This brief discussed a 2012 study that indicates less than 20% of national forest and national park lands in the Sierra Nevada are experiencing fuels treatments needed to mitigate continuing degradation from either the lack of fire or wildfire burning at high severity.
North, M., B. Collins, S. Stephens. 2012. Using fire to increase the scale, benefits, and future maintenance of fuels treatments. Journal of Forestry 110(7):392-401.