Managing for Forest Ecosystem Health:

A Reassessment of the " Forest Health Crisis"

by Robert L. Peters, Evan Frost, and Felice Pace

 

Foreward

Is there a "forest health crisis" in our National Forests? Is extraordinary emergency action necessary to avert "catastrophic" forest fires and epidemics of insect pests and diseases? This is the impression given to the average American by televised images of fires raging in the West and by industry representatives who proclaim that a massive program of "salvage" logging is necessary to remove dead trees that constitute a fire hazard. This notion that there is a severe and pervasive emergency is the impetus behind congressional proposals to accelerate logging and remove it from environmental oversight and public comment.

Answering these questions correctly depends on having a scientifically valid definition of "forest health," as well as an accurate characterization of conditions in U.S forests and scientifically sound prescriptions for resolving measures where needed. Our report provides this information and answers the preceding question based on comprehensive review of the scientific literature.

Our report reviews the state of U.S. forests, focusing primarily in the West -- the region of greatest controversy. We describe the magnitude of natural and human-caused changes occurring in the forests, identify the true causes of threats to forest ecosystem health, which by and large are not those advanced by the proponents of salvage logging, and we analyze the ecological effects of salvage logging and other commonly suggested "solutions" to the supposed crisis. Finally, we provide recommendations to serve as the basis for a long-term effort to restore the integrity, resiliency and benefits that come from healthy forest ecosystems.

We hope this report will help the public, policymakers and federal agencies separate scientific reality from the media images and rhetoric that have dominated the current debate over national forests. Our intent is to provide a firm scientific foundation for evaluating proposals that would expedite salvage logging, minimize public participation and sidestep environmental review in the name of a quick response to a so-called crisis. 

Robert L. Peters is a Defenders of Wildlife conservation biologist and co-author of the Defenders report, Endangered Ecosystems: A Status Report on America 's Vanishing Habitat and Wildlife.

Evan Frost is a staff ecologist with the Northwest Ecosystem Alliance, specializing in biodiversity and forest issues in the Pacific Northwest .

Felice Pace is executive director of the Klamath Forest Alliance, specializing in issues pertaining to preservation of biodiversity in the Klamath-Siskiyou Bioregion.

Managing for Forest Ecosystem Health:

A Reassessment of the " Forest Health Crisis"

by Robert L. Peters, Evan Frost, and Felice Pace  

Introduction: Defining Forest Ecosystem Health

The real meaning of "forest health" has become increasingly controversial in the debate over management of federal forest lands. Concern over the issue recently intensified in response to the dramatic 1994 fire season, during which, after years of drought, nearly 4 million acres were burned by wildfire. Some land managers, policymakers and legislators have concluded that the fires indicate a "forest health crisis" (e.g., O'Laughlin et al. 1993, Morelan et al. 1994, Sampson et al. 1994). This perception of crisis has led to a number of policy initiatives and congressional bills to restore "forest health" that have emphasized widespread salvage logging, commercial thinning and other intensive management techniques. These practices are ostensibly aimed at reducing the risk of fire, insect infestation and disease outbreaks.

Recent policy initiatives have exempted salvage logging from laws regulating national forest management and have increased appropriations for prescribed fire and other forms of "fuel treatment." Most recently, an amendment to the Federal Rescissions Act (Public Law 104-19) mandated dramatic increases in salvage logging. This amendment requires the logging of 4.5 billion board feet of dead, dying and green "susceptible" trees from national forest lands, limits the scope of the public involvement process and exempts all salvage timber sales from existing environmental laws. Similarly, the core of the Clinton Administration's 1994 Western Forest Health Initiative was salvage logging totaling more than one billion board feet of timber and commercial logging of an additional 600 million board feet of green trees. Many thousands of acres of roadless backcountry land were designated for logging as part of this initiative.

Traditionally, the term "forest health" has been used in a limited, utilitarian sense by professional foresters to refer to the growth and vigor of trees (see Kolb et al. 1994). For example, according to one Forest Service publication, a forest is healthy when "biotic and abiotic influences on forests do not threaten management objectives now or in the future" (USFS 1993). From this perspective, a forest is healthy if trees are free from insects and pathogens and growing at maximum rates; it is unhealthy if trees are dead or dying. Anything that decreases or threatens to decrease yield -- insects, disease, decaying trees, fire -- is something to be controlled or eliminated. Managers therefore argue for removal and commercial utilization of trees that are perceived to be in danger from such threats.

However, many conservationists and forest scientists have expressed concern about such thinking. This narrow definition of forest health does not consider the health of the entire ecosystem, such as water and soil quality and the diversity and interactions of other life forms. It does not provide guidance for management of resources other than timber. It has encouraged foresters to simplistically view insects and other non-timber elements of forest ecosystems as good or bad, based only on how they affect the growth rates of commercial tree species.

