‘Good fires’ gave forest managers a useful tool. Climate change may take it away

03 September 2021

USA – APACHE-SITGREAVES NATIONAL FORESTS — Plumes of smoke drifted across the sky, wispy columns that traced a path to a smattering of downed trees still smoldering in the wake of yet another wildfire.

Federal land managers have started their assessment of the burn scar, but already, life is finding its way back.

At the base of the tree trunks, in patches across the forest floor, grass has grown. The only evidence of the wildfire that burned through the area just a few days earlier was the blackened tips of each blade and the darkened soil where ferns sprout.

“This is good fire at its best,” said Justin Gabler, fire management officer for the Alpine Ranger District of the U.S. Forest Service. “This is fire doing exactly what nature always intended it to do, give life a fresh start.”

A decade after the 2011 Wallow Fire became the largest wildfire in Arizona state history, five lightning strikes across its burn scar ignited wildfires, which eventually joined to become the 2021 Horton Complex Fire.

Lightning-caused wildfires, like this one, historically burned at low severity, renewing ecosystems by revitalizing soil nutrients and keeping forests from over growing. But after decades of ardent fire suppression, such natural fires are now burning on unnatural landscapes.

Each season, land management agencies debate the risk of using natural fires to achieve forest health goals. And with warmer temperatures and less rain and snow each season, they are increasingly opting not to.

“We’ve been able to use good fire here and there over the years, but with trends pointing towards drier and warmer fire seasons there may come a point where the risk of a natural fire getting away from us is too much to take on,” Gabler said. “That’s exactly what happened with this fire. The risk of letting it run was just too much with how dry things are, so we had to put it out.”

It was a disappointing end to what fire managers refer to as a “good fire.” Under the right conditions, Gabler said the Horton Complex Fire could have aided the forest’s ongoing recovery from the Wallow Fire. Without natural fire as a management tool, agencies would be left to rely on forest thinning and prescribed burns to mitigate future wildfires.

“Fires can be a fresh start,” said Natasha Stavros, the director of the Earth Lab Analytics Hub at the University of Colorado Boulder. “The challenge is less on the ecological ecosystem and more on the political and managerial ecosystem. Because even if natural fires set the stage for us to reintroduce fires and manage our fuels, we’re not actually equipped and ready to do that on the landscape at the cadence that we want to.”

Stavros, who specializes in extreme events like megafires and has a background in fire ecology said, “We almost need to have the lightning-fires because they force us to have fire on the landscape whether or not we like it.”

Now, in the midst of yet another catastrophic wildfire season, federal agencies have announced a pause to their “let it burn” policies that allowed them to use natural, lightning-caused fires as a forest management tool.

With the pause in place, firefighting agencies are suppressing both natural and human-caused wildfires across the West.

“The use of natural fire is a major social issue that we have to come to grips with. Would we rather our forests burn when we have some control of the fire? Or no control at all?” said Tom Harbour, the former national director of fire and aviation management for the U.S. Forest Service.

“We don’t want another Wallow Fire or another Telegraph Fire,” he said. “But to avoid those fires we need to answer this question about what to do with random, natural ignitions. Do we put them out? Or do we try to allow them to achieve some kind of reasonable management objective?”

As forest managers weigh the cost of liability with the need for restoration, fire ecologists and researchers search to understand what warming climates could mean for the future of lightning-caused fires.

Wildfires:In Arizona, fires are bigger, hotter. How will the land recover?

‘A fresh start’

Red and black soil contrast across the landscape in patches where the Horton Complex Fire reburned the scar of the 2011 Wallow Fire. The red soil outlines where trees, downed by Wallow, had lain for years. The black soil outlines where Horton had burned some of those trees to ash.

“Most of those downed logs have been sitting here since 2011,” Gabler said. “Clearing out thousands of acres of burn scar is impossible. We often have to leave these logs till the next fire rolls through, which is risky because those logs can become fuel for high-severity fires.”

Horton was the next fire, but it was different.

“Since it was natural and burned at low severity this whole area got a fresh start,” Gabler said, crouching down to feel the ash. “This whole area was struggling to regrow after Wallow, but look at it now.”

Around him, signs of life were returning to the area.

Grasses and ferns were taking root across the scar, painting the forest floor green. The picked-clean skull of a big game species lay in contrast to the burned earth, proof that both predator and prey have returned.

As he begins his walk out of the two burn scars, Gabler’s eyes widened and he sharply side-stepped out of the shadow of a fallen tree.

“Definitely don’t get too close,” he said in an eerily calm voice.

He knelt down to take a picture of the Arizona black rattlesnake whose patterned-skin camouflaged seamlessly with the burned husk of the log.

