Fire is a natural phenomenon linked to the dynamics of many plant communities and animal populations. Understanding the benefits and the dangers of fire, the possible uses and avoidable misuses is a necessary act of environmental education. It has been used by humans since time immemorial to provide energy for heating and cooking, driving game, eliminating pests and disease, eliminating ambush sites, fostering the continuation of various plant species, improving wildlife habitat and range for livestock, clearing land for agriculture, and to facilitate transportation and communication. (Agee 1993)
Fire can be friend or foe depending on whether it is under control or out of control. Currently an estimated average of 30-32 million acres burn out of control each year worldwide. Australia began 1994 under the awesome sign of fire, with a huge blaze that devastated hundreds of thousands of acres of forest land, destroyed homes and belongings, and besieged the city of Sydney. A few months earlier, in the summer of 1993, the outskirts of Los Angeles had been reduced to ashes by a series of enormous fires. Catastrophic fires of 1994 burned up millions of acres and billions of board feet of timber in the fuel-loaded, drought ridden, and diseased forests of the Inland West, causing serious ecological damage.
The word fire is from the Greek 'pyra' meaning glowing embers. To start a fire, it takes combustible elements like the cellulose and lignin in wood, oxygen, and a heat source such as a lightning strike, a match, a carelessly discarded cigarette, or an unattended camp fire. Sustained combustion from an ignition source requires three elements, often referred to as the fire triangle: fuel, heat and oxygen. Fire behavior can be understood through the fire behavior triangle: weather, topography, and fuels.
The great Yellowstone fires of 1988 burned 1,408,000 acres. We set ourselves up for this catastrophic event by: controlling periodic low intensity fires, allowing extreme fuel-loading, and failing to remove dead and dying trees. This was just one high profile example of a much larger problem. People began to seriously question the wisdom of Smokey the Bear, that popular icon which we have known and loved since 1944. Did we oversell Smokey and his message to stop all fire at any cost? At age 50 is it time to update Smokey's message? We began to understand that we build our homes at great risk in areas where fire is an integral part of ecosystem dynamics. In the summer of 1994, the U.S. Forest Service had to abandon saving forests to save individual homes, and then had to abandon saving homes to save whole communities.
It was once believed that forest landscapes become increasingly stable over time until eventually reaching a "climax state" of complete stability. In his book Fire Ecology of the Pacific Northwest, James K. Agee, Professor of Forest Ecology at the University of Washington, says that "this idea has been challenged by a new understanding of the importance and inevitability of forces such as storms and fires that keep ecosystems in a state of constant change. The dynamics of fire ecology has emerged as a central feature of a new understanding as scientists and land managers redefine traditional assumptions about the growth and development of ecosystems." wildlife Impacts
Fire effects on wildlife are complex because they are often indirect, affecting habit more than individuals. Fire is beneficial to some species and detrimental to others. Death of large animals due directly to fire is rare. Many species ignore the presence of fire while others are attracted to it due to the availability of prey. The major effect of fire is on animal habitat: food, cover, and water. Fire may have different effects over time on an individual species. Some species tend to be "winners" and others "losers" as fire alters the habitat. Many species favored as game animals benefit from habitat changes which reduce forest cover or increase the edge around openings.
About 12,000 years ago the Paleo-Indians swept into North America across the Bering bridge through unglaciated Alaska, and down the melting ice corridor east of the Cordilleras. We can be confident that they were old hands at hunting woolly mammoths and other large Eurasian animals. Evidence suggests that the communal bands of Indians probably hunted with fire, to drive animals from cover, and stone-tipped spears. So as the glaciers receded, there were people on the landscape proactively shaping that landscape along with animals and natural disturbances to include: lightning fires, volcanoes, windstorms, and floods. One of the great myths that prevails in our society is that the Native Americans were "environmentally benign." Indians used fire aggressively, and in doing so, helped to shape the ancient forests into a diverse mosaic.