When viewing forests from an ecosystem health perspective, scientists do not recognize the "forest health crisis" described by the proponents of salvage logging who are concerned about losing economically valuable timber to fire or insects. To the scientists, insects, disease and fire are normal parts of healthy ecosystems, essential for forest regeneration, cycling of nutrients and maintaining a variety of dead and living trees for wildlife habitat. Attempts to control or eliminate these agents may lead to unforeseen and undesirable consequences. For example, widespread removal of dead and dying trees eliminates habitat required by bird species that feed on insects that attack living trees, with the result that outbreaks of pests may increase in size or frequency (Torgersen et al. 1990).

Some forest types, especially ponderosa pine, in some areas may be experiencing fire, insect or disease outbreaks that exceed historical norms. These forests may benefit from carefully planned and carried out restoration activities, but this should not be interpreted as a "crisis" demanding large-scale, poorly thought-out actions such as the accelerated salvage logging mandated in Public Law 104-19 and called for in proposed legislation. Evidence shows that these actions are actually detrimental to the forest ecosystems they are supposed to help (e.g., Beschta et al. 1995).

Fortunately, growing acknowledgment of the ecological harm caused by single-minded focus on timber is causing many forest scientists and land managers to recognize the importance of maintaining ecosystem integrity, including viable populations of native fish and wildlife, water quality and soil integrity, and critical ecological processes such as nutrient cycling, hydrological flows and natural disturbance regimes that sustain the diversity and productivity of forest ecosystems over time. This expanded perspective, which we adopt in this report, has recently been defined as forest ecosystem health (Dellasala et al. 1995b, Kolb et al. 1994, Langston 1995, Costanza et al. 1992).

 

Robert L. Peters is a Defenders of Wildlife conservation biologist and co-author of the Defenders report, Endangered Ecosystems: A Status Report on America 's Vanishing Habitat and Wildlife.

Evan Frost is a staff ecologist with the Northwest Ecosystem Alliance, specializing in biodiversity and forest issues in the Pacific Northwest .

Felice Pace is executive director of the Klamath Forest Alliance, specializing in issues pertaining to preservation of biodiversity in the Klamath-Siskiyou Bioregion.

Managing for Forest Ecosystem Health:

A Reassessment of the " Forest Health Crisis"

by Robert L. Peters, Evan Frost, and Felice Pace

Executive Summary

Many policy-makers and forest industry representatives argue that current forest conditions constitute a "forest health crisis." They point to what they say are unusually high levels of wildfire, insect infestations and tree disease and have passed legislation mandating widespread salvage logging -- the removal of dead, dying and nearby healthy trees. Their notion is that logging areas with perceived health problems will restore the forests to health.

But is there really a "crisis"? And is salvage logging appropriate management for our national forests? In order to help answer these questions, our report examines scientific evidence to evaluate: (1) the true nature and extent of ecological problems occurring within federal forest lands, (2) whether these problems have been correctly characterized by proponents of a "forest health crisis", and (3) whether salvage logging and other proposed treatments are an appropriate response to concerns about forest ecosystem health.

Because the concept of forest health has been mischaracterized in much of the political debate, our report puts forward a sound scientific definition. To scientists, forest health is a measure of the integrity of the entire forest ecosystem, including soil, water and all native species, and the evolutionary and ecological processes that maintain them. This definition recognizes that wildfire, tree pests and diseases are a normal part of well-functioning forest ecosystems and generally should not be cause for concern. This contrasts with the limited perspective of forest health held by the timber industry, which focuses on maximizing overall tree growth and timber production, often at the cost of soil productivity, water quality, fisheries or other components of the ecosystem. To underline this difference in perspective, we prefer the term "forest ecosystem health," which offers a broader, more appropriate context for managing public forest lands.

Even though tree mortality caused by fire, insects and disease may not appear desirable to those wishing to maximize short-term timber production, scientists recognize that natural disturbances help regenerate forests, maintain species diversity and create a beneficial patchwork of stands across the landscape that vary in age and species composition. Because fire and native insect and disease organisms play critical roles in recycling nutrients and other ecosystem functions, attempts to control, eliminate or "correct" them often harm the ecosystem. For example, widespread removal of dead and dying trees eliminates habitat required by bird species that feed on insects that attack living trees, with the result that outbreaks of pests may increase in size or frequency.

When we analyze the current condition of federal forests using an ecosystem-based definition of health, we find that many forest ecosystems are in need of restoration -- but largely not for the reasons proposed by the advocates of a "forest health crisis." Rather they have been degraded by human activities, including excessive and inappropriate logging, poorly managed livestock grazing, roads and introduction of exotic species. In contrast to those who maintain there is a forest health crisis, we find that there is not a pervasive problem with wildfire, insects or disease. In some localized areas of some forest types, such as ponderosa pine in the West, fire suppression, logging and livestock grazing have caused an increased probability of high-intensity fires and possibly more frequent insect and disease outbreaks than in the past. Yet care should be taken not to generalize these problems to all forest types or all areas -- many forests, particularly those in moist areas or high elevations, have not suffered from fire suppression and need no "treatment" except protection from improper management. Overall, problems from fire, disease and insects are not so widespread or severe as to constitute a crisis or require large-scale emergency action. For example, one careful study of 130,000 trees at 60 forest sites in five western states found that less than one percent of trees were recently dead or dying (Partridge 1993).

