Cattle or chainsaws: Is livestock grazing effective for thinning Arizona's fire-threatened forests?
It was a dry summer after a dry winter for Justun Jones’ cattle on the Kaibab National Forest in northern Arizona. Several watering holes had dried up. The mud trapped two cows, caking their legs in place until they died. Crows pecked out their eyes.
As the forest grew drier and water scarcer, the wildfire risk became greater.
“On a year like this it’s so dang dry that one lightning strike and it’s ... it’s gone,” Jones said, looking at thickets of small pine trees.
In the past, natural low-intensity ground fires thinned out the forests. But decades of fire suppression have let thickets like these grow dense, turning them into fuel for wildfires.
Droughts make the thick forests even more explosive.
Since the turn of the millennium, unprecedented wildfires have scorched the West, burning bigger, more intensely and more frequently.
It’s likely too late to stop this new breed of fire altogether, experts say, but reducing the fuel such wildfires burn is a common prescription for saving the most important parts of the forests.
The U.S. Forest Service clears small trees to prevent fires from burning through treetops and sets controlled ground fires to burn the forest floor before megafires engulf everything all at once.
The Forest Service also uses livestock grazing to control wildfire fuel, a method that last year accounted for about 12 percent of all fuel treatments and rivaled the acres of trees mechanically thinned in Arizona’s forests.
The agency recorded about 31,000 acres of fuel-reducing grazing in Arizona for fiscal year 2017, according to an analysis of the Forest Service Activity Tracking System database by The Arizona Republic, compared with about 33,000 acres of tree thinning.
But livestock don’t eat the woody fuel, such as trees, that propel these unprecedented fires at their core. And not everyone agrees that grazing prevents wildfire.
'We can’t afford not to'
State Rep. David Cook, R-Globe, who is also a rancher, believes livestock grazing helped Arizona escape a lot of wildfires this year.
“Thank God we’ve got a lot of cattle out there because, to me, if we didn’t have it, I’m sure we would have had a lot of fires,” he said.
Ranchers have a lot to lose in wildfires. The Arizona Cattle Growers’ Association has called on the Forest Service in the past to let cows graze more forage to reduce wildfire fuel. In 2011, the group proposed a fuel reduction plan after some of the biggest wildfires in Arizona's history charred tens of thousands of acres and displaced thousands of cattle.
It’s still an ideal plan, Cook said. He called it the “cattle and chainsaws” approach: chainsaws to log more trees and cattle to eat more plants, thereby reducing the fuel wildfires have to reach such extreme levels.
But researchers say more cattle isn’t necessarily the answer.
Grazing is an important tool to strategically slow down fire, said Karen Launchbaugh, a University of Idaho rangeland scientist.
“We can’t afford not to use all the tools we have,” she said.
But it shouldn’t be an excuse to increase the amount of livestock across the West, she said. Other researchers agree.
“A tricky factor is that overgrazing, as with big-tree logging, is what broke the old fire regimes of the Southwest, well before active fire suppression,” said Steve Pyne, an Arizona State University fire historian.
Targeted grazing can help, researchers say. But even then, the role it plays is limited.
“Grass is really not the problem,” University of Arizona fire ecologist Donald Falk said.
Crown fires that burn through tree canopies are more of a concern, although severe grass fires can potentially spread to the canopies, he said.
Grazing can reduce wildfire fuel in certain, targeted areas, said Retta Bruegger, a Colorado State University rangeland scientist, but it won’t stop high-intensity burns.
In southern Arizona, Bruegger found that targeted grazing can shorten flame lengths, depending on how dry wildfire fuels are. And it can potentially reduce the cost of fighting fire.
The results are going to vary depending on ecosystems, she said, adding that grazing isn’t a panacea.
At a certain point, fire is driven by climatic factors, Launchbaugh said. “The whole climate has changed.”
Under extremely dry and windy conditions, for example, grazing won’t do much to stop fire, she said.
Don't graze everything
Overgrazing can change the landscape and allow invasive plants to grow, adding wildfire risks.
“One concern, too, is that, of course, grazing can have negative impacts on ecosystems if not managed well,” Bruegger said. “So we’re not saying just get out there and graze everything.”
