067","author":[{"dropping-particle":"","family":"Boudreault","given":"Catherine","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Paquette","given":"M.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Pothier","given":"D.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canadian Journal of Forest Research","id":"ITEM-2","issue":"7","issued":{"date-parts":[["2018"]]},"page":"821-834","title":"Changes in bryophytes assemblages along a chronosequence in eastern boreal forest of Quebec","type":"article-journal","volume":"48"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1371/journal.pone.0191645","ISBN":"1111111111","ISSN":"19326203","PMID":"29414989","abstract":"Many studies project future bird ranges by relying on correlative species distribution models. Such models do not usually represent important processes explicitly related to climate change and harvesting, which limits their potential for predicting and understanding the future of boreal bird assemblages at the landscape scale. In this study, we attempted to assess the cumulative and specific impacts of both harvesting and climate-induced changes on wildfires and stand-level processes (e.g., reproduction, growth) in the boreal forest of eastern Canada. The projected changes in these landscape- and stand-scale processes (referred to as “drivers of change”) were then assessed for their impacts on future habitats and potential productivity of black-backed woodpecker (BBWO; Picoides arcticus), a focal species representative of deadwood and old-growth biodiversity in eastern Canada. Forest attributes were simulated using a forest landscape model, LANDIS-II, and were used to infer future landscape suitability to BBWO under three anthropogenic climate forcing scenarios (RCP 2.6, RCP 4.5 and RCP 8.5), compared to the historical baseline. We found climate change is likely to be detrimental for BBWO, with up to 92% decline in potential productivity under the worst-case climate forcing scenario (RCP 8.5). However, large declines were also projected under baseline climate, underlining the importance of harvest in determining future BBWO productivity. Present-day harvesting practices were the single most important cause of declining areas of old-growth coniferous forest, and hence appeared as the single most important driver of future BBWO productivity, regardless of the climate scenario. Climate-induced increases in fire activity would further promote young, deciduous stands at the expense of old-growth coniferous stands. This suggests that the biodiversity associated with deadwood and old-growth boreal forests may be greatly altered by the cumulative impacts of natural and anthropogenic disturbances under a changing climate. Management adaptations, including reduced harvesting levels and strategies to promote coniferous species content, may help mitigate these cumulative impacts.","author":[{"dropping-particle":"","family":"Tremblay","given":"Junior A.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Boulanger","given":"Yan","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Cyr","given":"Dominic","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Taylor","given":"Anthony R.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Price","given":"David T.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"St-Laurent","given":"Martin Hugues","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"PLoS ONE","id":"ITEM-3","issue":"2","issued":{"date-parts":[["2018"]]},"page":"1-25","title":"Harvesting interacts with climate change to affect future habitat quality of a focal species in eastern Canada’s boreal forest","type":"article-journal","volume":"13"},"uris":[""]}],"mendeley":{"formattedCitation":"(Winter and M?ller 2008; Boudreault et al. 2018; Tremblay et al. 2018)","plainTextFormattedCitation":"(Winter and M?ller 2008; Boudreault et al. 2018; Tremblay et al. 2018)","previouslyFormattedCitation":"(Winter and M?ller 2008; Boudreault et al. 2018; Tremblay et al. 2018)"},"properties":{"noteIndex":0},"schema":""}(Winter and M?ller 2008; Boudreault et al. 2018; Tremblay et al. 2018). Similarly, the temporal continuity of old-growth forests, where the last primary disturbance often occurred centuries ago, is vital for many low-dispersal (e.g., lichen and bryophyte species) or disturbance-sensitive species (e.g., woodland caribou (Rangifer tarandus caribou)) ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Silva Fennica","id":"ITEM-1","issue":"October 2010","issued":{"date-parts":[["2011"]]},"page":"983-994","title":"Dynamic old-growth forests ? A case study of boreal black spruce forest bryophytes","type":"article-journal","volume":"45"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1111/jvs.12552","ISSN":"16541103","author":[{"dropping-particle":"","family":"Barbé","given":"Marion","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Journal of Vegetation Science","id":"ITEM-2","issue":"5","issued":{"date-parts":[["2017"]]},"page":"915-927","title":"Boreal bryophyte response to natural fire edge creation","type":"article-journal","volume":"28"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1016/j.biocon.2010.08.001","ISSN":"00063207","abstract":"Conservation of forest-dwelling caribou (Rangifer tarandus caribou) is of great concern across most of its range. Anthropogenic disturbances, primarily logging activities, have been identified as the most important cause of caribou decline, although the mechanisms underlying this decline are not fully understood. Caribou commonly display fidelity to calving sites or seasonal ranges, but the potential role of this life-history trait has been largely overlooked in research and conservation planning. This is surprising because sites and ranges with high inter-annual use should have high conservation value. We investigated the relationship between habitat disturbances and home-range fidelity of forest-dwelling caribou across three study sites in Québec, Canada, using a broad range of natural and anthropogenic disturbances. Between 2004 and 2007, we tracked 47 adult female caribou using GPS collars. Home-range fidelity varied between seasons, being higher during calving and summer, and lower during winter. Caribou reduced fidelity following natural and anthropogenic disturbances, the latter having a stronger negative influence. Anthropogenic disturbances had a strong negative impact on home-range fidelity during annual, summer and winter periods, whereas natural disturbance was the dominant factor during calving. Despite this negative influence on fidelity, caribou tended to demonstrate range fidelity even in study sites most impacted by human activities. Habitat disturbances could produce two possible outcomes for caribou conservation: (1) a trend for females to reduce home-range fidelity which could translate into lower calf and female caribou survival through reduced familiarity with food distribution, escape cover and predation risk and (2) a global tendency to maintain range fidelity even in a drastically modified landscape which could turn into an ecological trap, particularly for calves when predation risk increases due to increased black bear density in early successional forests. Taking range fidelity behavior into consideration during forest management planning could direct conservation efforts toward the best available sites and therefore facilitate caribou persistence in managed landscapes. ? 2010 Elsevier Ltd.","author":[{"dropping-particle":"","family":"Faille","given":"Geneviève","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Dussault","given":"C.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Ouellet","given":"Jean Pierre","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fortin","given":"Daniel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Courtois","given":"Réhaume","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"St-Laurent","given":"Martin Hugues","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Dussault","given":"Claude","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Biological Conservation","id":"ITEM-3","issue":"11","issued":{"date-parts":[["2010"]]},"page":"2840-2850","title":"Range fidelity: The missing link between caribou decline and habitat alteration?","type":"article-journal","volume":"143"},"uris":[""]}],"mendeley":{"formattedCitation":"(Faille et al. 2010; Fenton and Bergeron 2011; Barbé et al. 2017)","plainTextFormattedCitation":"(Faille et al. 2010; Fenton and Bergeron 2011; Barbé et al. 2017)","previouslyFormattedCitation":"(Faille et al. 2010; Fenton and Bergeron 2011; Barbé et al. 2017)"},"properties":{"noteIndex":0},"schema":""}(Faille et al. 2010; Fenton and Bergeron 2011; Barbé et al. 2017). Old-growth forests also play a key role in the offering of ecosystem services, including carbon storage and water flux ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.5822/978-1-61091-891-6_14","ISBN":"9781610918916","abstract":"For decades forest scientists have thought that old-growth temperate forests were either carbon neutral or even carbon sources, emitting more greenhouse gases to the atmosphere through respiration and decomposition than they were absorbing through photosynthesis. However, recent research has questioned that assumption, showing that eastern old-growth forests may remain productive and have net positive carbon uptake later into succession and stand development than previously thought. These findings remain contentious and yet have profound implications for our understanding of the role of high-biomass, late successional forests in global carbon budgets. Emerging science strongly supports conservation of old-growth forests and management for old-growth structure as effective strategies in global efforts to reduce carbon dioxide emissions and moderate the intensity of future climate change (Luyssaert et al. 2008; Keith et al. 2009; Burrascano et al. 2013).","author":[{"dropping-particle":"","family":"Keeton","given":"William S.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecology and Recovery of Eastern Old-Growth Forests","id":"ITEM-1","issued":{"date-parts":[["2019"]]},"page":"267-288","title":"Source or sink? Carbon dynamics in eastern old-growth forests and their role in climate change mitigation","type":"article-journal"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.3390/f10100911","ISSN":"19994907","abstract":"Old-growth forests are widely recognised for the benefits they provide for biodiversity; however, a more comprehensive understanding of their role in climate change mitigation must still be established to find the optimal balance between different forest ecosystem services at a national or regional scale. Very few studies have assessed carbon pools in old-growth Scots pine (Pinus sylvestris L.)-dominated boreal forests, and none have been conducted in hemiboreal forests. Therefore, we assessed the carbon storage of the living tree biomass, deadwood, forest floor (soil organic horizon, including all litter and decomposed wood), and mineral soil in 25 hemiboreal old-growth (163-218 years) unmanaged Scots pine stands in Latvia. The studied stands were without known records of any major natural or human-made disturbance in the visible past. Our results show, that the total ecosystem carbon pool (excluding ground vegetation) was 291.2 ± 54.2 Mg C ha-1, which was primarily composed of living tree biomass (59%), followed by mineral soil (31%), deadwood (5%), and the forest floor (5%). Within the studied stand age group, the total carbon pool remained stable; however, interchanges among the carbon pools, i.e., living biomass and laying deadwood, did occur.","author":[{"dropping-particle":"","family":"Kenina","given":"Laura","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Jaunslaviete","given":"Ieva","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Liepa","given":"Liga","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Zute","given":"Daiga","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Jansons","given":"Aris","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-2","issue":"10","issued":{"date-parts":[["2019"]]},"page":"1-10","title":"Carbon pools in old-growth Scots pine stands in hemiboreal Latvia","type":"article-journal","volume":"10"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.5822/978-1-61091-891-6_9","ISBN":"9781610918916","abstract":"The largescale recovery of eastern forests from historic clearing is a remarkable example of forest ecosystem resilience (Foster and Aber 2004). More than 150 years after the peak of agricultural clearing in eastern North America, many forests across the region have reached maturity and some are progressing toward an old-growth condition (Brooks et al. 2012; figure 9-1). With this forest recovery and an increasing abundance of old-growth stands, we see the recovery of ecosystem functions and ecosystem services not only in the terrestrial environment but also in the streams and rivers that flow through this increasingly complex forested landscape (Warren et al. 2016; Urbano and Keeton 2017).","author":[{"dropping-particle":"","family":"Warren","given":"Dana R.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Keeton","given":"William S.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bechtold","given":"Heather A.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kraft","given":"Clifford E.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecology and Recovery of Eastern Old-Growth Forests","id":"ITEM-3","issued":{"date-parts":[["2019"]]},"page":"159-178","title":"Forest-stream interactions in eastern old-growth forests","type":"chapter"},"uris":[""]}],"mendeley":{"formattedCitation":"(Kenina et al. 2019; Warren et al. 2019; Keeton 2019)","plainTextFormattedCitation":"(Kenina et al. 2019; Warren et al. 2019; Keeton 2019)","previouslyFormattedCitation":"(Kenina et al. 2019; Warren et al. 2019; Keeton 2019)"},"properties":{"noteIndex":0},"schema":""}(Kenina et al. 2019; Warren et al. 2019; Keeton 2019). Maintaining remnant old-growth forests or enhancing old-growth attributes in managed stands has become, therefore, a common priority for forest and environmental managers ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1016/j.foreco.2009.01.053","ISSN":"03781127","author":[{"dropping-particle":"","family":"Bauhus","given":"Jürgen","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Puettmann","given":"Klaus","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Messier","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-1","issue":"4","issued":{"date-parts":[["2009","7"]]},"page":"525-537","title":"Silviculture for old-growth attributes","type":"article-journal","volume":"258"},"uris":[""]},{"id":"ITEM-2","itemData":{"author":[{"dropping-particle":"","family":"Kuuluvainen","given":"Timo","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"AMBIO: A Journal of the Human Environment","id":"ITEM-2","issue":"6","issued":{"date-parts":[["2009"]]},"page":"309-315","title":"Forest management and biodiversity conservation based on natural ecosystem dynamics in Northern Europe : The complexity challenge","type":"article-journal","volume":"38"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1016/j.foreco.2019.03.053","ISSN":"03781127","abstract":"Elements of forest structure are fundamentally associated with an array of ecosystem services and habitat characteristics. However, forest structure varies, in particular, through interactions with natural and human disturbances. Both variation in structural characteristics and associated relationships with ecosystem service outcomes have been poorly explored in mature, secondary forests redeveloped since 19th century agricultural abandonment in the eastern United States. Our study addressed this uncertainty focusing on carbon storage as an important climate regulation service. We conducted an inventory of 45 plots sharing similar land use history (i) to identify differences in forest structure, and (ii) to investigate links between stand structure and aboveground carbon storage. We derived 19 structural attributes and used these in Agglomerative Hierarchical Clustering (AHC) to categorize structurally different groups. Subsequently, we analyzed carbon density in each cluster and employed a random forest algorithm to derive partial effects of structural attributes on carbon storage. We found a distinctive disparity in forest structure inferred from two hardwood-dominated and one softwood-dominated clusters. Nine variables (cavity tree density, conifer ratio, foliage height index, gap area, live basal area, species diversity, variation in heights and diameters, and vertical shrub cover) explained significant differences between these clusters. Carbon storage varied markedly, and was highest in the softwood cluster. Structural complexity was overall positively associated with carbon storage, whereas this effect was more distinctive in hardwood compared to softwood-dominated forests. In particular, five variables exhibited a positive (conifer ratio, diameter variation, dead basal area, large live trees, and live basal area), one a negative (live tree density), and two (dead tree density and species diversity) a mixed relationship with carbon storage. Despite only moderate variation in climatic conditions across the investigated plots, we found a strong sensitivity of carbon storage to mean annual temperature. In contrast, annual precipitation and topography had no effect on carbon storage. The link between structural complexity and carbon storage suggests a high potential to actively increase forest carbon density. Based on our findings, a variety of options are available to enhance forest structure, and thus to improve carbon storage in managed forest eco…","author":[{"dropping-particle":"","family":"Thom","given":"Dominik","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Keeton","given":"William S.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-3","issue":"March","issued":{"date-parts":[["2019"]]},"page":"10-20","publisher":"Elsevier","title":"Stand structure drives disparities in carbon storage in northern hardwood-conifer forests","type":"article-journal","volume":"442"},"uris":[""]}],"mendeley":{"formattedCitation":"(Bauhus et al. 2009; Kuuluvainen 2009; Thom and Keeton 2019)","plainTextFormattedCitation":"(Bauhus et al. 2009; Kuuluvainen 2009; Thom and Keeton 2019)","previouslyFormattedCitation":"(Bauhus et al. 2009; Kuuluvainen 2009; Thom and Keeton 2019)"},"properties":{"noteIndex":0},"schema":""}(Bauhus et al. 2009; Kuuluvainen 2009; Thom and Keeton 2019). The success in achieving conservation objectives related to old-growth forests depends heavily, however, on fine- and multiscale (i.e., at the tree, stand, and landscape scales) knowledge of the dynamics of these ecosystems. Inappropriate management practices, based on superficial knowledge and/or simplification of natural dynamics, may produce limited and even no ecological benefits ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"ISBN":"9781597261456","author":[{"dropping-particle":"","family":"Puettmann","given":"Klaus J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Coates","given":"K. David","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Messier","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-1","issued":{"date-parts":[["2009"]]},"number-of-pages":"189","publisher":"Island Press","publisher-place":"Washington D.C.","title":"A Critique of Silviculture: Managing for Complexity","type":"book"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.5558/tfc2013-065","ISSN":"0015-7546","abstract":"Multi-cohort management that creates or maintains an uneven structure within forest stands has been widely advocated as a means to attenuate the impact of forest harvesting. An experimental network was put in place in black spruce forests of northwestern Quebec to test this assertion. Here we synthesize the biodiversity results in two main lessons: (1) at least 40% to 60% retention of pre-harvest basal area was required to maintain pre-harvest conditions for most species groups; (2) partial harvests showed the potential to be efficient deadwood delivery systems. In addition to these two main general conclusions, we emphasise that future research should examine whether partial harvest may be able to advance forest succession.","author":[{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Imbeau","given":"Louis","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Work","given":"Timothy","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Jacobs","given":"Jenna","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bescond","given":"Hervé","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Drapeau","given":"Pierre","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"The Forestry Chronicle","id":"ITEM-2","issue":"03","issued":{"date-parts":[["2014"]]},"page":"350-359","title":"Lessons learned from 12 years of ecological research on partial cuts in black spruce forests of northwestern Québec","type":"article-journal","volume":"89"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1139/er-2018-0041","ISSN":"11818700","abstract":"Loss of global forest, and in particular forest that has little human disturbance, is a standard against which we measure progress to conserve Earth's forests. The value of intact forest landscapes has taken hold in the global psyche. We provide a brief history of the intact forest landscape concept and discuss how this has moved to an operational definition used as a global and regional metric of forest conservation. We distinguish between a conceptual intact forest landscape and an operational definition. For the purposes of this paper we will use the term IFL to mean the operational definition and intact forest landscapes to mean the conceptual idea. We provide an overview of the science that supports the value of intact forest landscapes in a Canadian boreal context and analyse issues with using a standard operationalized IFL definition to both measure and promote conservation of forests at global and regional scales. We found many arguments for protecting large, intact forest landscapes that are relevant to the Canadian boreal forest, including conservation of biodiversity, ecological processes and ecosystem services, existence values, application of the precautionary principle, and the need for scientific benchmarks. But it is clear that the standard operational IFL size threshold of 50 000 ha in the boreal forest is inadequate to meet these broad conservation objectives. However, the concept of intact forest being large enough to allow for all natural processes and biodiversity is likely not logistically feasible in Canada's managed boreal forest. The scale at which the most extensive processes (e.g., fire and insects) occur and species (e.g., woodland caribou) function is likely too large. Management options incorporating local knowledge of conservation needs and the specifics of ecosystem function and composition are more likely to be effective in conservation than rigid IFL requirements. A standardized approach is useful for global tracking of IFLs but it is not the best approach to meet more regional forest conservation goals. Intact forest landscapes have exceptional value but should be managed in the context of integrated land use planning that includes protected areas, sustainable forest management, species at risk management, and ecosystem restoration.","author":[{"dropping-particle":"","family":"Venier","given":"L. A.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Walton","given":"R.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Thompson","given":"I. D.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Arsenault","given":"A.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Titus","given":"B. D.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Environmental Reviews","id":"ITEM-3","issue":"4","issued":{"date-parts":[["2018"]]},"page":"369-377","title":"A review of the intact forest landscape concept in the Canadian boreal forest: Its history, value, and measurement","type":"article-journal","volume":"26"},"uris":[""]}],"mendeley":{"formattedCitation":"(Puettmann et al. 2009; Fenton et al. 2014; Venier et al. 2018)","plainTextFormattedCitation":"(Puettmann et al. 2009; Fenton et al. 2014; Venier et al. 2018)","previouslyFormattedCitation":"(Puettmann et al. 2009; Fenton et al. 2014; Venier et al. 2018)"},"properties":{"noteIndex":0},"schema":""}(Puettmann et al. 2009; Fenton et al. 2014; Venier et al. 2018).Studies have increasingly highlighted the differences in diversity among stands of old-growth forests in terms of structure and composition, even within a relatively restricted landscape; this view of old-growth forests contrasts with the idea of these stands as being homogeneous ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1016/j.foreco.2017.07.051","ISSN":"03781127","abstract":"Mixed-severity disturbance regimes are prevalent in temperate forests worldwide, but key uncertainties remain regarding the variability of disturbance-mediated structural development pathways. This study investigates the influence of disturbance history on current structure in primary, unmanaged Norway spruce (Picea abies) forests throughout the Carpathian Mountains of central and eastern Europe, where windstorms and native bark beetle outbreaks are the dominant natural disturbances. We inventoried forest structure on 453 plots (0.1 ha) spanning a large geographical gradient (>1,000 km), coring 15–25 canopy trees per plot for disturbance history reconstruction (tree core total n = 11,309). Our specific objectives were to: (1) classify sub-hectare-scale disturbance history based on disturbance timing and severity; (2) classify current forest structure based on tree size distributions (live, dead, standing, downed); (3) characterize structural development pathways as revealed by the association between disturbance history and current forest structural complexity. We used hierarchical cluster analysis for the first two objectives and indicator analysis for the third. The disturbance-based cluster analysis yielded six groups associated with three levels of disturbance severity (low, moderate, and high canopy loss) and two levels of timing (old, recent) over the past 200 years. The structure-based cluster analysis yielded three groups along a gradient of increasing structural complexity. A large majority of plots exhibited relatively high (53%) or very high (26%) structural complexity, indicated by abundant large live trees, standing and downed dead trees, and spruce regeneration. Consistent with conventional models of structural development, some disturbance history groups were associated with specific structural complexity groups, particularly low-severity/recent (very high complexity) and high-severity/recent (moderate complexity) disturbances. In other cases, however, the distribution of plots among disturbance history and structural complexity groups indicated either divergent or convergent pathways. For example, multiple disturbance history groups were significantly associated with the high complexity group, demonstrating structural convergence. These results illustrate that complex forest structure – including features nominally associated with old-growth – can be associated as much with disturbance severity as it is with conventional notions of fores…","author":[{"dropping-particle":"","family":"Meigs","given":"Garrett W.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morrissey","given":"Robert C.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Ba?e","given":"Radek","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Chaskovskyy","given":"Oleh","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"?ada","given":"Vojtěch","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Després","given":"Tiphaine","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Donato","given":"Daniel C.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Janda","given":"Pavel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Lábusová","given":"Jana","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Seedre","given":"Meelis","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Mikolá?","given":"Martin","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Nagel","given":"Thomas A.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Schurman","given":"Jonathan S.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Synek","given":"Michal","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Teodosiu","given":"Marius","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Trotsiuk","given":"Volodymyr","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Vítková","given":"Lucie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Svoboda","given":"Miroslav","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-1","issue":"May","issued":{"date-parts":[["2017"]]},"page":"410-426","title":"More ways than one: Mixed-severity disturbance regimes foster structural complexity via multiple developmental pathways","type":"article-journal","volume":"406"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1016/j.foreco.2018.04.007","ISSN":"03781127","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-2","issue":"April","issued":{"date-parts":[["2018"]]},"page":"125-136","publisher":"Elsevier","title":"Structural diversity and dynamics of boreal old-growth forests case study in Eastern Canada","type":"article-journal","volume":"422"},"uris":[""]},{"id":"ITEM-3","itemData":{"author":[{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Silva Fennica","id":"ITEM-3","issue":"October 2010","issued":{"date-parts":[["2011"]]},"page":"983-994","title":"Dynamic old-growth forests ? A case study of boreal black spruce forest bryophytes","type":"article-journal","volume":"45"},"uris":[""]}],"mendeley":{"formattedCitation":"(Fenton and Bergeron 2011; Meigs et al. 2017; Martin et al. 2018)","plainTextFormattedCitation":"(Fenton and Bergeron 2011; Meigs et al. 2017; Martin et al. 2018)","previouslyFormattedCitation":"(Fenton and Bergeron 2011; Meigs et al. 2017; Martin et al. 2018)"},"properties":{"noteIndex":0},"schema":""}(Fenton and Bergeron 2011; Meigs et al. 2017; Martin et al. 2018). Variations in the nature, severity, and recurrence of secondary disturbances play a major role in forming these complex matrices ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.3390/f11030252","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Krause","given":"Cornélia","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-1","issued":{"date-parts":[["2020"]]},"page":"1-18","title":"Unveiling the diversity of tree growth patterns in boreal old-growth forests reveals the richness of their dynamics","type":"article-journal","volume":"11"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1016/j.jenvman.2018.07.100","ISSN":"10958630","abstract":"Boreal forests subject to low fire activity are complex ecosystems in terms of structure and dynamics. They have a high ecological value as they contain important proportions of old forests that play a crucial role in preserving biodiversity and ecological functions. They also sequester important amounts of carbon at the landscape level. However, the role of time since fire in controlling the different processes and attributes of those forests is still poorly understood. The Romaine River area experiences a fire regime characterized by very rare but large fires and has recently been opened to economic development for energy and timber production. In this study, we aimed to characterize this region in terms of live aboveground biomass, merchantable volume, stand structure and composition, and to establish relations between these attributes and the time since the last fire. Mean live aboveground biomass and merchantable volume showed values similar to those of commercial boreal coniferous forests. They were both found to increase up to around 150 years after a fire before declining. However, no significant relation was found between time since fire and stand structure and composition. Instead, they seemed to mostly depend on stand productivity and non-fire disturbances. At the landscape level, this region contains large amounts of biomass and carbon stored resulting from the long fire cycles it experiences. Although in terms of merchantable volume these forests seemed profitable for the forest industry, a large proportion were old forests or presented structures of old forests. Therefore, if forest management was to be undertaken in this region, particular attention should be given to these old forests in order to protect biodiversity and ecological functions. Partial cutting with variable levels of retention would be an appropriate management strategy as it reproduces the structural complexity of old forests.","author":[{"dropping-particle":"","family":"Portier","given":"Jeanne","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Cyr","given":"Guillaume","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Journal of Environmental Management","id":"ITEM-2","issue":"April","issued":{"date-parts":[["2018"]]},"page":"346-355","publisher":"Elsevier","title":"Does time since fire drive live aboveground biomass and stand structure in low fire activity boreal forests? Impacts on their management","type":"article-journal","volume":"225"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1111/jvs.12109","ISSN":"11009233","abstract":"Questions: How have the historical frequency and severity of natural disturbances in primary Picea abies forests varied at the forest stand and landscape level during recent centuries? Is there a relationship between physiographic attributes and historical patterns of disturbance severity in this system? Location: Primary P. abies forests of the Eastern Carpathian Mountains, Romania; a region thought to hold the largest concentration of primary P. abies forests in Europe's temperate zone. Methods: We used dendrochronological methods applied to many plots over a large area (132 plots representing six stands in two landscapes), thereby providing information at both stand and landscape levels. Evidence of past canopy disturbance was derived from two patterns of radial growth: (1) abrupt, sustained increases in growth (releases) and (2) rapid early growth rates (gap recruitment). These methods were augmented with non-metric multidimensional scaling to facilitate the interpretation of factors influencing past disturbance. Results: Of the two growth pattern criteria used to assess past disturbance, gap recruitment was the most common, representing 80% of disturbance evidence overall. Disturbance severities varied over the landscape, including stand-replacing events, as well as low- and intermediate-severity disturbances. More than half of the study plots experienced extreme-severity disturbances at the plot level, although they were not always synchronized across stands and landscapes. Plots indicating high-severity disturbances were often spatially clustered (indicating disturbances up to 20 ha), while this tendency was less clear for low- and moderate-severity disturbances. Physiographic attributes such as altitude and land form were only weakly correlated with disturbance severity. Historical documents suggest windstorms as the primary disturbance agent, while the role of bark beetles (Ips typographus) remains unclear. Conclusions: The historical disturbance regime revealed in this multi-scale study is characterized by considerable spatial and temporal heterogeneity, which could be seen among plots within stands, among stands within landscapes and between the two landscapes. When the disturbance regime was evaluated at these larger scales, the entire range of disturbance severity was revealed within this landscape. ? 