In the long-term, restoration of forest ecosystem health will depend on reducing the primary agents of degradation -- excessive and poorly planned logging, livestock grazing, road building, mining, fire suppression, introduction of exotic species and other detrimental human activities. For many forests, this is the only "treatment" necessary. For those relatively few forest types, such as ponderosa pine, that in some areas could benefit from active restoration, care must be taken to ensure that any management action is cautious, site-specific, scientifically sound and carefully monitored and that it emphasizes long-term health of the ecosystem above short-term economic gain.

Our report evaluates three techniques frequently proposed as "treatments" for forest health. They are:

Our analysis of the ecological effects of salvage logging indicates that not only is this practice often not effective in reducing the scale and intensity of subsequent fires, insect outbreaks and disease, it can cause serious damage to wildlife, soils, water and other ecosystem components and processes as well. In short, the overall effect of salvage logging is to decrease forest ecosystem health. Prescribed burning and thinning some of the smaller trees from below the overstory -- particularly in dense stands of dry, fire-prone forest types -- have potential as tools for improving forest ecosystem health, but they also have risks that must be carefully evaluated in each instance. For example, thinning may cause soil compaction, erosion and increased transmission of diseases and may require road construction. Thinning should be used to remove small, dense trees whose competition hurts large trees. Large or old trees, which are rare across the landscape, should not be removed.

The record of past mistakes shows that forest management must be redesigned to protect forest ecosystem health if the nation's forests are to sustainably provide us with economic benefits and protect biological diversity. Rather than legislate ill-advised, wholesale measures to cut more trees -- the very thing that caused many existing problems with forest ecosystem health -- the nation needs a coordinated, ecosystem-focused strategy that uses appropriate restoration techniques based on the best available science and carefully evaluated as to environmental impacts. We recommend:

None of our conclusions support salvage logging as a treatment to achieve ecosystem restoration and should not be interpreted as indicating a need for an expedited salvage program. Claims that there is a "forest health crisis" that justifies expedited environmental review or suspension of forest management laws and regulations are false. In fact the opposite is strongly suggested by the ecosystem science. Forest ecosystem recovery can only be accomplished through thorough analysis and planning at the ecosystem scale followed by careful implementation over the course of years.

If followed, these recommendations would preclude any forest laws, regulations or management plans that employ "quick fix" salvage logging or other hasty measures in place of carefully planned restoration. Any restoration measures should be based on the best available science, should be carefully tailored to the individual site and should be planned in the context of the entire landscape. This means, for example, that individual patches of dead trees in a landscape of living trees should not be picked out for salvage logging. We conclude that the claims of a forest health crisis, used to justify expedited salvage operations, are not based on good science.

Robert L. Peters is a Defenders of Wildlife conservation biologist and co-author of the Defenders report, Endangered Ecosystems: A Status Report on America 's Vanishing Habitat and Wildlife.

Evan Frost is a staff ecologist with the Northwest Ecosystem Alliance, specializing in biodiversity and forest issues in the Pacific Northwest .

Felice Pace is executive director of the Klamath Forest Alliance, specializing in issues pertaining to preservation of biodiversity in the Klamath-Siskiyou Bioregion.

Managing for Forest Ecosystem Health:

A Reassessment of the " Forest Health Crisis"

by Robert L. Peters, Evan Frost, and Felice Pace

Natural Disturbances to Forest Ecosystems

Much of the recent concern about "forest health" has focused on the effects of fire, insects and disease, particularly in their ability to create patches of dead trees. While such tree mortality may appear to be detrimental from the narrow perspective of individual tree health or timber production, a broader ecosystem-based perspective recognizes that natural disturbances are often a means for renewal of forests and diversification of landscapes. Instead of viewing fires, insect and disease outbreaks as catastrophes that threaten the health of the forest, we should recognize the dynamic nature of ecosystems and learn how to manage them in a way that allows such agents of disturbance to carry out their beneficial roles in shaping the landscape.

Wildfire. Fire performs critical functions as a diversifying agent that maintains the character of various forest types and the species that inhabit them. In fact, scientists and forest managers are increasingly aware of the importance of fire for maintaining forest ecosystem health (e.g., Agee 1994a, Agee 1994b, Mutch 1994). Wildfires have been a dominant force shaping the species, communities and processes of many forest types for at least the last several millennia. Historically, fires have helped maintain ecosystem health by releasing a steady supply of nutrients into the soil, helping to control populations of forest insects and disease organisms, and limiting tree density, thereby reducing competition and minimizing stress (Agee 1994a). Many of the nation's plant species have evolved in environments with regular fires and are dependent on fire for germination and recruitment (Kauffman 1990). In addition, fire can create mosaics of habitats, including different food sources and nest sites, that support a variety of mammals, birds and other animal species.

