On the lower slopes of Jackass Ridge, smoke wafted through an oak woodland canopy, its gray haze contrasting with the green, yellow and red hues of the forest.

A crackle of burning grass could be heard as low-lying flames crept uphill, consuming woody debris that carpeted the forest floor.

After hours of navigating the steep terrain of the Weaverville Community Forest, Tim Ritchey took a brief pause to reflect on a day spent lighting the fires like the one burning a few feet away.

“Overall, we were very pleased with the outcome we had,” Ritchey said.

Ritchey, fire management officer for the Shasta-Trinity National Forest, was referring to a prescribed fire project – one in which low-intensity fire is applied to the forest floor – that U.S. Department of Agriculture’s Forest Service employees undertook to remove excess flammable vegetation.

Accumulation of this vegetation, both live and dead, can lead to hazardous conditions ripe for wildfire – a threat to the town of Weaverville and other communities nearby.

But counter-intuitively, introducing low-intensity fire can go a long way toward restoring these woodlands to a more natural, fire-resilient state.

“What we want is for the forest to be able to withstand fire in a low to moderate severity, not so it can be managed, but so firefighters can be effective, and the structure of the forest is still here after a wildfire occurs,” Ritchey said.

Using fire as a tool

Setting fires like these isn’t new. Indigenous peoples used low-intensity fires for centuries to keep forests healthy.

That practice, as well as natural fires caused by lightning, helped forests like those surrounding Weaverville stay in a healthy balance.

That changed over time. Heavy fire suppression and a lack of active forest management over several decades left northern California’s forests choked with fuels that would otherwise have been burned naturally or removed by logging. That, plus the warm, dry conditions that exist throughout the West, left these woodlands vulnerable to high-intensity wildfire.

“Historically, these ecosystems burned in what we now call ‘wildfire season,’” said Nate Ulrich, a fuels planner for the Shasta-Trinity National Forest. “The difference then, is the fuel accumulation and the frequency these ecosystems burn. They generally didn’t burn with high severity and were not difficult to control.”

Whereas the annual wildfire season used to be a period of fire followed by a period of regeneration, it’s now a dangerous time as modern wildfires have grown larger, hotter and faster-moving than they once were. In the most severe wildfires, recovery can take decades or more.

Prescribed fire is one way the Forest Service can reduce the risk of severe wildfire. By burning excess vegetation on the forest floor when fire conditions are moderate, new wildfires won’t have as much fuel to burn during the hottest and driest months of the year. In turn, that can keep wildfires confined and prevent large trees from burning.

But current wildfire risks narrow the window for prescribed fire operations considerably. Broadcast burns – where low-intensity fire is spread on the forest floor – usually take place as cooler fall temperatures arrive, or just as temperatures begin to rise in the spring. Since the window of opportunity is limited, fire managers are always on the look out for ideal conditions.

When the conditions are right, it’s time to burn.

On the fire line

Back on Jackass Ridge, Forest Service firefighters stationed themselves along the trail that runs the spine of the ridge. Joining them were fuels technicians carrying drip torches – hand-held fuel cans with long, slender spouts with a small flame burning at the end.

They’d gathered here by the dozens, marching up the trail to the top of the ridge on a cool sunny day. A few last instructions were given out, then a test burn in a patch of manzanita and grass was lit. Satisfied with that, crews worked their way down the trail, lighting new fires in the underbrush.

Heard over hand-held radios: periodic weather updates and commands dispatching burn crews to different parts of the ridge. As the flames moved across the ridge, firefighters walked the fire line, making sure the flames remained confined inside the planned burn area.

Before long, thick plumes of gray and brown smoke rose into the air as flames spread, consuming grass, underbrush and fallen trees. Reducing these fuels is key to ensuring that if wildfire happens here in the future, threats to the safety of Weaverville and the health of the forest will be lessened.

Watching it unfold, it’s clear how carefully coordinated the operation is. People were placed deliberately to contain the flames, and they watched intently as acre by acre, the fire slowly spread across the ridge. Fire is chaotic by nature, but it was under control here, and that’s no accident.

Wind plays a big role – too much and you risk the fire spreading too fast, too little and smoke settles into the town below. On this day, the wind was just right.

The planning, timing, training and experience that goes into pulling off a prescribed fire is extensive.

“There’s an exceptional amount of training and experience that’s required to lead operations like that,” Ulrich said. “Generally, just to qualify to manage that type of work takes a minimum of 10 to 12 years or experience. That goes all the way down to the firing boss level, the person who supervises the prescribed fire. Under that, for igniters, the people who actually set the fire, we can work with a broad range of experience levels. But the more experienced folks certainly help us achieve a better result.”

Forest Service employees aren’t alone in this operation. Numerous partners from local, state and federal agencies are here, too, offering their time and experience to assist in the operation.

“In Trinity County, we’re pretty special because a lot of the agency folks who are doing the work are community members and so are all of our partners,” Ulrich said. “They all live here, and they all have a stake in how lands are managed. They really help us build that capacity.”

These relationships work both ways, as the Forest Service will help with other agencies’ projects as needed.

“We have pretty special working relationships with our partners that help us to be successful,” Ulrich said. “We look at active land management holistically when it comes to fire and all working together toward a common goal.”

The long game

“Prescribed fires are one of the most important tools we have for meeting our goals,” said Corey Davis, an environmental coordinator for the Forest Service who leads planning efforts in the high fire-risk areas of much of Trinity County and parts of Humboldt and Shasta counties.

“They increase the effectiveness and longevity of mechanical treatments by removing the accumulated ground fuels and make our forests more likely to burn less intensely in future wildfires,” Davis said. “They also restore fire to forests that typically burned more frequently than we’ve let them in recent decades. All of this helps to reduce the fire risk around communities and provides safer conditions for firefighters to engage wildfires.”

A prime example of how this works can be found in the Weaverville Community Forest itself.

The 2001 Oregon Fire burned more than 1,600 acres after starting near the Oregon Mountain summit north of Weaverville. The fire was devastating, forcing the town’s evacuation and destroying 33 structures. The 2014 Oregon Fire burned about 600 acres near the same area as the 2001 fire, but its growth slowed after running into an area where prescribed fire had taken place the year before. The 2014 fire destroyed one structure.

Last summer, another fire on Oregon Mountain started under the extreme heat that had baked northern California in early July. Temperatures peaked in the low 100s, making fire conditions particularly volatile. But firefighters stopped the fire after it burned just a quarter acre, in part because it was sparked in an area previously treated with prescribed fire and other fuels management techniques like thinning trees and removing brush.

The trauma caused by the 2001 Oregon Fire informs forest health work in the Weaverville Community Forest now. The area burned on Jackass Ridge in 2024 has been treated many times before, and looking ahead, will be treated with prescribed fire again.

Using low-intensity fire to prevent severe wildfire is an ongoing process, one that forest managers hope will return these woodlands to their natural, more fire-resilient state.

“We’ll never be done because we want to continue to put fire on the landscape within the natural times frames it would have existed,” Ritchey said. “The goal is when wildfire occurs on these landscapes, it’s low to moderate severity fire instead of high severity fire.”