2013 International Association for Vegetation Science.","author":[{"dropping-particle":"","family":"Svoboda","given":"Miroslav","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Janda","given":"Pavel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Ba?e","given":"Radek","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fraver","given":"Shawn","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Nagel","given":"Thomas A.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Rejzek","given":"Jan","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Mikolá?","given":"Martin","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Douda","given":"Jan","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Boublík","given":"Karel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"?amonil","given":"Pavel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"?ada","given":"Vojtěch","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Trotsiuk","given":"Volodymyr","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Teodosiu","given":"Marius","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bouriaud","given":"Olivier","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Biri?","given":"Adrian I.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"S?kora","given":"Ond?ej","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Uzel","given":"Petr","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Zelenka","given":"Ji?í","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Sedlák","given":"Vít","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Lehej?ek","given":"Ji?í","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Journal of Vegetation Science","id":"ITEM-3","issue":"2","issued":{"date-parts":[["2014"]]},"page":"386-401","title":"Landscape-level variability in historical disturbance in primary Picea abies mountain forests of the Eastern Carpathians, Romania","type":"article-journal","volume":"25"},"uris":[""]}],"mendeley":{"formattedCitation":"(Svoboda et al. 2014; Portier et al. 2018; Martin, Krause, et al. 2020)","plainTextFormattedCitation":"(Svoboda et al. 2014; Portier et al. 2018; Martin, Krause, et al. 2020)","previouslyFormattedCitation":"(Svoboda et al. 2014; Portier et al. 2018; Martin, Krause, et al. 2020)"},"properties":{"noteIndex":0},"schema":""}(Svoboda et al. 2014; Portier et al. 2018; Martin et al. 2020b). In particular, recent emphasis has been placed on the importance of moderate-severity disturbances—also known as intermediate-severity disturbances; a disturbance that exceeds the gap scale without being catastrophic ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.3390/f9090579","ISSN":"19994907","abstract":"The classification of discrete forest disturbance events is usually based on the spatial extent, magnitude, and frequency of the disturbance. Based on these characteristics, disturbances are placed into one of three broad categories, gap-scale, intermediate-severity, or catastrophic disturbance, along the disturbance classification gradient. We contend that our understanding of disturbance processes near the endpoints of the disturbance classification gradient far exceeds that of intermediate-severity events. We hypothesize that intermediate-severity disturbances are more common, and that they are more important drivers of forest ecosystem change than is commonly recognized. Here, we provide a review of intermediate-severity disturbances that includes proposed criteria for categorizing disturbances on the classification gradient. We propose that the canopy opening diameter to height ratio (D:H) be used to delineate gap-scale from intermediate-severity events and that the threshold between intermediate and catastrophic events be based on the influence of residual trees on the composition of the regeneration layer. We also provide examples of intermediate-severity disturbance agents, return intervals for these events, and recommendations for incorporating natural intermediate-severity disturbance patterns in silvicultural systems.","author":[{"dropping-particle":"","family":"Hart","given":"Justin L.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kleinman","given":"Jonathan S.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-1","issue":"579","issued":{"date-parts":[["2018"]]},"title":"What are intermediate-severity forest disturbances and why are they important?","type":"article-journal","volume":"9"},"uris":[""]}],"mendeley":{"formattedCitation":"(Hart and Kleinman 2018)","plainTextFormattedCitation":"(Hart and Kleinman 2018)","previouslyFormattedCitation":"(Hart and Kleinman 2018)"},"properties":{"noteIndex":0},"schema":""}(Hart and Kleinman 2018)—on the dynamics of these ecosystems ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1016/j.foreco.2014.02.024","ISBN":"0378-1127","ISSN":"03781127","abstract":"The conventional theory of boreal forest dynamics recognizes two distinct disturbance regime types, small-scale gap dynamics and dynamics driven by large stand-replacing disturbances. We used satellite imagery and extensive field measurements to examine the landscape-level pattern and impact of an extensive disturbance episode that occurred in the early 2000s in primeval forest dominated by Picea abies in the Arkhangelsk region, Russia, due to drought and subsequent bark beetle (Ips typographus) outbreak. We also quantified forest age structures and deadwood characteristics at the landscape-level to study how such disturbances shape forest structures over larger scales. Satellite image analysis revealed that disturbance patches covered about 16% of the land area in the 12. km. ×. 12. km landscape studied. The size of the disturbance patches was strongly skewed toward small ones (median size 0.12. ha) and they were distributed across the landscape with some tendency of aggregation. The landscape forest matrix was dominated by old-growth forest. The dominant trees in the forest were established prior to 1850, and approximately half of the forest had established prior to 1800. However, the patchy occurrence of younger forest suggests that the landscape previously was subject to patchy disturbance similar to the recent one. This conclusion also gained support from historical records. We conclude that the structure and dynamics of the studied primeval forest landscape was driven by the combined impact of small-scale \"background\" mortality (classical gap dynamics) and infrequent episodes of patchy intermediate severity and scale disturbances. ? 2014 Elsevier B.V.","author":[{"dropping-particle":"","family":"Kuuluvainen","given":"Timo","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Wallenius","given":"Tuomo H.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kauhanen","given":"Heikki","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Aakala","given":"Tuomas","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Mikkola","given":"Kari","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Demidova","given":"Natalia","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Ogibin","given":"Boris","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-1","issued":{"date-parts":[["2014"]]},"page":"96-103","publisher":"Elsevier B.V.","title":"Episodic, patchy disturbances characterize an old-growth Picea abies dominated forest landscape in northeastern Europe","type":"article-journal","volume":"320"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1007/s13595-019-0891-2","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Annals of Forest Science","id":"ITEM-2","issue":"108","issued":{"date-parts":[["2019"]]},"page":"1-16","title":"Secondary disturbances of low and moderate severity drive the dynamics of eastern Canadian boreal old-growth forests","type":"article-journal","volume":"76"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1016/j.foreco.2017.07.051","ISSN":"03781127","abstract":"Mixed-severity disturbance regimes are prevalent in temperate forests worldwide, but key uncertainties remain regarding the variability of disturbance-mediated structural development pathways. This study investigates the influence of disturbance history on current structure in primary, unmanaged Norway spruce (Picea abies) forests throughout the Carpathian Mountains of central and eastern Europe, where windstorms and native bark beetle outbreaks are the dominant natural disturbances. We inventoried forest structure on 453 plots (0.1 ha) spanning a large geographical gradient (>1,000 km), coring 15–25 canopy trees per plot for disturbance history reconstruction (tree core total n = 11,309). Our specific objectives were to: (1) classify sub-hectare-scale disturbance history based on disturbance timing and severity; (2) classify current forest structure based on tree size distributions (live, dead, standing, downed); (3) characterize structural development pathways as revealed by the association between disturbance history and current forest structural complexity. We used hierarchical cluster analysis for the first two objectives and indicator analysis for the third. The disturbance-based cluster analysis yielded six groups associated with three levels of disturbance severity (low, moderate, and high canopy loss) and two levels of timing (old, recent) over the past 200 years. The structure-based cluster analysis yielded three groups along a gradient of increasing structural complexity. A large majority of plots exhibited relatively high (53%) or very high (26%) structural complexity, indicated by abundant large live trees, standing and downed dead trees, and spruce regeneration. Consistent with conventional models of structural development, some disturbance history groups were associated with specific structural complexity groups, particularly low-severity/recent (very high complexity) and high-severity/recent (moderate complexity) disturbances. In other cases, however, the distribution of plots among disturbance history and structural complexity groups indicated either divergent or convergent pathways. For example, multiple disturbance history groups were significantly associated with the high complexity group, demonstrating structural convergence. These results illustrate that complex forest structure – including features nominally associated with old-growth – can be associated as much with disturbance severity as it is with conventional notions of fores…","author":[{"dropping-particle":"","family":"Meigs","given":"Garrett W.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morrissey","given":"Robert C.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Ba?e","given":"Radek","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Chaskovskyy","given":"Oleh","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"?ada","given":"Vojtěch","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Després","given":"Tiphaine","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Donato","given":"Daniel C.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Janda","given":"Pavel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Lábusová","given":"Jana","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Seedre","given":"Meelis","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Mikolá?","given":"Martin","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Nagel","given":"Thomas A.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Schurman","given":"Jonathan S.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Synek","given":"Michal","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Teodosiu","given":"Marius","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Trotsiuk","given":"Volodymyr","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Vítková","given":"Lucie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Svoboda","given":"Miroslav","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-3","issue":"May","issued":{"date-parts":[["2017"]]},"page":"410-426","title":"More ways than one: Mixed-severity disturbance regimes foster structural complexity via multiple developmental pathways","type":"article-journal","volume":"406"},"uris":[""]}],"mendeley":{"formattedCitation":"(Kuuluvainen et al. 2014; Meigs et al. 2017; Martin et al. 2019)","plainTextFormattedCitation":"(Kuuluvainen et al. 2014; Meigs et al. 2017; Martin et al. 2019)","previouslyFormattedCitation":"(Kuuluvainen et al. 2014; Meigs et al. 2017; Martin et al. 2019)"},"properties":{"noteIndex":0},"schema":""}(Kuuluvainen et al. 2014; Meigs et al. 2017; Martin et al. 2019). Although their existence and importance have been established, knowledge remains nevertheless limited in regard to the consequences of recurrent moderate-severity disturbances on the structure and dynamics of old-growth forests. Most research on forest disturbance regimes has generally focused on low-severity disturbances, i.e., gap-dynamics, or on catastrophic, stand-replacing disturbances ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.3390/f9090579","ISSN":"19994907","abstract":"The classification of discrete forest disturbance events is usually based on the spatial extent, magnitude, and frequency of the disturbance. Based on these characteristics, disturbances are placed into one of three broad categories, gap-scale, intermediate-severity, or catastrophic disturbance, along the disturbance classification gradient. We contend that our understanding of disturbance processes near the endpoints of the disturbance classification gradient far exceeds that of intermediate-severity events. We hypothesize that intermediate-severity disturbances are more common, and that they are more important drivers of forest ecosystem change than is commonly recognized. Here, we provide a review of intermediate-severity disturbances that includes proposed criteria for categorizing disturbances on the classification gradient. We propose that the canopy opening diameter to height ratio (D:H) be used to delineate gap-scale from intermediate-severity events and that the threshold between intermediate and catastrophic events be based on the influence of residual trees on the composition of the regeneration layer. We also provide examples of intermediate-severity disturbance agents, return intervals for these events, and recommendations for incorporating natural intermediate-severity disturbance patterns in silvicultural systems.","author":[{"dropping-particle":"","family":"Hart","given":"Justin L.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kleinman","given":"Jonathan S.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-1","issue":"579","issued":{"date-parts":[["2018"]]},"title":"What are intermediate-severity forest disturbances and why are they important?","type":"article-journal","volume":"9"},"uris":[""]}],"mendeley":{"formattedCitation":"(Hart and Kleinman 2018)","plainTextFormattedCitation":"(Hart and Kleinman 2018)","previouslyFormattedCitation":"(Hart and Kleinman 2018)"},"properties":{"noteIndex":0},"schema":""}(Hart and Kleinman 2018). Many silvicultural treatments considered as "close to nature" are more similar to moderate-severity disturbances than to gap-dynamics, particularly in boreal forests where continuous-cover forestry practices often harvest a marked proportion (i.e., >30%) of the basal area ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.5558/tfc2013-065","ISSN":"0015-7546","abstract":"Multi-cohort management that creates or maintains an uneven structure within forest stands has been widely advocated as a means to attenuate the impact of forest harvesting. An experimental network was put in place in black spruce forests of northwestern Quebec to test this assertion. Here we synthesize the biodiversity results in two main lessons: (1) at least 40% to 60% retention of pre-harvest basal area was required to maintain pre-harvest conditions for most species groups; (2) partial harvests showed the potential to be efficient deadwood delivery systems. In addition to these two main general conclusions, we emphasise that future research should examine whether partial harvest may be able to advance forest succession.","author":[{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Imbeau","given":"Louis","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Work","given":"Timothy","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Jacobs","given":"Jenna","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bescond","given":"Hervé","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Drapeau","given":"Pierre","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"The Forestry Chronicle","id":"ITEM-1","issue":"03","issued":{"date-parts":[["2014"]]},"page":"350-359","title":"Lessons learned from 12 years of ecological research on partial cuts in black spruce forests of northwestern Québec","type":"article-journal","volume":"89"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1093/forestry/cpt047","ISBN":"0015-752X","ISSN":"0015752X","abstract":"Over the last 25 years, greater understanding of natural dynamics in the boreal forest has led to the integration of forest ecosystem management principles into forest policy of several Canadian provinces and, in turn, to greater interest in developing silvicultural treatments that are grounded in natural stand-level dynamics – often referred to as natural disturbance-based silviculture. As a result, alternative silvicultural practices including variants of partial cutting are increasingly being applied in the boreal forest as an approach to balancing economic and ecological management objectives. While the numerous benefits of partial cutting reported in the literature are acknowledged, the objective of this paper is to provide an overview of factors or constraints that potentially limit the application of these practices in boreal Canada in the context of forest ecosystem management and natural disturbance-based silviculture. Among constraining factors, numerous studies have reported elevated mortality rates of residual stems following partial cutting, initial growth stagnation of residual trees, problems related to recruitment of desirable species and, on certain flat or lowland sites, risks of long-term decline in site and stand productivity. A number of operational challenges to partial cutting in the boreal forest are also presented and several avenues of research are proposed.","author":[{"dropping-particle":"","family":"Bose","given":"Arun K.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Harvey","given":"Brian D.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Brais","given":"Suzanne","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Beaudet","given":"Marilou","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Leduc","given":"Alain","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forestry","id":"ITEM-2","issue":"1","issued":{"date-parts":[["2014"]]},"page":"11-28","title":"Constraints to partial cutting in the boreal forest of Canada in the context of natural disturbance-based management: A review","type":"article-journal","volume":"87"},"uris":[""]}],"mendeley":{"formattedCitation":"(Bose et al. 2014; Fenton et al. 2014)","plainTextFormattedCitation":"(Bose et al. 2014; Fenton et al. 2014)","previouslyFormattedCitation":"(Bose et al. 2014; Fenton et al. 2014)"},"properties":{"noteIndex":0},"schema":""}(Bose et al. 2014; Fenton et al. 2014). In this context, it is therefore important to determine how disturbances of moderate severity influence the structure, resilience, and resilience of old-growth forests to ensure their sustainable management. Dendrochronological analysis is an effective tool for reconstructing disturbance dynamics and the associated response of the understorey. This reconstruction is usually done by identifying growth releases, i.e., abrupt changes in tree-ring width ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1890/0012-9615(1997)067[0225:RGACFR]2.0.CO;2","ISBN":"0012-9615","ISSN":"00129615","abstract":"A novel dendroecological procedure was developed to elucidate canopy disturbances spanning a >300-yr period for oak (Quercus) forests of central Pennsylvania. Running comparisons of sequential 10-yr ring-width averages may effectively neutralize both short-term (i.e., drought) and long-term growth trends associated with climate while enhancing detection of abrupt and sustained radial-growth increases characteristic of canopy disturbance. Thinning-response studies revealed the conservative tendencies of overstory oak, with substantial basal area reductions (>1/3) required to attain moderate and consistently detectable growth increases. Based on empirical evidence, a minimum growth-response threshold of 25% was established to depict canopy disturbances. This is in contrast to the 50-100% sustained radial-growth release often used to detect disturbance using understory trees in closed forests. Our default threshold was adjusted higher as necessary for those trees highly correlated to climatic trends (as represented by the Palmer drought severity index). Canopy disturbances detected with this dendroecological approach were further substantiated using tree-recruitment data (age cohorting). By coupling these data sets, we estimated return intervals of standwide disturbance from 21 yr in presettlement times (prior to 1775) and during heavy Euro-American exploitation (1775-1900) to 31 yr in modern times (after 1900). Although disturbance periodicity remained stable between presettlement and early post-settlement (exploitation) eras, the mode of disturbance shifted from mainly natural (wind and fire) to anthropogenic forces (intense harvesting for charcoal production), based on the historical record. In the process, presettlement oak-pine (Pinus)-chestnut (Castanea) forests on ridges were rapidly converted to young coppice stands of oak and chestnut. The reduction of harvesting and fire events coupled with the eradication of chestnut by blight this century have allowed these coppice stands to mature into oak-dominated forests that exist today. This analytical technique for ascertaining disturbance histories holds much potential and should be considered for use with mature, overstory trees in other forest types with appropriate modifications.","author":[{"dropping-particle":"","family":"Nowacki","given":"Gregory J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Abrams","given":"Marc D.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecological Monographs","id":"ITEM-1","issue":"2","issued":{"date-parts":[["1997"]]},"page":"225-249","title":"Radial-growth averaging criteria for reconstructing disturbance histories from presettlement-origin oaks","type":"article-journal","volume":"67"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1139/x05-092","ISBN":"0045-5067","ISSN":"0045-5067","abstract":"Information on historical disturbances is vital to our understanding of current forest conditions. Dendrochronological methods provide one means of reconstructing disturbance histories in temperate and boreal forests. In particular, the dates of significant growth releases recorded on surviving trees provide strong inferential evidence of past disturbance events. The most common method of detecting releases (the percent-increase method) expresses the postevent growth increase as a percentage of the preevent rate. Despite its widespread use, the method is known to be overly sensitive at low rates of prior growth and overly stringent at high rates. We present an alternative method that directly follows the percent-increase method, but instead of dividing the postevent growth rate by the preevent rate, we simply subtract the two. If the difference exceeds a predetermined species-specific threshold, the event is considered a release. This absolute-increase method has convenient properties that remedy the shortcomings of the percent-increase method. We tested the validity of the absolute-increase thresholds by binary logistic regressions, and we compared the absolute- and percent-increase methods by various methods. We conclude that for the species evaluated in this study, the absolute-increase method represents an improvement over the standard percent-increase method.","author":[{"dropping-particle":"","family":"Fraver","given":"Shawn","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"White","given":"Alan S","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canadian Journal of Forest Research","id":"ITEM-2","issue":"7","issued":{"date-parts":[["2005"]]},"page":"1648-1656","title":"Identifying growth releases in dendrochronological studies of forest disturbance","type":"article-journal","volume":"35"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1016/j.foreco.2014.09.005","ISSN":"03781127","abstract":"Natural disturbance regimes play key roles in shaping forest structure and development at stand and landscape levels. Disturbances are commonly complex and variable, such that classical dichotomous characterization of disturbance regimes as following large infrequent disturbances or patch dynamics is too simplistic, especially when the resulting damage is more severe than the baseline of a single tree patch dynamic, but not severe enough to represent large infrequent disturbance. Ongoing climate change affects mountain Picea abies forests in Central, East and Southeastern Europe by an increasing frequency of storms and bark beetle outbreaks. We present a unique study based on extensive dataset aimed to reveal the spatiotemporal pattern of the disturbance history and role of the mixed severity disturbances in primary spruce mountain forest landscapes in the Ukrainian Carpathians.We reconstructed canopy disturbance history and maximum disturbance severity using ca. 2396 tree cores in 96 sample plots. Neither large-scale stand-replacement nor fine scale dynamics was the prevailing disturbance over the last four centuries. Rather, we observed a complex spatiotemporal pattern of mixed severity disturbances. Canopy turnover time ranged between 50 and 300. years and depended on the maximum severity of the disturbance event. Spatial analyses revealed no similarity in spatiotemporal pattern across disturbance histories or maximum disturbance severities. We observed evidence of a combination of variable severity disturbances that fails to fit the classical scheme of gap or patch dynamics with sharply defined sizes and borders, but is more consistent with a mixed severity disturbance regime across the landscape. Windstorms were likely the most important past disturbance agent. The probability of an epidemic bark beetle attack was low, although the possibility of small local outbreaks cannot be excluded. An additional, potentially overlooked, agent of disturbance could be historic periods of extreme cold.This reconstructed disturbance regime may challenge existing silvicultural systems in the Carpathians, calling for a more complex spatiotemporal forest management approach. However, mimicking a mixed severity disturbance regime can be done at the forest management level by applying a range of disturbance severities at the stand level.","author":[{"dropping-particle":"","family":"Trotsiuk","given":"Volodymyr","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Svoboda","given":"Miroslav","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Janda","given":"Pavel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Mikolas","given":"Martin","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bace","given":"Radek","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Rejzek","given":"Jan","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Samonil","given":"Pavel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Chaskovskyy","given":"Oleh","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Korol","given":"Mykola","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Myklush","given":"Stepan","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-3","issued":{"date-parts":[["2014"]]},"page":"144-153","publisher":"Elsevier B.V.","title":"A mixed severity disturbance regime in the primary Picea abies (L.) Karst. forests of the Ukrainian Carpathians","type":"article-journal","volume":"334"},"uris":[""]}],"mendeley":{"formattedCitation":"(Nowacki and Abrams 1997; Fraver and White 2005; Trotsiuk et al. 2014)","plainTextFormattedCitation":"(Nowacki and Abrams 1997; Fraver and White 2005; Trotsiuk et al. 2014)","previouslyFormattedCitation":"(Nowacki and Abrams 1997; Fraver and White 2005; Trotsiuk et al. 2014)"},"properties":{"noteIndex":0},"schema":""}(Nowacki and Abrams 1997; Fraver and White 2005; Trotsiuk et al. 2014). Growth releases nevertheless highlight only punctual changes in growth. They therefore do not make it possible to determine precisely the manner and rate at which a tree grew before and after a disturbance. The study of a tree’s growth patterns, i.e., the changes in tree-ring width from the pith to the last formed ring, help to overcome this problem by making it possible to identify growth releases and also determine how the tree reacted to this release ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1016/j.foreco.2016.04.038","ISSN":"03781127","abstract":"Disturbances, both natural and human induced, influence forest dynamics, ecosystem functioning, and ecosystem services. Here, we aim to evaluate the consequences of natural disturbances on the magnitude and dynamics of tree- and stand-level biomass accumulation from decadal to centennial scales. We use tree-ring data from 2301 trees and biometric data from 4909 trees sampled in 96 plots (each 1000 m2) to quantify the influence of mixed severity disturbance regimes on annual aboveground biomass increment (AGBI) and total aboveground biomass accumulation (AGB) across a mountainous monotypic Norway spruce (Picea abies (L.) Karst.) primary forest. We hypothesise that the multiple internal and external factors constraining tree growth will cause differences in tree and stand-level biomass trajectories in these natural forests.Although we found that tree-level AGB growth increases with tree size, we also found that tree age and disturbance legacies plays a crucial role for AGB in the investigated Norway spruce forests. Importantly, while younger trees of the same diameter class have an average current AGBI rate that is ~225% higher than older trees (300-400 years), we find trees that have been suppressed for up to 120 years can respond vigorously when competition is reduced. On average, post disturbance AGBI was ~400% greater than pre-disturbance AGBI. Growth of suppressed trees, independent of their age, followed similar trajectories after canopy accession. While aboveground biomass generally increased through time, the time since disturbance and disturbance severity are important co-predictors for stand-level AGBI and AGB. These forests regained most of the above ground living biomass over short interval (~50 years) after low intensity disturbances. The highest stand-level living AGB was observed on plots that experienced >40% canopy removal 160-190 years ago, whereas the highest AGBI occurred in plots disturbed recently within the past 40-50 years.Our results emphasize the importance of including both individual tree age and disturbance legacies to accurately characterize biomass dynamics and trajectories in forest ecosystems. Importantly, the period of time that a tree is in the canopy, and not tree age, modulates the trajectory of tree level AGBI. Growth rates begin to decline after ~30 years (tree-rings width) and ~100 years (AGBI) in the canopy. We demonstrate that even late-seral forests can rapidly regain biomass lost to low intensity disturbance.","author":[{"dropping-particle":"","family":"Trotsiuk","given":"Volodymyr","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Svoboda","given":"Miroslav","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Weber","given":"Pascale","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Pederson","given":"Neil","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Klesse","given":"Stefan","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Janda","given":"Pavel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Martin-Benito","given":"Dario","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Mikolas","given":"Martin","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Seedre","given":"Meelis","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bace","given":"Radek","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Mateju","given":"Lenka","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Frank","given":"David","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-1","issued":{"date-parts":[["2016"]]},"page":"108-115","publisher":"Elsevier B.V.","title":"The legacy of disturbance on individual tree and stand-level aboveground biomass accumulation and stocks in primary mountain Picea abies forests","type":"article-journal","volume":"373"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.3390/f11030252","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Krause","given":"Cornélia","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-2","issued":{"date-parts":[["2020"]]},"page":"1-18","title":"Unveiling the diversity of tree growth patterns in boreal old-growth forests reveals the richness of their dynamics","type":"article-journal","volume":"11"},"uris":[""]}],"mendeley":{"formattedCitation":"(Trotsiuk et al. 2016; Martin, Krause, et al. 2020)","manualFormatting":"(Martin et al. 2020b; Trotsiuk et al., 2016)","plainTextFormattedCitation":"(Trotsiuk et al. 2016; Martin, Krause, et al. 2020)","previouslyFormattedCitation":"(Trotsiuk et al. 2016; Martin, Krause, et al. 2020)"},"properties":{"noteIndex":0},"schema":""}(Martin et al. 2020b; Trotsiuk et al., 2016). However, the identification of growth patterns has tended to be, at least partially, based on a subjective process, thereby limiting its use ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Lorimer","given":"Craig G.