Forests cover 1/3 of the United States, but today's forests differ significantly from ancient forests according to Dr. Thomas H. Bonnicksen a professor of forest science at Texas A&M University, who has been studying the ecology of ancient forests for 24 years. Professor Bonnicksen says that exotic plants, animals, and diseases continue to change America's forests. However, "the elimination of Indian burning and the suppression of lightning fires have produced the greatest changes." Dr. Bonnicksen says that the loss of nature's clearcuts threatens the health and productivity of America's forests. "Without nature's clearcuts, forests throughout America are growing thicker, and the mosaic structure that characterized the majority of ancient forests is disappearing. The most dramatic decline in forest health is in national parks, wilderness areas and other forests where timber management is prohibited. The decline in forest health is also causing a reduction in wildlife and fish habitat, a decrease in biodiversity and lower water yields." Bonnicksen concludes, that the deterioration of ancient forests caused by eliminating Indian and lightning fires demonstrates that diverse and healthy forests can only be sustained by active management. Active management means foresters must have a complete set of silvicultural tools, including prescribed fire and clearcutting.
Of the many ways in which pre-historic man modified the forest, only through his use of fire was his influence broad enough to significantly influence the evolution of forest types. Fire has been used by mankind as a cultural tool for nearly two million years in Africa. It was brought to America about 12,000 years ago by the original settlers who crossed the land bridge (Beringia) that connected Alaska with Siberia during much of the Pleistocene. It was/is a cultural tool that can quickly and easily modify large segments of the landscape, generally to the advantage of primitive human populations as it encouraged both the heliophytes and herbivores that were primary food sources (Oakes 1939). Fire today is the single most important tool in converting tropical forests to agricultural land.
Interacting with natural processes, human-caused fires were a primary vector shaping the pre-Colombian landscape, which was likely a mosaic of grasslands, open woodlands and closed forests. This diversity in landscape components provided habitat diversity that, in turn, accommodated wide species diversity of both plants and animals. The "wilderness" described in early American writings depicts closed forests, a condition that developed only after European diseases killed most of the native American population during the early part of the 16th century. Native population estimates go as high as 18 million, and mortality estimates as high as 90 percent. (Buckner 1993)
Before we can implement any sustainable model for forest management it is essential that we understand two things. The first is an understanding of the forces that shaped the forests or natural resource conditions. The second is that we have a vision of what the future landscape should be. As there will be greater input from the public on how our forests will be managed, particularly the public forests, it is essential that the public see more than just a snapshot in time when they look at a forest. The notion that some "natural" forest existed in 1492 in the sense of a broad landscape being composed of climax forest associations that formed independent of human influence is a myth. And, according to Ed Buckner, a professor of forestry at the University of Tennessee, "trying to devise management strategies today to recapture this "figment of our romantic nature and imagination" is not a viable option. Professor Buckner says that any significant effort in that direction is counterproductive.
The more successful we are at fire prevention the more we need to introduce other disturbances to the forest. Professor Bonnicksen points out that "increasing tree densities, thickets of understory trees, and the conversion of forest and brushland mosaics into a continuous cover of highly flammable fuel also makes wildfires larger and more severe, as the Yellowstone fires have shown. These unnaturally large fires increase the size of patches in the forest mosaic, which will drastically increase the destructiveness of future fires." Forests in many parts of the United States have been struck with a health problem of unprecedented proportion. Those on the east side of the Cascades in Washington and Oregon are hardest hit, but similar conditions exist across Montana, Idaho, Utah, Nevada, California, Arizona, and New Mexico. Since the 1980s large wildfires in dead and dying western forests have accelerated the rate of forest mortality, threatening people, property, and natural resources. Robert W. Mutch writing for the Journal of Forestry says that "much of today's forest health problems are associated with long-needled pines. Successful fire exclusion over the past 60 to seventy years has disrupted two or more fire cycles, contributing to greater stand densities and an increase in crown fire potential. Ecosystem management strategies to address this problem should include reducing stand density and dead-fuel accumulation. Prescribed fire can be a tool for maintaining more open stands. Consequently, our ability to restore and sustain forest health rests in large part on understanding and applying fire-related information to complex management issues."
