New research from the University of California, Davis, reveals that low- and moderate-severity wildfires may help reduce the intensity of future fires for up to 20 years in specific climates. The findings offer critical insights for forest management and wildfire risk reduction.
Not all forest fires leave a trail of destruction. New research by the University of California, Davis, reveals that low- and moderate-severity wildfires can significantly reduce the intensity of future fires for up to 20 years in certain climates, providing a much-needed silver lining in the fight against increasingly frequent wildfires.
The study, published in the journal Ecological Applications, highlights that the effects of these less severe fires in mitigating future blaze intensity can persist even under extreme weather conditions such as high temperatures, strong winds and drought. This breakthrough offers a promising perspective for land managers and ecologists who are tackling the heightened risk of wildfires fueled by climate change.
“We’re living in a time with increasing wildfire, which poses challenges for our communities and landscapes,” lead author Claire Tortorelli, an ecologist for the U.S. Forest Service who conducted the research as a doctoral student at UC Davis, said in a news release. “Some previous fires can have moderating effects on future fire behavior. It’s important to understand how past wildfires are going to affect what happens in the future.”
Bridging the Knowledge Gap
Previous studies have predominantly focused on high-severity fires, leaving a gap in understanding the impact of less intense fires. Tortorelli and her colleagues aimed to fill this void by examining more than 700 reburn fires over the last 50 years across the western United States using satellite remote sensing.
In addition to assessing the severity of both the initial and subsequent fires, the team evaluated factors such as weather, forest type and overall climate. They then modeled the reburn severity to gauge how long the initial mitigating effects would last under various conditions.
The researchers found that coastal California and Southwestern forests showed the longest-lasting effects compared to those in the Sierra Nevada and Cascade ranges.
“It’s all about the vegetation and fuels that are coming back after fire,” Tortorelli added. “We still need a more nuanced understanding of local fuels for managers to know how their specific system is going to burn in a future fire or how soon to come back and re-treat.”
Enhancing Forest Management
The findings could revolutionize approaches to wildfire management. By leveraging the moderating effects of low- and moderate-severity fires, land managers might be better equipped to plan and execute risk mitigation strategies. The study suggests that follow-up treatments, such as prescribed burns or mechanical thinning, can extend the protective benefits of the initial low-severity fires.
“We can leverage lower severity fires as a kind of initial fuel reduction treatment,” added Tortorelli. “While I don’t think they’re going to do all the work for us, and we need to pair them with management actions, they can do some of the heavy lifting, especially that initial lift.”
A Widespread Impact
The implications of this study could be vast, affecting even regions that have experienced high-severity wildfires. Andrew Latimer, a co-author and professor in the Department of Plant Sciences at UC Davis, emphasized that many high-severity fires contain areas that burn with lower intensity.
“If you add up how much area that is, that’s way more than we’ve so far been able to treat through mechanical thinning and prescribed burning, and so it’s the biggest form of fuel reduction that’s happening,” Latimer said in the news release. “It opens this window of opportunity to keep forests in good shape.”
The research, supervised by Derek Young in the Department of Plant Sciences, was supported by the University of California National Lab Fees Research Program.
By providing a better understanding of how low- and moderate-severity wildfires can serve as natural mitigators, this study offers hope and actionable insights for more effective wildfire management amidst a changing climate.