Stanford Researchers Publish First Paper to Quantify How Much Protection We Get From Beneficial Fires

Five years after the Camp Fire, the deadliest fire in California’s recorded history, the state is still grappling with how to prevent wildfire destruction and live in harmony with natural fire.

New research published Friday from Stanford University and Columbia University points the way forward. In it, researchers quantify for the first time the magnitude of protection an area enjoys following a mild, beneficial fire — such as a prescribed fire — and how long that protection lasts.

The authors find that after an area has experienced low-intensity fire, the likelihood of a future high-intensity fire — the kind that grows out of control and takes out neighborhoods — is reduced by 64%. The protection lasts at least six years and then diminishes after that.

“It totally substantiates what we already see on the ground and what we already know to be true, which is that low- to moderate-severity fire begets more of the same,” said Lenya Quinn-Davidson, the director of the UC Ag and Natural Resources Fire Network.

Xiao Wu, lead author, hopes policy makers will pay attention.

“We really provide a practical solution to fight against wildfires,” said Wu, now at Columbia University. “This is a critical moment for both federal and state policymakers.”

Congress is currently reassessing the U.S. Forest Service’s wildfire strategy as part of reauthorizing the Farm Bill. Both the U.S. Forest Service and the state of California are proposing dramatically increasing their use of prescribed fire.

The research may also find an audience among local officials and the public health community.

“There are debates in terms of the risk and the benefits of using prescribed fire,” Wu said. “This could help fill out the terms of that cost-benefit equation.”

While prescribed and low-intensity to moderate-intensity fires tend to leave an area much safer, they do come with risks of their own. Prescribed burns generate smoke and in some rare instances can escape control. Also, this research indicates there is little advantage to burning too often — it would just produce needless smoke.

To do the analysis, the research team looked at 20 years of satellite data in California over most of the state’s forested areas. Satellites can detect not just the location but also the intensity of, or heat radiated by, a fire. After analyzing all detectable fires and categorizing for intensity, the team could then see how likely a high-intensity fire was to burn in the same area in subsequent years.

To gather enough data for a robust statistical analysis, the researchers included low-intensity natural fires alongside prescribed fires. These fires mostly stay on the ground and do not destroy tree canopy. The authors say this is the first study to assess how much protection, both in size and duration, beneficial fires give at such a large scale — in all forests in California.

Quinn-Davidson, who frequently advises policy makers on fire resiliency, says this paper points to an important, but often overlooked fact: a mild wildfire can be just as good as a prescribed fire for cleaning up overgrown vegetation and promoting fire safety.

“It doesn’t matter if it’s prescribed fire or if it’s wildfire, if it’s having good effects on the ground. Those effects last for multiple years and change the trajectory of future fire,” she said, adding this should spur more conversations about intentionally managing wildfires to behave like prescribed fires.

“We can’t keep talking about wildfires if it’s always catastrophic. We need to assess where the areas that had good fire are and what that’s going to mean for the next fire that comes through. And this paper helps us think about that.”