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Frelich","given":"Lee E.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canada Journal of Forest Research","id":"ITEM-1","issued":{"date-parts":[["1989"]]},"page":"651-663","title":"A methodology for estimating canopy disturbance frequency and intensity in dense temperate forests","type":"article-journal","volume":"19"},"uris":[""]},{"id":"ITEM-2","itemData":{"ISBN":"9780521650823","author":[{"dropping-particle":"","family":"Frelich","given":"Lee E.","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-2","issued":{"date-parts":[["2002"]]},"number-of-pages":"266","publisher":"Cambridge University Press","publisher-place":"Cambridge, U.K.","title":"Forest Dynamics and Disturbance Regimes: Studies from Temperate Evergreen-Deciduous Forests","type":"book"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1007/s10310-011-0259-4","ISSN":"1341-6979","author":[{"dropping-particle":"","family":"Niukkanen","given":"Laura","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kuuluvainen","given":"Timo","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Journal of Forest Research","id":"ITEM-3","issue":"3","issued":{"date-parts":[["2011"]]},"page":"228-236","title":"Radial growth patterns of dominant trees in two old-growth forests in eastern Fennoscandia","type":"article-journal","volume":"16"},"uris":[""]}],"mendeley":{"formattedCitation":"(Lorimer and Frelich 1989; Frelich 2002; Niukkanen and Kuuluvainen 2011)","plainTextFormattedCitation":"(Lorimer and Frelich 1989; Frelich 2002; Niukkanen and Kuuluvainen 2011)","previouslyFormattedCitation":"(Lorimer and Frelich 1989; Frelich 2002; Niukkanen and Kuuluvainen 2011)"},"properties":{"noteIndex":0},"schema":""}(Lorimer and Frelich 1989; Frelich 2002; Niukkanen and Kuuluvainen 2011). ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.3390/f11030252","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Krause","given":"Cornélia","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-1","issued":{"date-parts":[["2020"]]},"page":"1-18","title":"Unveiling the diversity of tree growth patterns in boreal old-growth forests reveals the richness of their dynamics","type":"article-journal","volume":"11"},"uris":[""]}],"mendeley":{"formattedCitation":"(Martin, Krause, et al. 2020)","manualFormatting":"Martin et al. (2020b)","plainTextFormattedCitation":"(Martin, Krause, et al. 2020)","previouslyFormattedCitation":"(Martin, Krause, et al. 2020)"},"properties":{"noteIndex":0},"schema":""}Martin et al. (2020b) highlighted that the use of machine-learning algorithms provides an effective solution for identifying growth patterns both accurately and objectively. The combined analysis of growth releases and growth patterns therefore offers much promise for reconstructing the dynamics of old-growth forests driven by natural disturbances.The boreal forests of eastern Canada offer an ideal territory for addressing questions related to moderate-severity disturbances because remnant primary forests remain abundant and are dominated by stands at the old-growth stage ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1890/080088","ISBN":"1540-9309","ISSN":"15409295","PMID":"246","abstract":"Fire is fundamental to the natural dynamics of the North American boreal forest. It is therefore often suggested that the impacts of anthropopgenic disturbances (e.g. logging) on a managed landscape are attenuated if the patterns and processes created by these events resemble those of natural disturbances (e.g. fire). To provide forest management guidelines, we investigate the long-term variability in themean fire interval (MFI) of a boreal landscape in eastern North America, as reconstructed from lacustrine (lake-associated) sedimentary charcol. We translate the natural variability in MFI into a range of landscape age structures, using a simple modeling approach. Although using the array of possible forest age structures provides managers with some flexibility, an assesment of the current state of the landscape suggests that logging has already caused a shift in the age-class distribution toward a stronger representation of young stands with a concurrent decrease in old-growth stands. Logging is indeed quickly forcing the studied landscape outside of its long-term natural range of variability, implying that substantial changes in management practices are required, if we collectively decide to maintain these fundamental attributes of the boreal forest.","author":[{"dropping-particle":"","family":"Cyr","given":"Dominic","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Carcaillet","given":"Christopher","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Frontiers in Ecology and the Environment","id":"ITEM-1","issue":"10","issued":{"date-parts":[["2009"]]},"page":"519-524","title":"Forest management is driving the eastern North American boreal forest outside its natural range of variability","type":"article-journal","volume":"7"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1038/d41586-018-07183-6","ISSN":"14764687","abstract":"Global conservation policy must stop the disappearance of Earth’s few intact ecosystems, warn James E. M. Watson, James R. Allan and colleagues.","author":[{"dropping-particle":"","family":"Watson","given":"James E.M.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Venter","given":"Oscar","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Lee","given":"Jasmine","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Jones","given":"Kendall R.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Robinson","given":"John G.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Possingham","given":"Hugh P.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Allan","given":"James R.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Nature","id":"ITEM-2","issue":"7729","issued":{"date-parts":[["2018"]]},"page":"27-30","title":"Protect the last of the wild","type":"article-journal","volume":"563"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1186/s40663-018-0148-9","ISBN":"2197-5620","ISSN":"2197-5620","author":[{"dropping-particle":"","family":"Grondin","given":"Pierre","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Poirier","given":"Véronique","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Tardif","given":"Patrice","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Boucher","given":"Yan","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecosystems","id":"ITEM-3","issue":"1","issued":{"date-parts":[["2018"]]},"page":"30","publisher":"Forest Ecosystems","title":"Have some landscapes in the eastern Canadian boreal forest moved beyond their natural range of variability?","type":"article-journal","volume":"5"},"uris":[""]}],"mendeley":{"formattedCitation":"(Cyr et al. 2009; Grondin et al. 2018; Watson et al. 2018)","plainTextFormattedCitation":"(Cyr et al. 2009; Grondin et al. 2018; Watson et al. 2018)","previouslyFormattedCitation":"(Cyr et al. 2009; Grondin et al. 2018; Watson et al. 2018)"},"properties":{"noteIndex":0},"schema":""}(Cyr et al. 2009; Grondin et al. 2018; Watson et al. 2018). As well, these stands continue to be driven by natural disturbances, in particular by spruce budworm (Choristoneura fumiferana [Clem.]) outbreaks, which occur over an approximate 30-year cycle ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1139/X03-108","author":[{"dropping-particle":"","family":"Jardon","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canada Journal of Forest Research","id":"ITEM-1","issued":{"date-parts":[["2003"]]},"page":"1947-1961","title":"Périodicité et synchronisme des épidémies de la tordeuse des bourgeons de l ’ épinette au Québec","type":"article-journal","volume":"33"},"uris":[""]},{"id":"ITEM-2","itemData":{"author":[{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Laprise","given":"Danielle","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Simon","given":"A.A.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Amouch","given":"S.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecosystem management in the boreal forest","editor":[{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Vaillancourt","given":"Marie-Andrée","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Leduc","given":"Alain","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"De","family":"Grandpré","given":"Louis","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kneeshaw","given":"Daniel D.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Drapeau","given":"Pierre","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-2","issued":{"date-parts":[["2009"]]},"page":"156-182","publisher":"Les Presses de l’Université du Québec","publisher-place":"Québec","title":"Spruce budworm outbreak regimes in in eastern North America","type":"chapter"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1007/s13595-019-0891-2","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Annals of Forest Science","id":"ITEM-3","issue":"108","issued":{"date-parts":[["2019"]]},"page":"1-16","title":"Secondary disturbances of low and moderate severity drive the dynamics of eastern Canadian boreal old-growth forests","type":"article-journal","volume":"76"},"uris":[""]}],"mendeley":{"formattedCitation":"(Jardon and Morin 2003; Morin et al. 2009; Martin et al. 2019)","plainTextFormattedCitation":"(Jardon and Morin 2003; Morin et al. 2009; Martin et al. 2019)","previouslyFormattedCitation":"(Jardon and Morin 2003; Morin et al. 2009; Martin et al. 2019)"},"properties":{"noteIndex":0},"schema":""}(Jardon and Morin 2003; Morin et al. 2009; Martin et al. 2019). Although boreal old-growth forests are abundant in eastern Canada, they are nonetheless highly threatened by human activities. Forest management based on short-rotation (70?100 years) clearcutting is the main cause of old-growth forest loss because these stands are harvested first and at rate greater than that of primary disturbances ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1080/02827581.2018.1495254","ISSN":"0282-7581","author":[{"dropping-particle":"","family":"Barrette","given":"Martin","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Tremblay","given":"Stéphane","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Auger","given":"Isabelle","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Scandinavian Journal of Forest Research","id":"ITEM-1","issue":"8","issued":{"date-parts":[["2018"]]},"page":"756-763","publisher":"Taylor & Francis","title":"Commercial thinning that maintained species diversity of a mixed black spruce–jack pine stand enhanced productivity","type":"article-journal","volume":"33"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1093/forestry/cpx022","ISBN":"0015-752X","ISSN":"14643626","abstract":"In northeastern Canadian boreal forests, a coarse-filter approach was adopted to provide sustainable ecosystem services in order to maintain a balance between biodiversity, ecosystem function and timber production. An old forest (>100 years) maintenance target was established considering the range of historical variability in the proportion of this forest stage. However, the estimation of the harvesting rate that maintains the target level in old forests did not consider explicitly the impact of current and future, i.e. possibly higher, fire frequency. In this context, we compared historical, current, and future age structures according to recorded or projected fire activity and the current level of harvesting in western Quebec's boreal forest. Results show that under the current rates of harvesting and fire, the proportion of old forests could reach a minimum level rarely seen in the natural landscape in the past. The situation could become even more critical with the projected increase in fire activity under climate change. Numerous forest and fire management solutions exist, such as increasing rotation length, implementing a diversified silviculture, using a fire-smart approach or reaching a better balance between intensive management and conservation. We advocate their rapid implementation to reverse the projected decrease in the proportion of old forests.","author":[{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Vijayakumar","given":"Dinesh Babu Irulappa Pillai","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Ouzennou","given":"Hakim","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Raulier","given":"Frédéric","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Leduc","given":"Alain","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forestry","id":"ITEM-2","issue":"4","issued":{"date-parts":[["2017"]]},"page":"485-495","title":"Projections of future forest age class structure under the influence of fire and harvesting: Implications for forest management in the boreal forest of eastern Canada","type":"article-journal","volume":"90"},"uris":[""]},{"id":"ITEM-3","itemData":{"author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Boucher","given":"Yan","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Marchand","given":"Philippe","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-3","issued":{"date-parts":[["2020"]]},"page":"1-10","title":"Forest management has reduced the structural diversity of residual boreal old-growth forest landscapes in Eastern Canada","type":"article-journal","volume":"458"},"uris":[""]}],"mendeley":{"formattedCitation":"(Bergeron et al. 2017; Barrette et al. 2018; Martin, Boucher, et al. 2020)","plainTextFormattedCitation":"(Bergeron et al. 2017; Barrette et al. 2018; Martin, Boucher, et al. 2020)","previouslyFormattedCitation":"(Bergeron et al. 2017; Barrette et al. 2018; Martin, Boucher, et al. 2020)"},"properties":{"noteIndex":0},"schema":""}(Bergeron et al. 2017; Barrette et al. 2018; Martin et al. 2020a). In the boreal regions, climate change is also expected to increase the recurrence and severity of disturbances, in particular spruce budworm outbreaks ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.3390/f9080471","ISBN":"1999-4907","ISSN":"19994907","abstract":"<p>Natural disturbances are fundamental to forest ecosystem dynamics and have been used for two decades to improve forest management, notably in the boreal forest. Initially based on fire regimes, there is now a need to extend the concept to include other types of disturbances as they can greatly contribute to forest dynamics in some regions of the boreal zone. Here we review the main descriptors—that is, the severity, specificity, spatial and temporal descriptors and legacies, of windthrow and spruce bud worm outbreak disturbance regimes in boreal forests—in order to facilitate incorporating them into a natural disturbance-based forest management framework. We also describe the biological legacies that are generated by these disturbances. Temporal and spatial descriptors characterising both disturbance types are generally variable in time and space. This makes them difficult to reproduce in an ecosystem management framework. However, severity and specificity descriptors may provide a template upon which policies for maintaining post harvesting and salvage logging biological legacies can be based. In a context in which management mainly targets mature and old-growth stages, integrating insect and wind disturbances in a management framework is an important goal, as these disturbances contribute to creating heterogeneity in mature and old-growth forest characteristics.</p>","author":[{"dropping-particle":"","family":"Grandpré","given":"Louis","non-dropping-particle":"De","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Waldron","given":"Kaysandra","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bouchard","given":"Mathieu","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Beaudet","given":"Marilou","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Ruel","given":"Jean Claude","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Hébert","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kneeshaw","given":"Daniel D.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-1","issue":"8","issued":{"date-parts":[["2018"]]},"page":"1-20","title":"Incorporating insect and wind disturbances in a natural disturbance-based management framework for the boreal forest","type":"article-journal","volume":"9"},"uris":[""]},{"id":"ITEM-2","itemData":{"ISBN":"1359501908","author":[{"dropping-particle":"","family":"Bouzidi","given":"Hibat A.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Balducci","given":"Lorena","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Mackay","given":"John","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Deslauriers","given":"Annie","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Annals of Forest Science","id":"ITEM-2","issue":"21","issued":{"date-parts":[["2019"]]},"page":"1-12","publisher":"Annals of Forest Science","title":"Interactive effects of defoliation and water deficit on growth, water status, and mortality of black spruce (Picea mariana (Mill.) B.S.P.)","type":"article-journal","volume":"76"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1002/ece3.4779","ISSN":"20457758","author":[{"dropping-particle":"","family":"Pureswaran","given":"Deepa S.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Neau","given":"Mathieu","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Marchand","given":"Maryse","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Grandpré","given":"Louis","non-dropping-particle":"De","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kneeshaw","given":"Dan","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecology and Evolution","id":"ITEM-3","issued":{"date-parts":[["2019"]]},"page":"576-586","title":"Phenological synchrony between eastern spruce budworm and its host trees increases with warmer temperatures in the boreal forest","type":"article-journal","volume":"9"},"uris":[""]}],"mendeley":{"formattedCitation":"(De Grandpré et al. 2018; Bouzidi et al. 2019; Pureswaran et al. 2019)","plainTextFormattedCitation":"(De Grandpré et al. 2018; Bouzidi et al. 2019; Pureswaran et al. 2019)","previouslyFormattedCitation":"(De Grandpré et al. 2018; Bouzidi et al. 2019; Pureswaran et al. 2019)"},"properties":{"noteIndex":0},"schema":""}(De Grandpré et al. 2018; Bouzidi et al. 2019; Pureswaran et al. 2019). Hence, a better understanding of the resistance and resilience of boreal old-growth forests in eastern Canada to recurrent moderate-severity disturbances is vital to better evaluate the projected consequences of climate change and propose alternatives to clearcut-based forest management. This knowledge would also add to existing research on old-growth forests and therefore contribute to finding relevant management solutions, including for forests situated outside of the boreal regions of eastern Canada.This study focused on the boreal forests of eastern Canada, and more specifically, within a territory subjected to moderate-severity secondary disturbances caused by spruce budworm outbreaks over the 20th century ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Laprise","given":"Danielle","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canadian Journal of Forest Research","id":"ITEM-1","issued":{"date-parts":[["1990"]]},"page":"1-8","title":"Histoire récente des épidémies de la Tordeuse des bourgeons de l'épinette au nord du lac Saint-Jean (Québec) : une analyse dendrochronologique","type":"article-journal","volume":"20"},"uris":[""]},{"id":"ITEM-2","itemData":{"author":[{"dropping-particle":"","family":"Morin","given":"","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canadian Journal of Forest Research","id":"ITEM-2","issued":{"date-parts":[["1994"]]},"page":"730-741","title":"Dynamic of balsam fir forests in relation to spruce budworm outbreaks in the boreal zone of Québec","type":"article-journal","volume":"24"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.3389/FPLS.2018.01905","ISSN":"1664-462X","abstract":"In scenarios of future climate change, there is a projected increase in the occurrence and severity of natural disturbances in boreal forests. Spruce budworm (Choristoneura fumiferana) (SBW) is the main defoliator of conifer trees in the North American boreal forests affecting large areas and causing marked losses of timber supplies. However, the impact and the spatiotemporal patterns of SBW dynamics at the landscape scale over the last century remain poorly known. This is particularly true for northern regions dominated by spruce species. The main goal of this study is to reconstruct SBW outbreaks during the 20th century at the landscape scale and to evaluate changes in the associated spatiotemporal patterns in terms of distribution area, frequency, and severity. We rely on a dendroecological approach from sites within the eastern Canadian boreal forest and draw from a large dataset of almost 4 000 trees across a study area of nearly 800 000 km2. Interpolation and analyses of hotspots determined reductions in tree growth related to insect outbreak periods and identified the spatiotemporal patterns of SBW activity over the last century. We identified three insect outbreaks having different spatiotemporal patterns, duration, and severity. The first (1905–1930) affected up to 40% of the studied trees, initially synchronizing from local infestations and then migrating to northern stands. The second outbreak (1935–1965) was the longest and the least severe with only up to 30% of trees affected by SBW activity. The third event (1968–1988) was the shortest, yet it was also the most severe and extensive, affecting nearly up to 50% of trees and 70% of the study area. This most recent event was identified for the first time at the limit of the commercial forest illustrating a northward shift of the SBW distribution area during the 20th century. Overall, this research confirms that insect outbreaks are a complex and dynamic ecological phenomena, which makes the understanding of natural disturbance cycles at multiple scales a major priority especially in the context of future regional climate change.","author":[{"dropping-particle":"","family":"Navarro","given":"Lionel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Montoro Girona","given":"Miguel","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Frontiers in Plant Science","id":"ITEM-3","issue":"December","issued":{"date-parts":[["2018"]]},"page":"1905","title":"Changes in spatiotemporal patterns of 20th century spruce budworm outbreaks in eastern Canadian boreal forests","type":"article-journal","volume":"9"},"uris":[""]}],"mendeley":{"formattedCitation":"(Morin and Laprise 1990; Morin 1994; Navarro et al. 2018)","manualFormatting":"(Morin, 1994; Morin & Laprise, 1990; Navarro, Morin, Bergeron, & Montoro Girona, 2018)","plainTextFormattedCitation":"(Morin and Laprise 1990; Morin 1994; Navarro et al. 2018)","previouslyFormattedCitation":"(Morin and Laprise 1990; Morin 1994; Navarro et al. 2018)"},"properties":{"noteIndex":0},"schema":""}(Morin, 1994; Morin & Laprise, 1990; Navarro, Morin, Bergeron, & Montoro Girona, 2018). Innovative dendrochronological analyses, combining the study of growth releases and growth patterns, are used to reconstruct the disturbance regime of the studied stands and evaluate the success of understorey and overstorey trees in filling the gaps created by secondary disturbances. This study aims to reconstruct the disturbance and post-disturbance dynamics in boreal old-growth forests driven by moderate-severity disturbances. We hypothesize that (1) radial growth in the studied trees can be divided into several distinct growth patterns shaped by the secondary disturbance regime, and (2) each of these growth patterns corresponds to trees defined by specific characteristics (e.g., age, canopy layer), making it possible to reconstruct the post-disturbance dynamics of the forests that they constitute. In this study, we highlight the impacts of recurrent moderate-severity disturbances on the dynamics and structure of boreal old-growth forests. Our results will contribute to the development of sustainable development strategies that better correspond to the processes driving these ecosystems.Materials and methodsStudy territoryOur study took place in the natural boreal forest stands within the Monts-Valin region of Québec, Canada (Figure 1). The studied area ranges from 48°61′N to 49°30′N and from 70°34′W to 70°82′W in the balsam fir (Abies balsamea (L.) Mill.)–white birch (Betula papyrifera Marsh.) and the eastern black spruce (Picea mariana (Mill.) B.S.P.)–feather moss bioclimatic zones ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Saucier","given":"Jean-Pierre","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Grondin","given":"Pierre","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Brisson","given":"Jacques","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gosselin","given":"Jocelyn","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Lavoie","given":"Claude","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Leduc","given":"Alain","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morneau","given":"Claude","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Payette","given":"Serge","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Richard","given":"Pierre J.H.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Robitaille","given":"Andr","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Sirois","given":"Luc","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Thiffault","given":"?velyne","non-dropping-particle":"","parse-names":false,"suffix":""}],"chapter-number":"4","container-title":"Manuel de foresterie, édition revue et augmentée","editor":[{"dropping-particle":"","family":"[OIFQ] Ordre des ingénieurs forestiers du Québec","given":"","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-1","issued":{"date-parts":[["2009"]]},"page":"165-315","publisher":"?ditions Multimondes","publisher-place":"Québec, Canada","title":"?cologie forestière","type":"chapter"},"uris":[""]}],"mendeley":{"formattedCitation":"(Saucier et al. 2009)","plainTextFormattedCitation":"(Saucier et al. 2009)","previouslyFormattedCitation":"(Saucier et al. 2009)"},"properties":{"noteIndex":0},"schema":""}(Saucier et al. 2009). Mean annual temperature, recorded at a weather station located in the study area (Bernatchez station), is between 0.4 and 1.8°C and mean temperature during the growing season (May?September) is between 12.6 and 13.5°C. Average annual rainfall varies between 886 and 1109 mm, with an average daily precipitation during the growing season of approximately 2.93 mm/day ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.3389/FPLS.2020.01268","ISSN":"1664-462X","abstract":"New insights into the intra-annual dynamics of tree-ring formation can improve our understanding of tree-growth response to environmental conditions at high-resolution time scales. Obtaining this information requires, however, a weekly monitoring of wood formation, sampling that is extremely time-intensive and scarcely feasible over vast areas. Estimating the timing of cambial and xylem differentiation by modeling thus represents an interesting alternative for obtaining this important information by other means. Temporal dynamics of cambial cells can be extracted from the daily tree-ring growth rate computed by the Vaganov–Shashkin (VS) simulation model, assuming that cell production is tightly linked to tree-ring growth. Nonetheless, these predictions have yet to be compared with direct observations of wood development, i.e., via microcoring, over a long time span. We tested the performance of the VS model by comparing the observed and predicted timing of wood formation in black spruce [Picea mariana (Mill.)]. We obtained microcores over 15 years at 5 sites along a latitudinal gradient in Quebec (Canada). The measured variables included cell size and the timing of cell production and differentiation. We calibrated the VS model using daily temperature and precipitation recorded by weather stations located on each site. The predicted and observed timing of cambial and enlarging cells were highly correlated (R2 = 0.8); nonetheless, we detected a systematic overestimation in the predicted timing of cambial cells, with predictions delayed by 1–20 days compared with observations. The growth rate of cell diameter was correlated with the predicted growth rate assigned to each cambial cell, confirming that cell diameter developmental dynamics have the potential to be inferred by the tree-ring growth curve of the VS model. The mismatch between the observed and predicted timing of wood formation in black spruce within our study area can be reduced by better adapting the VS model to wet sites, a context for which this model has been rarely used. Integrating new knowledge related to the temporal dynamics of cell development into the model is also required to obtain more reliable predictions of the timing of xylem differentiation.","author":[{"dropping-particle":"","family":"Buttò","given":"Valentina","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Shishov","given":"Vladimir","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Tychkov","given":"Ivan","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Popkova","given":"Margarita","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"He","given":"Minhui","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Rossi","given":"Sergio","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Deslauriers","given":"Annie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Frontiers in Plant Science","id":"ITEM-1","issue":"August","issued":{"date-parts":[["2020"]]},"page":"1268","title":"Comparing the cell dynamics of tree-ring formation observed in microcores and as predicted by the Vaganov–Shashkin model","type":"article-journal","volume":"11"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1007/s13595-014-0399-8","ISSN":"1297966X","abstract":"? Context: The Canadian forest industry is turning its attention towards the unmanaged areas at higher latitudes, where the forest resource is still poorly understood because of lack of accessibility. Despite a lower productivity in terms of volume, northern stands are expected to produce wood of higher quality, which may make these areas attractive for management and production.\n? Aims: This study aims to test the hypothesis that trees at high latitudes produce wood with better basic properties than trees at lower latitudes.\n? Methods: Growth and wood characteristics were assessed according to cambial age in 25 black spruce (Picea mariana) trees from five sites located along an alti-latitudinal gradient in Quebec.\n? Results: Sites at higher latitudes and altitudes exhibited slower growth rates and lower stem volume. Wood density and mechanical properties were higher in the sites located at lower latitudes or altitudes. Fiber size had higher values in southern sites, but only at younger ages. Principal component analysis confirmed these results, with the northernmost site being the one where growth, density and mechanical properties were generally lowest.\n? Conclusion: The reduction in growth was not compensated by increases in the basic properties of wood. More extensive samplings are needed to validate the results at larger scale.","author":[{"dropping-particle":"","family":"Rossi","given":"Sergio","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Cairo","given":"Ernesto","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Krause","given":"Cornelia","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Deslauriers","given":"Annie","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Annals of Forest Science","id":"ITEM-2","issue":"1","issued":{"date-parts":[["2015"]]},"page":"77-87","title":"Growth and basic wood properties of black spruce along an alti-latitudinal gradient in Quebec, Canada","type":"article-journal","volume":"72"},"uris":[""]}],"mendeley":{"formattedCitation":"(Rossi et al. 2015; Buttò et al. 2020)","plainTextFormattedCitation":"(Rossi et al. 2015; Buttò et al. 2020)","previouslyFormattedCitation":"(Rossi et al. 2015; Buttò et al. 2020)"},"properties":{"noteIndex":0},"schema":""}(Rossi et al. 2015; Buttò et al. 2020). Regional topography is dominated by a hilly relief, and the elevation ranges between 400 and 1,000?m a.s.l. Forest is the main form of vegetation cover across this territory; black spruce, balsam fir, white birch, and aspen (Populus tremuloides Michx.) are the most common tree species. European settlement officially started in the region in 1842, but logging activities were mainly concentrated around inhabited areas and rivers before the second half of the 20th century ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Girard","given":"C.