“Although the fact that fire has always been an important ecological factor is recognized to a certain extent by most foresters, many of them disregard or minimize the possibility of utilizing fire as a silvicultural agent in the management of ponderosa pine forests.”
— Harold Weaver, Journal of Forestry, 1943
On a cool spring morning outside Sisters, Oregon, the Wolf Creek Hotshots weaved their way through ponderosa pines, drip torches in hand.
They dropped flaming dollops of a diesel-gas mix, setting burgundy manzanita and grounded golden pine needles aflame. It catches easily, begins to spread, and all at once the forest smelled of campfire.
Each year, foresters here thin out trees, clear brush and light fires like this to burn off fuels and lower the risk of large, uncontrollable wildfires.
This commitment to the full suite of fuel treatments — especially burning – has helped make the Deschutes National Forest a model and a success story in the effort to reduce fuel loads and lower the risk of wildfire.
But getting these acres burned is no easy task, and across the West, foresters are falling short of what they need to do with fire as a tool. That leaves many efforts to treat fuels incomplete. Fire scientists say that’s a problem.
A century of aggressive fire suppression left forests dense with too many trees, too much brush and too many dried-out leaves, twigs and needles. Combined with hotter and drier weather, those overloaded forests stoked a new era of extreme fire.
The timber industry and environmental groups alike recognize the need to rid the forest of those fuels before wildfire ignites them. As it stands, the Forest Service and Interior Department spend millions of dollars on hazardous fuels but treat a fraction of the acres needed each year to prevent the buildup from worsening.
Western lawmakers have called for more fuels reduction work and this year, Congress freed up more money in the Forest Service budget and loosened environmental regulations for such work. Sometimes that happens through controlled burning or mechanical activities like mowing. Most often it happens through selective logging projects known as thinning, which is often a pre-burning requirement — as well as an activity that can carry the added benefit of supporting rural jobs by generating timber.
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On hundreds of thousands of acres of public lands, federal agencies have thinned forests without using prescribed fire, according to Forest Service data. But in the aim of reducing the spread or severity of wildfire, that is a recipe fire scientists say has proven to be at best ineffective and, at worst, has the potential to be counterproductive.
“Politically, we’ve heard this — that we’re going to log our way out of the fire problem. That’s popular with some elected officials,” Mark Finney, a fire behavior scientist with the Forest Service, said in a presentation at the agency’s fire lab in Missoula, Montana. “Well, science shows us that thinning and mechanical activities may be necessary for restoring forest structure and fuel conditions. But they’re not sufficient by themselves.”
Thinning forests is often a must, scientists like Finney said. We need a lot more of it. But it cannot replace fire.
“Without fire … you’re not removing the fuels that other wildfires depend on,” Finney said. “Logging is called logging for a reason. It removes logs. Most logs are still there after the fire.”
Thinning and burning in the Northwest
Source: U.S. Forest Service Forest Activity Tracking System (FACTS)
A Big Catcher’s Mitt
Done right, forest thinning and fire treatments can work. Many say Sisters, Oregon, is proof.
“It makes it a lot easier for firefighters to come in here and catch it if there’s something blowing off the Cascades towards the Sisters,” said Allison Dean, a fire effects monitoring coordinator for the Bureau of Land Management. “This is part of a big catcher’s mitt.”
On scene for the prescribed burn this spring, Dean followed behind the line, taking weather readings and checking that the fire didn’t burn too much or too little to be effective.
“What we’re trying to do is open it up again, return it to more of its natural habitat, “ Dean said.
Crews have been thinning, mowing and burning the Deschutes National Forest for at least a decade. They think that work saved Sisters last summer, helping 675 firefighters stave off the Milli Fire as it raced toward town.
It has been praised as an example of how proactive forest work can prevent deadly wildfire disasters.
But even in the Deschutes, treatments fall short of historic burning rates by 30,000 acres every year. While burning at historic rates is an unattainable goal given how many people now live nearby, foresters use that to see just how far behind they are. They thin the forest about twice as much as they burn it.
Failing to follow through on prescribed burns can leave a dangerous amount of fuel on the land.
In 2015, the Canyon Creek Fire destroyed 43 homes in Eastern Oregon. Patches of land around those homes had been thinned, but it didn’t change fire behavior as foresters had hoped. The fire found plenty of fuel on the ground.
