HARDWARE RANCH -- When someone talks about helping wildlife or improving water quality, the first thing that comes to mind usually isn't flames raining down from the sky. But on a brisk October day in 2012, a helicopter passes low over a tight-knit grove of aspens while fire pours out from a hose below.
This is Hell's Hollow.
Hell's Hollow is the name given to a series of rolling hills and valleys on the
Uinta-Wasatch-Cache National Forest about 15 miles east of Logan. In the fall of 2012, like in previous years, U.S. Forest Service crews lit controlled fires over thousands of acres as part of long-term project to improve forest health around the region.
After nearly a century of fire suppression, scientists in recent decades have become more aware of the benefits of fire for forest health. Here in Hell's Hollow, the foresters, biologists and the general public are attempting to use prescribed fire to save the aspen ecosystems that cover much of the area.
"Sixty percent of the aspen stands are in a decline," said Jesse Kurpius, assistant fire management officer for the Forest Service. "We're working to try to get those back in small steps."
While that 60 percent number is specific to the local forest, the trend is the same throughout the Rocky Mountains.
"Aspen across the West has been in decline, not only in the number of stands out there, but in the size of those stands," said Kevin Labrum, wildlife biologist with the Forest Service.
Labrum and other wildlife biologists watch this change closely. The animals that draw everyone from birdwatchers to big-game hunters into the woods rely on these habitats for survival.
In 2004, people around the West began to notice the drop in aspen. As the deaths quickly increased in subsequent years, scientists gave the trend the ironically depressing name of SAD, or sudden aspen decline.
Like most changes in the environment, the causes of SAD are numerous and overlapping.
"There's not a straightforward answer to that," Labrum said when discussing the roots of die-off.
Over the decades leading up to the decline, fire has been suppressed, climate has changed, new grazing animals have been introduced, and insects, diseases and other trees have moved in. Through some combination of these, and other factors, the aspen have died.
In the flames of Hell's Hollow, Utah is trying to fight that decline.
A mosaic of flames
While not far from the cities of the Wasatch Front, on a summer weekday in Hell's Hollow, you won't see anyone beyond the occasional ATV rider or sheepherder. What the area lacks in recognition, it makes up for in local importance.
The rain and snow that fall on the ridges feed into multiple drainages in the area, and the rolling slopes provide habitat for wildlife from around the region.
From the dirt roads and rocky peaks, you can see the immediate impact of fire in Hell's Hollow. Blackened trunks rise along the forest edge. Months after the burn, black soot from the brush still leaves marks on the arms of anyone who walks through.
But the fires that are lit here aren't the massive firestorms that make national headlines.
"There's a mosaic pattern," Kurpius said. "That's what we're looking for."
"It's a mosaic of high severity, low and moderate severity that's created this patchiness across the landscape," said Christina Anabel, fuels technician with the Forest Service.
Mosaic. It's a word that gets used a lot when you start asking about the Hell's Hollow burns. The accuracy of the term becomes clear when you hike through the forest.
Walk 40 feet from the charred conifers, and you're in a grove of 80-year-old aspens. Walk another 40 feet, and you can barely move through the tangle of young aspen growth. Forty feet more, and you could be on the edge of a sagebrush clearing or a dark-green stand of Engelmann spruce.
This patchwork quilt of ecosystems is no accident.
After years of planning, crews burned the first 2,010 acres of Hell's Hollow in September 2009. Each year, the prescribed fires are lit during what Anabel describes as the "shoulder season between fall and winter."
After years of working as a firefighter, Anabel came to Northern Utah to start planning more fires. In the years before lighting a single flame, Anabel and her colleagues create a plan for where and when they want the fire.
As the burn gets closer, crews create pre-planned fire lines of bare ground surrounding the area.
When the day finally comes, the first flame is only lit when every measurement on the official burn plan is met.
If the wind blows 10 mph, no burn.
If the humidity drops below 15 percent, no burn.
