Healthy forest assumptions challenged
Thinning and controlled burning may not be answers

A ponderosa pine rises skyward in a thick forest below Missionary Ridge in the Animas Valley. Some fire ecologists believe the recently passed Healthy Forests
Restoration Act is not applicable to many of Colorado’s higher montane forests./Photo by Todd Newcomer.

A hundred years of fire suppression have led to overly mature dense stands of timber in our national forests that need cutting and thinning in order to restore the groves to a state of ecological health, right?

Well, not exactly.

Some forest varieties at some elevations may have suffered from the U.S. Forest Service’s Smokey the Bear campaign, but other forests haven’t changed significantly in the past 100 years from their natural range of variability, said Dr. Tom Veblen at a forest health conference in Frisco recently.

Sponsored by a coalition of environmental groups including Durango-based Colorado Wild, the group of fire ecology researchers, foresters and forest activists gathered March 6 to discuss the Wildland Fire and the Healthy Forests Restoration Act (HFRA). In particular, they discussed the impacts of Rep. Scott McInnis’ federal legislation, which was signed into law four months ago. HFRA is aimed at expediting the preparation and implementation of hazardous fuels-reduction projects on federal lands and helping state and local governments restore healthy forests.

“Wildfire is a physical inevitability and may be appropriate, under certain ecological conditions,” noted Jack Cohen, researcher with the Forest Service Fire Sciences Laboratory in Missoula, Mont. “We don’t have the option of having no fires.”

Veblen is a professor of geography at the University of Colorado at Boulder, whose specialty is forest dynamics and disturbance ecology. He has published more than a hundred papers on the interaction of fire and forests. He explained that his research on the Front Range, northern Colorado and the Grand Mesa National Forest had shown that it was mostly lower montane ponderosa pine stands that had suffered from 100 years of fire suppression. Management options like thinning and controlled burns were appropriate in that case, agreed Veblen. But that forest type only makes up about 20 percent of Colorado’s ponderosa pine stands.

He said spruce-fir, piF1on-juniper and the mixed ponderosa pine-douglas fir forests of the upper montane subalpine zone were not out of sync with earlier patterns of fire disturbance – the natural range of variability having been established through tree ring data and pollen studies.

Nor were insect infestations today substantially different from spruce budworm and piF1on bark beetles infestations of the past, according to Veblen.

He felt thinning forests as a technique for restoring health was only appropriate in certain limited forest types, and a better way to protect human communities from fire was to focus on improving defensible space in and around homes and restricting development in fire zones.

Cohen agreed.

“Fire is not capricious,” he insisted. “A human structure either meets the requirement for combustion, or not.”

A home sits in stark contrast to its charred surroundings on the west side of Highway 550 in the Animas Valley on Tuesday. Some fire ecologists and researchers believe that a home’s materials are more important in
staving off catastrophe in the event of a forest fire than the actual size and proximity of the fire./Photo by
Todd Newcomer

It’s not the walls of advancing flames that ignite whole communities caught in the path of an advancing wildfire, said Cohen. What determines whether a home burns or is spared has more to do with the construction materials and the defensible space around the structure – what Cohen calls the home ignition zone.

He showed slides and a video of his research, which demonstrated that even wood homes are highly unlikely to burst into flames if there is no combustible material within 100 to 200 feet. In fact, except under the most extreme conditions, he noted that simulated house walls 60 feet from huge flaming trees did not combust in numerous experiments.

It’s the blizzard of firebrands that are thrown front and back, up to a half mile out from a fire, that represent the real threat to homes. If these firebrands find chinks in a roof’s armor, vents in an attic, or even a broom by an outside door, ignition can occur and an entire structure can be compromised.

“The home ignition zone principally determines a home’s ignition potential during wildland fires,” said Cohen. And he advocates managing home ignition zones on private property as more effective than thinning forests in the wildland-urban interface, as HFRA envisions. “Instead of fuel breaks around the community,” he added, “the community4 becomes the fuel break.”

Since high fire-risk homes are sometimes built close together, Cohen also advocated for neighbors and local jurisdictions to work jointly on protecting home ignition zones. “The community that doesn’t mitigate together will then certainly burn together,”he said.

Colorado State Forester Jim Hubbard didn’t want to throw out the baby with the bathwater, however, when it came to fire.

“If we save a home and lose a forest,” said Hubbard, “or if we save the forest and lose a home, I still get sued.” Working on home ignition zones but also working on thinning and treating the wildland-urban interface to make for healthier forests were complementary strategies, he suggested.

And to do that, communities need to develop Community Wildfire Protection Plans, which are called for under HFRA, in order to qualify for federal funds.

Of course, as the Wilderness Society’s Dr. Lisa Dale pointed out, HFRA authorized $760 million for helping communities with hazardous fuels treatment. But no money has been allocated yet. In fact, the Forest Service is six months into its fiscal year, and it still doesn’t have an approved budget.

“There’s a big gap between what we hear politicians say is important and where the budget comes out,” said Dale.

But if money does ever come down for HFRA, noted Hubbard, communities that have prepared their Community Wildfire Protection Plans will have first priority. And that means updating fire plans to fit the new HFRA guidelines.

Francisco Romero, BLM fire officer, noted some false assumptions that people have about fire fighting, such as, if there is defensible space around a house, fire fighters will go to another house more at risk.

“Defensible space attracts fire fighters like moths to a light bulb,” said Romero. “We will go through a neighborhood and identify winners and losers.”

Another misconception, said Romero, is that defensible space is all one needs to worry about.

“Defensible space is good for direct exposure, but the rain of firebrands will find any weak link and exploit it,” Romero said. Preventing combustible vectors from getting into a home, or near it, is also critical.

Finally, Gary Severson, director of the Northwest Colorado Council of Governments, emphasized the importance of multijurisdictional cooperation in dealing with forest restoration and fire threats. And local conference host, Commissioner Gary Lindstrom, of Summit County, cited the local work by a collaborative group of volunteers to mitigate fire hazards in neighborhoods as a good example of solution-based activism.

These days, collaboration and restoration are the buzzwords of the healthy forest movement. Indeed, collaboration is crucial, in all instances, but restoration may be a bit more elusive – as we continue to learn more about the science and ecological niche of fire in our Western forests and communities.






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