Date of Award
2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Natural Resources
First Advisor
Anthony W. D'Amato
Abstract
Climate change is expected to impact forests in many ways. Changing temperatures, seasonal patterns, and storms may increase tree vulnerability to drought, frost, ice, and snow damage. Altered moisture regimes are expected to lead to more frequent droughts and heavy rain events. Invasive plants and insects are predicted to increase in abundance as temperatures warm. These threats are exacerbated by losses of structural complexity and compositional diversity in many temperate forests, both of which support adaptive capacity. One of several adaptation frameworks that have been developed to test potential silvicultural strategies to help forests adapt to unexpected and novel conditions centers on an adaptation gradient of resistance, resilience, and transition (RRT). Within this framework, adaptive silvicultural treatments have been co-developed based on best available science and informed by current management capabilities, but a key knowledge gap exists in how post-treatment forest structural and functional conditions generated by this framework fit with adaptation goals. To address this knowledge gap, we examined and quantified elements of forest structure, composition, and structural and functional complexity to better understand the adaptation mechanisms conferred by silvicultural treatments designed to address global change impacts.
First, we compared the application of this framework in two different ecosystem types and regions, red pine woodlands in the Lake States and northern hardwoods in New England, each of which faces distinctive challenges in a changing climate. By exploring the framework in forest types with different dominant drivers of ecosystem processes and associated vulnerabilities, we determined that pre-harvest stand conditions impact the outcomes of these treatments and require consideration. Next, we quantified large-scale spatial tree patterns in adaptation treatments in the context of canopy and resource complexity to elucidate potential resistance and recovery mechanisms afforded by the gradient of adaptation approaches in northern hardwood forests. Results showed that each adaptation treatment resulted in a unique spatial signature, reflecting objectives of each silvicultural treatment. Finally, we focused on the compositional and functional trait outcomes of three different adaptation approaches in the context of the forest regeneration layer, to provide insight into potential adaptation responses conferred by adaptive management strategies for global change. We found that adaptive management strategies led to notably different patterns of natural regeneration composition, but supplemental planting of future climate-adapted species better supported shifts in functional trait profiles.
Collectively, this work highlights the value of the RRT framework in designing approaches for climate adaptive forest management while providing valuable, region-specific outcomes of this framework that can be utilized by forest managers. Outcomes of this work suggest that these methods can be used to manage for desired future conditions centered on resistance, resilience, or transition in forested ecosystems, and provide examples of successful application of this framework, with quantified descriptions of their outcome on forest structures that support adaptive capacity.
Language
en
Number of Pages
195 p.
Recommended Citation
Wikle, Jessica, "Structural, Compositional, And Functional Outcomes Of Forest Adaptation In Northern Forest Ecosystems" (2024). Graduate College Dissertations and Theses. 1878.
https://scholarworks.uvm.edu/graddis/1878