AN ESTIMATED 6,895 fires have charred more than 742,000 acres of forest and range land in nine Western states this month, bringing out 18,000 fire fighters.
That battle in the Northwest follows a spring that saw fire destroy 73,000 woodland acres near the Atlantic coast of North Carolina, and it comes amid concerns of East Tennessee forestry officials that the months-long drought in the Southeast could set the stage for the worst season of forest fires in the history of that area.
Scenes of brave, weary firefighters combating these conflagrations are familiar fare for the daily papers and the nightly television news, and the idea of fire as anything but an intractable enemy seems strange indeed.
Yet for many plants and animals, fire is as important to survival as food and water.
While the notion of fire as an essential part of the environment may strike many as wrong, a growing body of research attests to the value of fire in maintaining complex balances in nature.
When woodlands or grasslands are deprived of fire for extended periods, as occurred in many parts of the United States for most of this century, the impact on the environment can be profound.
In the last few decades, state and federal officials who manage the nation`s forests have come to regard fire as a tool in that management–and also as an essential part of nature`s life cycle. Planned fires or prescribed burns are valuable both in restoring natural ecologic balance and in preventing major fires that do heavy damage to woodlands.
Yet at a time when forestry experts have come to accept the benefits fire can bring, they often find themselves hampered in realizing those benefits because of a trend they call forest urbanization.
People in search of the peace and tranquility of the forests are building homes there, often clearing only enough land for a dwelling, to enjoy the natural beauty of the woods all around.
This trend of populating the nation`s woods is creating a monumental fire hazard, say foresters, and has hampered implementation of man`s new understanding of the role of fire in nature.
Some say it is only a matter of time, and bad luck, until some catastrophe occurs on the order of the 1871 fire near Peshtigo, Wis., which claimed more than 1,500 lives.
Use of fire to clear land in preparaton for crops is a practice as old as agriculture itself. But only in recent years have scientists begun the serious study of how fire affects the countryside, charting specifically which species of plants and animals benefit and which are harmed.
For a healthy stand of oak trees to prosper, fire is essential, researchers have found. Oaks are of economic and ecologic importance in forests from New England to the Midwest and down to the Gulf of Mexico, said Ralph Nyland, professor of silviculture at the State University of New York in Syracuse.
Scientists have found charcoal in the soil of oak stands, indicating a history of fires, probably recurring fires, in those areas, Nyland said. They have also noted that when oak stands are undisturbed by fire for several years, oak sprouts fare poorly and other species such as red maple and beech trees begin to take over.
Such a transition of tree species has a subtle effect on the type of animals that live in a forest, Nyland said. Animals that depend upon acorns as food begin to leave a forest in transition from oaks to other species.
Researchers don`t know exactly why fire is necessary for oaks to flourish, Nyland said, but several factors apparently play a role. Oaks thrive in light and prefer a sunny, open forest.
In a forest with many tall oaks and a heavy undergrowth of bushes and trees that prosper in the shade, oak sprouts are at a disadvantage. As the debris of leaves, bark and other materials called slash builds up on the forest floor, acorns dropping to the ground have difficulty pushing out roots long enough to even reach the soil.
Small fires that race through such forests, burning up the slash, bushes and new sprouts, apparently leave acorns in a superior competitive position for resprouting. These fires don`t reach high enough to burn the crowns of mature oak trees or become hot enough to burn through their bark or harm their root systems, Nyland said.
Experimentation suggests that repeated fires of this nature, perhaps every four years or so, give oaks the greatest advantage, he said.
After setting fires for several years and observing the outcome, Nyland and his colleagues have found the optimal conditions for fires that benefit oaks. Typically these occur in the spring, after the ground has thawed and a rain has left the humus damp under a layer of leaves.
Ground fires of this kind are themselves a fire prevention measure because they consume combustible materials before a build-up that makes for a potential tinderbox that could harm mature trees if touched off during dry, windy conditions.
Several techniques taking terrain, wind and other factors into account are used to control prescribed burns so the fire doesn`t burn too long, become too hot or escape the target area.
In the South, fires have been found beneficial to several species of pine and to wildlife such as deer, wild turkeys and quail that thrive in open or semi-open settings.
Even when direct connections between fire and the environment are discovered, it is sometimes difficult to understand the precise relationship. Henry Webster, the Michigan state forester, notes that Kirtland`s warbler, an endangered bird species, shows a preference for nesting in jackpine trees.
The birds like jackpines that attain the size of an average Christmas tree, Webster said, and research has shown they prefer stands of jackpine that have grown following a fire.
The birds will nest in jackpine stands with no fire history, he said, but a postfire stand usually attracts more of the birds. Scientists offer no clear explanation for this.
In many cases, careful research has established precisely how fires accomplish ecological tasks. Some studies indicate smoke from burning pine needles can inhibit germination of several types of western rusts and fungi that attack trees.
Robert Mutch, a researcher for the U.S. Forest Service, said such discoveries suggest that fire may play a self-regulating disease control role. It is possible that plants far removed from a forest fire itself but situated downwind could benefit from the fire.