While fire has been an important factor in shaping the nationÕs forests, it is important to recognize that its influence varies among forest types. In dry forest types, such as ponderosa pine in the West and longleaf pine in the Southeast, the historic regime of frequent, low-intensity fires maintained primarily open stands of old, large-diameter trees (e.g., Agee 1994b, Everett et al. 1994, Langston 1995). Other forests, such as higher-elevation forests of the inland West and coastal maritime forests of the Northwest, have a history of much less frequent but more intense fires that kill a significant proportion of trees. High-intensity fires therefore should not be considered atypical when occurring in these forest types, and may in fact be essential for ensuring their perpetuation.

Even within a single forest type, the inherent natural variability of fire ensures that there will be a broad range of vegetation patterns and tree densities across the landscape (Agee 1994b). Because natural fires burn in a complex and unpredictable fashion owing to changes in weather, topography and slope, some stands may burn every few years, while nearby areas remain unaffected by fire for many decades (Arno et al. 1995; Wills and Stuart 1994). For example, moist riparian areas and north-facing slopes tend to be less prone to frequent fires.

 Insect and disease organisms. Insects and disease organisms, including those that attack and sometimes kill patches of trees, are integral components of healthy forest ecosystems. For example, insects and disease organisms help decompose and recycle nutrients, build soils, maintain genetic diversity within tree species, generate snags and down logs required by wildlife and fish, and create diverse patterns of vegetation at both site and landscape scales.

Many wildlife species depend upon insect and disease organisms for food or for creation of habitat. Dwarf mistletoe, a parasitic plant that has traditionally been regarded as a serious pest because it often causes a reduction in tree growth rates, provides a case in point. The "witch's broom" structures created in tree crowns by dwarf mistletoe are preferred as nesting platforms by many bird species, including northern and Mexican spotted owls, northern goshawks and some neotropical migratory songbirds (Fletcher and Hollis 1994; Moor and Henny 1983; Irwin et al. 1989, Bennetts & Hawksworth 1990). The plant itself is also a food source for some birds (notably Douglas-fir dwarf mistletoe for blue grouse) (Severson 1986), mule deer (Urness 1969, Currie et al. 1977), elk (Craighead et al. 1973), squirrels (Farentinos 1972, Hall 1981, Baranyay 1968), chipmunks (Broadbooks 1958) and porcupines (Taylor 1935).

Similarly, stem-decay fungi, also considered pests from a tree-oriented perspective, are important to cavity-nesting birds because they soften heartwood and thereby facilitate the excavation of cavities in both living and dead trees (Bull et al. 1992, McClelland & Frissell 1975). Populations of these cavity-nesting birds, in turn, feed on insects that can attack living trees (Torgersen et al. 1990, Dickson et al. 1979). Root-decay fungi may kill individual trees, thereby creating gaps in the forest canopy. These gaps are part of the forestÕs structural diversity, which maintains a variety of plants and animals (Hennon 1995, Van der Kamp 1991).

Populations of insects and pathogens in most forest ecosystems are usually kept in check by their natural predators and environmental factors such as wildfire and climate (Filip et al. 1996, Mason & Wickman 1994). However, major insect and disease outbreaks that kill trees over relatively large areas do occur. For example, recent mountain pine beetle epidemics in lodgepole pine forests of the inland West are part of a natural "boom and bust" cycle that has occurred for centuries. Mountain pine beetle populations typically increase to epidemic levels when large, homogeneous areas of lodgepole pine mature and provide suitable food resources. The insect selectively kills susceptible trees of a specific size and species, thereby facilitating development of a forest that is structurally, genetically and compositionally more diverse and less prone to beetle attack, starting the cycle over again ( Amman 1977). What some people perceive to be a crisis is in fact a normal and somewhat predictable ecological event that is not outside historical levels (Wickman et al. 1994, Swetnam and Lynch 1989).

Even large outbreaks of insect and disease organisms that irregularly reach "epidemic" levels are known to result in beneficial effects on the forest ecosystem. Spruce budworm, for example, may help maintain ecosystem health by selectively killing weaker, genetically inferior trees and increasing resistance to future outbreaks (Alfaro et al. 1982). Large-scale outbreaks of insects that defoliate trees are known to dramatically accelerate cycling rates of important nutrients that subsequently result in increased tree growth for many decades (Schowalter et al. 1986, Wickman 1980). Such examples demonstrate the danger of prematurely judging the effects of insects and pathogens solely on the basis of short-term tree mortality.

Robert L. Peters is a Defenders of Wildlife conservation biologist and co-author of the Defenders report, Endangered Ecosystems: A Status Report on America 's Vanishing Habitat and Wildlife.