Open ponderosa pine, larch, and Douglas-fir forests at lower elevations in the West burn naturally every 5 to 30 years, according to Mutch, "maintaining rather open, fuel-free stands with few fir trees. But in more recent times managers have harvested the larch and pine overstory extensively while excluding fire. In the absence of fire, stand composition has shifted toward an unnaturally dense understory of Douglas-fir, grand fir, white fir, or incense cedar. Spruce budworm, Douglas-fir bark beetles, other destructive pests, and forest diseases have enjoyed a steady diet of stressed fir trees, leading to mortality, fuel build ups, and high-intensity wildfires." A very high profile example of this problem is in the Lake Tahoe basin where bark beetle infestations are causing a browning of the forests.
Fires and ecosystems have interacted throughout time, establishing fire as an influence in ecosystem functions such as, recycling of nutrients, regulating plant succession and wildlife habitat, maintaining biological diversity, reducing biomass, plus controlling insect and disease populations. Mutch says "an understanding of fire's history, regimes, and effects is absolutely essential for today's resource managers. And this knowledge must be applied on a landscape scale to restore the health of forests that are both fire-adapted and fire-dependent." Mutch goes on to say that "the culprit in today's problem is not fire suppression, but the attempt at complete fire exclusion. In other words, we have not balanced our fire suppression program with an equally broad and important prescribed fire program applied on a landscape scale. Many stands are so dense with dead and dying trees, salvage logging will be a necessary step before initiating extensive prescribed burning programs. Keeping stands thinned, rapidly salvaging diseased and dying wood, and keeping the understory from becoming overstocked are important steps in reducing the threat of wildfire and disease."
Longleaf pine (pinus palustris) once covered nearly 70 million acres of the southeastern coastal plain of the United States. Today, less than 5 million acres of this important southern pine forest type remain. Despite recent concerns expressed over the recent declines of temperate and tropical rainforests, a far greater percentage (99.9%) of original longleaf pine forest has been lost. Longleaf pine forests are among the most fire dependent forest types in the world; naturally occurring fire regimes regularly burned most original longleaf forests on a frequency of 2-7 years. The natural structure of longleaf stands resembles a classic, open canopy park-like forest maintained by fire.
In a paper co-authored by Dr. Leonard A. Brennan, Director of Research, at Tall Timbers Research Inc. in Tallahassee, Florida, Brennan says " the widespread suppression of wildland fires in longleaf has seriously compromised the integrity and health of this system. For example, many of the remnant stands of longleaf suffer from midstory hardwood encroachment. Additionally, endemic vertebrates such as the red-cockaded woodpecker have suffered widespread decline as a function of fire suppression and type conversion in longleaf pine." These comments are taken from a paper titled Public-Private Partnerships for Ecosystem Management of Longleaf Pine Forests: A Research Agenda. Since the early 1960s Tall Timbers has published a series of 17 conference proceedings on fire ecology. These proceedings have played a key role in communicating the importance of fire as an ecosystem process.
During the past several decades, prescribed burning has become an accepted management practice for southeastern pine woods. In the 1940s when foresters first started using prescribed fire, they viewed it not as a natural part of the ecosystem being reinstated after years of suppression, but as a tool that could produce desired results. Without it hardwoods would eventually replace the commercially valuable pines. They burned only in the dormant season (winter months), but the natural fire season is the growing season of March-September, which is also the lightning season. The US Forest Service's recent vegetative management plan for the Coastal Plain/Piedmont allows growing season burns "to maintain certain fire dependent ecosystems." The debate in the south is not over whether to burn as much as when to burn.
