Differences in wildfires among ecoregions and land management agencies in the Sierra Nevada region, California, USA

Recent research has indicated that in most of the western United States, fire size is increasing, large fires are becoming more frequent, and in at least some locations percentage of high-severity fire is also increasing. These changes in the contemporary fire regime are largely attributed to both changing climate and land management practices, including suppression of fires and past timber harvesting, over the last century. Fire management, including suppression and using wildfire for resource benefits, varies among federal land management agencies, yet no published studies have directly compared fire statistics between federal land management agencies in our study area. The primary response to wildfire on Forest Service areas is immediate suppression, while the National Park Service is more likely to use wildfire for resource benefits. We use fire perimeters and satellite-derived estimates of fire severity to compare fire statistics for wildfires (fire size, percentage of high-severity fire and high-severity patch size) among ecoregions, forest types, and land management agencies 1984-2009 in the Sierra Nevada, Southern Cascades, and Modoc Plateau of California, USA. High-severity patch size and percentage of high-severity fire, regardless of forest type, were less ( P < 0.05) in Yosemite National Park than on Forest Service lands. Yosemite fires were smaller on average than fires on Forest Service lands on the east side of the Sierra Nevada, southern Cascades and Modoc Plateau. Depending upon whether fires that crossed boundaries were included or not, mean size of Yosemite fires was either smaller or not significantly different from Forest Service fires on the west side of the Sierra Nevada. Even under current conditions, it appears that fire management practices that emulate those used in Yosemite could moderate effects of past land management, restoring and helping to maintain old forest conditions within the greater Sierra Nevada region, including the southern Cascades and Modoc Plateau.