Assessing the Effects of Environmental Variables and Landscape Change on Tree Stands at The Ridges Land Lab

Abstract: This study explored the impacts of landscape variables on the tree stands of the Ridges Land Lab located in Athens, Ohio as assessed consequences of climate change on forest species composition. Understanding tree species composition within forest environments is crucial for effective forest management. Tree stands provide insights to disturbance regimes and are indicative of overall forest health. Forest stands have changed greatly due to human influences including climate change and are critical resources for understanding environmental change. I delineated ten standard plots and measured all contained trees to assess diversity, density, composition. I used a Digital Elevation Model (DEM) to record landscape variables. I assessed the effects of slope, aspect, and elevation on tree diversity and density and determined if landscape variables influenced tree stand composition. I also examined associations between shade tolerance, diameter at breast height (DBH), and species. No significant relationships were found between landscape variables and diversity or density. Significant relationships were found between shade tolerance and DBH and between DBH and species. Dominant species (white oak and sugar maple) abundances reflected their successional classes, revealing a lack of expected seedling white oaks. The observed species composition indicated features associated with landscape-scale mesophication, characterized by increased maples and declining oak populations due to the absence of fire regimes and climate change influences. This research contributes insights into the role of landscape variables and climate to forest succession.

All data, code, and the final report for this project are included in this repository.

Note: After reviewing this work with a better understanding of statistical methods, it has been determined that "shade tolerance" should have been treated as an ordinal variable rather than a nominal one. At this time, I do not believe that this has changed the findings of this study in an impactful way (Note added 5/2/2024).