FORESTS:

Record N.M. blaze behaving differently from last year's fires

SANTA FE, N.M. -- A wildfire has burned through more than 255,000 acres in the Gila National Forest, eclipsing last summer's Las Conchas fire as the largest blaze in New Mexico history.

Two years of drought and winds of up to 50 miles an hour have created perfect conditions for the fire, which began as two separate lightning-sparked blazes but merged May 23. As of this morning, the fire was "very active" and exhibiting "extreme behavior," including some flaring into treetops, the interagency Southwest Coordination Center said.

But the Gila blaze -- known as the Whitewater-Baldy fire -- is behaving much differently from last year's huge wildfire, officials say. The current fire, they say, is burning at a lower intensity, with 20 percent burning at high intensity so far.

"The intensity of it is lower than it was originally, but it's also wind-driven," said Lee Bentley, a fire information officer for the Forest Service. "We had some very high fire licks."

The lower intensity of the fire may be due to Gila National Forest's unusual fire-management regime.

Until recently, forest managers typically fought to contain any fire that burned in national forests. But for decades, Gila managers have taken advantage of the forest's remote location and massive wilderness areas to practice "wildland fire use" -- allowing lightning-ignited fires to burn as nature intended, with close monitoring by experts. The policy is becoming more common on Forest Service lands.

The behavior of the Gila fire contrasts to the way the Las Conchas fire moved across the landscape last June and July.

That fire spread quickly because of high winds, but it burned so hot in some areas that it incinerated almost all of the trees on the landscape, replacing what was once ponderosa pine habitat with a barren, blackened "moonscape," Craig Allen, a research ecologist with the U.S. Geological Survey, said during a presentation on climate change and drought here last March (Land Letter, March 1).

Fire ecologists won't know for sure how much of an influence previous burns on the Gila have had on the fire until it dies out and they can head into the forest to take measurements.

The Whitewater-Baldy fire reinforces the Southwest's dubious distinction as home to some of the largest fires in the country in recent memory. Others include the 469,000-acre Rodeo-Chediski fire in Arizona in 2002 and last summer's 538,000-acre Wallow fire on the Arizona-New Mexico border and the 156,000-acre Las Conchas fire.

As average temperatures in the region have risen, forests across the Southwest have become drier, Allen said. Drought conditions, along with fuel buildups from a century of fire suppression beginning around 1900, have led to an increase in severe fires in recent years.

The region's trees -- piñon pines and juniper at lower elevations; ponderosa pines at mid-elevations; and aspen, spruce and fir higher upslope -- have not seen such tremendous drought stress since the 13th century, he added.

During the last century, when forest managers snuffed out almost all fires on public lands -- before forest scientists understood the importance of fire to many forest types -- some of the Southwest's forests saw fewer fires than they had at any time in the past 9,000 years, according to Allen's research, which uses tree rings to reconstruct historic climate conditions.

Concerns about species, runoff

The Whitewater-Baldy fire was spreading to the Southwest this morning. Yesterday the Forest Service was forced to close the Gila Cliff Dwellings, an Ancient Puebloan site, because of hazardous smoke conditions. But there was good news for the few residents of the old ghost town, Mogollon: They were allowed to return to their homes after being evacuated a few days ago.

The area's rugged terrain, characterized by steep canyons and rocky ridges, has hindered firefighters' ability to battle the blaze, Forest Service officials said. About 1,200 firefighters are trying to hem in the blaze, but it is about 18 percent contained, Bentley said.

Forest managers are already beginning to worry about what conditions will be like in the aftermath of the massive blaze.

Their greatest concern: post-fire flooding, which could flush ash and debris into waterways, including those inhabited by native Gila trout. Debris flows in the aftermath of the Las Conchas fire caused considerable damage to rivers and streams, eroding huge chunks of stream bank and choking waterways (Land Letter, Aug. 4, 2011).

About 10,000 acres burned severely enough to blacken or consume almost all vegetation and sear the soil enough to hinder its ability to absorb rainfall. While the current conflagration is not burning nearly as hot, runoff and erosion could still send large amounts of sediment into waterways, officials said.

Meanwhile, wildlife managers are wondering how the fire will affect threatened and endangered species in the forest, which contains some of the best intact habitat in the Southwest.

The Fish and Wildlife Service has been monitoring two packs of Mexican wolves with 5-week-old pups whose territory lies near the perimeter of the fire, and though they were in the path of the fire a few days ago, the blaze has shifted direction and they no longer appear to be at risk, said Tom Buckley, a spokesman for the agency.

"Right now, we're not seeing any imminent danger to any packs," he said, adding that a lone wolf is within the fire line, but he appears to be alive and well. "We assume he's OK, but we don't have any confirmation at this point."

During last summer's Wallow fire, Mexican wolves, including several pups, were also able to avoid the fire.

But the long-term effect on the wolves' habitat is unknown. The Mexican wolf population numbers around 50 animals, so any harm could have a pronounced effect on the recovery effort, said Bryan Bird, public lands program director for WildEarth Guardians.

"They're in such small numbers, everything that happens to them can have an impact," he said. "I think they'll be fine in short run, but in long run, will dens be useful to them, or will they be burned up and hot?"

But native wildlife has evolved with fire, which is a natural part of Southwestern forests, and overall species here know how to survive a conflagration, he added. When a fire moves through an area, native species, such as northern goshawks, Mexican wolves and mule deer, will often get out of harm's way. Birds fly away, large mammals move to adjacent habitat, and small rodents and reptiles burrow underground. According to the Arizona Department of Fish and Game, burrowing just 6 inches below ground can protect animals from a fire burning as hot as 3,000 degrees Farenheit above ground.

In fact, recent research suggests that at least a few species, such as the Mexican spotted owl, appear to be able to reinhabit even the most severely burned areas.