The flux of carbon in trees is integral to their functioning; nearly every physiological process requires energy that is ultimately derived from carbon. Yet, a central question is how the carbon balance of trees is impacted during disturbance, particularly drought. To evaluate tree carbon dynamics during drought I leverage experimental and computational approaches to disentangle underlying patterns and processes. I begin with an ecosystem scale field experiment and demonstrate a coupling between photosynthesis and growth that portends the depletion of carbon reserves in a semi-arid conifer. Using a separate ecosystem drought experiment, I attribute carbon stores to the de novo synthesis of defenses in Pinus edulis. I demonstrate how carbon reserves alone cannot support a sufficient defense response in this species. I then use the biochemical network of plant carbon metabolism to derive a neutral theory of plant carbon flux dynamics. Neutral theory suggests that random flux dynamics can explain variation in carbon pool sizes often observed in the literature. Most importantly, it highlights that allocation to carbon reserves is the most probable event, regardless of its functional role in tree survival. Finally, I discuss recent work that incorporates dynamical systems theory with the carbon reserve formation in trees and how it can improve models of ecosystem carbon flux.
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Details
Title
The carbon balance of trees
Creators
Robert Alexander Thompson
Contributors
Henry D Adams (Advisor)
Nate G McDowell (Committee Member)
Michael G Ryan (Committee Member)
Arjan Meddens (Committee Member)
Nikolay Strigul (Committee Member)
Awarding Institution
Washington State University
Academic Unit
School of the Environment (CAHNRS)
Theses and Dissertations
Doctor of Philosophy (PhD), Washington State University