Utah’s policy leaders have long wanted to see a robust timber industry return to the state to support rural economies and fight fire.
But new research led by the University of Utah shows some types of logging could increase wildfire severity, particularly as the West experiences more extreme weather.
Studies have shown that privately owned forests with regular logging are more prone to severe fires — blazes that kill more than 95% of the canopy trees — than surrounding public forests with more logging protections. Jacob Levine, postdoctoral researcher at the U.’s Wilkes Center for Climate Science and Policy, wanted to understand why, and whether climate played a role.
“Without understanding the mechanism that’s driving that sort of discrepancy,” Levine said, “we can’t use it to inform management in a reliable way.”
He found some answers in California’s northern Sierra Nevada mountains. The area has a mix of private and public forestland. It also saw several large wildfires between 2019 and 2021, including the Dixie Fire, one of the largest in California’s history. The U.S. Forest Service and U.S. Geological Survey gathered light detection and ranging, or LiDAR, imagery of the forests the year prior, in 2018, which Levine was able to compare with data collected after the forests burned.
The results showed that privately managed forests tend to include tightly packed groups of trees that are uniform in species, spacing, size and age. The private “industrial forests” also had large amounts of ladder fuels like branches, shrubs or small trees that allow fires to climb from the forest floor to the canopy.
“They cut a big area down in a clear cut, and then they plant trees at a high density,” Levine said. “So as they grow up, their crowns are all touching.”
Those dense conditions make a forest more conducive to megafires, particularly during extreme heat and weather. The private industrial forests were 1.45 times more likely to burn at high severity than the surrounding public forest.
Levine published his findings this week in the journal Global Change Biology.
Severe fires can sterilize soils, damage watersheds, impair trees’ ability to reseed and permanently transform entire ecosystems.
California, of course, is different from Utah, with a separate climate and distinct types of trees. Very little of Utah’s forested land is owned by private industry. But Levine said his research shows thinning can be an effective management strategy in reducing fire severity in all types of forests throughout the region, particularly as it becomes hotter and drier.
“That is a positive finding,” Levine said, “because it tells us that even as fire conditions get worse and worse with climate change, we can take steps to change the way that we manage forests to mitigate the risk.”
Forestry experts have long known that tree density is much higher than before Western settlement, even in public forests. Prior to the arrival of modern forestry management, natural fires weren’t snuffed out by firefighters. And indigenous communities formerly used small, frequent controlled burns to manage woodlands in both California and Utah. But more than a century of suppression has resulted in more fuel on the landscape.
Levine said discussions about forest thinning can be controversial, with opponents of the method drawing on the public’s negative perceptions about logging.
“But what this study shows is that it’s a really important component of mitigating fire risk,” Levine said, “and it’s only going to become more important as the climate becomes worse.”
Utah’s approach to thinning should also consider the types of trees growing in its forests, according Bradley Washa, an assistant professor of wildland fire science at Utah State University Extension.
“It goes back to the fire regime that the vegetation grew up around,” said Washa, who was not involved in Levine’s study.
Clear cuts often get a bad rap, Washa said, but they can make sense for species like lodgepole pine, which adapted to destructive events like fire. But they also don’t work across the board. Ponderosa pine, for example, evolved with low-intensity fires that remove competing shrubs and allow the trees to grow large and uncrowded.
“In that case, a clear cut is not appropriate,” Washa said. “It does not simulate the natural processes.”
But, Washa asserted, it’s unlikely Utah will be able to log its way out of forestry problems.
The state doesn’t produce the same kind of valuable timber found in California, the Pacific Northwest and Canada. The local dry climate means trees grow slowly. Utah also lacks the infrastructure to support much timber harvesting. Two of its few remaining sawmills, in Kamas and Panguitch, burned down last year.
And while the Trump administration rescinded the Roadless Rule in national forests this summer, claiming it will help both firefighting and the lumber industry, Washa and Levine said more roads could cause more problems for forests.
“Roads themselves, especially if they’re gravel roads,” Levine said, “can have impacts on water quality. They can generate additional erosion.”
Roads also mean more access points for people, which could lead to more fire. Humans ignited 564 uncontrolled flames in Utah this year alone, State Forester Jamie Barnes told lawmakers this week, accounting for 70% of fires and burning more than 101,000 acres this season so far.
And the Roadless Rule already had mechanisms in place that allowed for road construction in limited circumstances, like research or fire prevention.
“Many areas are roadless either because there wasn’t a value to extract there,” Washa said, “[or] it was cost prohibitive to put roads in the terrain.”
That makes roads another unlikely panacea, he said, for Utah’s fragile forest health.