CASE STUDY: FOREST FIRES IN IDAHO
Focus Concept
A policy of fire suppression on public forest lands during the twentieth century has had
a negative effect on forest health and allowed a dangerous buildup of fuel. A new approach to
forest management is to encourage frequent small fires to clear the ground of excess fuel and
prevent large fires that would destroy more trees and threaten human life and property.
Introduction
On August 20 and 21, 1910, fire consumed 1.2 million ha (3.0 million acres) of virgin
timberland in northern Idaho and western Montana when 3,000 fires got out of control. While
flames shot hundreds of feet into the air and hurricane-speed winds flattened the flames to the
ground, 86 people died. It was the largest fire in the history of the United States. Under the
pressure of firestorms, millions of trees exploded and millions more were uprooted and
became incendiary missiles. Fireballs jumped from canyon to canyon over distances of 0.8km
(0.5 mi.). The smoke was so heavy that it was dark at noon on the 21st from western New York
to the Rockies and from Saskatchewan to Denver. Eight hundred kilometers (500 mi.) out into
the Pacific Ocean, ship navigators could not see the stars at night. Ten thousand men waged
war against this greatest of all fires: loggers, miners, bums, soldiers, and forest rangers. The
Forest Service spent eight years salvaging what was left and years more to clear away the dead
timber. In the aftermath, water hitting the fire-scorched ground caused extensive erosion, and
bark beetles attacked the trees. Millions of seedlings were replanted, only to be destroyed over
the next 30 years when parts of the area burned again, and even again.
The impact of the fire extended far beyond Idaho and Montana. It shaped the fire policy
of the U.S. Forest Service for more than half a century. And the policy that emerged as
dominant was that of fire prevention and suppression. The Forest Service trained an army of
fire fighters, ready to do battle at a moment's notice, and launched the most successful
advertising campaign in history with its mascot, Smokey the Bear, and its slogan,
“Only you can prevent forest fires." Not everyone was convinced that fire is always an enemy.
Early pioneers had imitated the use of fire by Native Americans to clear land, improve game
habitat, and make passage through the forest easier. Setting fires on purpose, a practice then
known as "light burning," was popular in many parts of the south and west in the late 19th and
early 20th centuries. One of its more eminent proponents was John Wesley Powell, the famous
explorer of the Grand Canyon, who later became head of the U.S. Geological Service. But light
burning had a serious public relations setback in 1910 when a fire deliberately set by a
Californian erupted and burned 13,200 ha (33,000 acres). Light burning was heresy to the
Forest Service in the 1920s, but it refused to go away. The conflict between advocates of light
burning and fire fighting smoldered under the surface until 1932, when the Forest Service
approved the use of fire to improve wildlife habitat. In 1934, it expanded the policy to include
management of the fire dependent longleaf pine forests of the south. Prescribed fire, as it
became known, continued to make headway and, by the 1970s, the Forest Service was
advocating its use.
Fires in Boise National Forest
On August 20 and 21, 1992, fire raced through 104,000 ha
(260,000 acres) of forest in the Foothills section of Boise National
Forest in southwestern Idaho. It was the largest single fire in
Idaho in the eighty-two years since the great fire of 1910.
Consuming more than 40,000 ha (100,000 acres) a day, it traveled
at a rate never before experienced in ponderosa pine forests. The
fire was remarkable, not only for its speed and the area it
covered, but for the degree of damage -- ninety-five' percent of
the area was completely blackened. (In comparison, in the
famous Yellowstone Fire of 1988, only half of the 600,000 ha (1.5 million acres) burned was
completely blackened.) The intense heat caused a waterproof layer to form 2.5 cm (I in.) under
the surface, which interfered with absorption of water. The government spent $27 million to
control the fire and another $8 million on rehabilitation. Two years later, 72,000 ha (180,000
acres) burned in Boise National Forest. Although not as large as the Foothills fire, the 1994 fire
lasted much longer and threatened the city of Boise. The cost of fighting the fire was
approximately $80 million, not counting the cost of rehabilitation, which was more than $3
million.