Southeastern Indians used fire to clear fields for cultivation, to drive game, and as a means of communication. Large Indian fires were set for signaling, and there is evidence that signal fires were widespread and used all year round. This is similar to the patterns in New England, the central Atlantic states, and Western North America where Indians used broadcast fire to drive game and to improve forage to attract game animals. European settlers were no less aggressive with fire, clearing land for livestock. Eventually for southerners, gaining control over fire was the equivalent of shifting the fire season from summer to winter. Now the south is considering whether to relinquish some of its hard-won control over fire by returning to a more natural (i.e. historic) fire regime.
Just like wildfires prescribed burning affects soils by altering their physical, chemical, and biological characteristics. Whether these changes are construed as beneficial, detrimental, or of little consequence depends on specific burn objectives and long-term management goals. Land managers may use prescribed burning for numerous reasons including one or more of the following:
Forest Health might be described as a desired condition of forest ecosystems that sustains their complexity while providing for human needs. In an article titled Assessing Forest Ecosystem Health in the Inland West, in the March/April 1994 edition of American Forests magazine...the authors, R. Neil Sampson et.al., state that millions of acres of inland forest are failing the test. In many areas of the inland West trees across large landscapes are dying faster than they are being replaced. "We have over 10 million acres in the West that is going to burn, we just don't know when" says Sampson who is Executive Vice President of American Forests, a conservation group based in Washington, D.C. "The forests have been subjected to years of drought, and are clogged with small trees competing for sun, water, and nutrients. They are stressed to the point where they have become extremely vulnerable to fire, insects, and disease. Fuel loading is so high that the fire intensity could cause severe ecological damage to the point of destroying the forests as we know them. Sampson and other scientists say that the onset of major ecosystem setbacks are assured by the existence of conditions that will inevitably lead to large, stand replacing wildfires. They suggest that we have a window of 15-30 years to concentrate on prevention and restoration of these forests before catastrophic events rob us of future options. The silvicultural prescriptions include salvage logging, heavy thinning, and prescribed burning."
Older trees, which can survive ground-level fires, don't live through flames that climb up small trees like ladders to engulf the treetops. As fire is carried into the crowns of the trees it is transported much further up slopes than was previously possible when fires were largely confined to the understory, further compounding the problem. That's what happened during the Foothills Fire of 1992 when an intense wildfire eventually burned 259,000 acres including 160,000 acres of the Boise National Forest in Idaho. Trees containing an estimated 300 million board feet of merchantable timber (enough to build 22,500 homes) were killed along with young tree growth across the fire area.
Note: 640 acres or one section represents a square mile. So the three Tillamook burns consumed over 984 square miles of forest land. That is equivalent to a strip of land one mile wide from Portland, Oregon to Los Angeles or from Chicago to New Orleans.
The yardstick for sustainable forestry is a healthy ecosystem as measured by forest productivity, diversity, resiliency, and the maintenance of ecological processes over large landscapes. Some would say that this adds up to a sustainable forestry. To achieve these desired outcomes interdisciplinary teams of resource managers must be free to work together, experiment, and use all of the tools at their disposal. There is a great deal of urgency in areas where fire dependent species have thrived and now face extinction. As it turns out one of the best ways to fight fire is with fire. However there are complications. Millions of acres of forest land are set aside in wilderness areas and other preserves where no timber harvesting is permitted and fire fighting is limited. Much of the remaining forest land is habitat to one or more threatened or endangered species. This imposes additional restrictions which may prohibit the salvage of dead or dying trees even after a burn or windfall.
The fate of public forests is being decided in the courts. The rash of litigation has made it impossible for federal land management agencies to comply with an avalanche of conflicting and redundant environmental laws, much less their own regulations. Their resources are being consumed by the never ending loop of handling appeals, litigation and responding to one crisis after another. In other words, federal agencies are so tied up in the process that there are no resources left to develop the product. The ultimate solution will have to be in Congress or the legislative branch. Existing laws must all be placed on the table and new laws must be created. Decision making must be delegated down to the ground, to people who know the ecology of various areas and they must be able to have rewarding careers while staying in given areas for long periods of time. It is often said in private industry that "it takes a resource manager about twelve years to really know a place."
