A new study from the University of Utah shows that privately owned forests used for industrial timber harvest are more susceptible to high severity fire.
The study looked at LiDAR data from forests in the Sierra Nevada Mountains in Northern California, where five wildfires burned 1.1 million acres. Using that data, they found that the odds of a high-severity wildfire were 1.5 times greater on industrial private lands than in forests on public lands.
Researchers say that’s due to how timber companies manage forests. Trees are planted densely at regular distances, with vegetation that runs from the understory all the way to the canopy. These trees are all planted at the same time, and are the same age, a system known as“plantation” or “even-aged” forestry. It creates a continuous fuel source for a fast-moving wildfire.
Jacob Levine, the lead researcher on the study with the Wilkes Center for Climate Science and Policy at the University of Utah, said climate change will have a bigger impact on those forests.
“We found that especially the effect of density is much more important under extreme weather conditions than it is under mild conditions,” he said.
The study says that during periods of extreme fire weather—characterized by low humidity, hot temperatures, and high winds—the number of trees per acre were the most important predictor of a high-severity fire.
“This issue with these plantation-type structures is going to become even worse under climate change,” Levine said. “But it also means that we can enact management practices, in particular, thinning of forests, that will continue to be effective even in the more extreme and warm climates of the future.”
Levine said that there’s already scientific consensus around the effectiveness of prescribed fire and forest thinning as tools to manage wildfire risk.
“Definitely learning that those practices will likely continue to be effective under extreme weather conditions is sort of a new finding that’s extremely heartening,” he said.
The Trump administration has indicated that it wants to ramp up logging operations throughout much of the Western United States.
Levine said any new policies around logging should find a balance between harvesting lumber sustainably and mitigating the risks of severe fires.
“If that increase in logging is done in such a way that thins the forest back to sort of a more historical density that is supported by the given climate, that creates additional structural heterogeneity that reduces what we call ‘ladder fuels,’ those vertically continuous fuels from the forest floor to the canopy— if it’s done in that way, it could be a really productive thing from a fire perspective,” he said.
“But if it’s just a policy of ‘cut everything down and establish dense plantations,’ it’s going to have completely the opposite effect.”
Previous research by Levine found that public lands near these private, industrial timberlands were also at increased risk of more severe fires. He said further research into that data could help inform land managers on where to perform treatments like prescribed fires and thinning.
“How can we most efficiently design our management approaches to mitigate the risks of these really devastating megafires?”
Copyright 2025 Rocky Mountain Community Radio. This story was shared via Rocky Mountain Community Radio, a network of public media stations in Colorado, Wyoming, Utah, and New Mexico, including Aspen Public Radio.