Meadowlands and prairies cannot exist without occasional fires to control intrusion by woody plant species. In southern Wisconsin, maintaining prairie grasses is the chief use for prescribed fires, said Duane Dupor, a planning analyst for the state`s bureau of forestry.
”Burning increases the nitrogen-fixing bacteria in the soil,” said Dupor, ”and the black ash absorbs heat, warming the soil. After a fire you get a flush of green vegetation that attracts ducks to wetland areas.”
Last spring, scientists at the New York Botanical Garden`s Cary Arboretum in Millbrook, N.Y., used mowing and burning in side-by-side areas to control encroaching woody plants and maintain a grassland meadow.
By mid-August, the burned area yielded 50 percent more grasses and they were taller and more vigorous than the grass in the mowed plot.
One reason for such vigorous growth after a burn may have to do with alleopathy, the chemical warfare between plants competing for the same growing space. Toxic chemical compounds leached from plant materials can build up in the soil, inhibiting the germination of seeds or interfering with the growth of seedlings. Fire has been shown in experiments to volatilize these toxic compounds, restoring the soil to normal growing conditions.
In some cases the benefits of fire to certain species are obvious and direct, and fire is necessary for the seed to begin germination. This is the case with the seed of redstem ceanothus, a Rocky Mountain plant producing seeds no larger than a pin head. The seeds remain dormant but viable up to 150 years, awaiting a fire to crack open their coating, allowing them to obtain moisture.
During the past decade, the value of fire, both as a planned tool of forestry management and as an unplanned part of a natural wilderness area, has won it a place in state and federal woodlands policy.
Some environmentalists such as Tim Mahoney, a Washington lobbyist for the Sierra Club, contend that old attitudes still linger in the U.S. Forest Service. Mahoney said some forestry managers still hate to see trees burn.
”In some places, the Forest Service would still rather cut trees than let them burn,” said Mahoney. ”In Texas and some other Southern states, the Southern Pine Beetle is a pest that kills pine trees. The Forest Service wants to fight the beetle by cutting down trees.
”But allowing natural fires to burn through the forest would control the beetle. We`re in federal court in Texas to oppose cutting trees. Our position is that the service shouldn`t intercede at all in a wilderness area.”
There are also environmental groups that criticize forestry managers who they say have embraced a pro-fire policy too eagerly.
In California, a group called the Save the Redwoods League contends that the National Park Service`s use of fire is harmful to the trees because it has left giant trees in Sequoia National Park with scarred bark. Park management has introduced fires to the area in an effort to restore a natural ecosystem balance similar to how things were 100 years ago, before the beginning of human intervention.
The park managers argue that while scarred bark may not be esthetically pleasing to some, it is part of the natural cycle of the forest and doesn`t pose a threat to the trees. In response to the criticism, a special advisory committee of experts has been convened to study the situation and is expected to issue a report this fall.
Use of prescribed fires to keep down the forest floor slash that serves as kindling for wildfires is a well-established fire prevention policy, said John F. Marker, national fire prevention officer for the forest service. Federal and state authorities have aggressive prescribed burn policies to prevent major wildfires, Marker said.
An irony is that the movement of people into woodlands in the last two decades makes wildfire prevention all the more important, but it hinders flexibility in using prescribed burning as a prevention measure, Marker said. Census figures indicate that in the last decade population in rural regions grew faster than in urban areas. Much of this growth is in forest lands.
This trend is producing a new fire hazard. Last year saw 1,400 homes destroyed or damaged by 83,000 wildfires that burned 3.3 million acres and killed 44 people, forest service records show. It was the greatest loss of lives and property to wildfires in this century.
When a wildfire threatens dwellings, firefighters must try to protect the property, Marker said. This often deprives them of traditional techniques for fighting wildfires, he said.
Instead of using wind and terrain to their advantage in stopping or containing a wildfire, the firefighters must go wherever dwellings or people are in danger, he said. Fire officials have held meetings and formed committees in an effort to develop strategies for fighting wildfires under urbanized conditions.
Urbanization of wooded fire-prone areas has long been a trend in California. It is a trend other states now share. ”Prior to 1985 we used to lose half a dozen homes a year to wildfires in Florida,” said John Bethea, Florida state forester. ”Last year we lost 130 in one fire in one afternoon. We lost 400 dwellings during the entire year.”
Florida has had an aggressive prescribed burn program to reduce slash and prevent major wildfires, but Bethea said urbanization is hampering that program.
”People are building homes on lots of two to five acres with just enough clearing to put a house,” Bethea said. ”It gives them an opportunity to smell the flowers and hear the birds.
”But you can`t run a prescribed burn through these subdivisions. You`d be too close to dwellings. Often you can`t even do a prescribed burn in a forest across the road, even though it is aimed at protecting these people.
”They don`t want to look at a charred forest. They don`t want ashes floating in their swimming pools. What you end up with is a first class fire hazard. The only reason we haven`t had a major disaster is because we`ve been lucky.”