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Perron","given":"N.","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-1","issued":{"date-parts":[["1989"]]},"number-of-pages":"665","publisher":"Institut Québécois de recherché sur la culture","publisher-place":"Québec, QC","title":"Histoire du Saguenay-Lac-Saint-Jean","type":"book"},"uris":[""]}],"mendeley":{"formattedCitation":"(Girard and Perron 1989)","plainTextFormattedCitation":"(Girard and Perron 1989)","previouslyFormattedCitation":"(Girard and Perron 1989)"},"properties":{"noteIndex":0},"schema":""}(Girard and Perron 1989). In black spruce forests, clearcutting was and still is favoured because of the small size of the trees. The old-growth forests still present in the study area can therefore be considered as primary or virgin forests, as no logging activity has directly affected them. SamplingWe randomly selected eight old-growth stands across the study territory using a stratified random sampling protocol. We based our sampling criteria on attributes derived from aerial forest survey maps, and these attributes were then verified in the field. We aimed to sample old-growth forests in this region that had been markedly disturbed by the last spruce budworm outbreak at the time of sampling. The last outbreak occurred between 1972 and 1984 ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Laprise","given":"Danielle","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canadian Journal of Forest Research","id":"ITEM-1","issued":{"date-parts":[["1990"]]},"page":"1-8","title":"Histoire récente des épidémies de la Tordeuse des bourgeons de l'épinette au nord du lac Saint-Jean (Québec) : une analyse dendrochronologique","type":"article-journal","volume":"20"},"uris":[""]},{"id":"ITEM-2","itemData":{"author":[{"dropping-particle":"","family":"Krause","given":"Cornelia","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canada Journal of Forest Research","id":"ITEM-2","issued":{"date-parts":[["1997"]]},"page":"69-75","title":"The use of dendrochronological material from buildings to get information about past spruce budworm outbreaks","type":"article-journal","volume":"27"},"uris":[""]}],"mendeley":{"formattedCitation":"(Morin and Laprise 1990; Krause 1997)","plainTextFormattedCitation":"(Morin and Laprise 1990; Krause 1997)","previouslyFormattedCitation":"(Morin and Laprise 1990; Krause 1997)"},"properties":{"noteIndex":0},"schema":""}(Morin and Laprise 1990; Krause 1997). We initially classified stands characterized as old (i.e., >100 years old), coniferous-dominated, and defined by a canopy containing at least 20% gaps; we considered this last factor as an indicator of a moderate-severity disturbance caused by spruce budworm outbreaks, as the stands still present marks of this disturbance several decades later. We also confirmed that all study stands were undisturbed by human activities, implying that all the selected sites were primary forests.Sampling occurred in 2009. In each selected stand, we established a 400-m2 (20 × 20?m) plot within which we surveyed all merchantable trees (diameter at breast height [DBH] ≥ 9?cm), alive or dead. For each tree, we identified the attributes of species, DBH, height, vitality (alive or dead), and crown status (the stem bearing the apical meristem as either intact or broken). We then felled all merchantable trees within the 400-m2 plots to obtain a more accurate measurement of height and to sample basal disks for subsequent dendrochronological analysis. We only selected basal disks from living coniferous trees, and we rejected any disks marked by substantial amounts of decay that prevented tree-ring analysis. We obtained 381 basal disks: 290 black spruce and 91 balsam fir. Finally, we also sampled saplings (living trees with a DBH <9?cm and a height ≥1.3?m) in two square 5-m2 plots situated at opposite sides and outside of each 400-m2 plot. For each sapling, we recorded its species, DBH, and height.For each living tree, we also defined its position in the canopy (hereafter, the “canopy layer,” i.e., dominant, codominant, intermediary, and suppressed) following the methodology of the Québec Ministry of Forests, Wildlife and Parks ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"ISBN":"9782550738572","author":[{"dropping-particle":"","family":"[MRNF] Ministère des Ressources Naturelles et de la Faune du Québec","given":"","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-1","issued":{"date-parts":[["2008"]]},"number-of-pages":"101","publisher":"Direction des inventaires forestiers","publisher-place":"Québec","title":"Norme de stratification écoforestière. Quatrième inventaire forestier","type":"report"},"uris":[""]}],"mendeley":{"formattedCitation":"([MRNF] Ministère des Ressources Naturelles et de la Faune du Québec 2008)","manualFormatting":"(MRNF, 2008)","plainTextFormattedCitation":"([MRNF] Ministère des Ressources Naturelles et de la Faune du Québec 2008)","previouslyFormattedCitation":"([MRNF] Ministère des Ressources Naturelles et de la Faune du Québec 2008)"},"properties":{"noteIndex":0},"schema":""}(MRNF, 2008). The canopy layers are based on the dominant height (DH), i.e., the mean height of the 100 tallest trees per hectare; therefore, in our case, we used the four tallest trees in each 400-m2 plot. We defined dominant trees as having a height greater or equal to DH, whereas codominant trees have a height less than DH but greater or equal to 2/3 DH. We defined intermediary trees as having a height less than 2/3 DH but greater than 1/2 DH, and suppressed trees have a height less than 1/2 DH. Data preparationThe 381 basal disks were air-dried and sanded mechanically in preparation for tree-ring measurements. We measured tree rings along two radii (radius series) to the nearest 0.01 mm using a manual Henson micrometer (Fred C. Henson, Mission Viejo, CA, USA) or a LINTAB measurement table and TsapWin software (Rinntech, Heidelberg, Germany). We used a combination of visual cross-dating and the COFECHA computer program ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Holmes","given":"R. l.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Tree-Ring Bulletin","id":"ITEM-1","issue":"43","issued":{"date-parts":[["1983"]]},"page":"69-78","title":"Computer-assisted quality control in tree-ring dating measurement","type":"article-journal"},"uris":[""]}],"mendeley":{"formattedCitation":"(Holmes 1983)","plainTextFormattedCitation":"(Holmes 1983)","previouslyFormattedCitation":"(Holmes 1983)"},"properties":{"noteIndex":0},"schema":""}(Holmes 1983) to correct the tree-ring series. We then obtained a single tree-ring series for each tree (tree series) by taking the mean value of each tree ring measured in the radius series of the corresponding tree.To identify a tree’s radial growth pattern, i.e., the main radial growth trends over time, we used the methods established by ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.3390/f11030252","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Krause","given":"Cornélia","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-1","issued":{"date-parts":[["2020"]]},"page":"1-18","title":"Unveiling the diversity of tree growth patterns in boreal old-growth forests reveals the richness of their dynamics","type":"article-journal","volume":"11"},"uris":[""]}],"mendeley":{"formattedCitation":"(Martin, Krause, et al. 2020)","manualFormatting":"Martin et al. (2020b)","plainTextFormattedCitation":"(Martin, Krause, et al. 2020)","previouslyFormattedCitation":"(Martin, Krause, et al. 2020)"},"properties":{"noteIndex":0},"schema":""}Martin et al. (2020b). Each tree series was divided into 20 segments (20-segment series), each segment containing a similar number of tree rings—the difference in the number of rings per segment for the same tree never exceeded one ring. The first segment began at the first ring after the pith, and the last segment ended at the last ring produced by the tree. This method allowed us to compare trees of different ages by smoothing interannual growth changes and keeping only the overall trend in radial thickness. The age of sampled trees ranged from 55 to 271 years (mean: 143 ± 39.2 years), and the mean number of tree rings per section was 7.13 ± 2 rings.For each tree, we also computed the following attributes, hereafter qualified as “growth attributes,” on the basis of the tree series: age, mean tree-ring width, ring-width standard deviation, 5th percentile ring width, and 95th percentile ring width. To reconstruct the disturbance history of the sample sites, we used the methods of ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1890/0012-9615(1997)067[0225:RGACFR]2.0.CO;2","ISBN":"0012-9615","ISSN":"00129615","abstract":"A novel dendroecological procedure was developed to elucidate canopy disturbances spanning a >300-yr period for oak (Quercus) forests of central Pennsylvania. Running comparisons of sequential 10-yr ring-width averages may effectively neutralize both short-term (i.e., drought) and long-term growth trends associated with climate while enhancing detection of abrupt and sustained radial-growth increases characteristic of canopy disturbance. Thinning-response studies revealed the conservative tendencies of overstory oak, with substantial basal area reductions (>1/3) required to attain moderate and consistently detectable growth increases. Based on empirical evidence, a minimum growth-response threshold of 25% was established to depict canopy disturbances. This is in contrast to the 50-100% sustained radial-growth release often used to detect disturbance using understory trees in closed forests. Our default threshold was adjusted higher as necessary for those trees highly correlated to climatic trends (as represented by the Palmer drought severity index). Canopy disturbances detected with this dendroecological approach were further substantiated using tree-recruitment data (age cohorting). By coupling these data sets, we estimated return intervals of standwide disturbance from 21 yr in presettlement times (prior to 1775) and during heavy Euro-American exploitation (1775-1900) to 31 yr in modern times (after 1900). Although disturbance periodicity remained stable between presettlement and early post-settlement (exploitation) eras, the mode of disturbance shifted from mainly natural (wind and fire) to anthropogenic forces (intense harvesting for charcoal production), based on the historical record. In the process, presettlement oak-pine (Pinus)-chestnut (Castanea) forests on ridges were rapidly converted to young coppice stands of oak and chestnut. The reduction of harvesting and fire events coupled with the eradication of chestnut by blight this century have allowed these coppice stands to mature into oak-dominated forests that exist today. This analytical technique for ascertaining disturbance histories holds much potential and should be considered for use with mature, overstory trees in other forest types with appropriate modifications.","author":[{"dropping-particle":"","family":"Nowacki","given":"Gregory J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Abrams","given":"Marc D.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecological Monographs","id":"ITEM-1","issue":"2","issued":{"date-parts":[["1997"]]},"page":"225-249","title":"Radial-growth averaging criteria for reconstructing disturbance histories from presettlement-origin oaks","type":"article-journal","volume":"67"},"uris":[""]}],"mendeley":{"formattedCitation":"(Nowacki and Abrams 1997)","manualFormatting":"Nowacki & Abrams (1997)","plainTextFormattedCitation":"(Nowacki and Abrams 1997)","previouslyFormattedCitation":"(Nowacki and Abrams 1997)"},"properties":{"noteIndex":0},"schema":""}Nowacki & Abrams (1997) to identify the annual percentage of growth change (%GC) of the 381 tree series, using the equation:%GC= M2-M1/M1×100 ,where M1 is the mean ring width for the first 10-year period, and M2 is the mean ring width for the subsequent 10-year period. We defined a major release when %GC ≥50%, a minor release when 50% > %GC ≥ 25%, a minor suppression when -25% ≥ %GC > -50%, and a major suppression when %GC was lower or equal to -50%. For each site, we then computed the percentage of trees experiencing a major release, minor release, minor suppression, and major suppression for each year covered by the chronologies. Changes in the annual percentage of growth release between sites were then observed using a locally weighted regression ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Trexler","given":"Joel C.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Travis","given":"Jospeh","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecology","id":"ITEM-1","issue":"6","issued":{"date-parts":[["1993"]]},"page":"1629-1637","title":"Nontraditional Regression Analyses","type":"article-journal","volume":"74"},"uris":[""]}],"mendeley":{"formattedCitation":"(Trexler and Travis 1993)","plainTextFormattedCitation":"(Trexler and Travis 1993)","previouslyFormattedCitation":"(Trexler and Travis 1993)"},"properties":{"noteIndex":0},"schema":""}(Trexler and Travis 1993) and smoothed with a 50% span using the ggplot package ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Wickham","given":"Hadley","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-1","issued":{"date-parts":[["2016"]]},"publisher":"Springer-Verlag","publisher-place":"New York","title":"ggplot2: Elegant Graphics for Data Analysis","type":"article"},"uris":[""]}],"mendeley":{"formattedCitation":"(Wickham 2016)","plainTextFormattedCitation":"(Wickham 2016)","previouslyFormattedCitation":"(Wickham 2016)"},"properties":{"noteIndex":0},"schema":""}(Wickham 2016) in R software, version 3.3.1 ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"R Core Team","given":"","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-1","issued":{"date-parts":[["2019"]]},"publisher":"R Foundation for Statistical Computing","publisher-place":"Vienna, Austria","title":"R: A language and environment for statistical computing","type":"article"},"uris":[""]}],"mendeley":{"formattedCitation":"(R Core Team 2019)","plainTextFormattedCitation":"(R Core Team 2019)","previouslyFormattedCitation":"(R Core Team 2019)"},"properties":{"noteIndex":0},"schema":""}(R Core Team 2019).To estimate the succession stage of each study stand, we calculated the cohort basal area proportion (CBAP) of each stand as defined by ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1139/a03-010","ISSN":"1208-6053","author":[{"dropping-particle":"","family":"Kneeshaw","given":"Daniel D.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Environmental Reviews","id":"ITEM-1","issue":"S1","issued":{"date-parts":[["2003","9"]]},"page":"S99-S114","title":"Old growth in the boreal forest: A dynamic perspective at the stand and landscape level","type":"article-journal","volume":"11"},"uris":[""]}],"mendeley":{"formattedCitation":"(Kneeshaw and Gauthier 2003)","manualFormatting":"Kneeshaw and Gauthier (2003)","plainTextFormattedCitation":"(Kneeshaw and Gauthier 2003)","previouslyFormattedCitation":"(Kneeshaw and Gauthier 2003)"},"properties":{"noteIndex":0},"schema":""}Kneeshaw and Gauthier (2003), using the methodology of ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1016/j.foreco.2018.04.007","ISSN":"03781127","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-1","issue":"April","issued":{"date-parts":[["2018"]]},"page":"125-136","publisher":"Elsevier","title":"Structural diversity and dynamics of boreal old-growth forests case study in Eastern Canada","type":"article-journal","volume":"422"},"uris":[""]}],"mendeley":{"formattedCitation":"(Martin et al. 2018)","manualFormatting":"Martin et al. 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(2018) and ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.3390/f11030252","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Krause","given":"Cornélia","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-1","issued":{"date-parts":[["2020"]]},"page":"1-18","title":"Unveiling the diversity of tree growth patterns in boreal old-growth forests reveals the richness of their dynamics","type":"article-journal","volume":"11"},"uris":[""]}],"mendeley":{"formattedCitation":"(Martin, Krause, et al. 2020)","manualFormatting":"Martin et al., 2020X.","plainTextFormattedCitation":"(Martin, Krause, et al. 2020)","previouslyFormattedCitation":"(Martin, Krause, et al. 2020)"},"properties":{"noteIndex":0},"schema":""}Martin et al. (2020b). CBAP indicates the replacement of the first cohort after the last primary disturbance by successive new cohorts of shade-tolerant species, and its value ranges between 0 and 1. A CBAP ≈ 0 represents a stand where all trees belong to the first cohort, and a CBAP ≈ 1 represents a stand where the first cohort has almost been entirely replaced by new cohorts, i.e., a true old-growth forest sensu ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Oliver","given":"C. D.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Larson","given":"B. 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(2020b)","plainTextFormattedCitation":"(Martin, Krause, et al. 2020)","previouslyFormattedCitation":"(Martin, Krause, et al. 2020)"},"properties":{"noteIndex":0},"schema":""}Martin et al. (2020b) methodology. We based the k-means clustering on the mean ring width for each of the 20 segments, preliminarily scaled and centred, with each segment considered as a different explanatory variable. To ensure the robustness of the obtained clusters, we performed 1,000 iterations of the k-means algorithm. We determined the optimal number of clusters (radial growth patterns) using the simple structure index (SSI;ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Dolnicar","given":"Sara","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Journal of Travel and Tourism Marketing","id":"ITEM-1","issue":"4","issued":{"date-parts":[["1999"]]},"page":"43-57","title":"Analyzing destination images: a perceptual charting approach","type":"article-journal","volume":"8"},"uris":[""]}],"mendeley":{"formattedCitation":"(Dolnicar 1999)","manualFormatting":" Dolnicar, 1999)","plainTextFormattedCitation":"(Dolnicar 1999)","previouslyFormattedCitation":"(Dolnicar 1999)"},"properties":{"noteIndex":0},"schema":""} Dolnicar, 1999) criterion, with the highest SSI value indicating the optimal k-means partition.To address our second hypothesis that each of these growth patterns corresponds to specific layers of the canopy, we then compared the differences in growth attributes, DBH, and height between the growth patterns using mixed-effect analyses of variance (mixed ANOVA). The fixed effects were the growth attributes, DBH, and tree height; we used sample sites as the random effect. The use of sites as a random variable limited their potential influence (e.g., in terms of fertility) on the size and growth of the trees studied. When necessary, we log-transformed the data or removed outliers (i.e., values below the 1st percentile and above the 99th percentile) to respect the requirements of mixed ANOVA (i.e., homoscedasticity and the normality of the independent variable for each group). In the case of tree height, we considered broken tree canopies as a possible source of bias because the measured height was, in our case, not the actual tree height. We therefore only considered trees having an intact canopy when comparing tree height between the various growth patterns. 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The distributions of the species and the canopy layers were also compared between the growth patterns using Fisher’s tests.For all analyses, we used R software ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"R Core Team","given":"","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-1","issued":{"date-parts":[["2019"]]},"publisher":"R Foundation for Statistical Computing","publisher-place":"Vienna, Austria","title":"R: A language and environment for statistical computing","type":"article"},"uris":[""]}],"mendeley":{"formattedCitation":"(R Core Team 2019)","plainTextFormattedCitation":"(R Core Team 2019)","previouslyFormattedCitation":"(R Core Team 2019)"},"properties":{"noteIndex":0},"schema":""}(R Core Team 2019), version 3.3.1, and the vegan ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Oksanen","given":"J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Blanchet","given":"G.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Friendly","given":"M.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kindt","given":"R.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Legendre","given":"P.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"MCGlinn","given":"D.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Minchin","given":"P. 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Despite the evident need for a common set of tools for verification, replication and comparison across studies, only a few DOS programmes for disturbance detection exist and they are for limited purposes only. Currently, the ideal statistical environment for the task is R, which is becoming the primary tool for various types of tree-ring analyses. This has led to the development of TRADER (Tree Ring Analysis of Disturbance Events in R), an open-source software package for R that provides an analysis of tree growth history for disturbance reconstructions. We have implemented four methods, which are commonly used for the detection of disturbance events: radial-growth averaging criteria developed by Nowacki and Abrams, 1997, the boundary-line method (Black and Abrams, 2003), the absolute-increase method (Fraver and White, 2005), and the combination of radial-growth averaging and boundary-line techniques (Splechtna et al., 2005). TRADER, however, enables the analysis of disturbance history by a total of 24 published methods. Furthermore, functions for the detection of tree recruitment and growth trends were also included. The main features of the presented package are described and their application is shown on a real tree-ring datasets. The package requires little knowledge of the R environment giving straightforward analyses with suitable parameters, but at the same time it is easily modifiable by the more experienced user. The package improves research efficiency and facilitates replication of previous studies. One of its major advantages is that it offers the possibility for comparison between different methods of disturbance history reconstruction.","author":[{"dropping-particle":"","family":"Altman","given":"J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fibich","given":"P.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Dolezal","given":"J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Aakala","given":"Tuomas","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Dendrochronologia","id":"ITEM-1","issue":"2","issued":{"date-parts":[["2014"]]},"page":"107-112","publisher":"Elsevier GmbH.","title":"TRADER: A package for tree ring analysis of disturbance events in R","type":"article-journal","volume":"32"},"uris":[""]}],"mendeley":{"formattedCitation":"(Altman et al. 2014)","plainTextFormattedCitation":"(Altman et al. 2014)","previouslyFormattedCitation":"(Altman et al. 2014)"},"properties":{"noteIndex":0},"schema":""}(Altman et al. 2014) packages, applying a p-threshold for significance of 0.05.ResultsOverall stand characteristicsIn general, black spruce dominated the sampled stands with a minor (<10%) contribution of balsam fir (Table 1). The exceptions were Site 5, where balsam fir dominated, and Site 8, where both species had a similar abundance. The mean tree age of the stands ranged between 122 and 207 years, and tree age varied considerably within stands, with several trees older than 200 years. CBAP values were mainly equal to 1, indicating stands where no first cohort trees remained. The exception was Site 7, for which the CBAP value was 0.93. Therefore, all studied stands were old-growth forests, defined by a complex age structure with multiple shade-tolerant cohorts, including several very old trees (Appendix A). The diametric structure was generally complex, with sapling density 1.75× to 7.5× that of trees. Dominant height ranged between 13.6 and 17.1?m, and mean tree height ranged between 9.4 and 12.7?m.Radial growth patternsThe SSI criterion reached a maximum at nine clusters (SSI criterion = 1.04; Figure 2B) for the 20-segment series. We therefore divided the 20-segment series into nine clusters (Figure 2A), which could be, in turn, grouped into four categories: 1) narrow and constant radial increments along all the sections (linear); 2) increasing or large radial increments along the first half of the chronology, followed by decreasing radial increments for the remaining portion (bell); 3) narrow radial increments over the first half of the chronology, followed by increasing radial increments within the remaining portion (ascending); and 4) narrow radial increments over the first third of the chronology, then an increase in radial increments within the second third, and finally a decrease in radial increments over the last third (sine). Growth patterns belonging to the ascending and sine groups were divided into three growth patterns distributed along a mean ring-width gradient (narrow, moderate, and large). For the bell group, we identified two growth patterns, one marked by a low growth rate (low-bell) and the other by a high growth rate (high-bell). The number of trees per growth pattern generally exceeded 20; the sole exception was for the high-bell, a pattern that we only observed for seven trees. Due to the high specificity of this growth pattern relative to the others, however, we kept this pattern for the further analyses.Growth patterns belonging to the sine and ascending patterns presented mainly growth releases, with a predominance of major releases (Figure 3). Suppressions were less frequent in these patterns, and there were almost no major suppressions. In general, we observed opposite trends for growth release and suppression. For the ascending patterns, suppressions were mainly observed in the first sections, whereas releases were observed in the others. We observed the opposite trends for the sine patterns, although some suppression could also be seen in the first sections. These results were generally consistent with the growth trends observed for each of these growth patterns. Growth releases and suppressions presented a more complex distribution for the linear, low-bell, and high-bell patterns. Growth suppressions were particularly dominant in the high-bell pattern, even though some growth releases can be observed in the first sections. For the low-bell patterns, growth releases were generally the most frequent, but they were progressively replaced by growth suppression in the final sections. Finally, the linear pattern presented an alternance between growth release and suppression. These results highlight that low-bell and linear patterns are defined by complex dynamics. Yet, the slow growth rate of these trees made these variations less marked than those defined by a sine or ascending pattern.We observed significant differences between patterns for all growth and tree attributes (Figure 4). There was, however, little difference between the ranges of tree age per growth pattern, although trees defined by low-ascending, low-sine, and high-sine patterns were, on average, significantly older than trees defined by the linear pattern. Trees defined by the high-bell and high-sine patterns included the larger and taller trees. In contrast, the linear, low-bell, low-ascending, and moderate-ascending patterns contained the smallest trees, in terms of both DBH and height. High-bell, high-ascending, and high-sine patterns were defined by the largest mean ring width, ring-width standard deviation, 5th percentile ring width (high-ascending excepted), and 95th percentile ring width. In contrast, the low-ascending pattern was generally characterized by the smallest mean ring width, ring-width standard deviation, 5th percentile ring width, and 95th percentile ring width. The other growth patterns presented intermediate results. The largest trees (DBH >15?cm) were generally defined by a mean tree-ring width >1 mm/year but also by an age <200 years (Figure 5). We observed almost all the high-sine, high-ascending, high-bell, and moderate-sine patterns in these trees. In contrast, trees older than 200 years were uncommon and variable in size and growth, with the low-ascending pattern being most frequent. Trees younger than 200 years and having a DBH <15?cm were characterized by diverse growth patterns and variable mean ring widths. Finally, we observed no significant differences in growth pattern occurrence between black spruce and balsam fir (Fisher’s p = 0.132; Appendix B).Distribution of the radial growth patterns in the canopyThe occurrence of specific growth patterns differed significantly between the various canopy layers (Fisher’s p < 0.001; Figure 6). In the dominant layers, growth patterns from the sine group were the most common, with the high-sine pattern being observed the most often, followed by growth patterns from the bell group. In the codominant layer, sine patterns were again the most abundant (with the low-sine pattern most dominant), but ascending patterns were the second most common group. For the intermediary and suppressed layers, the ascending patterns dominated, particularly the low- and moderate-ascending patterns. In the suppressed layer, however, the low-bell and linear patterns were the second and third most common patterns, with sine patterns almost absent.Overall, the codominant layer was the most common layer (53.2 ± 14% of the sampled trees; Table 2). For five of the sample sites (sites 1, 2, 4, 5, and 7), the majority of trees belonged to the codominant layer. At the other sites, the intermediary and suppressed layers contained more than half of the sampled trees. Nonetheless, codominant and dominant trees still represented at least one third of living trees within the stands. Moreover, saplings were always more abundant than trees (Table 1), indicating a dense regeneration in the understorey.Disturbance dynamicsAt all sites, we observed four distinct peaks of growth release (1870–1890, 1910–1940, 1950–1960, 1975–1990) between 1850 and 1999 (Figure 7). All peaks occurred during or after a spruce budworm outbreak period and were preceded by a period of suppression. The 1870–1890 peak was the least distinct, characterized by many simultaneously suppressed trees and marked differences in the percentage of released trees between sites. In contrast, the highest and longest peak was that of 1910–1940, when approximately 75% of the trees presented a growth release, two thirds of these were considered as major growth releases. This period was, however, preceded by the second-highest peak of trees experiencing suppression; these suppressions were, however, generally minor. The 1950–1960 and 1975–1990 peaks shared similar percentages of trees undergoing release (approximately 40%); however, most releases for the 1975–1990 peak were major, whereas the majority in the 1950–1960 peak were minor. The 1975–1990 peak was preceded by the highest suppression peak (approximately 35% of trees), whereas the percentage of suppressed trees before the 1950–1960 peak was relatively low (approximately 20% of trees). The study sites therefore appeared mainly driven by recurrent spruce budworm outbreaks, particularly related to a high mortality caused by the outbreak that occurred between 1910 and 1924 in this region.DiscussionTree radial growth was divided into nine distinct growth patterns. These patterns corresponded to four dominant groups that each contained one to three growth patterns, organized generally along a forest productivity gradient. This result supported our first hypothesis, highlighting that secondary disturbances have diverse impacts on overstorey tree growth. Canopy layers were each defined by specific radial growth patterns, thereby supporting our second hypothesis. Overall, spruce budworm was the main driver of secondary disturbance within the study sites. Therefore, our study clarifies how secondary disturbance dynamics shape the vertical structure of boreal old-growth forests that are driven by recurrent and severe insect outbreaks.Reaching the top of the canopy: a once-in-a-lifetime opportunityMost of the studied trees were defined by a sine or ascending growth pattern, indicating that black spruce and balsam fir reacted vigorously to the canopy openings caused by spruce budworm outbreaks. Both patterns are generally defined by a major increase in radial growth, a phenomenon observed in coniferous-dominated old-growth forests in North America and Europe ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canadian Journal of Forest Research","id":"ITEM-1","issued":{"date-parts":[["1994"]]},"page":"730-741","title":"Dynamics of balsam fir in relation to spruce budworm outbreaks in the Boreal Zone of Quebec","type":"article-journal","volume":"24"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1016/j.foreco.2016.04.038","ISSN":"03781127","abstract":"Disturbances, both natural and human induced, influence forest dynamics, ecosystem functioning, and ecosystem services. Here, we aim to evaluate the consequences of natural disturbances on the magnitude and dynamics of tree- and stand-level biomass accumulation from decadal to centennial scales. We use tree-ring data from 2301 trees and biometric data from 4909 trees sampled in 96 plots (each 1000 m2) to quantify the influence of mixed severity disturbance regimes on annual aboveground biomass increment (AGBI) and total aboveground biomass accumulation (AGB) across a mountainous monotypic Norway spruce (Picea abies (L.) Karst.) primary forest. We hypothesise that the multiple internal and external factors constraining tree growth will cause differences in tree and stand-level biomass trajectories in these natural forests.Although we found that tree-level AGB growth increases with tree size, we also found that tree age and disturbance legacies plays a crucial role for AGB in the investigated Norway spruce forests. Importantly, while younger trees of the same diameter class have an average current AGBI rate that is ~225% higher than older trees (300-400 years), we find trees that have been suppressed for up to 120 