Pine needles, deciduous leaves, and downed woody debris accumulate in the absence of fire along with grass and other dead plant material. This build-up of woody and herbaceous fuels increases the risk of hazardous wildfires. Fuel and fire managers benefit from knowing how much fuel has accumulated since the last wildfire.
U.S. Forest Service researchers and their partners mapped fuels using airborne light detection and ranging (LiDAR), a type of laser altimetry, and compared estimates to traditional measures of fuel biomass collected in destructive sample plots. They also measured thermal energy (heat) from five actively burning fires using a thermal infrared camera deployed on board the same aircraft used to collect the LiDAR data. By integrating the repeated measures of heat flux imaged over the whole duration of the fire, the total energy released was mapped across the entire burn area.
Previous research on small experimental fires shows that thermal energy released by a fire is linearly related to the fuel consumed. Subsequent comparison of the fuel loads, mapped from airborne LiDAR and the thermal energy release, mapped from airborne thermal imagery, revealed that this trend also holds at the landscape-scale for prescribed burns.
Surface fuels can be mapped from airborne LiDAR and associated fuel plot data.
The amount of heat radiated from a fire is indicative of the amount of fuel consumed.
Fuel loads and fire energy were linearly related when compared across sample units on five fires.
Data from this project is available through the U.S. Forest Service Research Data Archive:
RxCADRE: Prescribed fire combustion and atmospheric dynamics research experiment