Prescribed Fire in Boise National Forest
In the midst of the 1992 fire area was a 1,000 ha (2,500 acre) stand of ponderosa pine that had
been commercially thinned and then deliberately burned in 1990; it was the only area to
survive. The 1994 fire passed through, but did not completely destroy, 400 ha (1,000 acres) at
Cottonwood, which had been burned recently in a prescribed fire. These examples underscore
the value of prescribed fire in moderating, if not preventing, large fires. Although evidence of
the advantages of prescribed fire continues to pile up, the use of prescribed fire is still very
limited (as shown in the table below). For example, less than one percent of public forest land
has been subjected to prescribed fire. Widespread use of prescribed fire would be impractical
and prohibitively expensive.
The long-standing prejudice against prescribed fire is no longer the obstacle it once was.
In October, 1994, American Forests magazine conducted a poll that found two-thirds of
respondents in the inland west favored prescribed fire. Public opinion can shift quickly in the
face of large fires, however, such as occurred in Yellowstone in 1988, or in the 1994 South
Canyon fire in Colorado in which 14 fire fighters died. And people, understandably perhaps,
react differently to the idea of prescribed fire in the abstract and prescribed fire in their own
back yard. But funding is a problem. Whereas the Forest Service and Bureau of Land
Management have unlimited access to emergency funds for fighting fires, they must finance
prescribed fires from previously appropriated funds. In order to reduce fuel loads in national
forests effectively, the Forest Service believes it would need to increase the area of prescribed
burns by 30% each year for the next three years -- unquestionably a monumental task. A
program of public education, on the scale of the Smokey the Bear campaign of earlier years, is
probably needed to develop strong support among the public and in Congress for prescribed
fire.
An important advantage of prescribed fire is that the time and place can be selected
carefully. The most favorable times are in early spring when vegetation and soils are still
relatively moist and on days with little wind. But there is always the chance of a fire getting out
of control, even when all precautions have been taken, and this means that there is always a
potential for liability for an agency that initiates a fire. Another risk of prescribed fires, even
those that remain under control, is smoke pollution. It has been estimated that the fires on 1.5
million ha (3.8 million acres) of federal lands in 1994 produced over 1.2 million t (1.3 5 million
tons) of particulate matter less than 2.5 microns in diameter. Because prescribed fires are less
violent and more restricted in area, they should generate less smoke, but because they burn
cooler and smolder more, they may actually produce twice as much smoke per hectare as
wildfires. Wildfires can generate strong winds that disperse the smoke over a greater area, but
winds can change during a prescribed bum and bring the smoke over populated areas.
Prescribed fires are considered to be caused by humans and the pollution they produce is
regulated by the Clean Air Act, whereas wildfires are considered natural events.
Another deterrent to the use of prescribed fire is that modern fire fighting is a big
business. In 1994, fighting fires on 1.6 million ha (4.0 million acres) of public land cost $900
million. The cost of helicopter service (at $3,000-8,000/hour) in the western states alone
totaled $80 million. Those who risk their lives on the fire lines make good wages, in some cases
enough to last the rest of the year. Independent contractors have much to gain from large-scale
fire fighting operations, with some making three to four times their usual profits. Part of the
vast sums of money spent on fire fighting are used to defend remote cabins. For example, in
Payette National Forest in Idaho in 1994, $35 million was spent defending a half dozen ranches.
Timber companies can take advantage of the wood salvaged after fires. In the last four years,
salvage sales from 16 of the national forests in Utah, Nevada, Wyoming, and Idaho have
amounted to more than $100 million. A portion of the income from sales goes directly to
county governments (25% from income on Forest Service lands and 50% from income on
Bureau of Land Management lands), so that local governments have more to gain from fire
fighting, than from prescribed fire.
Forest Health in Idaho
For 300 years prior to 1900, the pine forests of Idaho were relatively stable and
sustainable, but in the past 95 years, parts of some forests have become an
unsustainable mix of species and densities. In 1989, the Idaho legislature created the
Idaho Policy Analysis Group, a public-private committee to study problems related to
health of Idaho's forests. A group of ecologists and other specialists assembled by the
committee concluded that Idaho's national forests are in serious condition, as
evidenced by: mortality exceeds gross annual growth (about half of the mortality is due
to insects and disease, the other half to fire) tree density is 1,333 trees ha (533 trees/acre)
compared to 75 trees/ha (30 trees/acre) before 1906 in ponderosa pine forests, pines are
declining and being replaced by firs and other species, which are less resistant to fire, insects,
and diseases and less valuable than pines.
