A report published this week by researchers in Montana indicates that century-old policies to suppress wildfires as quickly as possible is actually contributing to more severe and larger fires over time. The study, published Monday in the journal Nature Communications, examines what the researchers call “suppression bias.”
They identify “suppression bias” as the consequences of knocking down low- and moderate-intensity fires: Other fires will burn hotter and scorch broader areas of forest and land, and people experience more of the most destructive fires, according to a story in the Daily Montanan. “Over a human lifespan, the modeled impacts of the suppression bias outweigh those from fuel accumulation or climate change alone. This suggests that suppression may exert a significant and underappreciated influence on patterns of fire globally,” lead author Mark Kreider, a doctoral candidate at the University of Montana, said. “By attempting to suppress all fires, we are bringing a more severe future to the present.”
On the other hand, the researchers said less suppression of lower-intensity fires might make firefighting easier in the future. Kreider authored the paper along with four other UM researchers and professors and an ecologist with the Aldo Leopold Wilderness Research Institute in Missoula.
They compare suppression bias when it comes to fire management to doctors overprescribing antibiotics. “In our attempt to eliminate all fires, we have only eliminated the less intense fires (that may best align with management objectives such as fuel reductions) and instead selected for primarily the most extreme events (suppression bias) and created higher fuel loads and more ‘suppression-resistant’ fires.”
The USFS estimates that 98 percent of wildfires are fully suppressed before they reach 100 acres in size – most of them within 72 hours. In Montana, fire managers try to contain fires as quickly as possible; Gov. Greg Gianforte said last year that crews kept 95 percent of fires in Montana to 10 acres or less in 2022.
Since the late 1800s and early 1900s, policies have largely focused on protecting timber and homes from burning.
Montana’s state fire policy, adopted in 2007, specifies that minimizing property and resource loss is the priority in fighting fire and is “generally accomplished through an aggressive and rapid initial attack effort.” The policy also says that forest management including thinning and prescribed fire improves forests and that inadequate practices to reduce interface risk could jeopardize Montanans’ constitutional right to a clean and healthful environment.
But as more development, particularly in the West, encroaches on the wildland/urban interface, a century of fire suppression and climate change has ballooned federal suppression costs from hundreds of millions a year in the 1990s to an average of $2.8 billion a year from 2018-2022 (NIFC data). Total annual acreage burned has doubled, on average, from what burned in the mid-1980s, and traditional fire seasons have increased by a month in duration, according to federal fire managers.
But the new research suggests that reducing suppression for low-intensity fires and allowing them to burn when conditions are good could mean that fire managers won’t face so many extreme fires in the future.
Last year, federal agencies updated the Cohesive Wildland Fire Management Strategy to include more prescribed burns and more fuels treatments to reduce risk of wildfires and to better account for climate change when modeling future forecasts.
Philip Higuera, a co-author of the paper and a professor of fire ecology at UM, said it may seem counterintuitive, but the research shows that accepting that more wildfires should burn (when it’s safe) should be the main takeaway. “That’s as important as fuels reduction and addressing global warming,” he said.
~ Thanks and a tip of the hardhat to Dick for this one.
