The Science Seminar Series: March 27, 2008 4pm

Connecting Wildland Fire Fuel Heterogeneity with Fire Behavior and Forest Ecology.

Dr. Joseph O’Brien

USDA Forest Service

Powell Hall

Time: 4:00 - 5:00pm

Abstract

Predicting wildland fire behavior and ecological impacts is challenging. Both wildfires and prescribed fires are complex phenomena due to the many interactions and feedbacks among fire, the atmosphere, fuel loads, and fuel arrangement. Furthermore there is a fundamental lack of information on the effects of fuel bed heterogeneity on fire. In the southern US, much fuel heterogeneity is fine scale and determined by the interactions among patches of understory vegetation and canopy supplied fine fuels. Most fire behavior and fuel models of pine dominated grasslands assume fuel homogeneity at all scales, which limits their utility in predicting fire effects. By combining the remote sensing platform LIDAR (LIght Detection and Ranging) with traditional point intercept sampling and biomass clip plots, we were able to characterize fine-scale variation in fuel bed architecture and the spatial distribution of fuels. Within-fuel bed variation was categorized into discrete patches, termed fuel cells. Fuel cells varied at sub-meter scales and had distinct fuel characteristics, architecture, and loading. Thermal image analysis, allowed us to measure in situ fire behavior at fine scales. When measured with this precision, fire behavior varied at the fuel cell scales within plots. Our data suggest that such fine-scale variation in fire behavior may regulate the recruitment of woody plants and impact future forest structure as well as drive plat community dynamics. Fuels cells can seamlessly interface with numerical models or cellular automata models of fire behavior, representing a promising means to predict within burn heterogeneity.