Flames in Our Forest: Disaster Or Renewal?
248
Flames in Our Forest: Disaster Or Renewal?
248Overview
Shaped by fire for thousands of years, the forests of the western United States are as adapted to periodic fires as they are to the region's soils and climate. Our widespread practice of ignoring the vital role of fire is costly in both ecological and economic terms, with consequences including the decline of important fire-dependent tree and undergrowth species, increasing density and stagnation of forests, epidemics of insects and diseases, and the high potential for severe wildfires.
Flames in Our Forest explains those problems and presents viable solutions to them. It explores the underlying historical and ecological reasons for the problems associated with our attempts to exclude fire and examines how some of the benefits of natural fire can be restored Chapters consider:
- the history of American perceptions and uses of fire in the forest
- how forest fires burn
- effects of fire on the soil, water, and air
- methods for uncovering the history and effects of past fires
- prescribed fire and fuel treatments for different zones in the landscape
Flames in Our Forest presents a new picture of the role of fire in maintaining forests, describes the options available for restoring the historical effects of fires, and considers the implications of not doing so. It will help readers appreciate the importance of fire in forests and gives a nontechnical overview of the scientific knowledge and tools available for sustaining western forests by mimicking and restoring the effects of natural fire regimes.
Product Details
| ISBN-13: | 9781597266031 |
|---|---|
| Publisher: | Island Press |
| Publication date: | 04/10/2013 |
| Sold by: | Barnes & Noble |
| Format: | eBook |
| Pages: | 248 |
| File size: | 5 MB |
About the Author
Stephen F. Arno, now retired, was research forester with the USDA Forest Service Rocky Mountain Research Station in Missoula, Montana. He is co-editor of Whitebark Pine Communities, (Island Press, 2000).
Steven Allison-Bunnell is a science writer and educational multimedia producer based in Missoula, Montana.
Read an Excerpt
Flames in Our Forest
Disaster or Renewal?
By Stephen F. Arno, Steven Allison-Bunnell
ISLAND PRESS
Copyright © 2002 Stephen F. ArnoAll rights reserved.
ISBN: 978-1-59726-603-1
CHAPTER 1
Introduction: Why Learn about Fire?
Since the end of the last ice age fire has molded most forests in the western United States. Repeated patterns of burning heavily influenced which tree and undergrowth plant species prospered. Fires also helped determine the structures and patterns of forests on the landscape as well as their suitability as habitat for a myriad of birds and mammals. Pioneer western naturalists were sometimes alarmed by the destructive power of fire; but they also recognized that fires helped create many of the splendid old growth forests at which they marveled (Pinchot 1899). Now, for almost a century, we have tried to eliminate fire from most forests without considering possible adverse effects on native plants and animals and on the sustainability of the forest itself. Logging and other human activities have of course changed western forests dramatically. But our endeavors to eliminate fire have caused some of the most widespread and harmful changes.
This book explores the underlying historical and ecological reasons for the problems associated with fire exclusion. It also examines the scientific knowledge and available technology that could be used to mimic and restore some of the ecological effects of natural fires to help sustain western forests. The messages about forest fires that we have been exposed to for nearly a hundred years have bred skepticism as to the possibility, or even the desirability, of restoring some approximation of the natural fire process in western forests. This book presents a new picture of fire's role in maintaining forests, what options we have for restoring important effects of historical fires, and the consequences of not doing so.
To understand why fire is so universally feared, we begin with the history of European-American perceptions and uses of fire in the forest. (It may be surprising to learn that a century ago some influential people thought it was actually a good idea to burn the forest regularly.) Until the early twentieth century, the western states and their residents commonly encountered large, free-ranging fires. By midcentury, fire suppression had become quite effective, and the scale of burning had been greatly reduced. However, since the 1970s the extent and severity of fires has been on the rise. We will show how fire suppression has changed the extent of burning on the western landscape, and we will project future trends for fire.
How do forest fires burn? The principal factors and how they influence fire behavior may seem relatively simple, but nature has many ways of confounding our predictions of what fires will do. Different plants and animals have adapted in diverse ways to different kinds of burning. Through natural selection, contrasting patterns of burning were linked, and often fine-tuned, to different types of forests. Some trees produce so much fine fuel they virtually assure frequent burning, which in turn benefits their survival and continued abundance. Other trees are adapted to severe but infrequent fires. Although these fires destroy them, they can regenerate and grow afterward much more effectively than their competitors. Individual trees may not survive the fire, but the species and its unique forest community of associated plants and animals thrives.
