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Student Activity SheetTree Ring Expeditions (TREX)Lab 1: Launching an ExpeditionPart 1: What is DendrochronologyStop and Think1.1 What types of trees are the most useful for tree-ring research?It depends on your research questions. If you want to study moisture conditions, then the best trees to study are those that are in dry areas with limited precipitations (eg the US Southwest). Tree-ring patterns from trees growing in drier regions reflect summer moisture conditions. If you are interested in learning about temperature from tree-rings, the scientists would choose research sites at high elevation (e.g. treeline on a mountain top) where trees can’t grow any higher because it is too cold. Trees from the northern latitudes (e.g., Alaska, Canada, Siberia) are also sensitive to temperature conditions. 1.2 Why are trees growing in landscaped areas not useful to study past climate conditions?Trees in landscaped areas are watered regularly and typically taken care of. This practice leads to more or less equal tree-ring widths over time, something scientists call “complacent” trees. The result is that the rings of these trees are not very sensitive to climate and thus are not very useful for tree-ring researchers to answer questions about past climate.1.3 What governs the rate of tree growth at high altitudes?Temperature, instead of amount of available moisture, governs tree growth at high altitudes. Stop and Think1.4 Why is one part of each tree ring light in color and the other part dark in color?The light part of the ring is, called early-wood. It starts to forms in the spring and has large cells and thin walls. Toward the end of the growing season, in the late summer and fall, the cell walls thicken making the walls look darker. This is called late-wood. The early-wood and late-wood together form an annual tree-ring. 1.5 What factors did Dr. Davi consider in choosing a good tree to core at her location in the woods?Dr. Davi stressed the importance of not coring a dead or dying tree, so as not to get your tree-ring borer stuck. She also explained that it is best to core a tree at a position that is most comfortable to you, about chest height, so you have the most power. She also suggested that you place your borer between the ridges in the bark to get started, and to aim for the center of the tree.1.6 What instruments did you see in your tour of the Lamont Tree Ring Lab?Microscopes, computers, a microwave, and a couple of large unknown instruments.1.7 What kind of specimens did you see in the core room?Drawers of long, thin core samples from different types of trees, and some tree cross-sections.Part 2 - The Life of a Tree-ring Scientist Stop and Think2.1 What are the best parts of being a scientist as described by Drs. Cook and D'Arrigo?Both Drs. D’Arrigo and Cook talk about how fieldwork is in exotic locations all over the world being the big payoff in tree-ring research, and also experiencing different cultures. Dr.D’Arrigo talks about the importance of scientific freedom that scientists have, and the ability to explore questions that really interest you and tell you more about the world.2.2 What are some of the challenging aspects of being a scientist as described by Drs. Cook and D'Arrigo?The lab work can be tedious and boring. Also, raising funding through government agencies to cover your salary, research program and staff/students takes time and can be stressful. They talk about the need to continually come up with good ideas and keep up with the current science in the field.2.3 What drives Dr. D'Arrigo as a scientist?What keeps her going is that questions about Earth’s climate feels limitless. She explains that there always seems to be new problems or questions to be answered about how the climate system works and the potential impacts. 2.4 What advice do Drs. D'Arrigo and Cook have for students who are thinking about a career in science? Follow your interests and curiosity and take advantages of situations as they arise. If you have something you love to do, find a way to make it a career. Learn how to take criticism well.Explore Research SitesStop and Think2.5 Give a brief description of each of the four sites. Humpty Dumpty Talus Slope, Hudson Valley NY – has very rocky terrain, limited soil, and interspersed trees. This site is a classic moisture sensitive site for the Northeastern US. Mendenhall glacier, Juneau, Alaska– this site has both conditions needed to find temperature sensitive trees. Alaska is in the northern latitudes, and the mountains are quite high. These site conditions ensure that the ring patterns in the trees growing here will reflect temperature. Schulman Grove – High desert terrain, very dry, very little soil. It is easy to see that the trees here are stressed and slow growing. These trees are the longest lived in the world.J9 – San Juan River site – Arizona – Steep-walled canyon with a river running through it. Image taken during the winter in a dry, desert-like site. 2.6 What types of trees are seen at each site?Humpty Dumpty – Scattered white pine, hemlock and shrubs.Mendenhall – Mostly white spruce and hemlock can be seen on the slopes of the mountains.Schulman Grove – these stunted trees are bristlecone pine, the oldest trees on earth. J9 – San Juan River site – Arizona – these are pinyon pine and juniper growing in rocky soil on the slopes. 2.7 What difficulties might you encounter at each site assuming you would need to spend two full weeks in the field? When planning an expedition scientist need to consider many things. Some of those considerations are listed below. Scientific plan: Where do you plan to sample? How do you know that this has potential to be a good site? Are there local scientists that you can work with? Do you need permits to samples trees and take samples out of a foreign country?Emergency Plan: Do you have a plan if someone gets hurt? Do you have a first aid kit? If you are in a very remote region it would be smart to bring a satellite phone and know whom you would call in case of emergency. Some field scientists have emergency evacuation insurance. Provisions: Do you have enough food and water for every person on the team? Without enough freshwater, your expedition would quickly be over. Scientists sometimes bring water filters or iodine tablets so they can drink water from local sources like streams and rivers without getting sick. Water can be very heavy, so in many instances, this is the best option.Critters: Before working in a new study area scientists need to familiarize themselves with the critters that live in the area. Are there scorpions, poisons snakes, cougars, grizzly bears etc., and if so, how do you best handle an encounter with these creatures? Bear safety is particularly important when working in the northern latitudes. Clothing Because scientist travel to remote regions they need to be prepared for harsh conditions and exposure. A waterproof shell jacket is essential, as are layers to keep warm and dry. In the northern latitudes conditions can be mild, say 70 degrees, or you can wakeup with snow on your tent. Scientists need to be prepared for heat, cold, rain and snow, depending on where they work. Good sturdy shoes can also be very helpful. Stop and Think2.8 Briefly describe some of the major goals of the NSF research area (also called a division) that you selected.Answers will vary.2.9 Briefly describe the project described in the news article you reviewed.Answers will vary.Part 3 – Heading Up an Expedition3. Student tableName of siteInvestigatorLatitudeLongitude4. List answers to science mission details here.Answers will vary.6. Place your summary of the paper you chose here.Title: Summary:Stop and Think3.1 How close is the nearest tree-ring research site from where you live?Answers will vary.3.2 Describe one of the research projects you found near your community.Answers will vary.3.3 Why do you think it is important to do a search of the literature before you embark on a research effort? You must know what scientists have uncovered about your research site, or topic, before you begin your research efforts to break new ground in your field instead of repeating already known findings. ................
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