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Document Type
Poster
Publication Date
Fall 10-1-2026
Abstract
In recent decades, there has been a global decline in tree populations, and in this large-scale forest dynamics plot, we observed a change from accruing biomass(the organic material that trees store) to losing it. Many studies suggest that this trend may become more common, but few look for the mechanisms behind it. This study explores how much two factors, trees growing to their maximum size and non-indigenous pests and pathogens, contribute to the observed mortality and loss of biomass. We conducted an annual mortality census of all trees over ten centimeters wide on the plot using ArcGIS fieldmaps to add to a growing dataset of over eighteen years of censuses. For the analysis, twelve censuses were used to estimate how much mortality was due to each of the factors individually, combined with ForestGEO’s allodb package in Rstudio and building on past ForestGEO work. The results showed that the majority of trees were not wide enough to have size as the leading cause of their mortality, and that much of the mortality over the past twelve years has been due to non-indigenous pests and pathogens, such as Beech Leaf Disease, Emerald Ash Borer, and Oak Decline. After ruling out size and quantifying pests and pathogens as factors, further research will be conducted into other factors leading to tree mortality, such as global change drivers like CO2 or Nitrogen oxides, or ecological factors including competition.
Department
ForestGEO Ecosystems & Climate Lab, Smithsonian Conservation Biology Institute
Project Mentor
Dr. Kristina Anderson-Teixeira
Recommended Citation
Shivers, Charlie IV '28, "Investigating Factors of Tree Mortality" (2026). Annual Student Research Poster Session. 260.
https://scholarship.depauw.edu/srfposters/260
Funding and Acknowledgements
Funding provided by an NSF REU grant through the Smithsonian-Mason School of Conservation, and through an LTREB grant provided by the NSF to the ForestGEO Ecosystems & Climate Lab. A special thanks to Dr. Kristina Anderson-Teixeira and Dr. Luca Morreale for their mentorship.