Mitigating Megafires through Controlled Burns: The Efficacy in California, Oregon, and Washington

The Fire Management staff of Inland Northwest National Wildlife Refuge has recently concluded a fifty-acre controlled burn at Turnbull National Wildlife Refuge, as part of the initiative to prevent larger wildfires. Ken Meinhart from USFWS gives credit for this.

Managed fires in certain strategic locations could significantly lessen smoke dispersion across the entire western U.S.

Wildfire smoke poses significant risk to air quality, public health, and ecosystems across the U.S. In comparison to other parts of the country, the West usually experiences higher exposure to wildfire smoke. This holds true even in light of the recent Canadian wildfires. Collaborative research by Harvard University, the U.S. Forest Service, and the National Oceanic and Atmospheric Administration reveals that managed fires—mainly in the coastal regions of northern California and the Pacific Northwest—have the potential to drastically curtail the extent of wildfire smoke exposure in rural communities and densely populated urban areas across the West. The research findings were released on June 14 in the Earth’s Future journal.

“Beginning from the early 1900s, fire suppression efforts in the West, along with global warming, have led to the escalation of severe wildfires. There has been a lack of research regarding how land management strategies could affect smoke exposure,” says Makoto Kelp, the study’s principal author, who acquired his Ph.D. from Harvard under the Atmospheric Chemistry Modeling Group.

Kelp’s co-author, Loretta Mickley, who is also the co-leader of the modeling group and a Senior Research Fellow at the Harvard John A. Paulson School of Engineering and Applied Sciences, explains, “Smoke is a harmful blend of gases and particulates. These particles are dangerous to inhale as they can penetrate deep into your lungs, triggering numerous acute and chronic diseases. The West has become more susceptible to extensive, severe wildfires due to warmer and drier conditions and the accumulation of underbrush. Introducing smaller, managed fires could hinder the propagation of uncontrollable wildfires. Even though these controlled burns produce smoke, the ultimate result is a net reduction in smoke pollution.”

The research team, after examining wildfire data from 2018 and 2020 and running computer simulations of how controlled burns would behave, discovered that such fires in specific areas of northern California, western Oregon, and eastern Washington could greatly decrease wildfire smoke exposure throughout the western U.S. Prevailing winds that carry smoke across the continent and dense vegetation that fuels smoky fires contribute to this effect.

Government records and satellite observations show that only a few managed fires were initiated for land management purposes in the West from 2015 to 2020. Using fire for clearing agricultural lands and managing habitats is a more prevalent practice in the East and Southeast U.S. While Indigenous communities in the West have historically conducted controlled fires, over the past century, land managers have endeavored to swiftly extinguish wildfires, fearing their destructive spread. This has led to a “fire deficit.”

However, the tide might be turning as more research endorses the benefits of controlled burns. In August 2022, the Biden Administration allotted nearly $2 billion in the Inflation Reduction Act for reducing wildfire fuel through controlled burns and land management techniques.

“Our models show that controlled burns should be directed towards areas with dense vegetation, especially those located west of the Sierras and the Cascades, and upwind of populated areas,” Kelp adds.

The team’s computer modeling amalgamates environmental, meteorological, chemical, and physical factors to forecast the spread of wildfire smoke and its effects on communities. “This layered approach in our model enhances our comprehension of how and where to decrease wildfire smoke exposure,” Kelp states. “Though controlled burns carry their own risks, we know they can be better managed over smaller parcels of land, leading to more efficient combustion and less pollution over several hours or days. Wildfires, in contrast, are unpredictable and can spread rapidly across extensive areas, enveloping populated regions with harmful smoke.”

Matthew Carroll, a program specialist at the USDA Forest Service Rocky Mountain Research Station and a co-author of the paper, emphasizes the far-reaching impacts of wildfire smoke. “Anyone familiar with wildfire-prone areas can confirm that smoke from wildfires can traverse vast distances and greatly impact air quality. Our capacity to utilize highly predictive models of physical phenomena to understand impacts on social landscapes was surprising. This research on the effects of smoke from wildfires and controlled fires on different communities and population centers can guide fire managers in planning effective and fair fuel treatments.”

Earlier studies suggest that wildfire smoke disproportionately affects communities predominantly composed of people of color or a high number of individuals living below the poverty line. Although monitoring of wildfire smoke and its effects on public health has increased in urban population centers, the impacts on rural communities have likely been underestimated.

The research team studied smoke exposure in three major environmental justice communities in the West: agricultural communities in California’s Central Valley and central/eastern Washington, and the Navajo Nation in the Southwest. They found that controlled burns in crucial regions of northern California and the Pacific Northwest would reduce smoke dispersion to these vulnerable areas.

“This research aims to aid the public in understanding the physical and social aspects that we need to consider when planning and implementing controlled burns to confront the intricate issues related to wildfires and smoke,” Carroll comments. “The strength of this research lies in its interdisciplinary approach, integrating multiple scientific disciplines to analyze data in innovative ways, and using that information to support real-world decisions and actions.”

The study, titled “Prescribed Burns as a Tool to Mitigate Future Wildfire Smoke Exposure: Lessons for States and Rural Environmental Justice Communities,” by Makoto M. Kelp, Matthew C. Carroll, Tianjia Liu, Robert M. Yantosca, Heath E. Hockenberry, and Loretta J. Mickley, was published on June 14, 2023, in Earth’s Future.

Additional authors of the study include Tianjia Liu from the University of California Irvine, Robert Yantosca from Harvard SEAS, and Heath Hockenberry from NOAA. NOAA provided the funding for the research.

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More about Controlled Burns

• Harvard University
• U.S. Forest Service
• National Oceanic and Atmospheric Administration
• USDA Forest Service Rocky Mountain Research Station
• Earth’s Future Journal
• Harvard John A. Paulson School of Engineering and Applied Sciences