For many years, the Forest Service allowed timber companies to cut the large, valuable
ponderosa pines and leave the smaller, less-fire resistant fir trees. Fire suppression allowed fuel
loads to build so that instead of frequent, low intensity ground fires, fires were less frequent,
but vastly more intense and destructive. From 1717 to 1893, fires occurred about every 15
years in Boise National Forest, but between 1893 and 1983, there were no fires. The shorter
and highly flammable fir trees, with limbs close to the ground, act like ladders to carry the
flames to the tree crowns. Because the crowns are vital parts of the trees, gathering light for
photosynthesis, crown fires result in greater mortality than ground fires. When fires were small
and more frequent, the forest burned in patches, creating a variety of habitats that promoted
biodiversity. Farming, ranching, and mining also changed the forests as wood was cut for
housing, fuel, and mine supports. In recent years, more homes in and around the forest have
placed pressure on the Forest Service to suppress fires that threaten human life and property.
Blister rust, a disease introduced accidentally from Europe early in the 19th century, killed
many of the western white pines. As trees became more crowded, they became more
vulnerable to attack by insects and pathogens.
The Boise Plan
With 60% of the trees dead, ponderosa pine disappearing at an annual rate of 5%, and
the threat of more large fires looming ahead, the administration of Boise National Forest
decided that it had to do something. The plan they developed in 1992 has three major
components: (1) to salvage dead and dying trees (2) to reduce tree density by thinning and
reduce fuel loads by prescribed fires, and (3) to increase knowledge about how to assess and
maintain a healthy forest ecosystem. This plan differs from earlier management plans for Boise
National Forest, which emphasized harvesting high value ponderosa pine and Douglas-fir on
relatively few acres. In 1992 and 1993, the Forest Service allowed loggers to remove 300 million
board feet of dead and dying trees. The salvage operation generated $43.7 million, $11 million
of which went to local communities for schools and roads. According to the plan, unnaturally
dense stands of trees will be commercially thinned, and prescribed fires will be conducted on
12,000 ha (30,000 acres) in the forest. In partnership with the University of Idaho, American
Forests, Boise Cascade Corporation, Idaho Department of Lands, and the Intennountaih Forest
and Range Research Station, the staff at the Boise National Forest is developing a program of
prescribed fire. Using satellite imagery and the Geographic Information System, they are
analyzing the locations and potential risks of catastrophic fires. Based on the results, they are
identifying watersheds at moderate to high risk for wildfires and targeting them for prescribed
fires.
The Boise Plan has been criticized for being too focused on trees rather than on the
health of the forest ecosystem. The result of the narrower focus is to give too little attention to
other plants, wildlife, aquatic resources, and to ecological functions, such as energy flow and
nutrient cycling. Some scientists have suggested using fish, rather than trees, as indicators of
ecosystem health. Because fish depend upon the forest for many things-shade, nutrients, fallen
trees to channel water, for example-they provide information about many aspects of forests
that would be difficult to measure individually. The plan also emphasizes, critics say, pragmatic
values of forests without placing enough importance on broader social uses, such as clean
water and recreation, or on less quantifiable values, such as biodiversity and scenery. In
general, forest management has been faulted for giving too little weight to the role of chance in
natural events-for example, the role of several years of drought on the 1992 and 1994 fires in
Idaho. Finally, new policies are not sufficiently grounded in controlled studies in which adjacent
treated and untreated areas are compared.
Some scientists believe that managers of public forest lands may be pursuing strategies,
such as the use of thinning and prescribed fire, too aggressively. Although thinning can reduce
tree density, it is no substitute for fires, which have many benefits to the forest ecosystem.