“It’s us humans that say whether a fire is good or bad because of the way it affects us,” Gabler said. “But in reality, these natural fires always benefit something.”

New questions about megafire aftermath

In burn scars, the benefits of low-severity fires, like Horton, are abundant. But the same can’t be said for high-severity burns.

Andrea Thode, a professor in the School of Forestry at Northern Arizona University, is conducting research on how varying burn severities within burn scars affect the landscape.

“We know the trend in fire right now is that they are getting bigger and more severe and we will continue to see that as our temperatures go up,” Thode said. “It doesn’t matter if you believe how it’s happening. The negative effect of what is happening is serious and will have huge implications to our systems and our neighborhoods.”

Alongside a group of researchers, Thode is studying the Horseshoe II Fire burn scar in the Chiricahua Mountains to understand how varying fire severities affect an ecosystem.

“As we increase the amount of high severity fires and their size, we simply don’t know how regeneration is going to be affected,” Thode said. “When we do manage to have some regeneration, what happens to that when you reburn with another fire? Those are hard ecological questions to study but we’re beginning to try.”

In the aftermath of large wildfires, Burned Area Emergency Response teams are among the first to assess the impact of the flames. Paul Brown, the BAER coordinator for the Apache-Sitgreaves National Forests, led the assessment of the Horton Fire.

“In low severity fires, like this one, the root structure of the grasses are often left intact, meaning the soil structure is still in place,” Brown said. “All it needs is a little water and the grasses grow immediately.”

While the Horton Fire was burning at the ideal severity within the scar of the Wallow Fire, Brown and Gabler had to suppress it. Dry conditions made it too dangerous to manage.

“Typically, we like to manage fires when we have a little bit of moisture because we want predictable conditions. If it’s dry and windy, it’s just more difficult to control those fires. With climate change, that unpredictability makes it more difficult to manage wildfires,” Brown said. “It’s just too risky to let some fires burn, and if we continue on this climate trajectory there will be less opportunity to manage wildfires.”

That opportunity was snuffed out this season when the Forest Service announced that it would pause its policies that allowed for some natural-caused fires to burn, a decision made in response to limited firefighting resources, said Randy Moore, chief of the forest service.

After the announcement, over 40 scientists from universities and organizations around the country signed a letter to express concern over the new directives to stop managing fire for resource benefit.

“Fire exclusion, along with historic logging that removed larger fire-resistant trees, are in part responsible for our current fire and forest management challenges, with changing climate increasingly acting as a force multiplier,” the letter read. “Both the science and management experience around wildfire are clear — we are not able to exclude fire from these systems indefinitely, no matter how much we invest in direct suppression… If we seek to modify the way fire burns across our landscapes, we cannot afford to lose any more management opportunities.”

The pendulum of federal management of natural-caused fires has been swinging for decades. Over his 40 years fighting fires, Harbour has witnessed and implemented some of the biggest management changes.

“I’m a fire guy, through and through,” said Harbour, who spent over a decade as the national director of fire and aviation management for the U.S. Forest Service. “There is no question that we in America and Arizona, in particular, need more of the right kind of fire in our ecosystems. We need to burn in these forests, we need fire in these forests.”

But he didn’t always think so.

‘We didn’t let natural fire do its job’

As a wildland firefighter decades ago, Harbour was tasked with suppressing a fire in the Blue Range Primitive Area by the Arizona-New Mexico state line.

“I was on a late-season fire, where the assignment was to suppress a lightning-caused fire because that’s what we did in the 70s. We suppressed all fire,” Harbour said. “When we got to the fire, I could see that it was moving slowly through the forest. As it was burning, it was consuming duff, downed debris and clearing up the area. It was just great.”

But the orders were to suppress it. So, Harbour did.

As he and his crew put out the flames, Harbour remembers having the distinct thought for the first time: “Jeez, should we really be killing this one?”

“It was probably my first real, personal interaction with that question as a firefighter. We know that fire is just fire. It’s us as humans that, based on its impacts and effects, that we judge it as good and bad,” said Harbour, who now works as the chief fire officer for Cornea, a company that provides data services for natural disasters.

After working on wildfires during both the suppression and management eras, Harbour said he’d be highly concerned if the pendulum were to swing back.

“We’re in this situation because we suppressed fires. By suppressing all these fires, we didn’t let natural fire do its job. Now forests are overstocked with trees and those conditions help exacerbate wildfires,” Brown said. “If we’re not able to manage fire then those sorts of conditions will persist and we’ll be back where we were.”

