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

Abstract

Abstract. 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.

Empirical Support for the Use of Prescribed Burning as a Fuel Treatment

“…where naturally ignited fires are allowed to burn for resource benefits if they do not pose a threat to assets and communities [60,61]). One such area is the Yosemite National Park (located in the Sierra Nevada mountains of Central California), where fires are smaller, less of the landscape is burned by high-severity fire and high-severity patches are smaller in comparison with other Californian regions (Southern Cascades and the Modoc Plateau) that are under a different fire management policy [60].…”

“…where naturally ignited fires are allowed to burn for resource benefits if they do not pose a threat to assets and communities [60,61]). One such area is the Yosemite National Park (located in the Sierra Nevada mountains of Central California), where fires are smaller, less of the landscape is burned by high-severity fire and high-severity patches are smaller in comparison with other Californian regions (Southern Cascades and the Modoc Plateau) that are under a different fire management policy [60]. Because of the length of time, the wildland fire use policy has been in effect in Yosemite, free-burning fires in mixed conifer forest types are now self-limiting: both fire size and fire severity are inhibited by recently burned areas, which under non-extreme weather conditions are very effective barriers to fire spread for up to 8 years after fire [62].…”

Climate Change Refugia, Fire Ecology and Management

“…We expand 'climate change and its biological effects' to explicitly include ecological processes such as fire. In addition, we consider the importance of land management practices because of how policies, such as fire suppression, have drastically changed fire frequency and severity patterns in many forests [16]. Climate, species interactions, ecological processes, and land management combine to create conservation challenges and opportunities for individual refugia ( Figure 1).…”

“…While overall temperatures are warming, the weather patterns that produce cold-air pooling at a landscape scale Fire is one example of a changing ecological process. Fire frequency and severity are changing world-wide due to land management [16][17][18][19][20] and climate change [19,[21][22][23]. Refugia populations are at a greater risk from changing fire patterns [21] due to their predisposition to local extinction because of their small, isolated nature, especially if the plants are fire avoiders [24].…”

Nature of Forest Fires in Uttarakhand:Frequency, Size and Seasonal Patterns in Relation to Pre-Monsoonal Environment

“…In California, USA, a lightning-induced fire may burn thousands of hectares of forest, with rotation period ranging from 95 to 974 yrs (ref. 2).…”