While thinning may be appropriate in certain types of forests, such as Ponderosa pine, it is less
so in other types, such as those where Douglas-fir dominates. Scientists also express concern
about the effects of thinning of trees on the ecosystem, particularly if it involves road
construction or other changes to topography. Furthermore, in order to correct a century of fire
suppression and logging of high-grade timber, thinning would need to be carried out on a scale
that would be impossibly large and expensive. Environmental groups and other critics of the
timber industry fear that thinning for fire prevention will open the door to over-harvesting for
commercial purposes.
In conjunction with thinning, prescribed fires reduce fuel load, but primarily near ground
level, and they burn cooler than wildfires. Although this is seen as a benefit to those interested
in timber harvest, protecting property, or enjoying living trees, it is not necessarily a long-term
benefit to the ecosystem. Even so-called "catastrophic" fires are beneficial to ecosystems and
they are not entirely due to fire suppression policy. In presettlement times, very extensive fires
occurred every few hundred years in many areas of the west. Fire suppression did not cause
large fires so much as it shortened the time between them. Environmental groups and many
scientists are concerned also about environmental damage caused by the preparation for and
management of prescribed fires.
Perhaps most controversial of all is the practice of salvaging dead and dying trees after
fires or epidemics of insects. Dr. G. Wayne Minshall of Idaho State University believes that the
practice is based on two erroneous assumptions: that forests cannot recover from large fires
without human intervention and that dead or burned trees have no value. He points out that
certain salvage operations can actually interfere with natural processes of regeneration. The
trees that die from fire, as well as those that remain alive, are important in the natural recovery
process. Even dead trees provide shade, cover, wind protection, runoff control, and habitat-all
of which can protect plants and animals during the recovery period. As dead trees decay,
valuable nutrients are returned to the soil where they nourish new generations. Large woody
debris is important to the ecology of streams. Salvaging trees can disturb the ground and cause
problems in erosion, runoff, and sedimentation of streams. Cutting trees to fall across slopes
and placing hay bales on slopes are ineffective in preventing erosion. In fact, the effect may be
to channel water in patterns that only increase gully formation. Another problem Dr. Minshall
sees is that the human view of recovery is too short; when people do not see regeneration in
two to three years, they assume the system has been permanently damaged. In reality, he says,
valuable recovery processes are taking place which, if given time, will lead to restoration of the
forest. Salvage logging is usually done in connection with other measures, such as repairing
roads, seeding, contouring slopes, and stabilizing streams, but credit for any improvements is
attributed to salvaging. This gives legislators and the public unrealistic expectations for what
can be accomplished by salvaging alone. The solution is not to avoid all salvaging, thinning, and
prescribed fire, but to move cautiously and base actions on scientific evidence of long-term
benefits. While many forest managers believe the situation is too critical to wait for results
from long-term studies, many in the country fear that the new policies of today will be seen in
the future as the mistakes of the past.
CASE STUDY: FOREST FIRES IN IDAHO
Questions
I. If prescribed fires are limited by the Environmental Protection Agency under the Clean Air
Act, will the United States have more or less air pollution? Do you agree that wildfires are
natural and prescribed fires are caused by humans?
2. Industrial forests, in the areas that have been actively thinned and managed, do not have
the same level of mortality or catastrophic fires. Does this prove that similar methods of
forest management should be used in the national forests? Explain.
3. Elk were not found in the Boise National Forest area in presettlement times, but have been
introduced. People enjoy seeing them and think of them as part of the forest. Should the
forest be managed in such a way to perpetuate the elk population or should it be managed
so as to return it to presettlement conditions? Is the latter a realistic goal?
4. In some western habitats, large, catastrophic fires occurred every several hundred years for
the past tens of thousands of years. After each one, the ecosystem recovered and evolved.
In light of this, is the term "catastrophic" appropriate? If so, from what point of view are
such fires catastrophic? If not, why is the term inappropriate? How does the use of such
terms as "catastrophic" affect environmental policies?
5. Which of the goals below do you think should guide the management of national forest
lands? On what did you base your decision? What are weaknesses in the goals that you did
not select?
To maintain the forest in the condition they were in when European colonists first came
to America
To maintain the forest for maximum productivity of timber
To leave the forest to natural processes with as little human impact as possible
To manage the forest for multiple use, i.e., timber harvest, recreation, preservation of
biodiversity, etc.