Before industrialization allowed fire suppression to become the primary management tactic for natural-caused wildfires, Native American tribes across the West had built years of traditional ecological knowledge on how to manage fires, often letting natural fires run their course.

“Traditional ecological knowledge is a term used by Indigenous people to explain the practices different tribes have developed to manage their land over a long period of time,” said Jon Martin, director of Native American forest and rangeland management programming for the Ecological Restoration Institute, and a member of the Navajo Nation. “The knowledge we gain and the practices we have when managing our land is a large part of Native American culture.”

But in the aftermath of decades of federal fire suppression, Martin is beginning to question the relevance of traditional ecological knowledge in this current ecosystem, which resembles little of the past.

“The knowledge hasn’t changed, but the conditions have. If we don’t have even close to the same conditions, does that knowledge now even apply? We’ve excluded fire for so long that we’re now trying to catch up but we’ve put ourselves in a situation where catching up may be too dangerous,” Martin said. “You have this clash where your knowledge doesn’t fit the condition and we might have to modify that.”

Martin is hopeful that since traditional ecological knowledge was built through learning that solutions will present themselves.

“A core part of traditional ecological knowledge is that you learn from your mistakes and adapt your approach. That’s how this knowledge is acquired, by being on the ground, over time,” Martin said. “I just hope that figuring out what we need to know is not too costly.”

What’s happening with our lightning

Lightning is one of the only known ways that wildfires occur naturally.

Under historic conditions, these natural fires maintained the health of forests by rejuvenating soil nutrients and creating space for trees to grow.

“Now, the problem is the background conditions are changing. We’re not getting the same kind of lightning-caused fires that we used to see hundreds and thousands of years ago,” said Stavros from the Earth Lab Analytics Hub. “Instead we’re seeing more intense fires due to a combination of climate change and land management practices.”

While warming climates and drier conditions contribute to megafires, they could also lead to more lightning — a potentially devastating combination.

“CO2 warms the land surface, which creates a temperature difference with the upper atmosphere that makes it unstable. That creates more updrafts and it makes it more likely to produce lightning,” Stavros said. “Usually, when you have wildfires spark because of lightning they can wipe the slate clean.”

Under normal conditions, Stavros said this clean slate can allow the land management agencies the chance to return after the wildfire and begin reintroducing prescribed burning on a more regular basis after to create a more manageable fuel load.

But with current conditions so different from those of historic forests, researchers across the West are looking into what the future of lightning on the southwestern landscapes will look like.

Daniel Swain, a climate scientist with the Institute of the Environment and Sustainability at UCLA, said the way carbon dioxide affects lightning in the Southwest specifically is still not fully understood.

“There is evidence that lightning is increasing in some regions and perhaps on a global basis, but there is not yet a whole lot of evidence regarding lightning and climate change in the Southwest,” Swain said. “Even if there isn’t an increase in lighting, we could eventually begin to see an increase in the number of lightning-caused fires. That’s because the background climate conditions are increasingly favoring drier landscapes, drier vegetation and higher ignition rates.”

The Natural Fire Institute Center tracks lightning-caused fires and the number of acres those fires burn. Swain said it’s important to note that the data doesn’t detail how aggressively those fires are being suppressed, nor the severity on the acres burned.

“The wildfire question is always a nuanced one. It’s not true that all fires are bad. Some fires are probably beneficial both for humans and for ecosystems. It’s the character and quality of these fires that are really important,” Swain said. “The lightning-caused ignitions might be natural but the fire that results might be strongly influenced by human activity. Either through the effect of long-term climate change, vegetation management and fire suppression policies or the expansion of populated areas into high-risk zones.”

The evolution of lightning-caused, natural fire may have been completely altered by human intervention on the landscape and the climate, Swain said.

“Even if we take for granted the fact that probably all fires are influenced by humans now on some level, it doesn’t mean all fires are necessarily harmful,” Swain said. “We may still be getting fires that are all human influenced but a lot of them may still be performing ecosystem services and providing some benefits, especially when they are burning more gradually at a lower intensity.”

As the lands burned by the Wallow Fire a decade ago reap the benefits of the Horton Fire, the still-smoldering trees provide a subtle reminder of an uncertain future.

Firefighters often say the West is always between two fires. And while life is now taking root across the burn scars in the Apache-Sitgreaves National Forests, it’s only a matter of time until — as Gabler says — “the next fire rolls through.”

Environmental coverage on azcentral.com and in The Arizona Republic is supported by a grant from the Nina Mason Pulliam Charitable Trust. Follow The Republic environmental reporting team at environment.azcentral.com and @azcenvironment on Facebook, Twitter and Instagram.

3. September 2021/by GFMCadmin