Cows can clear the way for cheatgrass by suppressing native grasses, Launchbaugh said.
It’s not so much the amount of grass and plants that make good fodder for wildfires, she said, but how continuous and flammable they are.
That makes invasive cheatgrass an excellent conduit for wildfire. It’s incredibly flammable and it pops up in between plants, Launchbaugh said.
Targeted grazing can set cheatgrass back, but cows only eat it when it’s green in the early spring or when it softens up after it turns a reddish color in the winter, she said.
Jones, the rancher in the Kaibab forest, is working with the Grand Canyon Trust and other researchers on a pilot experiment to graze cheatgrass in select places. He runs his cattle on the trust's 830,000-acre grazing permit.
The experiment also includes strategically planting strips of native seeds to stop the spread of cheatgrass and break up wildfire fuel continuity.
They’ll finish collecting data in 2019. Whatever combination of targeted grazing and planting works best in the Kaibab forest isn’t going to be the same everywhere, said Ed Grumbine, the head of the Grand Canyon Trust’s ranching program on the North Rim.
“Every site is going to be different,” he said.
No one has a handle on cheatgrass and there are even worse invasive grasses out there, said Pyne, the Arizona State University fire historian.
'Too politically volatile'
How to thin forests, or whether to simply let wildfires do it, is a highly political negotiation.
Grazing isn’t the only way Cook, the lawmaker and rancher, wants to reduce wildfire fuels. He wants more logging, too.
Cook prefers the cattle growers’ plan over the Forest Service’s Four Forest Restoration Initiative — also know as 4FRI — a project that aims to thin and restore pine forests within a 2.4 million-acre boundary in Arizona.
From 2010 to 2017, the project has thinned, burned or let burn over 620,000 acres of forest.
It’s taking a long time to finish, Cook said.
“The problem is the environmental regulations and the bureaucracy of 4FRI,” he said.
He wants significantly less federal regulation to govern reduction of fuels.
The cattle growers' association called to suspend the National Environmental Policy Act's approval process for thinning wildfire fuel.
There’s a good case to be made for reforming this law, Pyne said. For example, agencies could widen the scope of fuel treatments they approve under the law.
Some agencies are already moving in this direction, he said. “That would remove some of the sand in the gears without destroying the process itself.”
But it was also a mistake to suggest that forest thinning under 4FRI would be commercially viable, Pyne said. There's no evidence selling wildfire fuel — mostly small-diameter trees — as commodities will pay for fuel reduction projects.
The interests involved seem politically incapable of coming to a consensus on how to reduce wildfire fuel, he said. But he supports subsidizing it like the federal government subsidizes other agricultural products.
Meanwhile, most wildfire fuel reduction comes from wildfire itself when the forest service gives it room to burn, Pyne said. The forest service will push and pull on a fire to let it clear out dense fuels.
“It’s too expensive, too complicated, too encumbered, too politically volatile, to try to negotiate all these things,” he said. “And nature seems to be sorting it out.”
The human element
Jones, the rancher, has seen officials lose control of wildfire while they milk it to reduce fuel.
“We worry about the human element,” he said. “We worry about the people in charge making bad decisions.”
In 2006, officials let the lightning-sparked Warm Fire burn for over two weeks to clear out fuel. It met the Forest Service’s criteria for letting a fire burn, but winds pushed it out of the agency's control and it spiraled into a high-intensity fire, scorching tens of thousands of acres.
Jones is still dealing with the aftermath. He lost access to large swaths of the forest, he said. Thick regrowth and scattered, dead, burned trees block him from these sections.
“The cattle can’t hardly get in there to graze. You can’t hardly ride in there to get ’em out,” he said. “It’s just become such a mess.”
Wildfires can do enough damage to a ranch in the short term to run it out of business, even when grass grows back in the long-term, said Bruegger, the rangeland scientist.
“Historically, (ranchers) didn’t have to worry every single year about if there was going to be a giant fire,” she said.
But amid the drought this summer, the risk of severe wildfire worried Jones nearly every day.
“We was extremely nervous,” he said. “I mean that’s our livelihood.”
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's environmental reporting team at environment.azcentral.com and at OurGrandAZ on Facebook, Twitter and Instagram.