years can respond vigorously when competition is reduced. On average, post disturbance AGBI was ~400% greater than pre-disturbance AGBI. Growth of suppressed trees, independent of their age, followed similar trajectories after canopy accession. While aboveground biomass generally increased through time, the time since disturbance and disturbance severity are important co-predictors for stand-level AGBI and AGB. These forests regained most of the above ground living biomass over short interval (~50 years) after low intensity disturbances. The highest stand-level living AGB was observed on plots that experienced >40% canopy removal 160-190 years ago, whereas the highest AGBI occurred in plots disturbed recently within the past 40-50 years.Our results emphasize the importance of including both individual tree age and disturbance legacies to accurately characterize biomass dynamics and trajectories in forest ecosystems. Importantly, the period of time that a tree is in the canopy, and not tree age, modulates the trajectory of tree level AGBI. Growth rates begin to decline after ~30 years (tree-rings width) and ~100 years (AGBI) in the canopy. We demonstrate that even late-seral forests can rapidly regain biomass lost to low intensity disturbance.","author":[{"dropping-particle":"","family":"Trotsiuk","given":"Volodymyr","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Svoboda","given":"Miroslav","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Weber","given":"Pascale","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Pederson","given":"Neil","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Klesse","given":"Stefan","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Janda","given":"Pavel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Martin-Benito","given":"Dario","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Mikolas","given":"Martin","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Seedre","given":"Meelis","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bace","given":"Radek","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Mateju","given":"Lenka","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Frank","given":"David","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-2","issued":{"date-parts":[["2016"]]},"page":"108-115","publisher":"Elsevier B.V.","title":"The legacy of disturbance on individual tree and stand-level aboveground biomass accumulation and stocks in primary mountain Picea abies forests","type":"article-journal","volume":"373"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.3390/f11030252","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Krause","given":"Cornélia","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-3","issued":{"date-parts":[["2020"]]},"page":"1-18","title":"Unveiling the diversity of tree growth patterns in boreal old-growth forests reveals the richness of their dynamics","type":"article-journal","volume":"11"},"uris":[""]}],"mendeley":{"formattedCitation":"(H. Morin 1994; Trotsiuk et al. 2016; Martin, Krause, et al. 2020)","manualFormatting":"(Martin et al., 2020b; Morin, 1994; Trotsiuk et al., 2016)","plainTextFormattedCitation":"(H. Morin 1994; Trotsiuk et al. 2016; Martin, Krause, et al. 2020)","previouslyFormattedCitation":"(H. Morin 1994; Trotsiuk et al. 2016; Martin, Krause, et al. 2020)"},"properties":{"noteIndex":0},"schema":""}(Martin et al., 2020b; Morin, 1994; Trotsiuk et al., 2016). Trees defined by a linear pattern were generally the smaller and younger individuals, reflecting suppressed trees that did not benefit from a canopy opening ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1016/j.foreco.2009.08.023","ISBN":"0378-1127","ISSN":"03781127","abstract":"The increasing commercial interest and advancing exploitation of new remote territories of the boreal forest require deeper knowledge of the productivity of these ecosystems. Canadian boreal forests are commonly assumed to be evenly aged, but recent studies show that frequent small-scale disturbances can lead to uneven-aged class distributions. However, how age distribution affects tree growth and stand productivity at high latitudes remains an unanswered question. Dynamics of tree growth in even- and uneven-aged stands at the limit of the closed black spruce (Picea mariana) forest in Quebec (Canada) were assessed on 18 plots with ages ranging from 77 to 340 years. Height, diameter and age of all trees were measured. Stem analysis was performed on the 10 dominant trees of each plot by measuring tree-ring widths on discs collected each meter from the stem, and the growth dynamics in height, diameter and volume were estimated according to tree age. Although growth followed a sigmoid pattern with similar shapes and asymptotes in even- and uneven-aged stands, trees in the latter showed curves more flattened and with increases delayed in time. Growth rates in even-aged plots were at least twice those of uneven-aged plots. The vigorous growth rates occurred earlier in trees of even-aged plots with a culmination of the mean annual increment in height, diameter and volume estimated at 40-80 years, 90-110 years earlier than in uneven-aged plots. Stand volume ranged between 30 and 238 m3 ha-1 with 75% of stands showing values lower than 120 m3 ha-1 and higher volumes occurring at greater dominant heights and stand densities. Results demonstrated the different growth dynamics of black spruce in single- and multi-cohort stands and suggested the need for information on the stand structure when estimating the effective or potential growth performance for forest management of this species. ? 2009 Elsevier B.V. All rights reserved.","author":[{"dropping-particle":"","family":"Rossi","given":"Sergio","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Tremblay","given":"Marie-Josée","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Savard","given":"Germain","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-1","issue":"9","issued":{"date-parts":[["2009"]]},"page":"2153-2161","title":"Growth and productivity of black spruce in even- and uneven-aged stands at the limit of the closed boreal forest","type":"article-journal","volume":"258"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1016/j.foreco.2016.04.038","ISSN":"03781127","abstract":"Disturbances, both natural and human induced, influence forest dynamics, ecosystem functioning, and ecosystem services. Here, we aim to evaluate the consequences of natural disturbances on the magnitude and dynamics of tree- and stand-level biomass accumulation from decadal to centennial scales. We use tree-ring data from 2301 trees and biometric data from 4909 trees sampled in 96 plots (each 1000 m2) to quantify the influence of mixed severity disturbance regimes on annual aboveground biomass increment (AGBI) and total aboveground biomass accumulation (AGB) across a mountainous monotypic Norway spruce (Picea abies (L.) Karst.) primary forest. We hypothesise that the multiple internal and external factors constraining tree growth will cause differences in tree and stand-level biomass trajectories in these natural forests.Although we found that tree-level AGB growth increases with tree size, we also found that tree age and disturbance legacies plays a crucial role for AGB in the investigated Norway spruce forests. Importantly, while younger trees of the same diameter class have an average current AGBI rate that is ~225% higher than older trees (300-400 years), we find trees that have been suppressed for up to 120 years can respond vigorously when competition is reduced. On average, post disturbance AGBI was ~400% greater than pre-disturbance AGBI. Growth of suppressed trees, independent of their age, followed similar trajectories after canopy accession. While aboveground biomass generally increased through time, the time since disturbance and disturbance severity are important co-predictors for stand-level AGBI and AGB. These forests regained most of the above ground living biomass over short interval (~50 years) after low intensity disturbances. The highest stand-level living AGB was observed on plots that experienced >40% canopy removal 160-190 years ago, whereas the highest AGBI occurred in plots disturbed recently within the past 40-50 years.Our results emphasize the importance of including both individual tree age and disturbance legacies to accurately characterize biomass dynamics and trajectories in forest ecosystems. Importantly, the period of time that a tree is in the canopy, and not tree age, modulates the trajectory of tree level AGBI. Growth rates begin to decline after ~30 years (tree-rings width) and ~100 years (AGBI) in the canopy. We demonstrate that even late-seral forests can rapidly regain biomass lost to low intensity disturbance.","author":[{"dropping-particle":"","family":"Trotsiuk","given":"Volodymyr","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Svoboda","given":"Miroslav","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Weber","given":"Pascale","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Pederson","given":"Neil","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Klesse","given":"Stefan","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Janda","given":"Pavel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Martin-Benito","given":"Dario","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Mikolas","given":"Martin","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Seedre","given":"Meelis","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bace","given":"Radek","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Mateju","given":"Lenka","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Frank","given":"David","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-2","issued":{"date-parts":[["2016"]]},"page":"108-115","publisher":"Elsevier B.V.","title":"The legacy of disturbance on individual tree and stand-level aboveground biomass accumulation and stocks in primary mountain Picea abies forests","type":"article-journal","volume":"373"},"uris":[""]}],"mendeley":{"formattedCitation":"(Rossi et al. 2009; Trotsiuk et al. 2016)","plainTextFormattedCitation":"(Rossi et al. 2009; Trotsiuk et al. 2016)","previouslyFormattedCitation":"(Rossi et al. 2009; Trotsiuk et al. 2016)"},"properties":{"noteIndex":0},"schema":""}(Rossi et al. 2009; Trotsiuk et al. 2016) or that were unable to sufficiently increase their growth following gap creation. Trees defined by a low-bell pattern were similar in size to those presenting a linear pattern albeit slightly older than the low-bell-pattern individuals. The minimal and short-duration increases in radial growth observed for this pattern also related to trees failing to significantly increase their growth following a disturbance. Finally, the high-bell pattern was highly specific, characterized by a marked growth and no identified juvenile suppression. This pattern was, however, very rare (7 occurrences within 381 studied trees), testifying to its limited influence on stand dynamics and structure.The identified growth patterns separated among the various canopy layers. Sine patterns were observed most commonly in the dominant and codominant layers, whereas ascending patterns were most frequent in the intermediary and suppressed layers. This distribution of patterns implies that trees defined by sine patterns had reached the top of the canopy already for several years, whereas trees sharing the ascending pattern continue to attempt to attain the highest layers. Considering the size and the age of the trees, those defined by the high-ascending or moderate-ascending patterns were likely to eventually reach the dominant and codominant layers. However, trees in the lower canopy layers and defined by slow growth were unlikely to benefit from the death of taller trees to access the upper layers ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.3390/f7100240","abstract":"Partial cutting is thought to be an alternative to achieve sustainable management in boreal forests. However, the effects of intermediate harvest intensity (45%–80%) on growth remain unknown in black spruce (Picea mariana (Mill.) B.S.P.) stands, one of the most widely distributed boreal species with great commercial interest. In this study, we analysed the effect of three experimental shelterwood and one seed-tree treatments on tree radial growth in even-aged black spruce stands, 10 years after intervention. Our results show that radial growth response 8–10 years after cutting was 41% to 62% higher than in untreated plots, with stand structure, treatment, tree position relative to skidding trails, growth before cutting and time having significant interactions. The stand structure conditioned tree growth after cutting, being doubled in younger and denser stands. Tree spatial position had a pronounced effect on radial growth; trees at the edge of the skidding trails showed twice the increase in growth compared to interior trees. Dominant trees before cutting located close to the skidding trails manifested the highest growth response after cutting. This research suggests that the studied treatments are effective to enhance radial wood production of black spruce especially in younger stands, and that the edge effect must be considered in silvicultural management planning.","author":[{"dropping-particle":"","family":"Montoro Girona","given":"Miguel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Lussier","given":"Jean-martin","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Walsh","given":"Denis","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-1","issued":{"date-parts":[["2016"]]},"page":"240","title":"Radial growth response of black spruce stands ten years after experimental shelterwoods and seed-tree cuttings in boreal forest","type":"article-journal","volume":"7"},"uris":[""]}],"mendeley":{"formattedCitation":"(Montoro Girona et al. 2016)","plainTextFormattedCitation":"(Montoro Girona et al. 2016)","previouslyFormattedCitation":"(Montoro Girona et al. 2016)"},"properties":{"noteIndex":0},"schema":""}(Montoro Girona et al. 2016). Therefore, trees defined by a low-ascending or low-bell pattern had missed out on the opportunity of reaching the top of the canopy; these trees remain as part of the intermediary or suppressed layers.Identifying the factors that determine a tree’s success or failure in reaching the upper canopy is challenging because these factors are dependent on conditions at the tree, stand, and disturbance levels. For example, local variations in microsite quality significantly influence regeneration growth and density ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1139/cjfr-2015-0484","ISBN":"0045-5067","ISSN":"12086037","abstract":"Some regenerating stands of the boreal forest exhibit low juvenile growth after major disturbances, which compromises sustainable forest management objectives. In black spruce - feather moss stands of eastern Canada subject to paludification, careful logging methods could decrease stand productivity with time by preventing a beneficial reduction in organic soil thickness. The aim of this project was to confirm decreases in juvenile growth between stands originating from careful logging and the former stands originating from old fires on the same sites. Stem analyses showed that stands originating from CPRS had significantly better juvenile height growth than the former stands but significantly lower growth than stands originating from recent fire in the study region. If organic matter thickness apparently played a role in the growth differences observed between fire and harvesting, it was not the only factor determining stand productivity. According to our results, cohort status, climatic regime, and quality of the residual organic matter are other factors that seem to drive productivity. Our results show that postharvest management approaches (e.g., site preparation) should be used to increase yields after harvest for the sites to express their full growth potential.","author":[{"dropping-particle":"","family":"Leroy","given":"C","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Leduc","given":"Alain","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Thiffault","given":"Nelson","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canadian Journal of Forest Research","id":"ITEM-1","issue":"6","issued":{"date-parts":[["2016"]]},"page":"783-793","title":"Forest productivity after careful logging and fire in black spruce stands of the Canadian Clay Belt","type":"article-journal","volume":"46"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.2980/i1195-6860-13-2-143.1","ISBN":"1195686013","author":[{"dropping-particle":"","family":"Jayen","given":"Karelle","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Leduc","given":"Alain","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"?coscience","id":"ITEM-2","issue":"2","issued":{"date-parts":[["2017"]]},"page":"143-151","title":"Effect of fire severity on regeneration success in the boreal forest of northwest Québec, Canada","type":"article-journal","volume":"13"},"uris":[""]}],"mendeley":{"formattedCitation":"(Leroy et al. 2016; Jayen et al. 2017)","plainTextFormattedCitation":"(Leroy et al. 2016; Jayen et al. 2017)","previouslyFormattedCitation":"(Leroy et al. 2016; Jayen et al. 2017)"},"properties":{"noteIndex":0},"schema":""}(Leroy et al. 2016; Jayen et al. 2017). Similarly, the spatial patterns of mortality caused by secondary disturbances are often complex, leaving survivor trees in the canopy ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1111/jvs.12057","ISSN":"11009233","abstract":"Questions: Can assumptions of the existence of spatially distinct patches (delineated structurally homogeneous parts of the forest, being either areas consisting of canopy trees or areas without canopy trees but in an early or later regenerative phase) and of directional development over time of the vegetation in such patches, as implied by current theory of storm gap dynamics, be verified by remapping previous study sites? Location: Natural, unmanaged boreo-nemoral spruce-dominated forest in eastern central Sweden. Methods: By re-mapping three plots, ca, 50 yr after the first inventory, we studied the structure and dynamics of gaps (patches without canopy tree cover) and major tree populations. The old and new maps allowed us to compare two independent assessments of the forest dynamics: one based on tree population changes and one on changes in gap area over time. Results: The current population structure could partly be described through the earlier-encountered structures of the different tree populations and consecutive processes of recruitment and mortality. However, the re-mapping exercise showed that spatially delineated patches did not develop directionally over time, nor was their development spatially discrete. Conclusions: Patch dynamics proceeds in such a way that the fate of a single patch may depend on the development of neighbouring patches. As gaps may partly close or merge into larger gaps, and as gap disappearance rate is a function of actual gap size, performance of an initially delimited patch is largely determined by developments in neighbouring patches and cannot be predicted from its momentary patch characteristics. Consequently, we propose an 'open matrix model' to describe the changes in a boreo-nemoral spruce forest, rather than a 'storm gap dynamics' model. ? 2013 International Association for Vegetation Science.","author":[{"dropping-particle":"","family":"Hytteborn","given":"H?kan","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Verwijst","given":"Theo","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Journal of Vegetation Science","id":"ITEM-1","issue":"1","issued":{"date-parts":[["2014"]]},"page":"100-112","title":"Small-scale disturbance and stand structure dynamics in an old-growth Picea abies forest over 54 yr in central Sweden","type":"article-journal","volume":"25"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.3390/f9090579","ISSN":"19994907","abstract":"The classification of discrete forest disturbance events is usually based on the spatial extent, magnitude, and frequency of the disturbance. Based on these characteristics, disturbances are placed into one of three broad categories, gap-scale, intermediate-severity, or catastrophic disturbance, along the disturbance classification gradient. We contend that our understanding of disturbance processes near the endpoints of the disturbance classification gradient far exceeds that of intermediate-severity events. We hypothesize that intermediate-severity disturbances are more common, and that they are more important drivers of forest ecosystem change than is commonly recognized. Here, we provide a review of intermediate-severity disturbances that includes proposed criteria for categorizing disturbances on the classification gradient. We propose that the canopy opening diameter to height ratio (D:H) be used to delineate gap-scale from intermediate-severity events and that the threshold between intermediate and catastrophic events be based on the influence of residual trees on the composition of the regeneration layer. We also provide examples of intermediate-severity disturbance agents, return intervals for these events, and recommendations for incorporating natural intermediate-severity disturbance patterns in silvicultural systems.","author":[{"dropping-particle":"","family":"Hart","given":"Justin L.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kleinman","given":"Jonathan S.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-2","issue":"579","issued":{"date-parts":[["2018"]]},"title":"What are intermediate-severity forest disturbances and why are they important?","type":"article-journal","volume":"9"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.3390/f9080471","ISBN":"1999-4907","ISSN":"19994907","abstract":"<p>Natural disturbances are fundamental to forest ecosystem dynamics and have been used for two decades to improve forest management, notably in the boreal forest. Initially based on fire regimes, there is now a need to extend the concept to include other types of disturbances as they can greatly contribute to forest dynamics in some regions of the boreal zone. Here we review the main descriptors—that is, the severity, specificity, spatial and temporal descriptors and legacies, of windthrow and spruce bud worm outbreak disturbance regimes in boreal forests—in order to facilitate incorporating them into a natural disturbance-based forest management framework. We also describe the biological legacies that are generated by these disturbances. Temporal and spatial descriptors characterising both disturbance types are generally variable in time and space. This makes them difficult to reproduce in an ecosystem management framework. However, severity and specificity descriptors may provide a template upon which policies for maintaining post harvesting and salvage logging biological legacies can be based. In a context in which management mainly targets mature and old-growth stages, integrating insect and wind disturbances in a management framework is an important goal, as these disturbances contribute to creating heterogeneity in mature and old-growth forest characteristics.</p>","author":[{"dropping-particle":"","family":"Grandpré","given":"Louis","non-dropping-particle":"De","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Waldron","given":"Kaysandra","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bouchard","given":"Mathieu","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Beaudet","given":"Marilou","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Ruel","given":"Jean Claude","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Hébert","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kneeshaw","given":"Daniel D.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-3","issue":"8","issued":{"date-parts":[["2018"]]},"page":"1-20","title":"Incorporating insect and wind disturbances in a natural disturbance-based management framework for the boreal forest","type":"article-journal","volume":"9"},"uris":[""]}],"mendeley":{"formattedCitation":"(Hytteborn and Verwijst 2014; De Grandpré et al. 2018; Hart and Kleinman 2018)","plainTextFormattedCitation":"(Hytteborn and Verwijst 2014; De Grandpré et al. 2018; Hart and Kleinman 2018)","previouslyFormattedCitation":"(Hytteborn and Verwijst 2014; De Grandpré et al. 2018; Hart and Kleinman 2018)"},"properties":{"noteIndex":0},"schema":""}(Hytteborn and Verwijst 2014; De Grandpré et al. 2018; Hart and Kleinman 2018) that may compete with understorey trees. We also observed little difference in species composition between the growth patterns, testifying to the similar behaviours of black spruce and balsam fir regeneration under moderate secondary disturbances. Our results therefore highlight that black spruce and balsam fir regeneration can significantly increase their growth after a secondary disturbance and rapidly fill the created gaps. Nonetheless, the time window for attaining the upper layers of the canopy is short, and trees unable to grow sufficiently fast are generally confined to the lower layers. In general, the dynamics observed in this study differ slightly from those identified in broadleaved or mixed temperate forests, where growth patterns can be more complex; for example, trees may access the canopy over several steps ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Lorimer","given":"Craig G.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Frelich","given":"Lee E.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canada Journal of Forest Research","id":"ITEM-1","issued":{"date-parts":[["1989"]]},"page":"651-663","title":"A methodology for estimating canopy disturbance frequency and intensity in dense temperate forests","type":"article-journal","volume":"19"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1890/0012-9615(1997)067[0225:RGACFR]2.0.CO;2","ISBN":"0012-9615","ISSN":"00129615","abstract":"A novel dendroecological procedure was developed to elucidate canopy disturbances spanning a >300-yr period for oak (Quercus) forests of central Pennsylvania. Running comparisons of sequential 10-yr ring-width averages may effectively neutralize both short-term (i.e., drought) and long-term growth trends associated with climate while enhancing detection of abrupt and sustained radial-growth increases characteristic of canopy disturbance. Thinning-response studies revealed the conservative tendencies of overstory oak, with substantial basal area reductions (>1/3) required to attain moderate and consistently detectable growth increases. Based on empirical evidence, a minimum growth-response threshold of 25% was established to depict canopy disturbances. This is in contrast to the 50-100% sustained radial-growth release often used to detect disturbance using understory trees in closed forests. Our default threshold was adjusted higher as necessary for those trees highly correlated to climatic trends (as represented by the Palmer drought severity index). Canopy disturbances detected with this dendroecological approach were further substantiated using tree-recruitment data (age cohorting). By coupling these data sets, we estimated return intervals of standwide disturbance from 21 yr in presettlement times (prior to 1775) and during heavy Euro-American exploitation (1775-1900) to 31 yr in modern times (after 1900). Although disturbance periodicity remained stable between presettlement and early post-settlement (exploitation) eras, the mode of disturbance shifted from mainly natural (wind and fire) to anthropogenic forces (intense harvesting for charcoal production), based on the historical record. In the process, presettlement oak-pine (Pinus)-chestnut (Castanea) forests on ridges were rapidly converted to young coppice stands of oak and chestnut. The reduction of harvesting and fire events coupled with the eradication of chestnut by blight this century have allowed these coppice stands to mature into oak-dominated forests that exist today. This analytical technique for ascertaining disturbance histories holds much potential and should be considered for use with mature, overstory trees in other forest types with appropriate modifications.","author":[{"dropping-particle":"","family":"Nowacki","given":"Gregory J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Abrams","given":"Marc D.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecological Monographs","id":"ITEM-2","issue":"2","issued":{"date-parts":[["1997"]]},"page":"225-249","title":"Radial-growth averaging criteria for reconstructing disturbance histories from presettlement-origin oaks","type":"article-journal","volume":"67"},"uris":[""]},{"id":"ITEM-3","itemData":{"ISBN":"9780521650823","author":[{"dropping-particle":"","family":"Frelich","given":"Lee E.","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-3","issued":{"date-parts":[["2002"]]},"number-of-pages":"266","publisher":"Cambridge University Press","publisher-place":"Cambridge, U.K.","title":"Forest Dynamics and Disturbance Regimes: Studies from Temperate Evergreen-Deciduous Forests","type":"book"},"uris":[""]}],"mendeley":{"formattedCitation":"(Lorimer and Frelich 1989; Nowacki and Abrams 1997; Frelich 2002)","plainTextFormattedCitation":"(Lorimer and Frelich 1989; Nowacki and Abrams 1997; Frelich 2002)","previouslyFormattedCitation":"(Lorimer and Frelich 1989; Nowacki and Abrams 1997; Frelich 2002)"},"properties":{"noteIndex":0},"schema":""}(Lorimer and Frelich 1989; Nowacki and Abrams 1997; Frelich 2002). Our results illustrate how moderate-severity disturbances are a once-in-a-lifetime opportunity for suppressed coniferous trees to access the top of the canopy in boreal old-growth forests.Recurrent moderate-severity disturbances are an intrinsic part of old-growth forest dynamicsThe impact of spruce budworm outbreaks on boreal landscapes is highly heterogeneous, ranging from the punctual death of isolated trees to the death of large and continuous forest areas ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Kneeshaw","given":"Daniel D.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Lauzon","given":"?ve","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"R?mer","given":"André","non-dropping-particle":"de","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Reyes","given":"Gerardo P.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Belle-Isle","given":"J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Messier","given":"J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecosystem management in the boreal forest","editor":[{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Vaillancourt","given":"Marie-Andrée","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Leduc","given":"Alain","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"De","family":"Grandpré","given":"Louis","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kneeshaw","given":"Daniel D.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Drapeau","given":"Pierre","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-1","issued":{"date-parts":[["2009"]]},"page":"235-260","publisher":"Presses de l’Université du Québec","publisher-place":"Québec","title":"Applying knowledge of natural disturbance regimes to develop forestry practices inspired by nature in the southern region of the Gaspé Peninsula","type":"chapter"},"uris":[""]},{"id":"ITEM-2","itemData":{"author":[{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Laprise","given":"Danielle","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Simon","given":"A.A.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Amouch","given":"S.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecosystem management in the boreal forest","editor":[{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Vaillancourt","given":"Marie-Andrée","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Leduc","given":"Alain","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"De","family":"Grandpré","given":"Louis","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kneeshaw","given":"Daniel D.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Drapeau","given":"Pierre","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-2","issued":{"date-parts":[["2009"]]},"page":"156-182","publisher":"Les Presses de l’Université du Québec","publisher-place":"Québec","title":"Spruce budworm outbreak regimes in in eastern North America","type":"chapter"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1007/s10021-018-0297-2","ISSN":"14350629","abstract":"Identifying the scales of variation in forest structures and the underlying processes are fundamental for understanding forest dynamics. Here, we studied these scale-dependencies in forest structure in naturally dynamic boreal forests on two continents. We identified the spatial scales at which forest structures varied, and analyzed how the scales of variation and the underlying drivers differed among the regions and at particular scales. We studied three 2 km × 2 km landscapes in northeastern Finland and two in eastern Canada. We estimated canopy cover in contiguous 0.1-ha cells from aerial photographs and used scale-derivative analysis to identify characteristic scales of variation in the canopy cover data. We analyzed the patterns of variation at these scales using Bayesian scale space analysis. We identified structural variation at three spatial scales in each landscape. Among landscapes, the largest scale of variation showed the greatest variability (20.1–321.4 ha), related to topography, soil variability, and long-term disturbance history. Superimposed on this large-scale variation, forest structure varied at similar scales (1.3–2.8 ha) in all landscapes. This variation correlated with recent disturbances, soil variability, and topographic position. We also detected intense variation at the smallest scale analyzed (0.1 ha, grain of our data), partly driven by recent disturbances. The distinct scales of variation indicated hierarchical structure in the landscapes studied. Except for the large-scale variation, these scales were remarkably similar among the landscapes. This suggests that boreal forests may display characteristic scales of variation that occur somewhat independent of the tree species characteristics or the disturbance regime.","author":[{"dropping-particle":"","family":"Kulha","given":"Niko","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Pasanen","given":"Leena","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Holmstr?m","given":"Lasse","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Grandpré","given":"Louis","non-dropping-particle":"De","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kuuluvainen","given":"Timo","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Aakala","given":"Tuomas","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecosystems","id":"ITEM-3","issue":"4","issued":{"date-parts":[["2019"]]},"page":"709-724","title":"At what scales and why does forest structure vary in naturally dynamic boreal forests? An analysis of forest landscapes on two continents","type":"article-journal","volume":"22"},"uris":[""]}],"mendeley":{"formattedCitation":"(Kneeshaw et al. 2009; Morin et al. 2009; Kulha et al. 2019)","plainTextFormattedCitation":"(Kneeshaw et al. 2009; Morin et al. 2009; Kulha et al. 2019)","previouslyFormattedCitation":"(Kneeshaw et al. 2009; Morin et al. 2009; Kulha et al. 2019)"},"properties":{"noteIndex":0},"schema":""}(Kneeshaw et al. 2009; Morin et al. 2009; Kulha et al. 2019). Hence, some regions are marked by significantly higher mortality rates than other areas for a given outbreak ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"","author":[{"dropping-particle":"","family":"Pureswaran","given":"Deepa S.