Systematic Examination of Sensitivity and Thresholds in Growth of Tree Species to Potential Changes in Climate Patterns

Description: There is increasing evidence that climate change is directly and indirectly affecting biological processes of trees and forests. In many cases, however, it is unknown what that evidence means for entire landscapes over time due to our inability to model the affected, local, short-term processes impacted climate change in a way that identifies long-term, landscape-level impacts. For example, multiple aspects of climate (e.g., magnitude and variability of temperature and precipitation) affect the growth of trees through many complex processes (e.g., soil moisture availability, winter dormancy requirements, etc.) but, how can we identify the cumulative impact of these affects when they might take decades to be realized? We developed approaches to model how local processes impacted by patterns in temperature and precipitation under climate change affect the tree growth among regions and over the long-term in the eastern U.S.  Stand-based results for biomass and numbers of stems indicated that tree species were most sensitive to increases in minimum and maximum temperatures and reductions in monthly precipitation. The mechanisms through which these changes impacted stand growth varied by species and region and spanned geochemical, environmental, and physiological processes. We show that tree species are quite sensitive to potential changes in climatic factors and that this sensitivity manifested in different forms, including the presence of thresholds.

Thomas Bonnot is an Assistant Research Professor at the University of Missouri Columbia and a Co-Principal Investigator for NE CASC.