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
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
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.
“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
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
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
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
“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
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.