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Grandpré","given":"Louis","non-dropping-particle":"De","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Paré","given":"David","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Taylor","given":"Anthony R.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Barrette","given":"Martin","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Régnière","given":"Jacques","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kneeshaw","given":"Daniel D.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecology","id":"ITEM-1","issued":{"date-parts":[["2015"]]},"page":"1480–1491","title":"Climate‐induced changes in host tree–insect phenology may drive ecological state‐shift in boreal forests","type":"article-journal","volume":"96"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.3389/FPLS.2018.01905","ISSN":"1664-462X","abstract":"In scenarios of future climate change, there is a projected increase in the occurrence and severity of natural disturbances in boreal forests. Spruce budworm (Choristoneura fumiferana) (SBW) is the main defoliator of conifer trees in the North American boreal forests affecting large areas and causing marked losses of timber supplies. However, the impact and the spatiotemporal patterns of SBW dynamics at the landscape scale over the last century remain poorly known. This is particularly true for northern regions dominated by spruce species. The main goal of this study is to reconstruct SBW outbreaks during the 20th century at the landscape scale and to evaluate changes in the associated spatiotemporal patterns in terms of distribution area, frequency, and severity. We rely on a dendroecological approach from sites within the eastern Canadian boreal forest and draw from a large dataset of almost 4 000 trees across a study area of nearly 800 000 km2. Interpolation and analyses of hotspots determined reductions in tree growth related to insect outbreak periods and identified the spatiotemporal patterns of SBW activity over the last century. We identified three insect outbreaks having different spatiotemporal patterns, duration, and severity. The first (1905–1930) affected up to 40% of the studied trees, initially synchronizing from local infestations and then migrating to northern stands. The second outbreak (1935–1965) was the longest and the least severe with only up to 30% of trees affected by SBW activity. The third event (1968–1988) was the shortest, yet it was also the most severe and extensive, affecting nearly up to 50% of trees and 70% of the study area. This most recent event was identified for the first time at the limit of the commercial forest illustrating a northward shift of the SBW distribution area during the 20th century. Overall, this research confirms that insect outbreaks are a complex and dynamic ecological phenomena, which makes the understanding of natural disturbance cycles at multiple scales a major priority especially in the context of future regional climate change.","author":[{"dropping-particle":"","family":"Navarro","given":"Lionel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Montoro Girona","given":"Miguel","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Frontiers in Plant Science","id":"ITEM-2","issue":"December","issued":{"date-parts":[["2018"]]},"page":"1905","title":"Changes in spatiotemporal patterns of 20th century spruce budworm outbreaks in eastern Canadian boreal forests","type":"article-journal","volume":"9"},"uris":[""]}],"mendeley":{"formattedCitation":"(Pureswaran et al. 2015; Navarro et al. 2018)","manualFormatting":"(Pureswaran et al., 2015; Navarro et al., 2018)","plainTextFormattedCitation":"(Pureswaran et al. 2015; Navarro et al. 2018)","previouslyFormattedCitation":"(Pureswaran et al. 2015; Navarro et al. 2018)"},"properties":{"noteIndex":0},"schema":""}(Pureswaran et al., 2015; Navarro et al., 2018). The three 20th-century spruce budworm outbreaks that occurred within the study territory are characterized by their severity ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Laprise","given":"Danielle","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canadian Journal of Forest Research","id":"ITEM-1","issued":{"date-parts":[["1990"]]},"page":"1-8","title":"Histoire récente des épidémies de la Tordeuse des bourgeons de l'épinette au nord du lac Saint-Jean (Québec) : une analyse dendrochronologique","type":"article-journal","volume":"20"},"uris":[""]},{"id":"ITEM-2","itemData":{"author":[{"dropping-particle":"","family":"Morin","given":"","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canadian Journal of Forest Research","id":"ITEM-2","issued":{"date-parts":[["1994"]]},"page":"730-741","title":"Dynamic of balsam fir forests in relation to spruce budworm outbreaks in the boreal zone of Québec","type":"article-journal","volume":"24"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.3389/FPLS.2018.01905","ISSN":"1664-462X","abstract":"In scenarios of future climate change, there is a projected increase in the occurrence and severity of natural disturbances in boreal forests. Spruce budworm (Choristoneura fumiferana) (SBW) is the main defoliator of conifer trees in the North American boreal forests affecting large areas and causing marked losses of timber supplies. However, the impact and the spatiotemporal patterns of SBW dynamics at the landscape scale over the last century remain poorly known. This is particularly true for northern regions dominated by spruce species. The main goal of this study is to reconstruct SBW outbreaks during the 20th century at the landscape scale and to evaluate changes in the associated spatiotemporal patterns in terms of distribution area, frequency, and severity. We rely on a dendroecological approach from sites within the eastern Canadian boreal forest and draw from a large dataset of almost 4 000 trees across a study area of nearly 800 000 km2. Interpolation and analyses of hotspots determined reductions in tree growth related to insect outbreak periods and identified the spatiotemporal patterns of SBW activity over the last century. We identified three insect outbreaks having different spatiotemporal patterns, duration, and severity. The first (1905–1930) affected up to 40% of the studied trees, initially synchronizing from local infestations and then migrating to northern stands. The second outbreak (1935–1965) was the longest and the least severe with only up to 30% of trees affected by SBW activity. The third event (1968–1988) was the shortest, yet it was also the most severe and extensive, affecting nearly up to 50% of trees and 70% of the study area. This most recent event was identified for the first time at the limit of the commercial forest illustrating a northward shift of the SBW distribution area during the 20th century. Overall, this research confirms that insect outbreaks are a complex and dynamic ecological phenomena, which makes the understanding of natural disturbance cycles at multiple scales a major priority especially in the context of future regional climate change.","author":[{"dropping-particle":"","family":"Navarro","given":"Lionel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Montoro Girona","given":"Miguel","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Frontiers in Plant Science","id":"ITEM-3","issue":"December","issued":{"date-parts":[["2018"]]},"page":"1905","title":"Changes in spatiotemporal patterns of 20th century spruce budworm outbreaks in eastern Canadian boreal forests","type":"article-journal","volume":"9"},"uris":[""]}],"mendeley":{"formattedCitation":"(Morin and Laprise 1990; Morin 1994; Navarro et al. 2018)","manualFormatting":"(Morin, 1994; Morin & Laprise, 1990; Navarro et al., 2018)","plainTextFormattedCitation":"(Morin and Laprise 1990; Morin 1994; Navarro et al. 2018)","previouslyFormattedCitation":"(Morin and Laprise 1990; Morin 1994; Navarro et al. 2018)"},"properties":{"noteIndex":0},"schema":""}(Morin, 1994; Morin & Laprise, 1990; Navarro et al., 2018), which produced recurrent and significant mortality in the study stands. The peaks in the percentage of trees undergoing release following these outbreaks ranged between 50% and 75% across the study territory, with 20% to 55% of the trees presenting major releases. In contrast, for the same outbreaks, old-growth forests situated approximately 150?km to the north experienced a percentage of trees in release between 20% and 40%, with 15% to 25% of these trees presenting a major release ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1007/s13595-019-0891-2","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Annals of Forest Science","id":"ITEM-1","issue":"108","issued":{"date-parts":[["2019"]]},"page":"1-16","title":"Secondary disturbances of low and moderate severity drive the dynamics of eastern Canadian boreal old-growth forests","type":"article-journal","volume":"76"},"uris":[""]}],"mendeley":{"formattedCitation":"(Martin et al. 2019)","plainTextFormattedCitation":"(Martin et al. 2019)","previouslyFormattedCitation":"(Martin et al. 2019)"},"properties":{"noteIndex":0},"schema":""}(Martin et al. 2019). ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1007/s13595-019-0891-2","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Annals of Forest Science","id":"ITEM-1","issue":"108","issued":{"date-parts":[["2019"]]},"page":"1-16","title":"Secondary disturbances of low and moderate severity drive the dynamics of eastern Canadian boreal old-growth forests","type":"article-journal","volume":"76"},"uris":[""]}],"mendeley":{"formattedCitation":"(Martin et al. 2019)","manualFormatting":"Martin et al. (2019)","plainTextFormattedCitation":"(Martin et al. 2019)","previouslyFormattedCitation":"(Martin et al. 2019)"},"properties":{"noteIndex":0},"schema":""}Martin et al. (2019) determined, therefore, that true old-growth forests in this territory were driven almost equally by low-severity and moderate-severity secondary disturbances. In contrast, spruce budworm outbreaks in our study territory were twice as severe as the outbreaks documented by ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1007/s13595-019-0891-2","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Annals of Forest Science","id":"ITEM-1","issue":"108","issued":{"date-parts":[["2019"]]},"page":"1-16","title":"Secondary disturbances of low and moderate severity drive the dynamics of eastern Canadian boreal old-growth forests","type":"article-journal","volume":"76"},"uris":[""]}],"mendeley":{"formattedCitation":"(Martin et al. 2019)","manualFormatting":"Martin et al. (2019)","plainTextFormattedCitation":"(Martin et al. 2019)","previouslyFormattedCitation":"(Martin et al. 2019)"},"properties":{"noteIndex":0},"schema":""}Martin et al. (2019), suggesting that all our study stands were driven primarily by secondary disturbances of moderate severity ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.3390/f9090579","ISSN":"19994907","abstract":"The classification of discrete forest disturbance events is usually based on the spatial extent, magnitude, and frequency of the disturbance. Based on these characteristics, disturbances are placed into one of three broad categories, gap-scale, intermediate-severity, or catastrophic disturbance, along the disturbance classification gradient. We contend that our understanding of disturbance processes near the endpoints of the disturbance classification gradient far exceeds that of intermediate-severity events. We hypothesize that intermediate-severity disturbances are more common, and that they are more important drivers of forest ecosystem change than is commonly recognized. Here, we provide a review of intermediate-severity disturbances that includes proposed criteria for categorizing disturbances on the classification gradient. We propose that the canopy opening diameter to height ratio (D:H) be used to delineate gap-scale from intermediate-severity events and that the threshold between intermediate and catastrophic events be based on the influence of residual trees on the composition of the regeneration layer. We also provide examples of intermediate-severity disturbance agents, return intervals for these events, and recommendations for incorporating natural intermediate-severity disturbance patterns in silvicultural systems.","author":[{"dropping-particle":"","family":"Hart","given":"Justin L.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kleinman","given":"Jonathan S.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-1","issue":"579","issued":{"date-parts":[["2018"]]},"title":"What are intermediate-severity forest disturbances and why are they important?","type":"article-journal","volume":"9"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1007/s13595-019-0891-2","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Annals of Forest Science","id":"ITEM-2","issue":"108","issued":{"date-parts":[["2019"]]},"page":"1-16","title":"Secondary disturbances of low and moderate severity drive the dynamics of eastern Canadian boreal old-growth forests","type":"article-journal","volume":"76"},"uris":[""]}],"mendeley":{"formattedCitation":"(Hart and Kleinman 2018; Martin et al. 2019)","plainTextFormattedCitation":"(Hart and Kleinman 2018; Martin et al. 2019)","previouslyFormattedCitation":"(Hart and Kleinman 2018; Martin et al. 2019)"},"properties":{"noteIndex":0},"schema":""}(Hart and Kleinman 2018; Martin et al. 2019). In some cases, recurrent and severe secondary disturbances may override stand resistance, thereby reinitiating forest succession ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1111/j.1654-1103.2011.01362.x","ISBN":"1100-9233","ISSN":"11009233","abstract":"Background: In forests subject to stand-replacing disturbances,\\nconventional models of succession typically overlook early-seral stages\\nas a simple re-organization/ establishment period. These models treat\\nstructural development in essentially `relay floristic' terms, with\\nstructural complexity (three-dimensional heterogeneity) developing\\nprimarily in old-growth stages, only after a closedcanopy `\\nself-thinning' phase and subsequent canopy gap formation. However, is it\\npossible that early-successional forests can sometimes exhibit spatial\\ncomplexity similar to that in old-growth forests -i. e. akin to an `\\ninitial floristic' model of structural development? Hypothesis: Based on\\nempirical observations, we present a hypothesis regarding an important\\nalternative pathway in which protracted or sparse forest establishment\\nand interspecific competition thin out tree densities early on -thereby\\nprecluding overstorey canopy closure or a traditionally defined\\nself-thinning phase. Although historically viewed as an impediment to\\nstand development, we suggest this process may actually advance certain\\nforms of structural complexity. These young stands can exhibit qualities\\ntypically attributed only to old forests, including: (1) canopy gaps\\nassociated with clumped and widely spaced tree stems; (2) vertically\\nheterogeneous canopies including under-and midstories, albeit lower\\nstature; (3) co-existence of shade-tolerant and intolerant species; and\\n(4) abundant dead wood. Moreover, some of these qualities may persist\\nthrough succession, meaning that a significant portion of eventual\\noldgrowth spatial patternmay already be determined in this early stage.\\nImplications: The relative frequency of this open-canopy pathway, and\\nthe degree to which precocious complexity supports functional complexity\\nanalogous to that of old forests, are largely unknown due to the paucity\\nof naturally regenerating forests in many regions. Nevertheless,\\nrecognition of this potential is important for the understanding and\\nmanagement of early-successional forests.","author":[{"dropping-particle":"","family":"Donato","given":"Daniel C.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Campbell","given":"John L.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Franklin","given":"Jerry F.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Journal of Vegetation Science","id":"ITEM-1","issue":"3","issued":{"date-parts":[["2012"]]},"page":"576-584","title":"Multiple successional pathways and precocity in forest development: Can some forests be born complex?","type":"article-journal","volume":"23"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.3390/f9080471","ISBN":"1999-4907","ISSN":"19994907","abstract":"<p>Natural disturbances are fundamental to forest ecosystem dynamics and have been used for two decades to improve forest management, notably in the boreal forest. Initially based on fire regimes, there is now a need to extend the concept to include other types of disturbances as they can greatly contribute to forest dynamics in some regions of the boreal zone. Here we review the main descriptors—that is, the severity, specificity, spatial and temporal descriptors and legacies, of windthrow and spruce bud worm outbreak disturbance regimes in boreal forests—in order to facilitate incorporating them into a natural disturbance-based forest management framework. We also describe the biological legacies that are generated by these disturbances. Temporal and spatial descriptors characterising both disturbance types are generally variable in time and space. This makes them difficult to reproduce in an ecosystem management framework. However, severity and specificity descriptors may provide a template upon which policies for maintaining post harvesting and salvage logging biological legacies can be based. In a context in which management mainly targets mature and old-growth stages, integrating insect and wind disturbances in a management framework is an important goal, as these disturbances contribute to creating heterogeneity in mature and old-growth forest characteristics.</p>","author":[{"dropping-particle":"","family":"Grandpré","given":"Louis","non-dropping-particle":"De","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Waldron","given":"Kaysandra","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bouchard","given":"Mathieu","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Beaudet","given":"Marilou","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Ruel","given":"Jean Claude","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Hébert","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kneeshaw","given":"Daniel D.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-2","issue":"8","issued":{"date-parts":[["2018"]]},"page":"1-20","title":"Incorporating insect and wind disturbances in a natural disturbance-based management framework for the boreal forest","type":"article-journal","volume":"9"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1016/j.foreco.2017.07.051","ISSN":"03781127","abstract":"Mixed-severity disturbance regimes are prevalent in temperate forests worldwide, but key uncertainties remain regarding the variability of disturbance-mediated structural development pathways. This study investigates the influence of disturbance history on current structure in primary, unmanaged Norway spruce (Picea abies) forests throughout the Carpathian Mountains of central and eastern Europe, where windstorms and native bark beetle outbreaks are the dominant natural disturbances. We inventoried forest structure on 453 plots (0.1 ha) spanning a large geographical gradient (>1,000 km), coring 15–25 canopy trees per plot for disturbance history reconstruction (tree core total n = 11,309). Our specific objectives were to: (1) classify sub-hectare-scale disturbance history based on disturbance timing and severity; (2) classify current forest structure based on tree size distributions (live, dead, standing, downed); (3) characterize structural development pathways as revealed by the association between disturbance history and current forest structural complexity. We used hierarchical cluster analysis for the first two objectives and indicator analysis for the third. The disturbance-based cluster analysis yielded six groups associated with three levels of disturbance severity (low, moderate, and high canopy loss) and two levels of timing (old, recent) over the past 200 years. The structure-based cluster analysis yielded three groups along a gradient of increasing structural complexity. A large majority of plots exhibited relatively high (53%) or very high (26%) structural complexity, indicated by abundant large live trees, standing and downed dead trees, and spruce regeneration. Consistent with conventional models of structural development, some disturbance history groups were associated with specific structural complexity groups, particularly low-severity/recent (very high complexity) and high-severity/recent (moderate complexity) disturbances. In other cases, however, the distribution of plots among disturbance history and structural complexity groups indicated either divergent or convergent pathways. For example, multiple disturbance history groups were significantly associated with the high complexity group, demonstrating structural convergence. These results illustrate that complex forest structure – including features nominally associated with old-growth – can be associated as much with disturbance severity as it is with conventional notions of fores…","author":[{"dropping-particle":"","family":"Meigs","given":"Garrett W.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morrissey","given":"Robert C.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Ba?e","given":"Radek","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Chaskovskyy","given":"Oleh","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"?ada","given":"Vojtěch","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Després","given":"Tiphaine","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Donato","given":"Daniel C.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Janda","given":"Pavel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Lábusová","given":"Jana","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Seedre","given":"Meelis","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Mikolá?","given":"Martin","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Nagel","given":"Thomas A.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Schurman","given":"Jonathan S.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Synek","given":"Michal","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Teodosiu","given":"Marius","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Trotsiuk","given":"Volodymyr","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Vítková","given":"Lucie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Svoboda","given":"Miroslav","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-3","issue":"May","issued":{"date-parts":[["2017"]]},"page":"410-426","title":"More ways than one: Mixed-severity disturbance regimes foster structural complexity via multiple developmental pathways","type":"article-journal","volume":"406"},"uris":[""]}],"mendeley":{"formattedCitation":"(Donato et al. 2012; Meigs et al. 2017; De Grandpré et al. 2018)","plainTextFormattedCitation":"(Donato et al. 2012; Meigs et al. 2017; De Grandpré et al. 2018)","previouslyFormattedCitation":"(Donato et al. 2012; Meigs et al. 2017; De Grandpré et al. 2018)"},"properties":{"noteIndex":0},"schema":""}(Donato et al. 2012; Meigs et al. 2017; De Grandpré et al. 2018). Yet, the structural attributes of the study stands matched those observed in other boreal old-growth forests in eastern Canada ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1016/j.foreco.2004.11.008","ISBN":"0378-1127","ISSN":"03781127","abstract":"We investigated stand development along a chronosequence on organic, clay and sand sites in black spruce boreal forest in northwestern Quebec, Canada. Our objectives were: (1) to describe trends and stages of structural development following fire; (2) to compare trends and stages of development both in isolation from and in conjunction with species replacement. We tested the hypothesis that although trends in structural development are similar among site types, productivity and composition affect the timing of developmental stages. Data on live trees, snags and logs were collected at 91 sites. Trends with time since fire were analyzed using segmented piecewise linear regression. On organic sites, tree basal area and density increased continuously with time since fire, while deadwood abundance decreased and then increased. Live tree basal area, tree density and deadwood abundance generally followed expected S-, N- and U-shaped trends, respectively, on clay sites, but often with decreases in later stages due to paludification. Fewer trends were significant on sand sites, although tree basal area decreased likely due to a change in species composition. Older forests on all site types were more structurally diverse. To estimate the timing of the stages of structural development, we introduce a new analysis technique which uses the breakpoints of the piecewise regressions. On organic sites, only three stages of stand development were evident, whereas a four-stage stand development model was appropriate for both clay and sand sites. We found that local conditions affected not only the timing of developmental stages, but also the number of stages and the trends themselves. We attributed these differences to changes in species composition and productivity. We refine the theory of structural development by representing patterns in both live and deadwood as two-stage trends with two possible outcomes for each stage. Our new method of determining the timing of the developmental stages using empirical data can be used to develop management practices that emulate structural development in order to conserve biodiversity on a landscape scale. ? 2004 Elsevier B.V. All rights reserved.","author":[{"dropping-particle":"","family":"Harper","given":"Karen A.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Drapeau","given":"Pierre","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Grandpré","given":"Louis","non-dropping-particle":"De","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-1","issued":{"date-parts":[["2005"]]},"page":"293-306","title":"Structural development following fire in black spruce boreal forest","type":"article-journal","volume":"206"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1016/j.foreco.2018.04.007","ISSN":"03781127","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-2","issue":"April","issued":{"date-parts":[["2018"]]},"page":"125-136","publisher":"Elsevier","title":"Structural diversity and dynamics of boreal old-growth forests case study in Eastern Canada","type":"article-journal","volume":"422"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1016/j.ecolind.2018.09.059","ISSN":"1470160X","abstract":"In managed boreal forests, partial harvesting has been proposed to promote forest structural complexity and to therefore maintain associated biodiversity. However, there have been few studies identifying forest structures that should be maintained within the forest matrix, and fewer still on changes in these structures during succession. Consequently, there is no tool to identify these different structures in the field or their sequence along natural succession. This study proposes a key that can be used in the field and allows for the identification of different forest diameter structures along a successional sequence in the black spruce boreal forest. The specific objectives of this study were (1) to classify the types of forest structures encountered in natural black spruce boreal forest based on their diameter distribution, and (2) to link this classification to time since last fire and its spatial homogeneity at the stand level. This study shows that the forest stand structure, in black spruce forests, is varied and that this structural variety is mainly controlled by time since last fire. It also shows that the timing of stand structural maturation varies with severity of the last fire and surficial deposit. The identification key suggests that based on tree diameter distribution it is possible to discriminate among young, mature and old forest structures, which could help forest managers select stands to be harvested according to different objectives and hence maintain the variety of black spruce forest structures at the landscape scale.","author":[{"dropping-particle":"","family":"Moussaoui","given":"Louiza","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Leduc","given":"Alain","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Lafleur","given":"Benoit","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecological Indicators","id":"ITEM-3","issue":"October 2018","issued":{"date-parts":[["2019"]]},"page":"89-99","publisher":"Elsevier","title":"Changes in forest structure along a chronosequence in the black spruce boreal forest: Identifying structures to be reproduced through silvicultural practices","type":"article-journal","volume":"97"},"uris":[""]}],"mendeley":{"formattedCitation":"(Harper et al. 2005; Martin et al. 2018; Moussaoui et al. 2019)","plainTextFormattedCitation":"(Harper et al. 2005; Martin et al. 2018; Moussaoui et al. 2019)","previouslyFormattedCitation":"(Harper et al. 2005; Martin et al. 2018; Moussaoui et al. 2019)"},"properties":{"noteIndex":0},"schema":""}(Harper et al. 2005; Martin et al. 2018; Moussaoui et al. 2019). This implies that the forests observed in this study maintained an old-growth structure despite the presence of a stressful disturbance regime. Approximately 30 years separated the outbreaks, a period that corresponds to the dynamics and periodicity of this insect in eastern Canada ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Laprise","given":"Danielle","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Simon","given":"A.A.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Amouch","given":"S.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecosystem management in the boreal forest","editor":[{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Vaillancourt","given":"Marie-Andrée","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Leduc","given":"Alain","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"De","family":"Grandpré","given":"Louis","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kneeshaw","given":"Daniel D.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Drapeau","given":"Pierre","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-1","issued":{"date-parts":[["2009"]]},"page":"156-182","publisher":"Les Presses de l’Université du Québec","publisher-place":"Québec","title":"Spruce budworm outbreak regimes in in eastern North America","type":"chapter"},"uris":[""]}],"mendeley":{"formattedCitation":"(Morin et al. 2009)","plainTextFormattedCitation":"(Morin et al. 2009)","previouslyFormattedCitation":"(Morin et al. 2009)"},"properties":{"noteIndex":0},"schema":""}(Morin et al. 2009). Therefore, it suggests that boreal forests in this region are sufficiently resistant to recurrent, moderate-severity disturbances if these events are sufficiently spaced apart in plex disturbance and growth processes produced simple vertical structuresCodominant and dominant trees were generally the most common layers in the canopy of the study stands, although the density of saplings was often high. A vertical structure characterized by a majority of dominant and codominant trees is expected in even-aged forests, whereas old-growth forests should normally be defined by a complex, multi-layered vertical structure ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Oliver","given":"C. D.