A recent study shows that more wildfires start on private land than on national forests, indicating that wildfire prevention might be more effective if it focuses on people, not forests.

Last week, the journal Nature published an Oregon State University study showing that recent wildfires have been more likely to burn their way onto national forests than escape from them. The results are based on information from more than 22,000 wildfires that have burned across one or more jurisdictional boundaries in the West over the past 27 years. Scientists from Colorado State University and the Forest Service’s Rocky Mountain Research Station contributed to the research.

Between 1992 to 2019, cross-boundary fires consumed slightly more than 17 million acres, and about half of the burned area was Forest Service land. The data showed that ignitions on Forest Service land resulted in fewer than 25% of the most destructive wildfires – those causing the loss of more than 50 structures.

“In the old framing, public agencies bear the primary responsibility for managing and mitigating cross-boundary fire risk and protecting our communities, with their efforts focused on prevention, fuel reduction and suppression,” Chris Dunn, OSU College of Forestry researcher, told Wildfire Today. “This has been the dominant management approach of years past, which is failing us.”

With more people building homes in the wildland-urban interface over the past 30 years, the chances of people starting forest fires on their own property has increased. A 2018 University of California study showed that the number of new houses built in the WUI between 1990 and 2010 had increased 41% while the amount of land being used as residential property increased by a third.

Add to that the fact that 85-90% of all wildfires are now caused by people instead of lightning. While people start some of those fires on public lands by being careless with campfires, they start more fires on private land. A study published in 2020 found that nationwide, almost a third of wildfires started in the WUI, even though the WUI accounts for only 10% of the nation’s land area. And within the WUI, almost 100% of the fires were human-caused.

People are now more likely to lose a home due to their neighbors starting a fire than from a public lands fire. For example, in the Seeley Lake area, the Braulik family lost their home last year because a man on their neighbor’s property had illegally strung an electrical wire from a nearby power line to a structure, which started a fire.

This is why for at least the past decade wildfire experts have been warning that increased development of the WUI would lead to more wildfires. Prevention efforts on private land in the WUI could eliminate at least a third of wildfires, but it requires increased emphasis on reducing fuels in the home ignition zone.

It’s why fire behaviorists like Missoula’s Jack Cohen advocate for a greater focus on making homes and property more fire-resistant. Dunn, Cohen and others emphasize that less priority and federal money should be put on logging national forests.

“The main source of our communities’ exposure to wildfire risk is clearly not our national forests,” Dunn said.

In Oregon, the 2021 Legislature passed a bill that requires that those living in areas identified as being at high risk of wildfire offset that risk by ensuring their home ignition zone – defined as the region within 200 feet of the main structures – is free of debris and vegetation.

As Dunn concludes in his paper, “given that private lands are where most high-value assets are located and where most (cross-boundary) fires originate, communities and private landowners may be best positioned to reduce losses from (cross-boundary) wildfire.”

Contact reporter Laura Lundquist at lundquist@missoulacurrent.com