Evaluating extreme drought-induced tree mortality and biomass loss in east Texas using Forest Inventory and Analysis (FIA) data

Background/Question/Methods

Forests in East Texas are important for lumber production, ecosystem services, and sustainable development. Although relatively wet years interspersed during droughts, East Texas has experienced frequent severe droughts over the past decade. Analyzing drought-induced tree mortality and biomass changes is critical in the region as forests are considered viable means to mitigate climate change impacts. Utilizing National Oceanic and Atmospheric Administration (NOAA) distributed climatic data, and USDA Forest Inventory and Analysis (FIA) Program; we evaluated baseline tree mortality, temporal and spatial patterns of drought-induced tree mortality and the associated aboveground biomass loss due to the 2011 extreme drought. Generalized mixed models were used to investigate the relationships between drought-induced tree mortality and tree attributes, key climatic variables and site characteristics. 

Results/Conclusions

We found significant increase in tree mortality and associated decrease in regional aboveground biomass as a consequence of the 2011 drought. The effects of the drought on forest growth and productivity, however, varied and were less significant. The spatial variation of the tree mortality and biomass loss were highly correlated with spatial drought distribution pattern. Tree mortality after the drought was more related to the length of the drought than that of drought severity. Our findings suggest that morality of trees due to direct and carry-over effects were related to survival strategies of tree species. Forest landscape simulation models will be used to improve our understanding on the longer-term drought effects on species composition, spatial pattern and forest dynamics.