Prescribed burns are key to reducing wildfire risk, but federal agencies are lagging
LOS ANGELES — When wildfire burned through a federal research area in Klamath National Forest this summer, scientists were dismayed to see more than 20 years of work go up in smoke.
But when they returned to the charred study area near California’s northern border, they realized they’d been given a unique opportunity.
Although the scientists had set out to understand how the thinning and controlled burning of vegetation could help regrow large trees more quickly, they now had a chance to study another urgent question: Could these same treatments make forests more resilient to wildfire? Or more specifically, could they moderate fire behavior so that flames were less intense and firefighters would have a better chance of snuffing a blaze before it barreled into a populated area?
The answer appeared to be a resounding yes.
“In areas where we didn’t do anything, the untreated controls, the predominant fire behavior was a crown fire which killed every tree and consumed the entire tree crown,” said Eric Knapp, research ecologist with the U.S. Forest Service.
However, the plots that had been thinned and then treated with broadcast burning — in which an area of land is set alight to mimic naturally occurring wildfire — emerged relatively unscathed, he said.
The results, once confirmed, will rank among the strongest scientific evidence supporting the effectiveness of these so-called fuels treatments, Knapp said. But they were not unexpected. Researchers have found in the past that the best outcome is reached by the combination of thinning crown fuels, or tree canopy, and burning surface fuels, or vegetation on the ground.
Despite this knowledge, however, the federal government, which manages about 57% of the forested land in California, has completed only half of the fuels treatments it had hoped to get done in the state for the year — a statistic that profoundly dismayed wildfire experts.
As of mid-September, the Forest Service had completed or contracted out fewer than 37,000 acres of prescribed fire projects in California since Oct. 1, 2020. The majority was the burning of stacks of vegetation that had been piled after thinning, in which crews prune branches or cut down smaller trees, often using chain saws or cranes.
An additional 6,063 acres of managed land included naturally ignited fires that were allowed to burn — a practice the Forest Service suspended after it came under heated criticism over the summer.
Another 5,000 acres were treated with broadcast burning, which in combination with thinning has shown to be most effective.
“That’s just depressing,” said Lenya Quinn-Davidson, fire adviser for the University of California Cooperative Extension. “That’s so little, given how much land the Forest Service manages in California. It is just a drop in the bucket.
“I think it speaks to the need for such drastic change around prescribed fire.”
In total, the Forest Service had, as of Sept. 17, met about 54% of its goal of treating 238,200 acres in the state during the fiscal year, which ended Sept. 30. The target does not discriminate between prescribed burning and other methods of vegetation removal. Those include grazing, thinning, chemical treatments such as herbicide, and disposing of the thinned vegetation, including biomass removal, chipping, crushing and piling.
The U.S. Bureau of Land Management and the National Park Service, which manage much less forested land in California, didn’t fare any better. The NPS performed a total of 616 acres of broadcast burning in the state so far this calendar year; the BLM plans to burn about 300 acres but has yet to begin.
Officials say the lag in forest treatment is due to several factors, including lack of funding and personnel, but also to fundamental changes in the fire season. They say that drought, climate change and fuel overloading have stretched out the season and narrowed the time frame in which prepared burns can be conducted.
“There’s a lot of structural issues that need to be overcome to burn at the scale that is needed,” Knapp said.
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The Klamath study, dubbed the Goosenest Adaptive Management Area, is a patch of old timberland that was heavily logged before it was turned over to the Forest Service in the mid-1950s. Before it was privately managed, fires had burned through the area every nine years or so, but by the time researchers began to focus on the area, it had not burned in decades, Knapp said.
The parcel was crowded with young trees competing for light and resources, and they had transitioned from primarily pine to fir, which is less fire- and drought-tolerant, he said.
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