One primary reason for that: prescribed burns were either never planned or never completed, a Forest Service review team found.
“The cumulative effect of all the treatments on that landscape, it doesn’t appear it did much to alter the spread or intensity of fires through that area,” said Frankie Romero, who served on the review team for the Forest Service.
“Certainly there’s been lots of good thinning. But the pace of the surface fuel treatments, particularly the prescribed fire, to follow those up, need to keep pace,” Romero said in his review of the fire.
A Thinning Argument
There are many reasons to thin an overgrown forest. Trees too tightly packed are stressed for light and water. They are prone to insect infestation and disease. Clearing a forest can lower the chances of a fire getting into the crowns of trees and give firefighters more room to operate. The logs taken out for all those reasons feed mills, often in places where drop-offs in timber harvests since the early 1990s have crushed local economies.
“I’ll argue with any of the communities that say you shouldn’t be doing any thinning,” said Mike Wheelock, owner of Grayback Forestry, a wildland firefighting and forestry contractor based in Grants Pass, Oregon.
Fuels reduction used to be 80 percent of Grayback’s workload, Wheelock said, with wildfire suppression making up the rest. That’s now essentially flipped.
“Anything’s better than what you have now,” he said. “I could show you just miles and miles of dead trees. And you know, overgrown forests. And they need to be thinned. Before you can start lighting matches.”
A deficit of natural fire
Burn ratio compared to historic rates
Source: Mark Finney, Charles Mchugh; U.S. Forest Service Rocky Mountain Research Station.
Many forests are so overgrown, fire ecologists and land managers fear burning them without logging first would likely result in a danger to the public or a forest burned too severely.
The inverse — logging without fire — provides a false sense of security, said James Agee, forestry professor emeritus at the University of Washington. In 2005, Agee authored a set of principles for forest treatments that many still use as a guide for the work.
“The average citizen … they hear that ‘Oh, thinning is good and it’s going to create a situation where my home is going to be saved,’” Agee said. “But it’s just one part of the equation.”
You need to think not just about what you take out of the forest when you log but what you leave behind, Agee said.
Unless you plan to rake and bag millions of acres of national forests, fire is the only way to reduce the so-called fine fuels on the forest floor that help wildfire spread.
“And if that’s not going to occur, there’s no way you’re ever going to log your way out of the problem. You’re probably going to make it worse,” Agee said. “Thinning by itself is not good.”
When the average person looks at a forest they see trees as fuel for wildfire, said veteran fire ecologist Ron Wakimoto. They should be looking down at the litter and duff, which are layers of decaying material on the forest floor. In the right conditions, Wakimoto said he’s seen 100-foot flames off pine needles alone.
Wakimoto said it can actually be counterproductive: besides the potential of leaving additional debris behind, when you thin a forest you open up the canopy and allow more sunlight in. You’ve also opened it up to let more wind through. So those layers of litter and duff dry out faster.
“Now that the forest is open, the forest floor is drier, and the fire can move even quicker to the houses, or whatever you did the thinning to protect,” said Wakimoto. “A lot of people who are just thinking about woody fuels are not thinking that.”
Further And Further Behind
In April, after years of attempts, Congress ended the Forest Service’s reliance on borrowing firefighting dollars from its other programs.
“We are ready to go on and talk about how we’re going to get back into the business of preventing forest fires,” Oregon Democrat Ron Wyden told colleagues in the Senate.
It was one of many efforts to promote forest fuels reduction.
In May, Northwest lawmakers announced $80 million in the new farm bill toward forest thinning. Late last year, the House passed a bill aimed at greatly reducing the barriers to thinning projects on federal forests. Around the same time, Sen. Maria Cantwell, D-Wash., introduced sweeping wildfire legislation in 2017 that would have prioritized thinning to generate new lumber products, while also calling for more prescribed burns.
“By targeting our most vulnerable pine forests, this science-based pilot program gives the Forest Service tools to address wildfire in our most vulnerable forests and prioritizes cross-laminated timber,” Cantwell said at the time.
“We have neglected thinning to make our forests resistant to fire for far too long. We must change that,” co-sponsor and Oregon Democratic Sen. Jeff Merkley said in a statement.
Thinning gets a mention in most public statements about treating fuels in the West. Burning does not. This was true for a September memo from Interior Secretary Ryan Zinke urging his staff to be aggressive reducing fuels.