If the humidity exceeds 40 percent, no burn.
If the moisture in the live sagebrush is at 57 percent instead of the required 60 percent minimum, no burn.
After burning in 2009 and 2010, the conditions didn't line up the following year and fires were never lit in Hell's Hollow in 2011.
"It's a pretty tricky balance," Kurpius acknowledged. "Aspen is a finicky stand to treat."
But in October 2012, the narrow burn plan parameters were met and the helicopter was in the air. The main fire is lit by a helitorch: a small helicopter with a metal, fuel-filled barrel hanging from its belly.
As it flies, thick fuel drops from the barrel, hits a suspended wick and catches fire before falling to the ground.
By limiting the ignition to one person in the sky, crews save money and avoid putting firefighters at unnecessary risk.
In the latest prescribed burn, fire spread through 5,700 acres of Hell's Hollow.
On its surface, the plan sounds contradictory. The fire was being lit to kill aspen, and the fire was being lit to improve aspen health. Below the surface, the plan is bit more complex.
The individual aspen trees you see in the woods are not separate organisms. Unlike most trees, each aspen tree is simply a shoot off a giant underground root ball, known as a colony.
Each colony is its own individual organism, and a single colony can keep reproducing trees for tens of thousands of years. In Southern Utah, an aspen colony that goes by the name of Pando reigns supreme over Fishlake National Forest at 80,000 years old with more than 40,000 individual trees.
Along with this unusual structure, new aspen rarely grow from seeds. Instead, new growth springs up from the underground colony when there is a disturbance. No disturbance, no new aspen. And when summer reaches Utah, there is one disturbance more common than any other: fire.
Starting in the early 20th century, wildfire became a menace that needed to be stopped at all costs.
In aspen forests, a century without fire can mean lots of 100-year-old trees, but no new growth ready to fill the gap when those older trees die. While these old trees look beautiful as the fall colors change, a forest needs diversity in the ages of trees in order to survive.
Effects of the fire
"You look at things such as forest health, stand health, wildlife habitat benefits; we look at all those things on a landscape scale," Anabel said.
While the prescribed fire encourages the growth of new aspen, the impact is on more than just a few trees.
"When I first got here in 2010, we walked in there and there was aspen just waist high and there was deer and elk just running out of the brush all over the place," Kurpius said.
"The burning of the aspen will produce a lot of suckers, and those suckers are pretty nutritious," Labrum said. "Aspen is one of the main food sources for elk in some areas."
In addition to the increased food source, young elk use the thick young regrowth as shelter and a place to hide from predators.
With the "mosaic" that foresters love to mention, spotty fires essentially create numerous different overlapping habitats.
"Some bird species rely on mature forest; other species utilize intermediate forests; other birds utilize younger forest," Labrum said. "Just to have a variety of those forest stages allows us to have greater biodiversity."
Even the fire-killed trees will provide habitat to certain species of woodpecker.
The effects go beyond providing immediate food and shelter to wildlife.
At Hell's Hollow, downed and dying trees are gradually removed each fall with the relatively small fires instead of waiting for a dry August day when the wind catches an abandoned campfire in a forest piled with years of fuel buildup.
Huge, stand-replacing fires can have negative impacts for years after the smoke has cleared.
Without trees to hold a hillside together, landslides become more common, and streams and rivers get choked with runoff, not to mention the hazards that comes when these fires spread to populated areas or the smoke fills the air.
Stand-replacing fires will always exist -- some tree species are well adapted to them -- but through the use of prescribed burns, firefighters are able to pre-emptively fight fire with fire.
Hell's Hollow's future
Eight months after the October burn, Anabel gets out of her Forest Service truck on the edge of the most recent fire.
"Right now, you'll probably see grasses and forbs," she said, "but in the next year or two, you'll start seeing aspen sprouting up."
With those small aspen shoots in mind, Anabel and others are already making plans for lighting off Hell's Hollow in 2013 and beyond.