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Yellowstone Forest Fires
Forest Fires
I. How They Work
II. Fire Management
I. Map of Yellowstone
II. Yellowstone Fire
III. One Year After
IV. Six Years After

Earth Sys. Analysis
Yellowstone Fire Analysis
Sphere Analysis Tool

Fire Management
Man and nature, the way it starts, with control, suppression...

In the early decades of the 20th century, after several catastrophic wildfires destroyed newly formed logging operations, the U.S. government adopted a policy of aggressive fire suppression. Professional firefighters were trained to detect and fight fires, and tower lookouts were built in remote sections throughout our country's forests. A forest ranger would live in the lookout for weeks on end, catching up on reading and watching for tell-tale wisps of smoke on the horizon. From the time Yellowstone was established, park managers did their best to suppress fires. Rule number one in park fire-control policy was, let no fire get out of hand.

The aim of fire suppression is, first, to stop or slow down the rate of a fire's spread, and secondly, to put it out. There are three components to any fire — fuel, temperature, and oxygen — which have become known as the fire triangle. To suppress a fire, firefighters must break this triangle, by removing the combustible materials, by reducing its temperature, or by smothering it so that it has no oxygen.

Suppressing fires became considerably more effective after World War II and after the tragedy of the Mann Gulch fire, when airplanes, helicopters, smokejumpers, fire retardant clothes and new fire fighting strategies were introduced into the fight against forest fires. It seemed as if the raging infernos that had destroyed forests and terrorized people would become the gigantic disasters of the past, limited to small outbreaks that could be quickly brought under control.

This photo, taken in October of 2003, shows firefighters using fire retardant sprays and digging tools to battle a blaze in California. Image courtesy of the National Interagency Fire Center.

Worst-case scenario
On August 20, 1910, hurricane-force winds sent fires careening through forests in Idaho and Montana. Dubbed "the big blowup," these fires destroyed 1,215,000 hectares of forest in just 48 hours.

Perhaps the way it should be...let it Burn
With the introduction of new equipment and methods, firefighting efforts became more sophisticated and more effective, as did the science of ecology, the study of the relationships between organisms and their environment. Ecologists began to doubt the wisdom of the policies of fire suppression. Forests have always experienced periodic fires, they argued. Before the arrival of humans, forests in the U.S. West burned naturally every 25 to 30 years, and these fires played an important role in the life cycle of the forests. Fires get rid of dead or dying trees, clear away accumulated litter, and refertilize the soil, allowing an increase in the variety of plant and animal life. Since the beginnings of life on this Earth as we know it, forests have adapted to the continuing recurrence of fires. Foresters should not try to manipulate forests, the ecologists cautioned: they should let nature, in this case fire, take its course, and permit the forests to burn naturally.

By 1972 the voices of ecologists were beginning to be heard, and Yellowstone, like all the other parks in the National park system, initiated a natural-burn fire policy. The new policy let naturally occurring fires run their course over about 15 percent of the park's total land area (provided they did not pose a threat to visitor areas). By 1976 this policy was expanded to all wilderness areas of Yellowstone, about 700,000 hectares.

Consequently, between 1972 and 1987, only 13,800 hectares of Yellowstone's 890,000 hectares of grasslands and forests were overrun by fires. Tremendous amounts of decaying litter and dead wood built up in Yellowstone's forests. Under these conditions, when fires did occur, they quickly ballooned into immense, uncontrollable conflagrations. Nowhere was this more dramatically shown than in the Yellowstone fires of 1988.

We can handle that
Before the summer of 1988, the worst fire in the history of Yellowstone Park (occurring in 1886) had burned only 10,100 hectares.

Review Questions

  1. What is the "fire triangle"?
  2. Firefighters attempt to suppress fires by: ________________, ________________, and ________________
  3. Distinguish between a “fire suppression” policy and a "natural-burn" policy.