Fire is not only a biological phenomenon. Fires at any given location might produce vastly different effects on the soil, water, and air. Depending upon weather and the quantity and moisture of fuels, fire in a given forest may lead to negligible or massive erosion. Heavy erosion after fire is a natural phenomenon in some forests, but in other forests such erosion is related to human alterations. Even fires that have little impact on the natural system can hurt humans, as in the case of smoke pollution. However, through management of vegetation and use of prescribed burning, we can reduce the negative impacts of fire. To help you consider how a forest—perhaps your own local forest—could be protected or restored, we present a method for uncovering the history and effects of past fires in any particular forest.
People and forests can benefit from planned and prioritized prescribed fire and fuel treatments for different zones on the landscape. Intensive fuel treatments are suitable for the residential forest zone; we recommend broader-scale fuel treatments for the general forest zone; and the use or simulation of natural fires is appropriate for large, remote natural areas. Each alternative for managing wildland forests, including continued exclusion of fire, use of natural fires, thinning and fuel removal, and prescribed burning, has its own benefits and drawbacks. For people living in the woods, reducing fuels around forest homes and managing the homesite's forest is more important than is often realized. Finally, with all of these historical, ecological, and new land management challenges in mind, we believe that the time is ripe for changing our perception and management of fire-dependent forests. The opportunity to act lies before us but is likely to disappear if we do not seize it soon.
Wildland Forests and Their Fires
Western forests and woodlands cover hundreds of millions of acres of diverse and rugged country in a confusing array of tree species, each adapted to different growing conditions and different frequencies and intensities of fire. Some types of forests burned naturally in frequent, low-intensity fires, whereas others burned infrequently in high-intensity, stand-replacement fires, and still others experienced a range of burning intensities. Still more confounding is that, depending on the type of forest, a high-intensity conflagration may be a natural phenomenon or the result of human-caused changes in the forest.
The native tree species, undergrowth plants, and animals constitute forest communities that in many cases are direct descendants of forests that developed over at least the past 11,000 years following the last ice age. The assemblages of trees, undergrowth plants, and animals are still primarily influenced by the same processes that shaped them over thousands of years. They are called wildland forests to distinguish them from the homogeneous, cultivated plantation forests that are prevalent today in much of the world. Roads, logging, livestock grazing, and residential subdivisions have affected many of our western wildland forests. Still, they are predominantly natural communities.
Westerners interested in the outdoors cannot escape the topic of fire in the forest. Consider our most extensive and heavily populated type of forest. Dominated by the drought-tolerant ponderosa pine (Pinus ponderosa), it stretches from the Great Plains of Nebraska and South Dakota almost to the Pacific Ocean and from northern Mexico to southern British Columbia (Fig. 1.1). Today, hundreds of thousands of people live in the shade of stately ponderosa pines. Historically, in the majority of these areas, frequent low-intensity fires maintained parklike stands of trees mostly pruned of low branches with open grassy understories. Fallen pine needles and cones make an ideal fuel bed capable of burning throughout much of the year. With protection from fires, needle litter and thickets of small trees have transformed much of this forest into a dense fuel type that burns in severe fires. For example, well after the traditional summer fire season in mid-October 1991, a windstorm-driven fire destroyed over 100 homes in the suburbs of Spokane, Washington. Yet, with good management of forest fuels, ponderosa pine forests and the homes within them can be relatively safe from fire damage.
Anyone following the news no doubt realizes that western forests are prone to burning from time to time. What's usually missing from the stories is the fact that the magnificent old growth forests extolled by naturalists and featured in western national parks were shaped by recurrent fires over thousands of years. Both the giant sequoia (Sequoiadendron giganteum) groves high in California's Sierra Nevada and the towering redwood (Sequoia sempervirens) forests of the fog-bound coastal lowlands often had open understories as a result of frequent low-intensity fires (Brown and Swetnam 1994, Fritz 1931, Swetnam 1993). Giant sequoias and redwoods have thick-barked trunks over 10 feet in diameter splotched with char from historical fires. Although they are set aside within national parks and other natural areas, it is often difficult to gain public support to allow prescribed fire for maintaining these ancient forests.