Evan Frost is a staff ecologist with the Northwest Ecosystem Alliance, specializing in biodiversity and forest issues in the Pacific Northwest .

Felice Pace is executive director of the Klamath Forest Alliance, specializing in issues pertaining to preservation of biodiversity in the Klamath-Siskiyou Bioregion.

 

Managing for Forest Ecosystem Health:

A Reassessment of the " Forest Health Crisis"

by Robert L. Peters, Evan Frost, and Felice Pace

Human Disturbances to Forest Ecosystem Health

The natural disturbances of fire, insect outbreaks and disease have over the millennia shaped the structure and function of native forests. During the last century or more, people have introduced the following new disturbances to which the forests are not adapted and which therefore have caused decreases in forest ecosystem health.

Logging. Timber production has traditionally taken precedence over other uses on federal forest land throughout the United States . The intensity and spatial patterns of logging have until recently rarely considered the habitat requirements of native species or the need to protect soils, water quality and other non-timber resources. Clearcut logging has removed large blocks of forest and fragmented what remains into smaller, more isolated pieces, with the result that critical ecological processes have been disrupted and populations of many wildlife species dependent upon large, connected habitat blocks are now in danger of extinction (Henjum et al. 1994, Noss and Cooperider 1994, Harris 1984).

In addition to the direct effects of habitat loss and fragmentation, logging typically reduces ecosystem health by (a) damaging aquatic habitats through siltation, reduction in stream complexity and increased water temperatures (McIntosh et al. 1994, Meehan 1991); (b) reducing soil integrity through increased erosion and compaction (Childs et al. 1989); (c) removing significant quantities of nutrients and organic material (Harvey et al. 1994); and (d) replacing structurally heterogeneous forest with homogeneous stands of same-aged trees. These simplified replacement forests lack the variety of habitats necessary for all species (FEMAT 1993, Holling 1990) and are prone to attack by insects and diseases that flourish in forests that are densely populated by one or a few species of trees (Schowalter 1990, Perry 1988).

Various types of selective logging have also decreased the health of forest ecosystems. "High-grade" logging, a practice that has been commonly practiced in the dry forests of West, has removed the largest, most valuable trees, such as old-growth ponderosa pine and western larch, which are relatively fire and disease resistant (Langston 1995, Oliver et al. 1994). High-grading in western dry forests has resulted in reduced genetic diversity among the remaining trees and removed large live trees that provide habitat, conserve soil and play other important roles. It has also increased the relative abundance of shade-tolerant trees that are more susceptible to insects, disease and fire (Habeck 1990, Henjum et al. 1994, Langston 1995).

Livestock grazing. Commercial grazing of cattle and sheep has degraded forests, grasslands and riparian habitats throughout the West, resulting in an overall reduction in ecosystem health (e.g., Belsky and Blumenthal 1995, Fleischner 1994). Some of the adverse effects include (a) removal of grass and other flammable vegetation from beneath trees in dry forests, thereby reducing fire frequency, increasing tree density and creating a buildup of potentially harmful woody fuels (Belsky and Blumenthal 1995, Touchan et al. 1995); (b) damage to native grasslands, resulting in the spread and establishment of exotic, weedy plant species on millions of acres of federal land (Johnson et al. 1994); (c) damage to soil by reduction of protecting vegetation, with results that include increased erosion, compaction and reduced long-term productivity; and (d) damage to riparian and aquatic habitats, including increased erosion and sedimentation, elevated water temperatures due to reduction of shade-providing vegetation, reduced bank stability, stream channelization, and alteration of riparian vegetation structure and species composition. The cumulative effects of livestock grazing on federal lands has contributed to the decline of more than 400 species currently listed as threatened or endangered (NWF 1994), including salmon fisheries in the West (Irwin et al. 1994, Marcus et al. 1990, Meehan 1991).

Road construction. Roads have been constructed throughout federal forest lands to facilitate logging and other forest management activities. Our national forests alone contain more than 360,000 miles of roads. Although roads were intended as innocuous corridors for human transportation, they are one of the most important contributors to the deterioration of forest ecosystem health. Significant adverse impacts include (a) elimination and fragmentation of wildlife habitat (Noss and Cooperider 1994); (b) increased human disturbance and harassment of sensitive wildlife (Lyon 1979, McLellan and Shackleton 1988); (c) increased rates of erosion and sediment delivery to streams, with resultant impacts on fish and other aquatic species (FEMAT 1993, McIntosh et al. 1994); (d) alteration of natural streamflow patterns, particularly the timing and intensity of high and low flows (Megahan 1987, Chamberlin et al. 1991); and (e) increased spread and establishment of exotic plants and animals (Getz et al. 1978, Harrod 1994).

