A new study from researchers in the Department of Environmental Science, Policy, and Management and the UC Berkeley Center for Fire Research and Outreach—published online in advance of print in Environmental Research Letters—demonstrates that vegetation management and firefighting play major roles in determining fire risk in California.
Using 65 years of historical fire data, authors Van Butsic, Carlin Starrs, William Stewart, and Connor Stephens reveal that on comparable lands, federal ownership, federal firefighting, and “reserve” designation were associated with significantly higher fire probability. This difference increased over time: wildfires in the most recent time period (2000-2015) were 2-3 times more common on federally owned lands compared to similar non-federally owned lands.
A possible explanation for the greater increase in fire probability on federally owned lands, the study says, is a desire to increase fire frequency in an effort to restore historic fire management practices. This is further supported by the universally higher rate of fire frequency on lands categorized as “reserve”—typically parks and wilderness areas primarily managed for ecological benefits. In these areas, there is evidence that reintroducing fire can restore natural ecosystem functioning with limited risk to homes and people.
For lands where restoring historic fire regimes is not practical or appropriate—such as those adjacent to cities, or areas where it not possible to safely introduce fire—this study offers evidence that it is possible to successfully mitigate fire risk through vegetation management and firefighting. Although non-reserve lands generally permit activities such as grazing and commercial timber harvesting, these practices are more common on non-federal lands. While this study did not directly measure the effect of these activities, use of these tools declined more drastically on federal land post-1970s than on non-federal lands, and may offer another explanation for why fire frequency diverged so sharply between land ownerships over this time frame, with the greatest increase in fire frequency on federal lands. This is in line with other research, which has shown that intelligent application of these tools to reduce fuel loads can lead to decreased fire risk. “We are not simply at the mercy of climate change—there are known practices that can successfully be applied,” says Butsic.
While fire has always been an issue in California, the 2017 fire season has put fire as a major priority among state legislators. Governor Jerry Brown’s January 2018 State of the State speech highlighted the need to “review thoroughly the way our forests are managed and suggest ways to reduce the threat of devastating fires.” As Starrs notes, “Our research shows that land managers, firefighters, and other stakeholders need to work together to proactively address fire risk.”