While scientists have been discussing fire as a crucial management tool since the 1940s, it has yet to gain a foothold in policy.
It doesn’t help local economies the way logging can. It has a non-zero chance of burning out of control. And even if it grew more politically popular, it remains thwarted by red tape and logistics.
Thinning can happen year-round but foresters need the right conditions to light a fire, leaving a narrow window of suitable days in the spring and fall. State and federal agencies just don’t have the resources to burn as much as they’d want to in such a short span. Over the past year, the Deschutes National Forest had 30 suitable burn days.
Controlled burns require air quality permits because of the smoke. At the edge of wildlands near communities, those can be hard to get.
And then there’s the money issue. If you’re willing to remove some larger trees, thinning can at least help pay for itself as a timber sale. But money for burning comes entirely out of agency budgets. On the Deschutes, that’s up to $250 per acre plus ongoing maintenance costs.
“It’s kind of like mowing the lawn. It’s not like it’s one and done once we have our fuels consumed,” Sisters District Ranger Ian Reid said.
The end goal in all this fuels reduction would get the forest back to more self-regulating. But in areas close to town, that’s always going to require intervention, Reid said.
Annual Forest Treatments Compared To Historic Burning
Source: Nicole Vaillant and Elizabeth Rhinehardt, U.S. Forest Service
The reality is both thinning and burning are going to need to increase dramatically if they’re going to make a noticeable difference during projected longer, hotter fire seasons. Nicole Vaillant, a Forest Service researcher in Bend, found the combination of thinning, prescribed fire and wildfire affects only 45 percent of lands each year that historically would have burned.
That debt compounds. For all the investment in fuels treatments, we are still trending in the wrong direction, like a garage where old boxes and junk pile up faster than the annual yard sale can offload them.
“We’re getting farther and farther behind,” Vaillant said. “We’re getting deeper and deeper into the hole.”
Editor’s note: Reporting for this story was supported by the Institute for Journalism and Natural Resources.
Why does this story matter?
Wildfire is one of the West’s biggest issues. We spend millions to treat an overload of fuel for those wildfires in our forests. Many are advocating we spend more. This story focuses on what is most effective if foresters are to make progress in reducing the risk of extreme fire behavior.
What questions did we set out to answer?
- What landscape treatments are most effective in reducing the risk of wildfire?
- How often are we using those treatments?
What do we know now?
- There is a significant overload of hazardous fuels in the West. Forests have become too dense and too cluttered, in large part because we have been suppressing wildfires for so long.
- There is broad acceptance that these fuels need to be dealt with to reduce our risk of large wildfires, but at our current rates fuels are accumulating faster than we are treating them.
- The most effective treatment for reducing fire severity is to thin and use a prescribed burn. But that is not the most common treatment in much of the West. In the Northwest and California, thinning without burning is common.
- There are many logistical, political and financial hurdles to prescribed burning, which contribute to the disparity in treatments.
Who is in this story?
Not everyone we spoke with appears in the story. We spoke with several fire scientists with the U.S. Forest Service and various universities. Also in this story are district rangers and federal agency staff who are working to reduce fuel loading on public lands. We also spoke with multiple people who do work in the forests on thinning or burning projects and fire suppression. We quoted one person who runs a forestry company, and does both fire suppression and fuels treatments. This story also features public statements from elected officials.
What’s the evidence?
Numerous studies have shown the combination of mechanical treatments such as thinning combined with prescribed burning to be the most effective way to treat fuels, and that treatments without both of these are largely ineffective. Here’s one literature review of several studies. Some research has indicated thinning alone can reduce fire severity (Martinson and Omi, 2003). There is some speculation as to whether that is dependent on the conditions of the fire when it enters the treated area: for instance, a canopy fire is unlikely to sustain as a canopy fire. Multiple studies have indicated thinning alone can increased burn severity compared to untreated sites (Raymond and Peterson, 2005, Wimberly et al., 2009; Graham et al., 2012).
Forest Service data shows that. Using satellite data over a four-year span, researchers at the Forest Service also tracked how many acres are affected each year by mechanical treatments, prescribed fire and wildfire.
How can you respond or get involved?
You can contact elected officials, the Forest Service, the Interior Department or state forestry agencies about wildfire management. You can contact us about our coverage at firstname.lastname@example.org.