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1923360 
Journal Article 
Quantitative Evidence for Increasing Forest Fire Severity in the Sierra Nevada and Southern Cascade Mountains, California and Nevada, USA 
Miller, JD; Safford, HD; Crimmins, M; Thode, AE 
2009 
Yes 
Ecosystems
ISSN: 1432-9840
EISSN: 1435-0629 
12 
1 
16-32 
WOS:000263794200002 
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 km 2) 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. 
California; fire ecology; fire severity; burn severity; Sierra Nevada; Sierra Nevada Forest Plan Amendment; relative differenced Normalized Burn Ratio