Jacob Levine, a postdoctoral researcher at the University of California, who recently led a study that sheds light on this deeply concerning connection. This groundbreaking research underscores the important role that forest management practices play in contributing to or mitigating megafires. In 2022, researchers studied data on five of the largest and most devastating wildfires. These back-to-back disasters charred over 1.1 million acres in the northern Sierra Nevada region of California. The study’s findings suggest that privately managed forests are significantly more prone to high-severity wildfires compared to publicly owned forests.
With the help of cutting-edge lidar tech, Levine and his collaborators produced intricate three-dimensional maps of public and private forests alike. This one-of-a-kind dataset allowed them to look deeper into the structural forces of the forest that are making these areas more prone to dangerous fires. It found that industrial private land is at the greatest risk of exposure to high-severity wildfires. Indeed, the chances are almost a time-and-half higher than for forests managed by the public.
Insights from the Study
Published in the scientific journal Global Change Biology with DOI 10.1111/gcb.70400, the study illustrates a concerning trend in timber harvest practices. Levine’s research is the first to pinpoint concrete forest structures. These constructs explain why some places are uniquely positioned to experience uncharacteristically high-severity fires more than others.
Perhaps most importantly, Levine emphasized just how pivotal their findings are. As he put it, “What we have is a really detailed picture of what the forest looked like immediately before these massive fires. It’s an unbelievably valuable thing to have. This level of detailed analysis is extremely important in creating effective fire mitigation strategies.
As they dug into their investigation, Levine and his team found something incredible. Most of the trees in the Sierra Nevada lack the genetic and phenotypic predispositions to recover from high-severity fires. To us, this is the most troubling issue. It’s a sign that today’s forests are more vulnerable due to fire suppression policies that the U.S. government put in place in the 1800s. Though these policies were initially implemented with the intention of expanding timber resources, they had the unintended consequence of fostering an environment for more severe wildfires.
The Role of Forest Structure
Her work focuses on illuminating the interplay of forest density and structure as key factors influencing fire behavior. Levine likened the arrangement of trees to matches stacked in a grid: “You can think about stacking a bunch of matches together in a grid—that’s going to burn a lot better than if you have those matches dispersed as smaller clumps.” This analogy demonstrates that spacing and density play just as critical a role in how fires spread.
Levine went on to describe how dense forests, in dense fuels, can allow for larger fires to reach the canopy, producing extreme fire behavior. “A bigger [fire] can easily reach the canopy in dense forests. Then it’s ripping through one tree after another, tossing out chunks of burning material miles in advance. It’s a different story,” he noted.
The impacts of these findings reach far beyond short-term fire hazards. Levine continued, “This has enormous implications not just for timber—and we all should care about that—but for carbon sequestration, water quality, wildlife habitat and recreation.” As forest management practices continue to develop, it is ever more important to focus on these larger effects on ecosystems and communities.
Addressing Future Fire Risks
Levine’s study suggests some sort of a major re-thinking of prevailing forest management tactics is in order. He warned that without major changes, future generations may inherit a landscape drastically different from the cherished forests of today. There is some special beauty to shrub and grasslands. When we think about the Sierra Nevada, we picture its incredible forests first,” Levine said.
He expressed hope that adjustments in forest management could mitigate fire risks. That’s just a very hopeful conclusion to reach. It indicates that we’re learning how we might manage these landscapes in ways that will determine the manner in which fires move through them,” he said.
To improve the health and resilience of forests, Levine favors a landscape approach to thinning fosters stands of both young and mature trees. As a result, he found that removing small trees while thinning large trees will help promote healthier and hardier forests. Not only will this strategy improve their resiliency to fire long term,