Fire-Driven Forest Transitions in Response to Land-Use Impacts and Moisture Availability

Portland State University, Portland OR

Investigators

Abstract

This research project will investigate the complex ways in which changing environmental conditions, changes in types and abundance of fuels, and wildfires have altered forest patterns and regeneration dynamics in forest ecosystems. This project will offer new insights regarding how environmental variability and land-use practices affect the probability of extreme fire events, and it will provide a better understanding of the ecological processes and human-related factors that are responsible for rapid shifts from forest to non-forest vegetation. The project has the potential to improve modeling of forest resilience, advance scientific understanding of factors affecting the occurrence of forest fires, and provide valuable support to the resource-management community. The investigators will interact with forest and national park managers to address land management challenges caused by increased occurrence of extreme wildfire events. The project will open new pathways into science, technology engineering, and mathematics and provide research experiences for undergraduate and graduate students, including students from underrepresented minority groups. The global increase in wildfire activity is causing shifts from forest to non-forest vegetation types in many regions of the world. These changes have important implications for future supplies of forest products and other forest benefits. Knowledge of where and when wildfire occurs and how wildfire alters the potential for subsequent wildfires is critical for understanding the long-lasting, fire driven shifts in ecosystem states. The research will address two basic geographic questions: (1) What are the conditions and mechanisms that initiate shifts from forests to more fire-prone vegetation types? (2) What are the factors and mechanisms that tend to favor continued dominance of the more fire-prone vegetation and impede tree regeneration? The project will be conducted in a summer-dry, temperate forest ecosystem that is widely recognized as a region that is highly sensitive to long-lasting shifts in forest covers and forest collapse driven by environmental factors and land-use practices. The investigators will integrate broad-scale spatial modeling of fire and vegetation changes with intensive, fine-scale field measurements and analytical field experiments of microclimate and tree regeneration. Findings from this project will provide new understandings about global land-use practices and ecological processes relevant to increased occurrence of extreme fire events that factor in rapid shifts from forest to non-forest vegetation. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.