EFFECT OF FUEL TREATMENTS ON CARBON FLUX DURING A WILDFIRE USING SATELLITE IMAGERY: OKANOGAN-WENATCHEE NATIONAL FOREST

摘要

Forests are one of the largest stores of terrestrial carbon and can be a significant source of carbon during wildfire events. To mitigate the severity of fires and corresponding carbon flux, forest managers can utilize a variety of fuel treatments including tree harvesting and prescribed burning. The relative effect of fuel treatments on carbon flux from a 70,000-ha fire, the Tripod Complex fire, in north central Washington State was evaluated. Ground-based measurements to determine forest biomass were done in ten treatment units inside the Tripod Complex fire perimeter. The biomass measurements were compared to normalized difference vegetation index and gross primary productivity, along with others, derived from MODIS and Landsat imagery to evaluate the change in carbon sequestration rates of the ecosystem, both before and after the fire. Carbon dioxide emissions from the wildfire were also calculated. On average, the ten treatment areas were found to emit 71% less CO2 m~(-2) during the fire when compared to the emissions from the total fire area. Treatment areas were also found to retain higher rate of primary productivity, on average 120 g C m~2, than the remainder of the fire. While it is not feasible to treat entire forests, in the future the effect fuel treatments have on carbon flux should be considered.