Fire suppression methods increase the severity of wildfires

The global surge in extreme wildfires has sparked an urgent re-evaluation of current wildfire management practices. A recent study led by the University of Montana has found that the prevalent approach of fire suppression not only fails to mitigate wildfire severity but, paradoxically, may lead to more devastating fires by intensifying the conditions under which wildfires burn.

Fire suppression has unintended consequences

Using sophisticated computer simulations, the experts discovered that a policy of blanket wildfire suppression contributes to fires with more severe ecological consequences, further fueled by climate change and the accumulation of combustible materials in forests.

“Fire suppression has unintended consequences,” said lead author Mark Kreider, a Ph.D. student in forest and conservation sciences at the University of Montana. “We’ve known for a long time that suppressing fires leads to fuel accumulation. Here, we show a separate counter-intuitive outcome.”

A landscape more prone to severe wildfires 

To explain this, the researchers introduce the concept of “suppression bias,” highlighting how current firefighting efforts, while reducing the total area affected by fires, disproportionately eliminate low- and moderate-intensity fires. This, in turn, leaves a landscape more prone to severe wildfires.

“Over a human lifespan, the modeled impacts of the suppression bias outweigh those from fuel accumulation or climate change alone,” Kreider said. “This suggests that suppression may exert a significant and underappreciated influence on patterns of fire globally.”

Fire suppression exacerbates the challenges of climate change

Supported by a National Science Foundation Graduate Research Fellowship, Kreider’s doctoral work reveals that suppression strategies exacerbate the challenges posed by climate change and fuel buildup, potentially accelerating the increase in burned areas by three to five times compared to scenarios without suppression efforts. “By attempting to suppress all fires, we are bringing a more severe future to the present,” he warned.

Andrew Larson, Kreider’s doctoral advisor and a professor of forest ecology, emphasized the ecological implications of favoring suppression, noting the disruption to natural forest regeneration processes and potential alterations to evolutionary pressures on flora and fauna.

Altering natural selection with fire suppression

“Traditional suppression removes the low-severity fires that help perpetuate healthy forests by consuming fuels and preferentially killing thin-barked tree species. I wonder how much we are altering natural selection with fire suppression by exposing plants and animals to relatively less low-severity fire and relatively more high-severity fire,” he explained.

However, the study also offers a glimmer of hope, suggesting that a more nuanced approach to fire management – allowing for low- and moderate-intensity fires under controlled conditions – can mitigate or even reverse the adverse effects of the suppression bias.

Such a strategy, which entails letting fires burn when conditions are less severe, could lead to a reduction in overall fire severity and a more sustainable rate of area burned.

Effective strategies and technologies are needed

“It may seem counterintuitive, but our work clearly highlights that part of addressing our nation’s fire crisis is learning how to accept more fires burning when safely possible,” said study co-author Philip Higuera, a professor of fire ecology at the University of Montana.

Professor Higuera highlighted the importance of this approach alongside other critical measures such as addressing climate change and reducing human-caused fire ignitions.

The experts stress the necessity of developing and implementing effective strategies and technologies to manage wildfires under moderate conditions. This balanced approach is essential for confronting the fire crisis, alongside broader efforts to mitigate climate change and decrease accidental ignitions.

The study is published in the journal Nature Communications.

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