Environment

Study: Wildfire ‘suppression bias’ can lead to more intense, destructive blazes

Boise State Public Radio News | By Murphy Woodhouse

Published March 28, 2024 at 6:57 PM MDT

The Four Corners wildfire is burning west of Lake Cascade in Central Idaho.

It’s well understood that decades of trying to extinguish most blazes quickly is a major factor in the current wildfire crisis, in part by allowing for the buildup of brush and other fuels. However, new research points to another way that suppression makes intense fires more likely.

Because it’s easier to put out low- or moderate-intensity fires, more destructive fires account for a much larger portion of acres burned. This is the suppression bias discussed by University of Montana PhD candidate Mark Kreider and his coauthors in a recent Nature Communications paper.

“In contemporary fire management, which easily suppresses and removes low-intensity fire, this bias is inevitably toward higher-intensity burning occurring under extreme weather,” the paper says. “Thus, the fires which ecosystems, species, and people experience are skewed towards the most severe and destructive.”

Kreider added, “Through this … suppression bias, we're taking those inherent increases from climate change to fuel accumulation, and we're sort of tacking on an extra bump up in severity.”

Using thousands of wildfire simulations, he and his fellow researchers found that the bias increases severity as much as a century of fuel accumulation and climate in recent decades. And the amount of area burned increased much faster under a conventional suppression approach compared to allowing less intense fires to burn.

“The amount of area burned doubled every 14 years with conventional fire suppression under simulated climate change, instead of every 44 years when low- and moderate-intensity fires were allowed to burn,” Kreider wrote in a summary of the research in the Conversation. “That raises concerns for how quickly people and ecosystems will have to adapt to extreme fires in the future.”

Asked about the policy implications of the research, he said that “anytime that you can safely allow lower intensity fire to burn in more places, our paper shows that that is a good thing.”

But he also said that suppression isn’t inherently a bad thing, and is often necessary to “protect human lives and structures.”Proactive policies like home hardening, prescribed fire and fuels reduction can make it easier to let more moderate fires burn, according to Kreider.

This story was produced by the Mountain West News Bureau, a collaboration between Wyoming Public Media, Nevada Public Radio, Boise State Public Radio in Idaho, KUNR in Nevada, KUNC in Colorado and KANW in New Mexico, with support from affiliate stations across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting.