Department Seminar: Park Williams

Title: Using fire and ecosystem modeling to understand the increase in western U.S. forest-fire activity over the past four decades

Abstract: Since the mid-1980s the annual area burned in the western U.S. has increased by approximately 300%. In forested areas, the increase has exceeded 1000%. Simple regression analyses strongly suggest that this increase has been largely driven by warming and drying trends and climate models indicate that anthropogenic climate change has been an important contributor to these trends. However, these regression results tend to paint an overly simplistic picture. For example, fuel characteristics as well as ignitions suppression efforts from humans, which are all spatially heterogeneous and have changed substantially in areas over the past century, strongly modulate the ability of aridification to promote wildfire. In this talk I will use new, spatially explicit forest-fire and forest-ecosystem models that colleagues and I have developed for the western U.S. to present a preliminary assessment of the magnitude and spatial structure of the contribution of anthropogenic climate change to observed changes in western U.S. forest-fire activity over the past four decades, providing insights for what to expect in the coming decades.