University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Doctoral Dissertations Graduate School 8-2015 Population Dynamics and Ecophysiology of Fraser fir (Abies fraseri) in the High Elevation Forests in the Southern Appalachian Mountains Steven Douglas Kaylor University of Tennessee - Knoxville, [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss Part of the Forest Biology Commons Recommended Citation Kaylor, Steven Douglas, "Population Dynamics and Ecophysiology of Fraser fir (Abies fraseri) in the High Elevation Forests in the Southern Appalachian Mountains. " PhD diss., University of Tennessee, 2015. https://trace.tennessee.edu/utk_graddiss/3431 This Dissertation is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a dissertation written by Steven Douglas Kaylor entitled "Population Dynamics and Ecophysiology of Fraser fir (Abies fraseri) in the High Elevation Forests in the Southern Appalachian Mountains." I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, with a major in Natural Resources. Jennifer A. Franklin, Major Professor We have read this dissertation and recommend its acceptance: Timothy M. Young, Jennifer A. Schweitzer, Joseph K. Bailey Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) Population Dynamics and Ecophysiology of Fraser fir (Abies fraseri) in the High Elevation Forests in the Southern Appalachian Mountains A Dissertation Presented for the Doctor of Philosophy Degree The University of Tennessee, Knoxville Steven Douglas Kaylor August 2015 Copyright © 2015 by S. Douglas Kaylor All rights reserved. ii Dedication Dr. Tom Pauley once told me our job as biologists is to speak for the things that had no voice, to be their mouthpiece in the world of men. To the voiceless, I dedicate mine. iii Acknowledgements Though our cultural image of a scientist is one of a lone explorer making discoveries, science is truly a collaborative effort, and there are a number of people who supported, helped and guided me throughout my graduate career and the completion of my dissertation research. First and foremost, I am thankful to Joe Hughes for his continual support, both as my husband and the other half of the forest disturbance ecology lab. I’d like to express my thanks to my advisor, Jennifer Franklin, for the opportunity to work on this project, for guidance and training in tree physiology, and constructive advice while writing. Additionally I’d like to thank my committee, Tim Young, Jen Schweitzer, and Joe Bailey, and earlier committee members Jason Henning and Amy Johnson for their good advice throughout the completion of this dissertation. They all have helped me shape and present my work, and their efforts have contributed significantly to my development as a scientist. I’m grateful as well to Harry Richards and SCALE-IT and Dan Hayes and ORNL, for their valuable mentorship and stipend support while completing my research and the opportunity to work on various other projects while at UTK. Thanks are also due to the National Park Service for providing funding, gear, and field crews while taking measurements, and for providing previous data sets. I’m happy to be a part of this long-term monitoring study and to have assisted management efforts in conserving this beautiful ecosystem. Thanks especially to Josh Albritton and Blaise Moehl for climbing mountains and measuring plots with me all summer. I’m grateful to Jacob Hilton, Saint Thomas Ledoux, and Austin Milt for assistance in collecting measurements and tissue samples, and to Becca Smith for help in the lab. Additional thanks to Seth Worley and Cal McKinney for their work on our needle morphology projects and for helping to parameterize MIMSI. I’d also like to thank two dear friends and cheerleaders, Carrie Nilles and Justin Lessard-- thank you for helping me believe in myself. Thanks also go to all those scientists who formed my regular dinner party group: Jenn Krauel, Josh Birkebak, Tyler Pannell, Anthony Walker, Alex Pilote, Jonathon Pruitt, Sean Tallman, and Rachel Fovargue, for your support and friendship and all those geeky science conversations over dinner and cocktails. Lastly, I want to thank my parents for teaching me useful camping skills, instilling in me a love of nature, and helping me take those initial steps in becoming a PhD plant scientist. iv Abstract Dominated by the endemic Fraser fir (Abies fraseri), the high-elevation forests of the Southern Appalachians are one of the most endangered ecosystems in the United States, and the future of these forests remains uncertain. Fraser fir is showing signs of decline in health and increased mortality throughout its range, possibly due to multiple environmental stresses. Using twenty years of forest monitoring data, this dissertation documents change in forest structure and species composition in high-elevation red spruce-Fraser fir forests in southern Appalachia and generates predictions of future forest change. Additionally, it quantifies physiological measures of carbon fixation, storage and growth in adult Fraser fir in situ under multiple stresses, which has been unstudied previously, and explores environmental constraints associated with climate, soil chemistry and acidic deposition on physiological metrics. We find no evidence of previously hypothesized shifts in forest composition to greater dominance of northern hardwood species across elevation and nitrogen deposition gradients or between different initial stand types. Using a stage-structured Bayesian hierarchical model to predict Fraser fir populations through 2050, we predict robust recovery of populations on Clingmans Dome and Mount LeConte for at least the next several decades, as well as continued decline for populations on a number of mountains, notably Mount Sterling at the lowest end of Fraser fir’s elevation range. We find that maximum photosynthetic rates are low throughout the high elevation mountains of Great Smoky Mountains National Park, indicating trees are under considerable stress, but are highest in trees growing on the highest, steepest slopes. Trees from Clingmans Dome have significantly higher maximum photosynthetic rates and water use efficiency than trees on other mountains, which may indicate stress resistance in this population. Additionally both photosynthetic water use efficiency and leaf architecture are affected by maximum July temperature, suggesting future climate change will impact the foliar physiology of Fraser fir. Measurements of nonstructural carbohydrate pools are consistent with those found in mature trees of other species which suggests the capacity for resistance of future stress events, particularly at the highest elevations where photosynthetic rates are the highest. v Preface 29 June 0627 The cold mountain fog makes coffee a necessity. Firs the color of smoke in the early Dawn light. I stumble toward the spring. Water, the life blood pouring out of the rocks of Mount Uyaye, Guardian Mountain of the Cherokee. Going to the Water, the first people's Holy Rite. I, too, am rising early, going to the water. Cleansing, invigorating, icy water-- Though pure no longer. When did filtration become essential on this holy mount? Are the spirits still here, or have they left the land, tainted by smog and ozone? A single snake shed, improbable in this altitude, holds my answer. A sign and a gift in the stiff dawn. vi Table of Contents Chapter 1 Introduction .......................................................................................................................... 1 1.1 A Review of Relevant Literature ............................................................................................ 2 1.1.1 Natural Variation within Species ....................................................................................... 2 1.1.2 Biogeography and Evolution of Fraser fir ........................................................................ 3 1.1.3 Southern Appalachian Spruce Fir-Spruce Forests ........................................................... 4 1.1.4 Tree Stress .............................................................................................................................. 5 1.1.5 Atmospheric Deposition ..................................................................................................... 5 1.1.6 Ozone ..................................................................................................................................... 7 1.1.7 Elevated Atmospheric CO2 ................................................................................................ 7 1.1.8 Climate Change .................................................................................................................... 8 1.1.9 Balsam Woolly Adelgid ..................................................................................................... 10 1.1.10 Multiple Stresses ...........................................................................................................