Quantitative Evidence for Increasing Forest Fire Severity in the Sierra Nevada and Southern Cascade Mountains, California and Nevada, USA.
Authors:
Miller, J. D. Safford, H. D. Crimmins, M. Thode, A. E. USDA, FS
Source:
Ecosystems. 2009 Feb., v. 12, no. 1 New York : Springer-Verlag, p. 16-32.
NALT Subjects:
wildfires forest fires fire severity montane forests temporal variation remote sensing image analysis Landsat spatial data vegetation structure vegetation cover climatic factors forest types fire ecology statistical analysis Sierra Nevada region (California) Nevada Western United States
Other Subjects:
Cascade Mountain region relative differenced Normalized Burn Ratio
Issue Date:
Feb-2009
Abstract:
Recent research has concluded that forest wildfires in the western United States are becoming larger and more frequent. A more significant question may be whether the ecosystem impacts of wildfire are also increasing. We show that a large area (approximately 120000 km²) of California and western Nevada experienced a notable increase in the extent of forest stand-replacing (“high severity”) fire between 1984 and 2006. High severity forest fire is closely linked to forest fragmentation, wildlife habitat availability, erosion rates and sedimentation, post-fire seedling recruitment, carbon sequestration, and various other ecosystem properties and processes. Mean and maximum fire size, and the area burned annually have also all risen substantially since the beginning of the 1980s, and are now at or above values from the decades preceding the 1940s, when fire suppression became national policy. These trends are occurring in concert with a regional rise in temperature and a long-term increase in annual precipitation. A close examination of the climate-fire relationship and other evidence suggests that forest fuels are no longer limiting fire occurrence and behavior across much of the study region. We conclude that current trends in forest fire severity necessitate a re-examination of the implications of all-out fire suppression and its ecological impacts.
