Paper Reviewed
Hanson, C.T. and Odion, D.C. 2014. Is fire severity increasing in the Sierra Nevada, California, USA? International Journal of Wildland Fire 23: 1-8.

According to Hanson and Odion (2014), "there is widespread concern about an increase in fire severity in the forests of the western United States," citing Agee and Skinner (2005), Stephens and Ruth (2005) and Littell et al. (2009); but they say that prior studies of the subject have "provided conflicting results about current trends of high-severity fire," possibly due to the fact that they "have used only a portion of available fire severity data, or considered only a portion of the Sierra Nevada." In an effort to help resolve this conflict, using remote sensing data obtained from satellite imagery to assess high-severity fire trends since 1984, Hanson and Odion analyzed the entire region included within the Sierra Nevada Ecosystem Project (SNEP, 1996), which includes all of the Sierra Nevada and the southern Cascade mountains located within California.

In discussing their findings the two researchers say they could find "no trend in proportion, area or patch size of high-severity fire," while also noting that "the rate of high-severity fire has been lower since 1984 than the estimated historical rate." And in the concluding paragraph of their paper, Hanson and Odion say their results suggest that the predictions that there will be excessive, high-severity fire throughout the Sierra Nevada in the future "may be incorrect."

References
Agee, J.K. and Skinner, C.N. 2005. Basic principles of forest fuel reduction treatments. Forest Ecology and Management 211: 83-96.

Littell, J.S., McKenzie, D., Peterson, D.L. and Westerling, A.L. 2009. Climate and wildfire area burned in western US ecoprovinces, 1916-2003. Ecological Applications 19: 1003-1021.

SNEP. 1996. Sierra Nevada Ecosystem Project, Final Report to Congress, Vol. I. University of California at Davis, Centers for Water and Wildland Resources, Davis, California.

Stephens, S.L. and Ruth, L.W. 2005. Federal forest-fire policy in the United States. Ecological Applications 15: 532-542.