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Larson","given":"B. C.","non-dropping-particle":"","parse-names":false,"suffix":""}],"edition":"4th","id":"ITEM-1","issued":{"date-parts":[["1996"]]},"number-of-pages":"520","publisher":"John Wiley & Sons, Inc.","publisher-place":"New York","title":"Forest Stand Dynamics","type":"book"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1016/S0378-1127(01)00575-8","ISBN":"0378-1127","ISSN":"03781127","abstract":"Forest managers need a comprehensive scientific understanding of natural stand development processes when designing silvicultural systems that integrate ecological and economic objectives, including a better appreciation of the nature of disturbance regimes and the biological legacies, such as live trees, snags, and logs, that they leave behind. Most conceptual forest development models do not incorporate current knowledge of the: (1) complexity of structures (including spatial patterns) and developmental processes; (2) duration of development in long-lived forests; (3) complex spatial patterns of stands that develop in later stages of seres; and particularly (4) the role of disturbances in creating structural legacies that become key elements of the post-disturbance stands, We elaborate on existing models for stand structural development using natural stand development of the Douglas-fir-western hemlock sere in the Pacific Northwest as our primary example; most of the principles are broadly applicable while some processes (e.g. role of epicormic branches) are related to specific species. We discuss the use of principles from disturbance ecology and natural stand development to create silvicultural approaches that are more aligned with natural processes. Such approaches provide for a greater abundance of standing dead and down wood and large old trees, perhaps reducing short-term commercial productivity but ultimately enhancing wildlife habitat, biodiversity, and ecosystem function, including soil protection and nutrient retention. (C) 2002 Elsevier Science B.V All rights reserved.","author":[{"dropping-particle":"","family":"Franklin","given":"Jerry F","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Spies","given":"Thomas A","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"Van","family":"Pelt","given":"Robert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Carey","given":"Andrew B","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Thornburgh","given":"Dale A","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Berg","given":"Dean Rae","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Lindenmayer","given":"David B","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Harmon","given":"Mark E","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Shaw","given":"David C","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bible","given":"Ken","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Chen","given":"Jiquan","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-2","issued":{"date-parts":[["2002"]]},"page":"399-423","title":"Disturbances and structural development of natural forest ecosystems with silvicultural implications, using Douglas-fir forests as an example","type":"article-journal","volume":"155"},"uris":[""]}],"mendeley":{"formattedCitation":"(Oliver and Larson 1996; Franklin et al. 2002)","plainTextFormattedCitation":"(Oliver and Larson 1996; Franklin et al. 2002)","previouslyFormattedCitation":"(Oliver and Larson 1996; Franklin et al. 2002)"},"properties":{"noteIndex":0},"schema":""}(Oliver and Larson 1996; Franklin et al. 2002). Our results showing a simpler vertical structure matched those of ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"dx.10.1139/cjfr-2019-0177","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canadian Journal of Forest Research","id":"ITEM-1","issued":{"date-parts":[["2020"]]},"page":"155-169","title":"Boreal old-growth forest structural diversity challenges aerial photographic survey accuracy","type":"article-journal","volume":"50"},"uris":[""]}],"mendeley":{"formattedCitation":"(Martin, Fenton, et al. 2020)","manualFormatting":"Martin, Fenton, & Morin (2020)","plainTextFormattedCitation":"(Martin, Fenton, et al. 2020)","previouslyFormattedCitation":"(Martin, Fenton, et al. 2020)"},"properties":{"noteIndex":0},"schema":""}Martin et al. (2020c), which showed that the vertical structure of dense black spruce?dominated old-growth forests was often similar to that of even-aged stands.A factor that may explain this counterintuitive result is the low height of boreal stands, which limits the development of complex, stratified vertical structures, such as those observed in temperate and tropical forests ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Harper","given":"Karen A.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Old-growth forests: function, fate and value","edition":"Ecological","editor":[{"dropping-particle":"","family":"Wirth","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gleixner","given":"Gerd","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Heimann","given":"Martin","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-1","issued":{"date-parts":[["2009"]]},"page":"285-300","publisher":"Springer","publisher-place":"New York","title":"Old-growth forests in the Canadian boreal: the exception rather than the rule?","type":"chapter"},"uris":[""]}],"mendeley":{"formattedCitation":"(Bergeron and Harper 2009)","plainTextFormattedCitation":"(Bergeron and Harper 2009)","previouslyFormattedCitation":"(Bergeron and Harper 2009)"},"properties":{"noteIndex":0},"schema":""}(Bergeron and Harper 2009). In addition, the government of Québec established the height threshold between regeneration and canopy layers at 7 m for Québec ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"ISBN":"9782550738572","author":[{"dropping-particle":"","family":"[MRNF] Ministère des Ressources Naturelles et de la Faune du Québec","given":"","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-1","issued":{"date-parts":[["2008"]]},"number-of-pages":"101","publisher":"Direction des inventaires forestiers","publisher-place":"Québec","title":"Norme de stratification écoforestière. Quatrième inventaire forestier","type":"report"},"uris":[""]}],"mendeley":{"formattedCitation":"([MRNF] Ministère des Ressources Naturelles et de la Faune du Québec 2008)","manualFormatting":"(MRNF, 2008)","plainTextFormattedCitation":"([MRNF] Ministère des Ressources Naturelles et de la Faune du Québec 2008)","previouslyFormattedCitation":"([MRNF] Ministère des Ressources Naturelles et de la Faune du Québec 2008)"},"properties":{"noteIndex":0},"schema":""}(MRNF, 2008). The dominant height of the study stands varied, however, between 13 and 18?m, implying that suppressed trees had maximum heights ranging between 6.5 and 9?m. It is therefore likely that trees below this height threshold were generally too small to be considered as merchantable trees (i.e., DBH ≥9?cm) and were therefore classified as regeneration (saplings). Because of the low height and small diameter of boreal trees, the thresholds used to define the different layers may overrepresent codominant trees. In contrast, most suppressed trees are ignored because they do not attain a sufficient height and/or DBH.Moreover, black spruce regenerates mainly through layering in old-growth forests ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1016/S0378-1127(01)00573-4","ISBN":"0378-1127","ISSN":"03781127","abstract":"Forest ecosystem management, based partly on a greater understanding of natural disturbance regimes, has many variations but is generally considered the most promising approach to accommodating biodiversity concerns in managed forested regions. Using the Lake Duparquet Forest in the southeastern Canadian boreal forest as an example, we demonstrate an approach that attempts to integrate forest and stand-level scales in biodiversity maintenance. The concept of cohorts is used to integrate stand age, composition and structure into broad successional or stand development phases. Mean forest age (MFA), because it partly incorporates historic variability of the regional fire cycle, is used as a target fire cycle. At the landscape level, forest composition and cohort objectives are derived from regional natural disturbance history, ecosystem classification, stand dynamics and a negative exponential age distribution based on a 140 year fire cycle. The resulting multi-cohort structure provides a framework for maintaining the landscape in a semi-natural age structure and composition. At the stand level, the approach relies on diversifying interventions, using both even-aged and uneven-aged silviculture to reflect natural stand dynamics, control the passage (\"fluxes\") between forest types of different cohorts and maintain forest-level objectives. Partial and selective harvesting is intended to create the structural and compositional characteristics of mid- to late-successional forest types and, as such, offers an alternative to increasing rotation lengths to maintain ecosystem diversity associated with overmature and old-growth forests. The approach does not however supplant the necessity for complementary strategies for maintaining biodiversity such as the creation of reserves to protect rare, old or simply natural ecosystems. The emphasis on maintaining the cohort structure and forest type diversity contrasts significantly with current even-aged management in the Canadian boreal forest and has implications for stand-level interventions, notably in necessitating a greater diversification of silvicultural practices including more uneven-aged harvesting regimes. The approach also presents a number of operational challenges and potentially higher risks associated with multiply stand entries, partial cutting and longer intervals between final harvests. There is a need for translating the conceptual model into a more quantitative silvicultural framework. Silvicultural…","author":[{"dropping-particle":"","family":"Harvey","given":"Brian D.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Leduc","given":"Alain","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-1","issue":"1-3","issued":{"date-parts":[["2002"]]},"page":"369-385","title":"Stand-landscape integration in natural disturbance-based management of the southern boreal forest","type":"article-journal","volume":"155"},"uris":[""]}],"mendeley":{"formattedCitation":"(Harvey et al. 2002)","plainTextFormattedCitation":"(Harvey et al. 2002)","previouslyFormattedCitation":"(Harvey et al. 2002)"},"properties":{"noteIndex":0},"schema":""}(Harvey et al. 2002). ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1371/journal.pone.0230221","ISBN":"1111111111","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Montoro Girona","given":"Miguel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"PLoS ONE","id":"ITEM-1","issued":{"date-parts":[["2020"]]},"page":"1-27","title":"Driving factors of conifer regeneration dynamics in eastern Canadian boreal old-growth forests","type":"article-journal"},"uris":[""]}],"mendeley":{"formattedCitation":"(Martin, Montoro Girona, et al. 2020)","manualFormatting":"Martin et al. (2020d)","plainTextFormattedCitation":"(Martin, Montoro Girona, et al. 2020)","previouslyFormattedCitation":"(Martin, Montoro Girona, et al. 2020)"},"properties":{"noteIndex":0},"schema":""}Martin et al. (2020d) hypothesized that these layers are under the hormonal control of the mother tree; the process of apical dominance can inhibit layers vertical growth because they are still partially connected to the mother tree as branches. Therefore, the death of the mother tree is often required for layers to increase their vertical growth. Similarly to black spruce, balsam fir can regenerate by layers in old-growth forests ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"V.","family":"Bakuzis","given":"E.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Hansen","given":"H. L.","non-dropping-particle":"","parse-names":false,"suffix":""}],"id":"ITEM-1","issued":{"date-parts":[["1965"]]},"number-of-pages":"468","publisher":"University of Minnesota Press","publisher-place":"Minneapolis, MN","title":"Balsam Fir, Abies balsamea (Linnaeus) miller: A monographic review","type":"book"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1080/11956860.1997.11682413","ISSN":"11956860","abstract":"A regional assessment of balsam fir distribution along a transect between 49° 30′ N and 53° 30′ N suggests that balsam fir exists as isolated populations scattered across large expanses of Québec's boreal forest. At its northern limit, balsam fir is primarily associated with environments that have a low fire frequency, such as the coastal lands along James Bay and the shores of major hinterland water bodies. Detailed mapping of balsam fir populations, stratigraphical study of supporting organic soils, and age-structure data of forest stands around Duncan Lake (53° 30? N, 78° w) constituted the core of the local analysis of balsam fir ecology at its northern limit. The presence of macrofossils in a representative organic soil profile of the spruce-fir forests of the Duncan Lake area suggests that balsam fir is present in the region since 3830 years BP. Its scarcity in the peat profile indicates a low population density during much of the site history. Age-structure analysis indicates the four spruce-fir forests studied in the Duncan Lake area are old-growth, dating back to at least the 17th or 18th centuries. Balsam fir behaves like a late successional species, appearing 100-150 years after black spruce in each site. Layering started during the 19th century, and became the principal means of regeneration for both species during the 20th century. The correlation between age frequency distribution and negative exponential model estimates ranges from 0.57-0.93 for balsam fir, and 0.93-0.95 for black spruce. The distribution of residuals along the regression slope suggests a period of low black spruce recruitment between ca 1860-1930; this was followed by a sharp increase until ca 1970. Balsam fir followed a similar, though delayed, pattern. The results suggest that marginal spruce-fir communities in the Duncan Lake area have experienced accelerated layering during the 20th century. Because few dead fir trees were found in the field, this may represent a long-term increase in fir population densities. Increased snow fall since the turn of the century may have favoured the growth of Sphagnum and the rooting of basal branches; this has resulted in a continuous increase in population density.","author":[{"dropping-particle":"","family":"Sirois","given":"Luc","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecoscience","id":"ITEM-2","issue":"3","issued":{"date-parts":[["1997"]]},"page":"340-352","title":"Distribution and dynamics of balsam fir (Abies balsamea [L.] Mill.) at its northern limit in the James Bay area","type":"article-journal","volume":"4"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1016/j.dendro.2005.12.001","ISSN":"11257865","abstract":"After a disturbance, balsam fir stands (Abies balsamea (L.) Mill.) regenerate primarily by seedlings, but layering is also known to occur and to contribute to the subsequent population base. We examined in detail the lower part of one balsam fir stem, stump and roots in order to: reconstruct the establishment of one mature balsam fir with evidence of layer-origin. The life history of this tree was then reconstructed by measuring tree-ring widths, dating all the sections, and by identifying the presence or absence of pith to differentiate between stem and root structures. We located a pith structure in this tree 51 cm below ground level. This lowest section with pith was characterized by a diameter of only 3 mm and contained 40 concentric tree-rings, suggesting that it originated from a branch. Radial and height growth measured were small until the beginning of 1930s. This period was abruptly followed by an increase in growth in both height and diameter as well as a massive production of adventitious roots, probably produced by partial harvesting of the parent tree/stand. ? 2005 Elsevier GmbH. All rights reserved.","author":[{"dropping-particle":"","family":"Krause","given":"Cornelia","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Dendrochronologia","id":"ITEM-3","issue":"3","issued":{"date-parts":[["2006"]]},"page":"139-143","title":"Growth development of a balsam fir (Abies balsamea (L.) Mill.) originating from layering","type":"article-journal","volume":"23"},"uris":[""]}],"mendeley":{"formattedCitation":"(Bakuzis and Hansen 1965; Sirois 1997; Krause 2006)","plainTextFormattedCitation":"(Bakuzis and Hansen 1965; Sirois 1997; Krause 2006)","previouslyFormattedCitation":"(Bakuzis and Hansen 1965; Sirois 1997; Krause 2006)"},"properties":{"noteIndex":0},"schema":""}(Bakuzis and Hansen 1965; Sirois 1997; Krause 2006), suggesting, a priori, similar dynamics. Knowledge related to the importance of layering in balsam fir regeneration remains fragmentary and requires further research. Balsam fir also regenerates by seed under its own cover ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1139/x98-112","ISBN":"0045-5067","ISSN":"0045-5067","PMID":"2769","abstract":"In this review, we focus on the biotic parameters that are crucial to an understanding of the recruitment dynamics of North American boreal tree species following natural (fire, budworm infestation, windthrow) or humaninduced (clearcut, partial cut) disturbances. The parameters we emphasize are (i) the production of seeds and asexual stems (both of which, we argue, are a function of basal area density), (ii) the dispersal of seeds by wind (or the dispersion of asexual stems) as a function of distance from source, (iii) dormant seed bank capacity, (iv) organic layer depth as a determinant of germinant mortality and asexual bud response, and (v) shade tolerance as a partial arbiter of the density of advanced regeneration. Having identified the gaps in our knowledge, we conclude by suggesting a shortterm research agenda whose completion would lead to the parameterized functions that would constitute the recruitment subroutine in a landscape-scale forest dynamics simulator.","author":[{"dropping-particle":"","family":"Greene","given":"D F","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Zasada","given":"J C","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Sirois","given":"L","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kneeshaw","given":"Daniel D.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Charron","given":"I","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Simard","given":"M -J","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canadian Journal of Forest Research","id":"ITEM-1","issue":"6","issued":{"date-parts":[["1999"]]},"page":"824-839","title":"A review of the regeneration dynamics of North American boreal forest tree species","type":"article-journal","volume":"29"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1016/S0378-1127(01)00573-4","ISBN":"0378-1127","ISSN":"03781127","abstract":"Forest ecosystem management, based partly on a greater understanding of natural disturbance regimes, has many variations but is generally considered the most promising approach to accommodating biodiversity concerns in managed forested regions. Using the Lake Duparquet Forest in the southeastern Canadian boreal forest as an example, we demonstrate an approach that attempts to integrate forest and stand-level scales in biodiversity maintenance. The concept of cohorts is used to integrate stand age, composition and structure into broad successional or stand development phases. Mean forest age (MFA), because it partly incorporates historic variability of the regional fire cycle, is used as a target fire cycle. At the landscape level, forest composition and cohort objectives are derived from regional natural disturbance history, ecosystem classification, stand dynamics and a negative exponential age distribution based on a 140 year fire cycle. The resulting multi-cohort structure provides a framework for maintaining the landscape in a semi-natural age structure and composition. At the stand level, the approach relies on diversifying interventions, using both even-aged and uneven-aged silviculture to reflect natural stand dynamics, control the passage (\"fluxes\") between forest types of different cohorts and maintain forest-level objectives. Partial and selective harvesting is intended to create the structural and compositional characteristics of mid- to late-successional forest types and, as such, offers an alternative to increasing rotation lengths to maintain ecosystem diversity associated with overmature and old-growth forests. The approach does not however supplant the necessity for complementary strategies for maintaining biodiversity such as the creation of reserves to protect rare, old or simply natural ecosystems. The emphasis on maintaining the cohort structure and forest type diversity contrasts significantly with current even-aged management in the Canadian boreal forest and has implications for stand-level interventions, notably in necessitating a greater diversification of silvicultural practices including more uneven-aged harvesting regimes. The approach also presents a number of operational challenges and potentially higher risks associated with multiply stand entries, partial cutting and longer intervals between final harvests. There is a need for translating the conceptual model into a more quantitative silvicultural framework. Silvicultural…","author":[{"dropping-particle":"","family":"Harvey","given":"Brian D.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Leduc","given":"Alain","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bergeron","given":"Yves","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-2","issue":"1-3","issued":{"date-parts":[["2002"]]},"page":"369-385","title":"Stand-landscape integration in natural disturbance-based management of the southern boreal forest","type":"article-journal","volume":"155"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.3732/ajb.1200267","ISBN":"4185455011","ISSN":"00029122","abstract":"Premise of the study: In ecosystems where seed production is low and masting years are sporadic, or with species that have short-lived seeds, regeneration is assured by seedling banks rather than seed banks. Seedling establishment and survival play a critical role in determining the composition of these plant communities by supplying new individuals for their maintenance. Seedling emergence and mortality were investigated to test the hypothesis that recruitment into the seedling bank is periodic. Materials and methods: Seed production and seedling emergence and survival was monitored during 1994-2007 in balsam fir (Abies balsamea) and white spruce (Picea glauca) in four pristine stands of the boreal forest of Quebec, Canada. Measurements were collected twice per month by sampling one permanent plot of 20 × 20 m per stand. Key results: Seed-rain abundance reached 9 × 103 seeds m-2 year-1, and was characterized by synchronous sequences of low and high seed production. New seedlings appeared only during the year following a seed production of at least 1 × 103 and 1.5 × 102 seeds m-2 year-1 for balsam fir and white spruce, respectively. Seedlings emerged in July and survived 34-52 d on average, with balsam fir showing a longer lifespan and lower mortality, although 85-99% of seedlings died before completing one year of life. Conclusions: The emergence of young seedlings was coupled with massive seed rains, which allowed synchronous replenishment of the seedling banks among stands and species, and generated different cohorts, yielding a discontinuous age structure. ? 2012 Botanical Society of America.","author":[{"dropping-particle":"","family":"Rossi","given":"Sergio","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gionest","given":"Fran?ois","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Laprise","given":"Danielle","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"American Journal of Botany","id":"ITEM-3","issue":"12","issued":{"date-parts":[["2012"]]},"page":"1942-1950","title":"Episodic recruitment of the seedling banks in balsam fir and white spruce","type":"article-journal","volume":"99"},"uris":[""]}],"mendeley":{"formattedCitation":"(Greene et al. 1999; Harvey et al. 2002; Rossi et al. 2012)","plainTextFormattedCitation":"(Greene et al. 1999; Harvey et al. 2002; Rossi et al. 2012)","previouslyFormattedCitation":"(Greene et al. 1999; Harvey et al. 2002; Rossi et al. 2012)"},"properties":{"noteIndex":0},"schema":""}(Greene et al. 1999; Harvey et al. 2002; Rossi et al. 2012). Balsam fir seedlings can remain suppressed for decades ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"ISSN":"00157546","author":[{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gagnon","given":"Réjean","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forestry Chronicle","id":"ITEM-1","issue":"3","issued":{"date-parts":[["1991"]]},"page":"275-283","title":"Structure et croissance de peuplements d'epinette noire issus de regeneration preetablie, une quarantaine d'annees apres coupe au Lac Saint-Jean, Quebec","type":"article-journal","volume":"67"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1139/x99-231","ISSN":"00455067","abstract":"The age structure of balsam fir (Abies balsamea (L.) Mill.) regeneration is frequently used to investigate boreal forest dynamics of North America. Tree ages are usually estimated by counting annual growth rings at the shoot-root interface located above or close to the root system. Inaccurately locating the shoot-root interface could lead to imprecise age determination. In this study, balsam fir seedlings (<2 m height) were harvested in whole from closed forest stands located in the province of Quebec, Canada. Seedling age was determined by (i) counting the number of annual growth rings at the presumed shoot-root interface, and (ii) counting all terminal bud scars from the apex to the base of the hypocotyl (true collar). For all seedlings with adventitious roots, the number of terminal bud scars on the entire trunk was higher than the number of growth rings at the shoot-root interface. The formation of adventitious roots on the belowground trunk was accompanied by a reverse taper phenomenon, i.e., the number of annual growth rings decreased from the presumed shoot-root interface to the true collar. Counting annual growth rings at any level on the trunk of balsam fir seedlings that form adventitious root systems would not be reliable, underestimation's exceeding 20 years are possible and the resulting age structures could lead to erroneous interpretations of regeneration dynamics.","author":[{"dropping-particle":"","family":"Parent","given":"Sylvain","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Messier","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canadian Journal of Forest Research","id":"ITEM-2","issue":"3","issued":{"date-parts":[["2000"]]},"page":"513-518","title":"Effects of adventitious roots on age determination in Balsam fir (Abies balsamea) regeneration","type":"article-journal","volume":"30"},"uris":[""]},{"id":"ITEM-3","itemData":{"author":[{"dropping-particle":"","family":"McCarthy","given":"John W.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Weetman","given":"Gordon","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Silva Fennica","id":"ITEM-3","issue":"2","issued":{"date-parts":[["2006"]]},"page":"209-230","title":"Age and size structure of gap-dynamic , old-growth boreal forest stands in Newfoundland","type":"article-journal","volume":"40"},"uris":[""]}],"mendeley":{"formattedCitation":"(Morin and Gagnon 1991; Parent et al. 2000; McCarthy and Weetman 2006)","plainTextFormattedCitation":"(Morin and Gagnon 1991; Parent et al. 2000; McCarthy and Weetman 2006)","previouslyFormattedCitation":"(Morin and Gagnon 1991; Parent et al. 2000; McCarthy and Weetman 2006)"},"properties":{"noteIndex":0},"schema":""}(Morin and Gagnon 1991; Parent et al. 2000; McCarthy and Weetman 2006), and their growth rapidly increases only once a gap is created in the canopy ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Morin","given":"","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canadian Journal of Forest Research","id":"ITEM-1","issued":{"date-parts":[["1994"]]},"page":"730-741","title":"Dynamic of balsam fir forests in relation to spruce budworm outbreaks in the boreal zone of Québec","type":"article-journal","volume":"24"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1139/cjfr-2014-0444","ISSN":"0045-5067","abstract":"Forest management regimes increasingly focus on the emulation of natural disturbance events, e.g., fire or insect outbreaks, to help increase ecosystem sustainability. We determined the residual stand response to a variable retention harvest inspired by spruce budworm (Choristoneura fumiferana (Clemens)) outbreaks in New Brunswick, Canada. Our objectives were to analyze the differences between surviving residual trees and those that succumbed towindthrow andtoquantify growth release. The treatment was based on harvesting the estimated spruce budworm outbreak mortality, i.e., 90% of mature balsam fir (Abies balsamea (L.) Mill., 60% of mature spruce (Picea spp.), and no hardwoods. Windthrow increased with the proportion of trees harvested and averaged 52% over 7–9 years in these stands with high balsam fir – spruce content. One-third of 42 harvested plots sustained >30% windthrow, whereas 73% of 11 similar unharvested plots had <10% windthrow. Balsam fir had higher windthrow than spruce at 53% and 41%, respectively. Windthrown balsam fir trees had significantly larger diameters at breast height (DBH, 1.3 m), larger heights, and smaller crown ratios than surviving residual trees. Substantial growth release occurred, with DBH increment of residual trees 48%–64% greater than trees in unharvested plots. Balsam fir and intolerant hardwoods exhibited the largest growth response. We suggest that future spruce budworm inspired harvests in stands with high balsam fir – spruce content use two or three entries about 5 years apart to reduce windthrow.","author":[{"dropping-particle":"","family":"Wilson","given":"Edward A.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"MacLean","given":"David A.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canadian Journal of Forest Research","id":"ITEM-2","issue":"6","issued":{"date-parts":[["2015"]]},"page":"659-666","title":"Windthrow and growth response following a spruce budworm inspired, variable retention harvest in New Brunswick, Canada","type":"article-journal","volume":"45"},"uris":[""]}],"mendeley":{"formattedCitation":"(Morin 1994; Wilson and MacLean 2015)","manualFormatting":"(Morin, 1994; Wilson & MacLean, 2015)","plainTextFormattedCitation":"(Morin 1994; Wilson and MacLean 2015)","previouslyFormattedCitation":"(Morin 1994; Wilson and MacLean 2015)"},"properties":{"noteIndex":0},"schema":""}(Morin, 1994; Wilson & MacLean, 2015). Generally, the smallest black spruce and balsam fir seedlings present the greatest increases in growth ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"ISSN":"00157546","abstract":"La coupe avec protection de la régénération consiste à éliminer le couvert principal en une seule opération de fa?on à dégager la régénération installée sous ce couvert. Après la coupe, les semis acclimatés au sous-bois seraient vulnérables à subir un stress hydrique, particulièrement les juvéniles i.e., ceux de six ans et moins. L’objectif de cette recherche est de déterminer si un semis de sapin bau- mier acclimaté au sous-bois a la capacité de répondre immédiatement et positivement après la coupe. La réaction à l’ouverture a été étudiée sur deux populations de semis provenant de deux régions climatiques distinctes du Québec, soit la sapinière à bouleau blanc de l’Est et celle de l’Ouest. Les résultats montrent que les patrons de réaction à l’ouverture étaient similaires pour les deux popula- tions. Chez les semis, la réaction à l’ouverture se fait en deux étapes. Un an après l’ouverture, les cernes produits à la base des troncs étaient en moyenne cinq fois plus larges que ceux produits l’année avant la coupe (p > 0,001). C’est à la deuxième année après l’ouver- ture que la croissance en hauteur moyenne est devenue nettement supérieure aux années antérieures (p < 0,001). En moyenne, les juvéniles ont eu des taux d’accroissement en hauteur significativement plus importants par rapport aux semis plus ?gés. Le taux d’accroisse- ment en hauteur était corrélé négativement avec la hauteur des semis avant la coupe ( r = -0,68, p < 0,001). Notre étude montre claire- ment que les semis de sapin peuvent réagir immédiatement et positivement à de grandes ouvertures. La réaction vigoureuse des juvéniles à l’ouverture suggère qu’une proportion importante de ceux-ci a le potentiel de contribuer au nouveau peuplement. Considérant les conditions contrastées des deux régions étudiées, les résultats devraient être valides pour une large gamme de sapinières.","author":[{"dropping-particle":"","family":"Parent","given":"Sylvain","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Ruel","given":"Jean Claude","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forestry Chronicle","id":"ITEM-1","issue":"6","issued":{"date-parts":[["2002"]]},"page":"876-885","title":"Chronologie de la croissance chez des semis de sapin baumier (Abies balsamea (L.) Mill.) après une coupe à blanc avec protection de la régénération","type":"article-journal","volume":"78"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1007/s13595-019-0891-2","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Annals of Forest Science","id":"ITEM-2","issue":"108","issued":{"date-parts":[["2019"]]},"page":"1-16","title":"Secondary disturbances of low and moderate severity drive the dynamics of eastern Canadian boreal old-growth forests","type":"article-journal","volume":"76"},"uris":[""]}],"mendeley":{"formattedCitation":"(Parent and Ruel 2002; Martin et al. 2019)","plainTextFormattedCitation":"(Parent and Ruel 2002; Martin et al. 2019)","previouslyFormattedCitation":"(Parent and Ruel 2002; Martin et al. 2019)"},"properties":{"noteIndex":0},"schema":""}(Parent and Ruel 2002; Martin et al. 2019). As indicated by our results, the accession to the canopy is therefore often made in one major step rather than over several moderate ones. As a result, old-growth forests in this region are often defined by dense regeneration layers that increase minimally in height as long as the canopy is not disturbed (Martin et al. 2020d).Finally, spruce budworm outbreaks were periodic disturbances that caused phases of regular and significant mortality in the study stands. This secondary disturbance regime is therefore different from that regularly observed in old-growth forests, generally defined by a background noise of small-scale mortality punctuated at random by more severe disturbances ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1016/j.foreco.2014.02.024","ISBN":"0378-1127","ISSN":"03781127","abstract":"The conventional theory of boreal forest dynamics recognizes two distinct disturbance regime types, small-scale gap dynamics and dynamics driven by large stand-replacing disturbances. We used satellite imagery and extensive field measurements to examine the landscape-level pattern and impact of an extensive disturbance episode that occurred in the early 2000s in primeval forest dominated by Picea abies in the Arkhangelsk region, Russia, due to drought and subsequent bark beetle (Ips typographus) outbreak. We also quantified forest age structures and deadwood characteristics at the landscape-level to study how such disturbances shape forest structures over larger scales. Satellite image analysis revealed that disturbance patches covered about 16% of the land area in the 12. km. ×. 