Climate and wildfire area burned in western U.S. ecoprovinces, 1916-2003
The authors applied generalized linear models to large-scale, interannual and/or seasonal climate variables of precipitation, temperature, and the Palmer drought severity index (PDSI) to area burned across vegetation types of the western U.S.
The authors found that climate-fire relationships exist across the western U.S. with approximately 39% (1916-2003) and 64% (1977-2003) of area burned directly related to climate, however the strength of the seasonal or interannual effects of climate varied across the different vegetation types. Southwestern deserts and semiarid desert ecoprovinces tend to be fuel limited. Wetter conditions in the winter prior to the fire season followed by dry condition during the year of the fire resulted in greater area burned. The authors suggest that climate change may lead to one of two paths: first a reduction in fuels due to persistent drought, limiting area burned, or second, wetter conditions leading to an increase in vegetation biomass along with an earlier onset of warmer temperatures that dry these fuels and increase the area burned. The mountainous ecoprovince of Arizona and New Mexico also did not correlate to year-of-fire precipitation, but did have a relationship with precipitation from the winter previous. However, temperature during the year-of-the fire was related to area burned in these areas as well as annual (water year) PDSI.