Farther north, in the western portions of Oregon, Washington, and British Columbia, much of the original forest was dominated by gigantic coastal Douglas-firs (Pseudotsuga menziesii variety menziesii), which were dependent on infrequent fires burning at higher intensities that give this species a competitive advantage over the shade-tolerant ("shade-loving") western hemlock (Tsuga heterophylla). Large areas of old coastal Douglas-fir are protected in national parks and national forests. But by keeping fire out, we are suppressing the primary natural process that perpetuates Douglas-fir.
Inland, in the Rockies and other high mountain ranges, most of the forest trees are adapted in different ways to fire. Some forests contained trees that commonly survived fires. Stand-replacement fires typically killed trees in lodgepole pine (Pinus contorta) forests and in the towering stands of Engelmann spruce (Picea engelmannii) at higher elevations. Then trees regenerated from seeds that survived in closed cones or light seeds that blew in from adjacent forests. With protection from fire, these forests often become virtual monocultures of the most shade-tolerant tree accompanied by sparse undergrowth and scant forage for wildlife. In contrast, the historical forests subjected to natural fires often had more diverse mixtures of trees, shrubs, and herbaceous species that could support a richer community of birds and mammals.
Eliminating Fire
Political and social pressures propelled the campaign to eliminate fire in the early twentieth century. To people frightened by the power and destructiveness of wildfires, it seemed logical and necessary to try to remove fire from the forest. However, proponents of the crusade against fire did not understand the long-term consequences of trying to eradicate an intrinsic part of the forest ecosystem. Although natural resource management today strives to protect and preserve wildland forests on public lands, many biologists and foresters have concluded that the forests are instead deteriorating (General Accounting Office [GAO] 1999, O'Laughlin and others 1993). A root cause is that for nearly a century, our policy has been largely based on eliminating fire. Paradoxically, most of these ecosystems depend on characteristic patterns of fires to shape and rejuvenate them. In some of these forests, attempts to remove fire have led to overly dense, stagnant tree growth, which ultimately leads to fires of extreme severity that are dangerous and costly, if not impossible, to control (Ferry and others 1995, Williams 1995).
Ecological science makes it clear that fire is just as integral to the life of western forests as wind, rain, and sunshine. But, unlike other forces of nature, fire's role in the forest can be controlled or altered by humans. Are we employing our best knowledge as the basis for managing fire in the forest? No, according to an analysis by Congress's General Accounting Office (GAO 1999). This is not a new revelation. In the early 1900s several private timberland owners argued that practical forestry should employ fire as a management tool (Hoxie 1910), and a pioneer in the newly emerging science of forest ecology urged the Forest Service to use controlled burning in management of lodge-pole pine forests (Clements 1910).
Our counterproductive relationship with fire became manifestly obvious during the record-setting wildfire season in the summer of 2000. Federal agencies spent about $1.6 billion combating fires in the western states (Perkins 2001). That amount does not include substantial costs to rehabilitate bulldozed firelines, plant trees, and prevent or repair runoff damage related to fire. In spite of that effort, over 5 million acres burned. Thousands of dollars per acre were spent fighting fires that threatened residential areas in the forest. Moreover, high-intensity burning and bulldozed fire-control lines damaged soils. In many of these forests, fire history studies suggest that under natural conditions, fire damage to soils was minor, and many trees typically survived fires (DeLuca 2000).
Understanding Fire in the Forest
Because of their close relationships with fires, western forest ecosystems are considered fire dependent. If we hope to sustain the communities of trees, plants, and animals that characterize these wildland forests, we need to understand the natural role of fire, changes brought about by suppressing fire, and alternatives for restoring some reasonable semblance of the natural fire process.
Understanding the role of fire is a mind-stretching exercise not only because it embraces the concept of working with nature instead of controlling it, but also because it relies on highly technical scientific information. Managing wildland forests with fire is an ancient technique used by subsistence farmers and hunter–gatherers worldwide (Pyne 1997). These people, who absolutely depended on nature, employed fire for a variety of purposes, including increasing the abundance and vigor of plants used for food and forage (Lewis 1985, Pyne 1982). At the same time, the ecological effects of fire are so complex and intricate that even the most sophisticated computer models provide only rough approximations (Keane, Ryan, and Running 1996).