12. km landscape studied. The size of the disturbance patches was strongly skewed toward small ones (median size 0.12. ha) and they were distributed across the landscape with some tendency of aggregation. The landscape forest matrix was dominated by old-growth forest. The dominant trees in the forest were established prior to 1850, and approximately half of the forest had established prior to 1800. However, the patchy occurrence of younger forest suggests that the landscape previously was subject to patchy disturbance similar to the recent one. This conclusion also gained support from historical records. We conclude that the structure and dynamics of the studied primeval forest landscape was driven by the combined impact of small-scale \"background\" mortality (classical gap dynamics) and infrequent episodes of patchy intermediate severity and scale disturbances. ? 2014 Elsevier B.V.","author":[{"dropping-particle":"","family":"Kuuluvainen","given":"Timo","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Wallenius","given":"Tuomo H.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kauhanen","given":"Heikki","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Aakala","given":"Tuomas","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Mikkola","given":"Kari","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Demidova","given":"Natalia","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Ogibin","given":"Boris","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-1","issued":{"date-parts":[["2014"]]},"page":"96-103","publisher":"Elsevier B.V.","title":"Episodic, patchy disturbances characterize an old-growth Picea abies dominated forest landscape in northeastern Europe","type":"article-journal","volume":"320"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1016/j.foreco.2014.09.005","ISSN":"03781127","abstract":"Natural disturbance regimes play key roles in shaping forest structure and development at stand and landscape levels. Disturbances are commonly complex and variable, such that classical dichotomous characterization of disturbance regimes as following large infrequent disturbances or patch dynamics is too simplistic, especially when the resulting damage is more severe than the baseline of a single tree patch dynamic, but not severe enough to represent large infrequent disturbance. Ongoing climate change affects mountain Picea abies forests in Central, East and Southeastern Europe by an increasing frequency of storms and bark beetle outbreaks. We present a unique study based on extensive dataset aimed to reveal the spatiotemporal pattern of the disturbance history and role of the mixed severity disturbances in primary spruce mountain forest landscapes in the Ukrainian Carpathians.We reconstructed canopy disturbance history and maximum disturbance severity using ca. 2396 tree cores in 96 sample plots. Neither large-scale stand-replacement nor fine scale dynamics was the prevailing disturbance over the last four centuries. Rather, we observed a complex spatiotemporal pattern of mixed severity disturbances. Canopy turnover time ranged between 50 and 300. years and depended on the maximum severity of the disturbance event. Spatial analyses revealed no similarity in spatiotemporal pattern across disturbance histories or maximum disturbance severities. We observed evidence of a combination of variable severity disturbances that fails to fit the classical scheme of gap or patch dynamics with sharply defined sizes and borders, but is more consistent with a mixed severity disturbance regime across the landscape. Windstorms were likely the most important past disturbance agent. The probability of an epidemic bark beetle attack was low, although the possibility of small local outbreaks cannot be excluded. An additional, potentially overlooked, agent of disturbance could be historic periods of extreme cold.This reconstructed disturbance regime may challenge existing silvicultural systems in the Carpathians, calling for a more complex spatiotemporal forest management approach. However, mimicking a mixed severity disturbance regime can be done at the forest management level by applying a range of disturbance severities at the stand level.","author":[{"dropping-particle":"","family":"Trotsiuk","given":"Volodymyr","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Svoboda","given":"Miroslav","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Janda","given":"Pavel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Mikolas","given":"Martin","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bace","given":"Radek","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Rejzek","given":"Jan","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Samonil","given":"Pavel","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Chaskovskyy","given":"Oleh","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Korol","given":"Mykola","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Myklush","given":"Stepan","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forest Ecology and Management","id":"ITEM-2","issued":{"date-parts":[["2014"]]},"page":"144-153","publisher":"Elsevier B.V.","title":"A mixed severity disturbance regime in the primary Picea abies (L.) Karst. forests of the Ukrainian Carpathians","type":"article-journal","volume":"334"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.3390/f9090579","ISSN":"19994907","abstract":"The classification of discrete forest disturbance events is usually based on the spatial extent, magnitude, and frequency of the disturbance. Based on these characteristics, disturbances are placed into one of three broad categories, gap-scale, intermediate-severity, or catastrophic disturbance, along the disturbance classification gradient. We contend that our understanding of disturbance processes near the endpoints of the disturbance classification gradient far exceeds that of intermediate-severity events. We hypothesize that intermediate-severity disturbances are more common, and that they are more important drivers of forest ecosystem change than is commonly recognized. Here, we provide a review of intermediate-severity disturbances that includes proposed criteria for categorizing disturbances on the classification gradient. We propose that the canopy opening diameter to height ratio (D:H) be used to delineate gap-scale from intermediate-severity events and that the threshold between intermediate and catastrophic events be based on the influence of residual trees on the composition of the regeneration layer. We also provide examples of intermediate-severity disturbance agents, return intervals for these events, and recommendations for incorporating natural intermediate-severity disturbance patterns in silvicultural systems.","author":[{"dropping-particle":"","family":"Hart","given":"Justin L.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kleinman","given":"Jonathan S.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-3","issue":"579","issued":{"date-parts":[["2018"]]},"title":"What are intermediate-severity forest disturbances and why are they important?","type":"article-journal","volume":"9"},"uris":[""]}],"mendeley":{"formattedCitation":"(Kuuluvainen et al. 2014; Trotsiuk et al. 2014; Hart and Kleinman 2018)","plainTextFormattedCitation":"(Kuuluvainen et al. 2014; Trotsiuk et al. 2014; Hart and Kleinman 2018)","previouslyFormattedCitation":"(Kuuluvainen et al. 2014; Trotsiuk et al. 2014; Hart and Kleinman 2018)"},"properties":{"noteIndex":0},"schema":""}(Kuuluvainen et al. 2014; Trotsiuk et al. 2014; Hart and Kleinman 2018). For this reason, ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"ISSN":"00375330 (ISSN)","abstract":"Due to the unprecedented loss of old-growth forests to harvesting throughout circumboreal regions an understanding of similarities and differences in old-growth dynamics is needed to design effective restoration, management and conservation efforts. This paper reviews concepts, prevalence and variability of old-growth forests across landscapes, and evaluates different stand scale dynamics at the old-growth stage across the circumboreal zone. Oldgrowth historically dominated many boreal forest landscapes in both Eurasia and North America. Throughout much of North America, and to some extent in western Siberia, the natural prevalence and development of old-growth forests are regulated by the occurrence of stand-replacing fires. In eastern North America and Siberia, insect outbreaks may, however, be more important. Insect outbreaks as well as recurrent non-stand replacing surface fires and windthrows, when occurring at the old-growth stage, often form stands characterized by several tree age-class cohorts. This multi age-class forest development type is common in Europe and eastern Siberia but its prevalence and importance in boreal North-America is not well documented. Similarities in successional dynamics across the circumboreal region are found in the development of mono-dominant even-aged stands, the replacement of shade intolerant tree species by shade tolerant species, as well as in all-aged stands driven by smallscale gap dynamics. The message to land managers is that the focus should not only be on setting aside remaining old-growth forests or in restoring static old-growth attributes, but also in emulating natural disturbances and successional dynamics at landscape and regional scales to maintain natural variability in old-growth attributes through time.","author":[{"dropping-particle":"","family":"Shorohova","given":"Ekaterina","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kneeshaw","given":"Daniel D.","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kuuluvainen","given":"Timo","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Silva Fennica","id":"ITEM-1","issue":"5","issued":{"date-parts":[["2011"]]},"page":"785-806","title":"Variability and dynamics of old- growth forests in the circumboreal zone: implications for conservation, restoration and management","type":"article-journal","volume":"45"},"uris":[""]}],"mendeley":{"formattedCitation":"(Shorohova et al. 2011)","manualFormatting":"Shorohova et al. (2011)","plainTextFormattedCitation":"(Shorohova et al. 2011)","previouslyFormattedCitation":"(Shorohova et al. 2011)"},"properties":{"noteIndex":0},"schema":""}Shorohova et al. (2011) hypothesized that many boreal old-growth forests of eastern Canada are defined by cohort dynamics, i.e., regeneration of new cohorts under the cover of old cohorts due to moderate-severity disturbances (ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Angelstam","given":"Per","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kuuluvainen","given":"Timo","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecological bulletins","id":"ITEM-1","issue":"51","issued":{"date-parts":[["2004"]]},"page":"117-136","title":"Boreal forest disturbance regimes, successional dynamics and landscape structures : A European perspective","type":"article-journal"},"uris":[""]}],"mendeley":{"formattedCitation":"(Angelstam and Kuuluvainen 2004)","manualFormatting":"Angelstam and Kuuluvainen, 2004)","plainTextFormattedCitation":"(Angelstam and Kuuluvainen 2004)","previouslyFormattedCitation":"(Angelstam and Kuuluvainen 2004)"},"properties":{"noteIndex":0},"schema":""}Angelstam and Kuuluvainen, 2004), similar to Scots pine (Pinus sylvestris L.) stands in Fennoscandia or Russia ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Angelstam","given":"Per","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kuuluvainen","given":"Timo","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Ecological bulletins","id":"ITEM-1","issue":"51","issued":{"date-parts":[["2004"]]},"page":"117-136","title":"Boreal forest disturbance regimes, successional dynamics and landscape structures : A European perspective","type":"article-journal"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1051/forest/2008083","ISBN":"1286-4560","ISSN":"1286-4560","abstract":"This review summarizes early stand-scale studies of pristine forest structures, disturbance regimes and successional patterns carried out in boreal Eurasia. We attempt to reveal, characterize and classify stand dynamic types that can be used as templates for nature-based forest management. The studies reviewed demonstrate multiple successional pathways in stand development in all types of pristine forests. All-aged stands driven by small-scale disturbances are formed over successional development of several hundreds of years. This endogenous development can be interrupted by stand-replacing or partial disturbances leading to successions with even-aged or cohort-structured stands, respectively. In Western Europe, the most common disturbances are windthrows, surface fires and fluctuations in moisture regime; in Eastern Europe and Siberia, the most common disturbances are crown and surface fires and insect outbreaks. Type, return interval and severity of disturbances are strongly influenced by the site conditions and successional stage of a stand. Based on characteristics of forest stands and disturbance regime, four main types of pristine boreal forest stand dynamics can be distinguished: (1) even-aged, compositional change dynamics, (2) even-aged, mono-dominant dynamics, (3) cohort dynamics and (4) fine-scale gap dynamics. These types can be mimicked in developing scenarios of ecological sustainable forest management in Eurasian boreal forests.","author":[{"dropping-particle":"","family":"Shorohova","given":"Ekaterina","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kuuluvainen","given":"Timo","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kangur","given":"Ahto","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"J?giste","given":"Kalev","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Annals of Forest Science","id":"ITEM-2","issue":"2","issued":{"date-parts":[["2009"]]},"page":"201-201","title":"Natural stand structures, disturbance regimes and successional dynamics in the Eurasian boreal forests: a review with special reference to Russian studies","type":"article-journal","volume":"66"},"uris":[""]}],"mendeley":{"formattedCitation":"(Angelstam and Kuuluvainen 2004; Shorohova et al. 2009)","plainTextFormattedCitation":"(Angelstam and Kuuluvainen 2004; Shorohova et al. 2009)","previouslyFormattedCitation":"(Angelstam and Kuuluvainen 2004; Shorohova et al. 2009)"},"properties":{"noteIndex":0},"schema":""}(Angelstam and Kuuluvainen 2004; Shorohova et al. 2009). Most studied trees presented evidence of juvenile suppression, implying that most seeds or layers appeared before the disturbances. Spruce budworm outbreaks are “top-to-down” disturbances, which kill trees in the canopy but preserve some regeneration ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.3390/f9080471","ISBN":"1999-4907","ISSN":"19994907","abstract":"<p>Natural disturbances are fundamental to forest ecosystem dynamics and have been used for two decades to improve forest management, notably in the boreal forest. Initially based on fire regimes, there is now a need to extend the concept to include other types of disturbances as they can greatly contribute to forest dynamics in some regions of the boreal zone. Here we review the main descriptors—that is, the severity, specificity, spatial and temporal descriptors and legacies, of windthrow and spruce bud worm outbreak disturbance regimes in boreal forests—in order to facilitate incorporating them into a natural disturbance-based forest management framework. We also describe the biological legacies that are generated by these disturbances. Temporal and spatial descriptors characterising both disturbance types are generally variable in time and space. This makes them difficult to reproduce in an ecosystem management framework. However, severity and specificity descriptors may provide a template upon which policies for maintaining post harvesting and salvage logging biological legacies can be based. In a context in which management mainly targets mature and old-growth stages, integrating insect and wind disturbances in a management framework is an important goal, as these disturbances contribute to creating heterogeneity in mature and old-growth forest characteristics.</p>","author":[{"dropping-particle":"","family":"Grandpré","given":"Louis","non-dropping-particle":"De","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Waldron","given":"Kaysandra","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Bouchard","given":"Mathieu","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Gauthier","given":"Sylvie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Beaudet","given":"Marilou","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Ruel","given":"Jean Claude","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Hébert","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Kneeshaw","given":"Daniel D.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-1","issue":"8","issued":{"date-parts":[["2018"]]},"page":"1-20","title":"Incorporating insect and wind disturbances in a natural disturbance-based management framework for the boreal forest","type":"article-journal","volume":"9"},"uris":[""]},{"id":"ITEM-2","itemData":{"author":[{"dropping-particle":"","family":"Lavoie","given":"Janie","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Girona","given":"Miguel Montoro","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Forests","id":"ITEM-2","issue":"850","issued":{"date-parts":[["2019"]]},"page":"1-14","title":"Vulnerability of conifer regeneration to spruce budworm outbreaks in the eastern Canadian boreal forest","type":"article-journal","volume":"10"},"uris":[""]}],"mendeley":{"formattedCitation":"(De Grandpré et al. 2018; Lavoie et al. 2019)","plainTextFormattedCitation":"(De Grandpré et al. 2018; Lavoie et al. 2019)","previouslyFormattedCitation":"(De Grandpré et al. 2018; Lavoie et al. 2019)"},"properties":{"noteIndex":0},"schema":""}(De Grandpré et al. 2018; Lavoie et al. 2019). Therefore, in coniferous forests recently disturbed by spruce budworm outbreaks, most of the observed regeneration germinated decades before the disturbance and not immediately after ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"DOI":"10.1139/x02-194","ISSN":"00455067","abstract":"This study examines balsam fir (Abies balsamea (L.) Mill.) recruitment in old fir stands. Studying the regeneration of these stands is essential to understand the regeneration dynamic of the species in the absence of standdestroying disturbances. The objectives were (1) to obtain substrate-seedling associations for different age-classes and according to the presence or absence of adventitious roots; (2) to evaluate the contribution of the seed rain to seedling recruitment; (3) to re-examine age structures using the most appropriate method that minimizes estimation errors due to the presence of adventitious roots. A total of 90 quadrats (1 m2) were established along transects. In each quadrat, subtrates were characterized (type and topography) and their area was estimated. All balsam fir seedlings (<50 cm tall) present in the quadrats were located, harvested whole (root and shoot), and described (age, height, presence of adventitious roots, etc). Fir seedlings were strongly associated with woody mounds covered with thin mats of mixed mosses and Pleurozium shreberi (Bird.) Mitt. but negatively associated with flat topography particularly dominated by Hylocomium splendens (Hedw.) B.S.G. The presence of adventitious root is related to seedling age more than substrate type or topography. The age structure is in agreement with seed production and disturbance regime.","author":[{"dropping-particle":"","family":"Parent","given":"Sylvain","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Simard","given":"Marie Josée","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Messier","given":"Christian","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canadian Journal of Forest Research","id":"ITEM-1","issue":"4","issued":{"date-parts":[["2003"]]},"page":"597-603","title":"Establishment and dynamics of the balsam fir seedling bank in old forests of northeastern Quebec","type":"article-journal","volume":"33"},"uris":[""]},{"id":"ITEM-2","itemData":{"DOI":"10.1139/x11-037","ISSN":"00455067","abstract":"The renewal of balsam fir (Abies balsamea (L.) P. Mill.) stands is related to the recurrent spruce budworm (Archips fumiferana Clemens [syn.: Choristoneura fumiferana (Clemens)]) outbreaks that favour the growth of the regeneration following death of the dominant trees. The aim of this study was to investigate the population demography and the spatial relationships among individuals in four permanent plots of the boreal forest of Quebec, Canada, after a spruce budworm outbreak. This was realized by collecting data on trees and saplings every five years from 1994 to 2004 and by using Ripley's K statistics. The younger plots showed recruitment of up to 90 new trees·ha-1·year-1, and mortality following competition among individuals affected up to 27% and 50% of the trees and saplings, respectively. In the plot with the lowest tree density, sapling recruitment was estimated as 378 new individuals·ha-1·year-1. Saplings were aggregated at all spatial scales, whereas trees showed a random pattern of stem distribution. A significant tendency to separation between saplings and trees was observed. The specific stand dynamics observed in balsam fir are connected to an abundant advance regeneration and an age-dependent competition for resources in a heterogeneous environment with different levels of resource availability.","author":[{"dropping-particle":"","family":"Rossi","given":"Sergio","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canadian Journal of Forest Research","id":"ITEM-2","issue":"5","issued":{"date-parts":[["2011"]]},"page":"1112-1120","title":"Demography and spatial dynamics in balsam fir stands after a spruce budworm outbreak","type":"article-journal","volume":"41"},"uris":[""]},{"id":"ITEM-3","itemData":{"DOI":"10.1007/s13595-019-0891-2","author":[{"dropping-particle":"","family":"Martin","given":"Maxence","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Fenton","given":"Nicole J.","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Annals of Forest Science","id":"ITEM-3","issue":"108","issued":{"date-parts":[["2019"]]},"page":"1-16","title":"Secondary disturbances of low and moderate severity drive the dynamics of eastern Canadian boreal old-growth forests","type":"article-journal","volume":"76"},"uris":[""]}],"mendeley":{"formattedCitation":"(Parent et al. 2003; Rossi and Morin 2011; Martin et al. 2019)","plainTextFormattedCitation":"(Parent et al. 2003; Rossi and Morin 2011; Martin et al. 2019)","previouslyFormattedCitation":"(Parent et al. 2003; Rossi and Morin 2011; Martin et al. 2019)"},"properties":{"noteIndex":0},"schema":""}(Parent et al. 2003; Rossi and Morin 2011; Martin et al. 2019). We therefore consider that the dynamics observed in the study stands likely do not correspond to cohort dynamics. We suggest rather that the dynamics of these forests result from the combination of several interdependent processes: (i) a slow vertical growth of the understorey as long as the canopy is not disturbed; (ii) a disturbance regime driven by periodic and moderate-severity disturbances that preserve the regeneration layer; (iii) after a disturbance, understorey trees reaching the canopy in one major increase in height and diameter; and (iv) once the canopy is attained, the trees changing minimally in height.ConclusionThis study underscored the resistance of boreal old-growth forests to recurrent moderate-severity disturbances. Three notable insect outbreaks have marked the history of the studied stands over the last century, with an interval of about 30 years between each outbreak. The growth patterns of the trees indicated that a major portion of the suppressed trees to rapidly reach the upper layers of the canopy and fill the gaps created following the disturbances. The structure of the stands at the time of the sampling was similar to that commonly observed in primary boreal forests driven by a less severe secondary disturbance regime. Hence, the studied old-growth forests demonstrated their ability to withstand repeated moderate-severity disturbances. The combination of low stand height, periodic disturbances, and rapid canopy closure often resulted, however, in relatively simple vertical structures, with a high frequency of dominant and codominant trees. This particularity in the structure of boreal old-growth forests should therefore be better acknowledged to avoid their misclassification as even-aged forests in aerial forest surveys.Several forestry practices have been proposed to maintain old-growth structures and attributes in boreal landscapes (e.g., partial and stem-selection cuts). Because of limited tree size and volume, however, foresters generally harvest at least a third of the stand basal area. The effect of such practices can be considered as equivalent moderate-severity disturbances, with uncertain long-term impacts on the forests. Our results nevertheless highlight that such silvicultural practices may be close to the natural disturbance dynamics observed in some primary boreal forests. Although complementary research is required, continuous-cover forest treatments appear as plausible and sustainable alternatives to clearcutting in boreal old-growth forests. Authors contributionMM and HM conceived the ideas and designed methodology; HM organized and supervised the data collection; MM prepared and analysed the data; CK and HM supervised the analysis and interpretation of the results; MM led the writing of the manuscript. All authors contributed critically to the drafts and gave final approval for publication.AcknowledgementsWe would like to thank Moussa Marou-Dodo, ?milie Lessard, Marie-Josée Girard, Isabelle Grenon, Sergio Rossi, Marie-Josée Tremblay, and Jean-Guy Girard for their contributions during data collection and preparation. We also thank Jean Bégin, scientific collaborator on the project, and Damien C?té and Serge Gosselin, collaborators from the Ministère de la Forêt, de la Faune et des Parcs du Québec, for their assistance with this project. This research was funded by the Fonds Québécois de la Recherche sur la Nature et les Technologies (FQRNT), project no. 2008-FS-124391.Data availabilityIn the case that the article is accepted for publication, the data used for this article will be archived in the institutional repository of the Université du Québec à Chicoutimi. If the institutional repository is not considered acceptable according to the Journal of Ecology policy, we could otherwise use a public repository (e.g., Figshare or Dryad).ReferencesADDIN Mendeley Bibliography CSL_BIBLIOGRAPHY Achard F, Eva H, Mollicone D, Popatov P, Stibig H-J, Turubanova S, Yaroshenko A. 2009. Detecting intact forests from space: hot spots of loss, deforestation and the UNFCCC. In: Wirth C, Gleixner G, Heimann M, editors. Old-growth forests: Function, fate and value. Ecological Studies 207. Berlin: Springer-Verlag. p. 411–428.Aksenov D, Karpachevskiy M, Lloyd S, Yaroshenko A. 1999. 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Details of age, diameter, and height structure are provided in Appendix A.CategoryAttributeSite 1Site 2Site 3Site 4Site 5Site 6Site 7Site 8Living treesTree density (n?ha-1)1125.001625.00900.001025.001700.001250.001475.00616.67?Sapling density (n?ha-1)4000.004800.005200.006000.003000.005000.006200.004600.00SnagsTree basal area (m2?ha-1)16.5227.5017.5920.1334.1925.2324.069.98?Snag density (n?ha-1)75.0025.00125.00175.00300.00250.00125.00275.00?Snag basal area (m2?ha-1)1.530.215.444.405.634.003.105.43CompositionBlack spruce proportion (%)*94.1293.8795.4393.8030.7683.9393.9348.37?Balsam fir proportion (%)*5.886.134.576.1969.2416.076.0749.96HeightMaximum height (m)13.6414.7815.0817.6016.4017.3315.5414.27?Dominant height (m)13.6417.7715.6218.0016.4016.9315.5314.55?Mean height (m)9.6910.209.4712.7011.2011.5011.309.36?Height standard deviation (m)2.472.773.012.983.313.262.062.90Age structureOldest tree age (years)221.00246.00251.00267.00177.00205.00179.00206.00?Mean tree age (years)159.00131.00133.00207.00132.00139.00133.00122.00?Tree age standard deviation (years)28.2028.0040.6043.2022.6031.7022.6035.70Cohort basal area proportion1.001.001.001.001.001.000.931.00Table 2: Distribution (%) of canopy layers within the study sites.Canopy layerSiteSite 1Site 2Site 3Site 4Site 5Site 6Site 7Site 8Dominant2.33.12.35.13.94.11.83.1Codominant59.157.831.866.756.942.969.637.5Intermediary27.320.327.317.919.626.525.031.2Suppressed11.418.838.610.319.626.53.628.1Figure 1 Location of the study sites on the study territory. The inset maps indicate the location of the study territory in Canada (left) and in Québec (right).Figure 2 (a) Scatterplots of the growth patterns identified using a k-means cluster algorithm. Grey dots represent the values of each segment of the 20-segment series of the trees constituting the clusters. The coloured lines represent the loess smoothing of the data with a 50% span. (b) Values of the SSI criterion according to the number of clusters. The red dot indicates the maximum SSI criterion value. Mod.: moderate, n: number of sampled trees per cluster.Figure 3: Frequency of growth release and growth suppression observed in the studied trees per growth pattern and section. Figure 4 Boxplots of tree and growth attributes per growth pattern. Letters indicate significant differences, with a > b > c > d > e > f > g. Details of the model results are presented in Appendix B. Lines in the boxes represent the median, box boundaries are the 25th and 75th percentiles, vertical lines are values 1.5× higher or lower than the box boundaries, and the dots represent outliers.Figure 5 Scatterplot of the studied trees according to their age, DBH, growth pattern, and mean tree-ring width. Shaded grey areas above and to the right of the scatterplot indicate point density along the x and y axes, respectively. The dashed line separates trees younger or older than 200 years old; the dotted line separates trees having a DBH greater or less than 15?cm.Figure 6 Occurrence (%) of the growth patterns in the different layers of the canopy.Figure 7 Number of trees sampled and growth changes in the period 1850–2000 for the studied stands (pale blue points). “All releases” includes both minor and major releases; “all suppressions” includes both minor and major suppressions. Dark blue lines represent a loess smoothing of the data with a 50% span. Brackets indicate periods of spruce budworm outbreaks in this region according to ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Morin","given":"Hubert","non-dropping-particle":"","parse-names":false,"suffix":""},{"dropping-particle":"","family":"Laprise","given":"Danielle","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canadian Journal of Forest Research","id":"ITEM-1","issued":{"date-parts":[["1990"]]},"page":"1-8","title":"Histoire récente des épidémies de la Tordeuse des bourgeons de l'épinette au nord du lac Saint-Jean (Québec) : une analyse dendrochronologique","type":"article-journal","volume":"20"},"uris":[""]}],"mendeley":{"formattedCitation":"(Morin and Laprise 1990)","manualFormatting":"Morin & Laprise (1990)","plainTextFormattedCitation":"(Morin and Laprise 1990)","previouslyFormattedCitation":"(Morin and Laprise 1990)"},"properties":{"noteIndex":0},"schema":""}Morin & Laprise (1990) and ADDIN CSL_CITATION {"citationItems":[{"id":"ITEM-1","itemData":{"author":[{"dropping-particle":"","family":"Krause","given":"Cornelia","non-dropping-particle":"","parse-names":false,"suffix":""}],"container-title":"Canada Journal of Forest Research","id":"ITEM-1","issued":{"date-parts":[["1997"]]},"page":"69-75","title":"The use of dendrochronological material from buildings to get information about past spruce budworm outbreaks","type":"article-journal","volume":"27"},"uris":[""]}],"mendeley":{"formattedCitation":"(Krause 1997)","manualFormatting":"Krause (1997)","plainTextFormattedCitation":"(Krause 1997)","previouslyFormattedCitation":"(Krause 1997)"},"properties":{"noteIndex":0},"schema":""}Krause (1997).AppendixAppendix A: (A) age structure, (B) diameter structure, and (C) height structure of the study sites.Appendix B: Details of the mixed ANOVA. DF: numerator degrees of freedom, DenDF: denominator degrees of freedom, Log: logarithmic, DBH: diameter at breast height, RW: ring widthAttributeDFDenDFF-valuep-valueTransformationTree age83654.18<0.0001LogMean RW8365163.342<0.0001LogTree DBH836532.375<0.0001LogTree height835719.897<0.0001?RW standard deviation836586.182<0.0001LogRW 5th percentile836130.188<0.0001Log + outlier removalRW 95th percentile8365108.065<0.0001LogAppendix C. Absolute and relative frequency of the different growth patterns by species. χ2: chi-square, df: degrees of freedom.Growth patternSpeciesTotalBlack spruceBalsam firLinear138214.5%8.8%5.5%Low-bell42135514.5%14.3%14.4%High-bell4371.4%3.3%1.8%Low-ascending54237718.6%25.3%20.2%Moderate-ascending47156216.2%16.5%16.3%High-ascending189276.2%9.9%7.1%Low-sine60107020.7%11%18.4%Moderate-sine265319%5.5%8.1%High-sine265319%5.5%8.1%Total29091381100%100%100%χ2 = 12.166 · df = 8 · Cramer's V = 0.179 · Fisher's p = 0.132 ................
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