Where there is conflict there is a conflict industry. Ultimately, to implement any type of sustainable ecosystem management on public lands requires the support of the public. The public is understandably confused by the heated rhetoric of special interest groups which are polarized on the fringes. What the public needs is very clear articulation of the issues and options so that they can make their own informed choices. It is helpful here to differentiate between ecology, environmentalism, and belief systems. Dr. Hamish Kimmins, a Professor of Forest Ecology at the University of British Columbia, has done this in his book "Balancing Act." He points out that ecology is a pure science free of value judgements. Environmentalism is the act of working hard to have a healthy economy and a healthy environment, and strong communities... something most of us want. A belief system, on the other hand, is something based on faith which requires no absolute proof. Some people may believe that wildfires like those in Yellowstone should be allowed to burn and some don't, but those opinions are not necessarily based on science. Perhaps any meaningful discussion of ecosystem management should start with a basic understanding of ecology itself.
Aldo Leopold said that "the first rule of intelligent tinkering is to save all the pieces." He never said we shouldn't tinker. The greatest risk to our forests is to leave the outcome to chance. We must act in the absence of complete and perfect knowledge, something we will never have. We now have silvicultural tools, monitoring and modeling programs, and forestry equipment which were not at out disposal in years past. We are learning to do adaptive management, where new scientific knowledge is immediately factored into management decisions and action. We must use every means at our disposal to educate the public on the issues and options. All options have strengths, weaknesses, risks and trade-offs. Most scientists agree, the option with the greatest risk is to do nothing. Doing nothing on public lands can also have severe consequences on adjoining private land. Insects, disease, and fire do not recognize property lines.
Avoiders - Plants that have little adaptability to fire.
Crown fire - A fire burning into the crowns of the vegetation, generally associated with an intense understory fire.
Endurers - Plants that resprout following a fire or endure the effects of fire.
Fire regime - The combination of fire frequency, predictability, intensity, seasonality, and extent of fire in an ecosystem.
Invaders - Plants which invade a site after fire.
Prescribed fire - A fire ignited under known conditions of fuel, weather, and topography to achieve specific objectives.
Prescribed natural fire - A fire ignited by natural processes (usually lightning) which is allowed to burn within specified parameters of fuels, weather, and topography to achieve specific objectives.
Surface fire - A fire burning along the surface without significant movement into the understory or overstory, with flame length usually below 1 meter.
Understory fire - A fire burning in the understory, more intense than a surface fire and with flame lengths of 1-3 meters.
Water repellency - The resistance to soil wettability, which can be increased by intense fires.
Wildfire - A fire, naturally caused or caused by humans, that is not meeting land management objectives.
American Forests, A History of Resiliency and Recovery, 1992 USDA Forest Service (FS-540) in conjunction with the Forest History Society.
American Forests Magazine, American Forests, March/April 1994.
Balancing Act, Hamish P. Kimmins, UBC Press/Vancouver, 1992, ISBN 0-7748-0426-2.
Changes in America's Forests, paper by Ed Buckner, Overton Professor, University of Tennessee, Institute of Agriculture, Department of Forestry, Wildlife and Fisheries.
Fire, Environmental Education Dossier, UNESCO 1994, ISSN 1022-3304.
Fire Ecology of the Pacific Northwest, James K. Agee, 1193 Island Press 1993 ISBN 1-55963-229-1.
Forest Fires, Margaret Fuller, John Wiley & Sons, Inc., 1991, ISBN 0-471-52189-2.
Journal of Forestry, Society of American Foresters, November 1994.
Private-Public Partnerships for Ecosystem Management of Longleaf Pine Forests: A Research Agenda, Leonard A. Brennan et. al., Tall Timbers Research Station.
Seasonal Effects of Prescribed Burning in Florida, Louise E. Robbins and Ronald L. Myers, Tall Timbers Research Inc., Miscellaneous Publication No. 8.
The Future of America's Forest, Thomas M. Bonnicksen, Essay 1994.
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