Slow burn

A shift in forest management strategy could offer a new way to think about how we live with wildfire


Angie Busby woke up surrounded by a haze. Smoke from the East Troublesome Fire, the second largest wildfire in Colorado’s history, was covering Busby’s home north of Jamestown. She couldn’t see her hand in front of her face.

Just a few hours later, sustained wind gusts up to 80 mph helped start the nearby Cal-Wood Fire. While her home was not at risk, Busby, a trained wilderness firefighter and EMT, was on the scene “pretty much after the first smoke report till the end.” 

“You disconnect from the fact that this is your home territory, and you just do what you need to do to make sure everybody is safe,” she says. 

The Cal-Wood fire burned through more than 10,000 acres and 26 structures, including half of the Cal-Wood Education Center’s 1,200-acre property, where Busby is the natural resources manager. 

Prior to the fire, most of Busby’s fire mitigation measures included things like thinning trees, opening up tree canopies, taking out diseased trees and creating openings for meadows in an effort to emulate historical forest compositions and reduce fuel loads. 

Three years later, she sees where those efforts worked and where they didn’t — and it’s changing how she approaches managing her land.

“In the last couple of years, there’s been a switch from just fuels reduction in the forest to home-hardening,” she says. Now, half of her time post-fire is spent increasing structure resilience. 

Busby’s shifting views on land management are part of a larger discussion among scientists and land managers about what historical forest structures actually looked like. One new study published last month in the scientific journal Fire questions the science that informed today’s best practices in wildfire mitigation. 

Ongoing discussion

After more than a century of fire suppression and a two-decade megadrought, Colorado is experiencing more large fires than ever before. Ten of Colorado’s 20 largest fires by acreage have occurred since 2018. The 2021 Marshall Fire is the state’s most destructive fire by strucutre loss.  

Tony Cheng, director of the Colorado Forest Restoration Institute, says Colorado has always had big fires, but “the key is those fires may be becoming more frequent over a longer period of the year and those fires are also intersecting with a variety of human values (like protecting structures) that are on today’s landscape that weren’t there 250 years ago.”

On Boulder County public lands, forest management and fire mitigation strategies center around land stewardship to improve forest health and structure, which includes forest-thinning and patch-cutting. 

“Research for us on the Colorado Front Range tells us that the overgrown dense structure that we have is the issue,” says Stefan Reinold, resource management division manager at Boulder County Parks and Open Space. 

A lot of the thinning in the county occurs in the lower montane forests where species like the ponderosa pine dominate the landscape. Patch cuts (clearing an entire area of trees) are done in the upper montane forests to species like the lodgepole pine to build age diversity and fire breaks. Those are typically less than 15 acres, according to Reinold. 

“How a fire would burn with a more open structure is really what we’re after, [so we’re] changing the structure to one that can receive fire, rather than one that when it does receive fire, it is devastating,” says Reinold, adding that forest structure has historically been more open than it is today

But the April 3 study in Fire, an international and peer-reviewed journal, found tree density and fire severity in pre-industrial dry forests were more variable than previously thought. 

The study challenges the “low-severity” model, which argues these forests were low in tree density and had low- and moderate-severity fires. Instead, it highlights evidence indicating a “mixed-severity” model with both low and high tree densities and a mixture of fire severities. According to the study, there is competing evidence supporting both models since the 1990s. 

Climate consequences

Because of these findings, Chad Hanson, an author of the study and director of the John Muir Project, says thinning projects on wild lands are “misguided” and shouldn’t happen at all. 

Hanson argues forest management projects “under euphemisms like fuel reduction” increase the intensity of wildfires by reducing the cooling shade of the forest canopy, creating hotter and drier conditions on the forest floor and allowing higher wind speeds to sweep through open areas. 