Those who revere wildland forests desire to protect them from all human influence. In recent history, preservation has usually included fire suppression, which, as already described, is a radical departure from the natural processes that produced the forests. Given this irony, should we just allow natural fires to return? This can work to some extent in the largest and most remote natural areas. However, many factors make this proposition extremely costly and dangerous for most forestlands. First, fires historically spread across large landscapes by way of broad valleys covered with dry grass and other combustible vegetation. Today these valleys are no longer available for burning due to grazing and other agricultural uses, roads, suburban homes, and other development. Second, many wildland forests at lower or middle elevations have now missed three or more natural fires as a result of fire suppression, and many have also been altered by logging. As a result, these forests differ so greatly from historical forests in both stand age structure and species composition that now lightning fires often burn more intensely than fires of the past. Finally, people have built hundreds of thousands of homes in and adjacent to wildland forests in the past 30 years. Few of these homes use fire-resistant building materials, and few homeowners have reduced fuels in the surrounding forest. To live safely in these conditions, we have almost universally attempted to eliminate fire rather than adapt to a fire-prone environment. (Those who belong to the small minority living in a fire-resistant house in a defensible area deserve congratulations.)
Restoring Fire
One potential solution to our dilemma with fire in western forests lies in acknowledging fire's important ecological role and directing our efforts toward restoring some representation of natural fire (Arno and Brown 1989, GAO 1999). This would involve many kinds of treatments designed to meet restoration needs in different forests, some of which were historically characterized by low-intensity fires and others by high-intensity conflagrations. In some locations remote from homes and private lands, treatments could include managing lightning fires rather than suppressing them. Treatments can be designed to restore fire's natural influence to help maintain forests that are sustainable through time for a variety of purposes, including habitat for wildlife, watershed protection, and reduced hazard of severe fires to developed areas. Many foresters, ecologists, government leaders, and community groups support this restoration concept, which both Congress and the White House endorsed in the fall of 2000. Barriers to this undertaking are huge, but not insurmountable. They include finding ways to finance restoration and dealing with environmental and smoke regulations that complicate prescribed burning. For the past hundred years, forest management regulations and procedures have been based on the assumption that fire is a damaging agent rather than a vital force of nature. The institutional culture of the agencies responsible for stewardship of wildlands emphasizes fire suppression over management of fire and fuels. Nevertheless, the major federal land management agencies in both the United States and Canada have the knowledge and technical ability to restore fire in some beneficial form. Implementing any appreciable amount of this forest restoration will require a high level of public support.
Many people with long experience in the woods see such restoration as a win–win scenario that could provide continuing benefits such as improved habitat for wildlife and recreational opportunities, and products such as clean water and other ecosystem services, fish and game, lumber and fuelwood. In contrast, others argue that "restoration" is a subterfuge to reopen federal lands to road building and massive commercial logging. We agree that these concerns must be addressed by ensuring that restoration is guided by broadly agreed upon goals, based on state of the art ecological knowledge and supported by good administration and oversight.
(Continues...)
Excerpted from Flames in Our Forest by Stephen F. Arno, Steven Allison-Bunnell. Copyright © 2002 Stephen F. Arno. Excerpted by permission of ISLAND PRESS.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
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Table of Contents
PrefaceAcknowledgments
Chapter 1. Introduction: Why Learn about Fire?
Chapter 2. Mixed Signals: A Brief History of American Perceptions of Fire
Chapter 3. Fire on the Landscape: Past, Present, and Future
Chapter 4. Fire Behavior: Why and How Fire Burns 37
Chapter 5. Nature's Creative Force: How Fire Shapes the Forest
Chapter 6. Different Forests, Different Fires
Chapter 7. Environmental Impacts: Fire's Influence on Soils, Water, and Air
Chapter 8. Fire History: Discovering Effects of Past Fires in a Forest
Chapter 9. Fire-Prone Forests: Can We Adapt to Them?
Chapter 10. Restoring Nature's Creative Force
Chapter 11. Managing Wildland Fuels around Homes
Chapter 12. Lessons from Nature: Will We Learn?
Appendix: Getting Help: Information and Educational Resources for Forest Landowners
References
About the Authors
Index