Introduction of exotic species. Introduction of non-native species by humans, either intentional or accidental, is another of the most serious threats to the long-term maintenance of ecosystem health and biodiversity (Mooney and Drake 1986, McKnight 1993, Groves and Burdon 1986, Bright 1996). More than half of all federally listed species are harmed by interactions with non-native species (Flather et al. 1994). In forests, introduced insects and pathogens that attack trees often cause large-scale mortality. The native tree species, not previously exposed to these agents, may lack defenses or immunity. For example, chestnut blight fungus was accidentally introduced to the United States from Europe in the early 1900's, virtually eliminating American chestnut from eastern hardwood forests, where it was previously one of the dominant tree species (Bridges 1995). The U.S. Forest Service has identified more than 300 exotic pest species, of which the most damaging to forest include the Asian gypsy moth, European spruce beetle and balsam wooly adelgid (Pimentel 1986, OTA 1993).

Noxious weeds and other introduced plants decrease ecosystem health in forests, savannas and grasslands throughout the United States . Cheatgrass, Russian thistle, spotted knapweed and hundreds of other non-native plants have spread along human transportation routes and other disturbed areas to invade millions of acres in the West (BLM 1995; BLM 1996). These plant invasions may lower water tables, decrease food available to wildlife or alter other important ecological processes and resources (see Melgoza et al. 1990), affecting food webs (Harty 1986) and leading to endangerment of native species (Parenti and Guerrant 1991, Flather et al. 1994).

Similarly, the survival of many native fishes in streams and rivers on and off forest lands is threatened by introduced non-native fishes and aquatic invertebrates. For example, Yellowstone and westslope cutthroat trout have declined due to hybridization with introduced trout (Allendorf and Leary 1988). Predation by exotics is also a problem (Williams et al. 1990). While some introductions allow increased public fishing opportunities, some have led to large declines in commercial fisheries and required increased expenditures to manage declining stocks (Wydoski and Bennett 1981, Gresswell 1991). As in the terrestrial environment, the effects of exotic fish introductions frequently have cascaded throughout entire ecosystems (Winter and Hughes 1995), harming ecological structure and function (Bowles et al. 1991, Magnuson 1976, Moyle et al. 1986).

Air pollution. Air pollution harms some forest ecosystems, particularly those that are adjacent to large human population centers. For example, air pollution in southern California increases mortality and decreases growth rates of ponderosa pine, jeffrey pine, and other conifers in the San Bernadino and San Gabriel Mountains (MacKenzie and El-Ashry 1988) and along the western slope of the Sierra Nevada (Pronos & Vogler 1981). Effects of air pollution on forest ecosystem health are more severe in the eastern United States , where levels of airborne pollutants are generally higher. In the Appalachians , acid deposition plays a major role in the decline of high-elevation spruce-fir forests, home to rare species such as the spruce-fir moss spider and the rock gnome lichen (Grossman et al. 1994). Changes in community structure as pollution-sensitive species are replaced by more tolerant species can disrupt ecological processes and impact native species (Grossman et al. 1994).

Water manipulation. Creation of dams and diversion of water for irrigation and other uses has had major impacts on the health of the aquatic environment in national forest lands, including local extirpations of native fishes from national forest lands (e.g., Keifenheim 1992). One major problem caused by dams is alteration of stream flow. In extreme cases, enough water can be withdrawn to dry up streams, rivers and riparian habitat. Even when substantial water flow remains, it is often regulated so that periods of high and low flow are eliminated. Loss of historic flooding patterns can cause simplification of river channels, including loss of backwater channels required as habitat by native fish and other aquatic species. Dams also interfere with the ability of fish to travel along streams. For example, spawning and rearing areas in the upper Columbia River Basin were inaccessible to salmon after completion of the Grand Coulee Dam in 1941 and the Chief Joseph Dam in 1955. Passage problems are not limited to large dams -- most of the thousands of small dams in Oregon , Washington , Idaho and California do not have fish passage facilities (National Research Council 1995).

Fire Suppression. Some dry forest ecosystems -- such as those dominated by longleaf and ponderosa pine -- depend on relatively frequent, low-intensity fires to maintain their characteristic structure and species composition. Over the past 80 years, people have prevented or put out fires in these forests to protect timber resources, human life and property. Fires have also been inadvertently suppressed by the creation of roads and other clearings that can prevent them from spreading. In some cases, exclusion of fire has resulted in undesirable changes in forest structure and composition -- changes that alter ecological processes and make forests less resilient to change (e.g., DeSelm and Murdock 1993, Schwartz 1994). Not only does fire suppression harm the ecosystem by decreasing the natural frequency of fires, but the actual act of fighting fires also can cause ecological damage -- constructing firelines increases soil erosion and water removal that can dry up streams and small lakes.

