United States Department of Agriculture Fire History of ...

United States Department of Agriculture

Fire History of the Appalachian Region:

A REVIEW AND SYNTHESIS

Charles W. Lafon, Adam T. Naito, Henri D. Grissino-Mayer, Sally P. Horn, and Thomas A. Waldrop

Forest Service Southern Research Station General Technical Report SRS-219 January 2017

Authors Charles W. Lafon is a Professor of Geography and the Assistant Department Head in the Department of Geography at Texas A&M University, College Station, TX 778433147; Adam T. Naito is a Postdoctoral Research Associate in the School of Natural Resources and the Environment at the University of Arizona, Tucson, AZ 85721; Henri D. Grissino-Mayer is a Professor of Geography in the Department of Geography at the University of Tennessee, Knoxville, TN 37996-0925; Sally P. Horn is a Professor of Geography in the Department of Geography at the University of Tennessee, Knoxville, TN 37996-0925; and Thomas A. Waldrop is a Supervisory Research Forester (retired) with the U.S. Department of Agriculture, Forest Service, Southern Research Station, Clemson, SC 29634-0331.

Cover photo View to the east from the top of Reddish Knob on the Virginia-West Virginia border, George Washington National Forest. In this photo can be seen the oak-pine mosaic that is the typical vegetation cover on mountain slopes in the Ridge and Valley province. The pine stands are dominated by Table Mountain pine (Pinus pungens) and pitch pine (Pinus rigida), some of which have been scarred by fires in the past. These fire-scarred trees are a valuable source of information about fire history. The Reddish Knob fire history site discussed in this report is located on the slope to the south (right) of the pond in the middle ground. The Shenandoah Valley and the Blue Ridge Mountains lie in the background.

Photograph Disclaimer All photographs are provided courtesy of the authors, unless otherwise noted.

Product Disclaimer The use of trade or firm names in this publication is for reader information and does not imply endorsement by the U.S. Department of Agriculture of any product or service.

January 2017 Southern Research Station

200 W.T. Weaver Blvd. Asheville, NC 28804

srs.fs.

Fire History of the

Appalachian Region:

A REVIEW AND SYNTHESIS

Charles W. Lafon, Adam T. Naito, Henri D. Grissino-Mayer, Sally P. Horn, and Thomas A. Waldrop

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Abstract

The importance of fire in shaping Appalachian vegetation has become increasingly apparent over the last 25 years. This period has seen declines in oak (Quercus) and pine (Pinus) forests and other fire-dependent ecosystems, which in the near-exclusion of fire are being replaced by fire-sensitive mesophytic vegetation. These vegetation changes imply that Appalachian vegetation had developed under a history of burning before the fire-exclusion era, a possibility that has motivated investigations of Appalachian fire history using proxy evidence. Here we synthesize those investigations to obtain an up-to-date portrayal of Appalachian fire history. We organize the report by data type, beginning with studies of high-resolution data on recent fires to provide a context for interpreting the lower-resolution proxy data. Each proxy is addressed in a subsequent chapter, beginning with witness trees and continuing to fire-scarred trees, stand age structure, and soil and sediment charcoal. Taken together, these proxies portray frequent burning in the past. Fires had occurred at short intervals (a few years) for centuries before the fire-exclusion era. Indeed, burning has played an important ecological role for millennia. Fires were especially common and spatially extensive on landscapes with large expanses of oak and pine forest, notably in the Ridge and Valley province and the Blue Ridge Mountains. Burning favored oak and pine at the expense of mesophytic competitors, but fire exclusion has enabled mesophytic plants to expand from fire-sheltered sites onto dry slopes that formerly supported pyrogenic vegetation. These changes underscore the need to restore firedependent ecosystems.

Keywords: Age structure, Appalachian Mountains, charcoal, fire history, fire regime, fire scars, witness trees.

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Fire History of the Appalachian Region: A Review and Synthesis

Acknowledgments

We are grateful for the funding of this synthesis report through the Consortium of Appalachian Fire Managers and Scientists (CAFMS), which is supported by the Joint Fire Science Program (JFSP). We also thank the reviewers, Steven Q. Croy and Don Hagan, for their many useful suggestions that helped us improve this report. More broadly, we are especially grateful to Steve for all the assistance and ideas he has offered us during our years of studying Appalachian fire history. The work we report here has also benefitted from conversations, collaborations, and encouragement from many others, particularly Rob Klein, Helen Mohr, Beth Buchanan, Margit Bucher, Carol Croy, Nelson Lafon, and Dave Cairns, and from several current and former students, especially Serena Aldrich, Joanne Ballard, Mathew Boehm, Georgina DeWeese, Ian Feathers, Will Flatley, Ellen Gass, Alisa Hass, Jennifer Hoss, Lisa LaForest, and Chris Underwood. The studies that we and our students have carried out on fire history in the Appalachian region have been supported by grants from the Joint Fire Science Program (#01C-3-3-09, #06-3-1-05), the National Science Foundation (#0538420, #0623321, #0822824, #0928508), the Nature Conservancy (#VA022205A, #VA022305B), the Great Smoky Mountains Conservation Association, and our universities. Funding for this synthesis report was provided through agreement #15-JV-11330136-004 between Texas A&M University and the USDA Forest Service, Southern Research Station.

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