Could More Controlled Burns Have Stopped the L.A. Fires?

Once the fires stop burning in Los Angeles and the city picks itself up from the rubble, the chorus of voices asking how such a disaster could have been prevented will rise. In California, the answer to that desperate query is so often “better forestry management practices,” and in particular “more controlled burns.” But that’s not always the full story, and in the case of the historically destructive L.A. fires, many experts doubt that prescribed burns and better vegetation management would have mattered much at all.

Controlled burns are intentionally set and supervised by land managers to clear out excess fuels such as shrubs, trees, and logs to reduce wildfire risk. Many habitats also require fire to thrive, and so ensuring they burn in a controlled manner is a win-win for natural ecosystems and the man-made environment. But controlled burns also pose a series of challenges. For one, complex permitting processes and restrictions around when and where burns are allowed can deter agencies from attempting them. Community backlash is also an issue, as residents are often concerned about air quality as well as the possibility of the prescribed fires spiraling out of control. Land management agencies also worry about the liability risks of a controlled burn getting out of hand.

Many of the state’s largest and most destructive fires — including the Camp Fire in 2018, lightning complex fires in 2020, and Dixie Fire in 2021 — started in forests, and would therefore have likely been severely curtailed had the state done more controlled burns. According to ProPublica, anywhere between 4.4 million and 11.8 million acres used to burn annually in prehistoric California. By 2017, overzealous fire suppression efforts driven by regulatory barriers and short-term risk aversion had caused that number to drop to 13,000 acres. While the state has increased the amount of prescribed fire in recent years, the backlog of fuel is enormous.

But the L.A. fires didn’t start or spread in a forest. The largest blaze, in the Pacific Palisades neighborhood, ignited in a chaparral environment full of shrubs that have been growing for about 50 years. Jon Keeley, a research scientist with the U.S. Geological Survey and an adjunct professor at the University of California, said that’s not enough time for this particular environment to build up an “unnatural accumulation of fuels.”

“That’s well within the historical fire frequency for that landscape,” Keeley told my colleague, Emily Pontecorvo, for her reporting on what started the fires. Generally, he said, these chaparral environments should burn every 30 to 130 years, with coastal areas like Pacific Palisades falling on the longer end of that spectrum. “Fuels are not really the issue in these big fires — it’s the extreme winds. You can do prescription burning in chaparral and have essentially no impact on Santa Ana wind-driven fires.”

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We still don’t know what ignited the L.A. fires, and thus whether a human, utility, or other mysterious source is to blame. But the combination of factors that led to the blazes — wet periods that allowed for abundant vegetation growth followed by drought and intensely powerful winds — are simply a perilously bad combination. Firebreaks, strips of land where vegetation is reduced or removed, can often prove helpful, and they do exist in the L.A. hillsides. But as Matthew Hurteau, a professor at the University of New Mexico and director of the Center for Fire Resilient Ecosystems and Society, told me bluntly, “When you have 100-mile-an-hour winds pushing fire, there’s not a hell of a lot that’s going to stop it.”

Hurteau told me that he thinks of the primary drivers of destructive fires as a triangle, with fuels, climate, and the built environment representing the three points. “We’re definitely on the built environment, climate side of that triangle for these particular fires around Los Angeles,” Hurteau explained, meaning that the wildland-urban interface combined with drought and winds are the primary culprits. But in more heavily forested, mountainous areas of Northern California, “you get the climate and fuels side of the triangle,” Hurteau said.

Embers can travel impressive distances in the wind, as evidenced by footage of past fires jumping expansive freeways in Southern California. So, as Hurteau put it, “short of mowing whole hillsides down to nothing and keeping them that way,” there’s little vegetation management work to be done at the wildland-urban interface, where houses bump up against undeveloped lands.

Not everyone agrees, though. When I spoke to Susan Prichard, a fire ecologist and research scientist at the University of Washington School of Environmental and Forest Sciences, she told me that while prescribed burns close to suburban areas can be contentious and challenging, citizens can do a lot on their own to manage fuel risk. “Neighborhoods can come together and do the appropriate fuel reduction in and around their homes, and that makes a huge difference in wildfires,” she told me. “Landscaping in and around homes matters, even if you have 100-mile-an-hour winds with a lot of embers.”

Prichard recommends residents work with their neighbors to remove burnable vegetation and organic waste, and to get rid of so-called “ember traps” such as double fencing that can route fires straight to homes. Prichard pointed to research by Crystal Kolden, a “pyrogeographer” and associate professor at the University of California Merced, whose work focuses on understanding wildfire intersections with the human environment. Kolden has argued that proper vegetation management could have greatly lessened the impact of the L.A. fires. As she recently wrote on Bluesky, “These places will see fire again. I have no doubt. But I also know that you can rebuild and manage the land so that next time the houses won’t burn down. I’ve seen it work.”

Keeley pointed to the 2017 Thomas Fire in Ventura and Santa Barbara Counties, however, as an example of the futility of firebreaks and prescribed burns in extreme situations. That fire also ignited outside of what’s normally considered fire season, in December. “There were thousands of acres that had been prescribed burned near the eastern edge of that fire perimeter in the decade prior to ignition,” Keeley explained to Emily. “Once that fire was ignited, the winds were so powerful it just blew the embers right across the prescribed burn area and resulted in one of the largest wildfires that we’ve had in Southern California.”

Kolden, however, reads the Thomas Fire as a more optimistic story. As she wrote in a case report on the fire published in 2019, “Despite the extreme wind conditions and interviewee estimates of potentially hundreds of homes being consumed, only seven primary residences were destroyed by the Thomas Fire, and firefighters indicated that pre-fire mitigation activities played a clear, central role in the outcomes observed.” While the paper didn’t focus on controlled burns, mitigation activities discussed include reducing vegetation around homes and roads, as well as common-sense actions such as increasing community planning and preparedness, public education around fire safety, and arguably most importantly, adopting and enforcing fire-resistant building codes.

So while blaming decades of forestry mismanagement for major fires is frequently accurate, in Southern California the villains in this narrative can be trickier to pin down. Is it the fault of the winds? The droughts? The humans who want to live in beautiful but acutely fire-prone areas? The planning agencies that allow people to fulfill those risky dreams?

Prichard still maintains that counties and the state government can be doing a whole lot more to encourage fuel reduction. “That might not be prescribed burning, that might actually be ongoing mastication of some of the really big chaparral, so that it’s not possible for really tall, developed, even senescent vegetation — meaning having a lot of dead material in it — to burn that big right next to homes.”

From Hurteau’s perspective though, far and away the most effective solution would be simply building structures to be much more fire-resilient than they are today. “Society has chosen to build into a very flammable environment,” Hurteau put it. California’s population has increased over 160% since the 1950’s, far outpacing the country overall and pushing development further and further out into areas that border forests, chaparral, and grasslands. “As people rebuild after what’s going to be great tragedy, how do you re-envision the built environment so that this becomes less likely to occur in the future?”