Forest Ecosystem Decline

Cumulatively, the effects of the preceding activities have changed forests across the nation. In fact, when the current condition of forests is evaluated using an ecosystem-based definition of health, many ecosystems show signs of serious degradation, what Aldo Leopold referred to as "land sickness" (Leopold 1944). This degradation includes loss of soil and soil nutrients, pollution of water, invasion by exotic species and extirpation of native species. Two recent reports on the status of U.S. ecosystems concluded that many ecosystem types are disappearing throughout the country, along with the native animal and plant species that are sustained by them (Noss and Peters 1995; Noss et al. 1995). A list of endangered ecosystem types identified by Noss and Peters (1995) includes forest types found on federal lands, including longleaf pine forests in the Southeast, southern bottomland hardwood forests, and Appalachian spruce-fir forests.

In particular, many types of old-growth forests have been dramatically reduced from their historic abundance and are now considered some of the most endangered ecosystems in the country. In the East, only one percent of historic old-growth forest is estimated to remain ( Davis 1993). Present levels of western old growth also fall far below historic levels, particularly at low-and mid-elevations. Low-elevation forests once dominated by old-growth ponderosa pine in the inland West and coastal Douglas fir were especially hard hit because they had big, valuable trees and were relatively accessible to early logging operations. In the Pacific Northwest, where old-growth inventories have recently been conducted, more than 85 percent of the old-growth ponderosa pine has already been logged (Henjum et al. 1994), and approximately 90 percent of the old-growth Douglas-fir forests present at the time of Euro-American settlement are gone (Norse 1990). Old-growth inventories in other regions, including the Rocky Mountains and Sierra Nevada , are showing similar declines (DellaSala et al. in press, Losensky 1993). Loss and degradation of old-growth and other forest types now threaten the existence of many plant and animal species (Norse 1990).

Many rivers, streams, lakes and wetlands in and around forest lands are degraded and are undergoing increased siltation, pollution, altered temperatures and flow levels, presence of exotic species and loss of natives. Many watersheds have declined in their ability to support fisheries, control floods, purify water, and recharge aquifers (Abramovitz 1996, Doppelt et al. 1993). In the Pacific Northwest and California , more than 100 stocks of wild salmon have already become extinct, and hundreds of others are considered to be at risk of extinction (FEMAT 1993, The Wilderness Society 1993). Salmon production in the Columbia River has been reduced by approximately 95 percent from historic levels (Nehlsen et al. 1991). Today, most relatively intact assemblages of native fishes are found in wilderness and roadless areas (Moyle and Sato 1992, Henjum et al. 1994).

Causes of degradation to stream and riparian systems include logging of streamside forests, removal of woody debris from channels and construction of roads that increase the amount of sediment flowing into streams (FEMAT 1993). In the Pacific Northwest , rates of sedimentation are significantly higher than under historic conditions (FEMAT 1993, Sedell and Everest 1991). Other major threats include competition or predation by exotic fishes, genetic contamination of native stocks by mixture with hatchery fish, overharvesting, water withdrawal and dams.

Although we do not have data for the fraction of streams and rivers that are seriously degraded on forest lands specifically, nationwide it has been estimated that only four percent of all streams are considered to have "maximum ability to support populations of sport fish and species of special concern" (Judy et al. 1984) and less than two percent of streams retain enough natural characteristics to be worthy of federal designation as wild, scenic or recreational rivers (Benke 1990). As a result, more than 300 fish species in the United States -- 29 percent of the total fish fauna -- are extinct, threatened, endangered or of special concern (Hughes and Noss 1992, Miller et al. 1989).

Robert L. Peters is a Defenders of Wildlife conservation biologist and co-author of the Defenders report, Endangered Ecosystems: A Status Report on America 's Vanishing Habitat and Wildlife.

Evan Frost is a staff ecologist with the Northwest Ecosystem Alliance, specializing in biodiversity and forest issues in the Pacific Northwest .

Felice Pace is executive director of the Klamath Forest Alliance, specializing in issues pertaining to preservation of biodiversity in the Klamath-Siskiyou Bioregion.

Managing for Forest Ecosystem Health:

A Reassessment of the " Forest Health Crisis"

by Robert L. Peters, Evan Frost, and Felice Pace

Is There a " Forest Health Crisis"?

Many U.S. forests have lost ecological integrity because of logging and other human activities, but does this add up to the "forest health crisis" claimed by some land managers and policymakers?

As discussed previously, fire, insects and disease are integral parts of forest ecosystems, and recurring disturbances by these and other agents are critical in shaping and maintaining dynamic landscapes. Fire suppression, considered by many to be the factor most responsible for today's unhealthy forests, has not universally affected all forests. Many forest types -- particularly those found in moister climates, at higher elevations and on northerly aspects -- are characterized by infrequent fires that typically occur at intervals that are much longer than the more than 80 years that fire suppression policies have been in effect (Agee 1990). These forests have not changed significantly in terms of their structure or composition, and recent fires, insect and disease outbreaks are therefore not outside historic norms.