There’s also a climate consequence. More than 200 scientists, including Hanson, signed an open letter to President Joe Biden and members of Congress on Nov. 4, 2021 calling for logging to be removed from the Budget Reconciliation and Infrastructure provisions, stating “logging [in U.S. forests] conducted as commercial ‘thinning,’ under the rubric of fire management, emits about three times more CO2 than wildfire alone.”

Reinold says even if patch-cutting creates more wind paths for fire, “its [impact has] been over exaggerated in terms of trying to stop any kind of treatments in the forest.” 

Forest thinning isn’t an exact science. For example, the county doesn’t have a diameter cut limit, but avoids cutting large “legacy trees.” Sometimes, though, bigger trees are taken out to favor smaller ones to establish higher age diversity. Reinold says the county rarely sells the material they take out of the forest to a mill. 

He describes the forest landscape as a mosaic. 

“Getting on the ground and setting up the structure is an art form,” he says. 

Focus on resilience 

Rather than forest thinning, Hanson thinks resources should be spent protecting communities by creating defensible space around homes (especially bordering national forests) and making them more resilient to fire.

“The answer is to focus our resources and our attention on communities, on keeping homes from burning, and on helping people evacuate,” he says. 

One recent study found a 246% increase in the number of homes and structures destroyed by wildfire in the last two decades. Researchers attribute that increase to climate change, more buildings located near flammable vegetation and human ignitions. 

Despite 88% of Western wildfires in the past two decades not destroying any structures, 76% of wildfires that do burn homes or other structures were caused by humans.

Last May, the county added new building requirements to its code to help protect against future wildfires in east Boulder County after the Marshall Fire, which is an expansion of its ignition resistant construction requirements in the foothills and mountains of the county. 

In an Oct. 17, 2022 interview, Cottonwood Custom Builders CEO Jeff Hindman said all of the projects his company had under construction switched to non-combustible exterior materials after the Marshall Fire. 

Cheng brings a risk-management science approach to fire mitigation that includes both traditional forest mitigation practices and more emphasis on home-hardening techniques, adding there isn’t good evidence that forest thinning alone saves homes. The important question for him is asking what management actions can lessen the consequences to the values people care about. 

“We need to have a much more robust and explicit discussion … as a community and a society about how we want our fire and where we want our fire, because fire is going to happen,” he says. 

Changing relationship 

While a lot of trees were lost on Angie Busby’s property where the Cal-Wood fire burned, she says those areas are more biodiverse than the unburned areas. 

“You go out there and see flowers you’ve never seen on the property, you see an increase of wildflowers and grass species and more wildlife out there,” she says.

One thing all parties agree on is that we need more fire — which is essential for both forest and grassland ecosystems. One way to do that is through prescribed burns.

“The research shows that when you have more prescribed fire, it actually helps mitigate the impacts of a wildfire,” Cheng says. “It makes it less destructive in terms of human values, and makes it easier to control in terms of fire management.”

The county aims to have controlled burns on more than 250 acres a year, but have only completed about 100 acres in the past four years combined. Reinold says weather (like wind or temperature), drought, air quality, smoke restrictions and additional staffing resources in the event something goes wrong are barriers. 

“Without more ‘good’ fire on the landscape, we will ultimately be less effective in controlling risk,” he says. 

There’s also inherent risk with prescribed fires — last summer one in New Mexico turned into the biggest wildfire recorded in the state’s history. 

Coming to terms with more fire can be difficult, Chey says, especially since humans have viewed fire as the enemy and “something to be conquered and squashed” since the 20th century — not to mention devastating fires that can be life changing. He says we need to shift how we think about fire “as a tool that can make our community safer and that can rejuvenate the forest and the wildlife and the plants.”

Busby says kids who visit the Cal-Wood Education Center “know what smoke means and they get scared and emotions run high — it’s the same for adults.”

In the end, instead of adapting fire to a human landscape, maybe humans should adapt to a fire landscape. 

“Standards are always meant to be changed as new science comes about with current and new wildfire activity, research studies, and with climate change,” Busby says. “We all essentially change the forest management standards as we learn from each other.”