Researchers put the “let burn” narrative to the test and examine large, lightning-ignited wildfires on Forest Service lands

Photo Credit

Forest Service photo by Mike Elson

In 2021, lightning struck on a ridge top in the Humboldt-Toiyabe National Forest in California and ignited the Tamarack Fire. The area is rocky, rugged, and buffered by natural barriers, but about a week later, the fire changed course. Strong winds drove the fire downslope, causing it to spread rapidly toward several communities and highways. This threat prompted over 2,000 people from several communities to evacuate their homes; and while no lives were lost, the fire ultimately destroyed 25 structures. 

The Tamarack Fire brought scrutiny to the initial fire response strategy, which was designed to limit risks to firefighters. Many members of the public attributed the negative outcomes to an unofficial Forest Service “let burn” policy that takes advantage of lightning-caused fires to restore fire-adapted landscapes rather than immediately suppress them. 

Led by Fire Management Specialist Brad Pietruszka, researchers at the U.S. Department of Agriculture, Forest Service’s Rocky Mountain Research Station examined incident reports from wildfires like the Tamarack – large, lightning-ignited wildfires on Forest Service lands – that occurred between 2009 and 2020. The authors set out to determine how often this type of fire occurred, which management objectives drove response strategies, and how strategic decisions documented in the ICS-209 reporting form related to outcomes of the fires, such as structure los). Their research asks whether data support public perceptions represented in the “let burn” narrative and offers insight into how managers balance competing objectives during wildfire response. 

They believed answers to these questions would have important implications for wildland fire management and safety, especially as efforts ramp up to actively manage forests and reduce fuels to help decrease fire severity and improve fire outcomes in high-risk firesheds. Since 2009, the federal fire policy implementation guidance has allowed land management agencies to manage naturally ignited fires for resource benefits so long as firefighter and public safety remains the top priority. The 2023 National Cohesive Wildland Fire Strategy Addendum Update and the 2023 Wildland Fire Mitigation and Management Commission final report advocate for proactive use of fire to restore landscapes and reduce frequency of extreme events.

Photo Credit

Forest Service photo by Kari Greer

In this context, managers of fire-adapted ecosystems must balance land management goals with firefighter safety. On the one hand, we rely on forest managers to care for our forests, and the agency has set high targets to reduce fuels to mitigate the effects of severe wildfires and restore forest health long-term. In fire-adapted ecosystems, restoring forests means restoring fire on the landscape. On the other hand, the agency and the public expect managers to safeguard lives and property from wildfire hazards. These potentially competing priorities can put managers in a difficult position, especially when fires are growing more dangerous, and no two wildfires are the same. How do managers balance these priorities? 

Out of 940 potential candidates, the researchers identified 32 wildfires that resembled the Tamarack Fire: similar size, caused by lightning, and originating on Forest Service lands. While rare, these 32 analog fires accounted for a significant portion of destruction to homes and other structures, 61.6 percent, and resource commitments. They also found that, in fact, very few of these large fires involved an initial response strategy intending to take advantage of the lightning-caused ignitions to benefit land management objectives. Among the six cases that did, even fewer structures—only four—were destroyed. More commonly, high risks to firefighter safety drove initial response strategies, which consequently delayed action to suppress the fire directly. 

The researchers concluded that this category of fire represents rare but salient events. Their findings also suggest that managers act cautiously and aim to minimize risks to firefighters above pursuing ecological benefits from lightning-caused ignitions, in line with policy directives. The findings further support previous research that found that most structure loss stems from human-ignited wildfires that start on private lands rather than from lightning on publicly managed forests. 

Photo Credit

U.S. Forest Service

Where does the “let burn” narrative come from? There’s no definite answer, but it is possible that the existing fire reporting system falls short in the high-stress, post-fire environment in which people seek to understand what happened. The ICS-209 reporting form, where managers document their decisions and underlying objectives, often is used as the primary source document when communicators report about a wildfire incident. Managers select one of four categories to classify the intent behind each management decision; however, these categories may not capture enough of the nuance and complexity of the decision environments in which they are made. In turn, this information gap may permit inaccurate explanations to dominate the conversation. In addition to an improved reporting system, managers might benefit from focused communication training tailored to prepare them for the unique conditions they face when they engage with the public during and after wildfire incidents. These situations can be high stress, high stakes, and emotionally charged, conditions that could challenge even the strongest communicators. 

Prolonged fire seasons and increasingly severe fire behavior will continue to challenge land management agencies. Under the right conditions, opportunistic use of fire within fire-adapted systems can help reduce the risk of high-severity wildfires over the long term, caused by an excess of accumulated fuels in these forests.  

This research offers a baseline for risk analysis and could inform the agency when evaluating future wildfire events. Together, better defined risk tolerance and improved communication about strategy on wildfire incidents could benefit organizational learning, guard against misunderstanding, and facilitate advancement toward the vision of the National Cohesive Wildland Fire Strategy, “to safely and effectively extinguish fire, when needed; use fire where allowable; manage our natural resources; and collectively, learn to live with wildland fire.”