Available evidence suggests that the adverse effects of fire suppression on forest ecosystem health are generally only present in those dry forest types characterized by frequent, low intensity fire. In these forests, found primarily in the low and mid-elevations of the inland West, changes in fire patterns due to suppression, in conjunction with high-grade logging, livestock grazing, and other human-caused stresses, have harmed the ecological health and resiliency of some areas. Former open, park-like forests previously maintained by fire have developed understory thickets of shade-tolerant species, primarily true fir and Douglas fir. In these stands, trees may be stressed from overstocking, potentially increasing susceptibility to attack by insects and pathogens. Where there are abnormally high rates of tree mortality, the dead trees can provide more than normal amounts of fuel, possibly contributing to stand-replacing fires that were previously uncommon in this forest type.

Although some dry forests may have abnormally high tree densities and fuel loads, this is not true for the entire forest landscape. Fire suppression has not been universally effective at preventing wildfires. For example, many roadless areas that offer limited access to fire fighters have continued to benefit from the effects of fire. This is not to ignore that some areas, such as those in the Blue Mountains of northeastern Oregon , may have higher tree mortality and different stand structure than in the past. In these instances, specific actions designed to help restore and maintain normal ecological conditions will generally be necessary.

While tree mortality may have increased in some areas due to fires, insects or disease, the problems have been relatively minor on a regional or national scale. For example, Partridge (1993) found that, out of 130,000 trees sampled at more than 60 sites in national forests throughout Idaho , Montana , Oregon , Washington and Wyoming , less than one percent were recently dead or dying. Similarly, data recently compiled by the Forest Service show little or no increase in dying trees over the past 40 years, with mortality remaining well under one percent (Smith 1994).

Even in areas where disease or insect outbreaks are occurring, natural recovery is often relatively rapid. For example, many forests in the Blue Mountains that were hard hit in the early 1990s by large outbreaks of western spruce budworm and Douglas-fir tussock moth have largely recovered (Johnson et al. 1995).

Moreover, the die-offs resulting from insect and disease attacks may actually help restore the tree species composition altered by fire suppression and other human activity (Henjum et al. 1994, Langston 1995, Schowalter 1994). For example, in areas where open ponderosa pine forest has been invaded by true or Douglas fir, insects and pathogens often selectively attack and kill these commercially less valuable trees, increasing the growth and reproduction of the better-adapted pines (Hessburg et al. 1994, Wickman 1978, Schowalter 1994).

In addition, available evidence suggests that wildfires, insects, and disease pose relatively little threat by themselves to the health of the aquatic environment. High-intensity wildfires can cause short-term harm to streams, such as increased delivery of sediment and, in extreme cases, direct fish mortality from elevated water temperatures (Rieman 1994). But if these fire effects are not compounded by additional human-caused stresses, such as salvage logging and road building, streams and aquatic species will recover quickly and often benefit from such disturbances in the long-term (Minshall et al. 1994, Beschta et al. 1995, Rieman 1994). Indeed, streams experiencing fires intense enough to kill fish may have a full complement of all age classes of fish by the year following the fire (Rieman 1994).

Fires can actually improve fish habitat because water runoff from burned slopes carries nutrients that fertilize riparian and aquatic plants. Fallen logs and branches from trees killed by disease, insects or fire are also carried into streams, where they dam water and create pools that are important fish habitat (FEMAT 1993, Maloney and Thorton 1995, Maser and Sedell 1994, Meehan 1991.)

We do not mean to say there are no problems with insects, disease or fire -- some forests in specific areas are undergoing changes caused by the agents -- but we cannot conclude that they constitute the "crisis" that proponents of new "forest health" legislation claim. This is particularly true in that the primary threats to ecosystem health are not fire or native insects or pathogens to which western forests have adapted. The primary threats are the new chronic disturbances to which they are not adapted -- logging, livestock grazing, road building, exotic species and other human-caused factors. The key is to address all of the stresses to ecosystem health, not just those related to fire, insects and disease, and to do so in a way that solves some problems without exacerbating others -- something that we do not see in currently proposed "forest health" legislation.

Robert L. Peters is a Defenders of Wildlife conservation biologist and co-author of the Defenders report, Endangered Ecosystems: A Status Report on America 's Vanishing Habitat and Wildlife.

Evan Frost is a staff ecologist with the Northwest Ecosystem Alliance, specializing in biodiversity and forest issues in the Pacific Northwest .

Felice Pace is executive director of the Klamath Forest Alliance, specializing in issues pertaining to preservation of biodiversity in the Klamath-Siskiyou Bioregion.

 

Managing for Forest Ecosystem Health:

A Reassessment of the " Forest Health Crisis"

by Robert L. Peters, Evan Frost, and Felice Pace

Frequently Proposed "Solutions" to the " Forest Health Crisis"

Despite the fact that there is no forest health "crisis" in the sense used by proponents of salvage logging, various "solutions" have been proposed in legislation, namely salvage logging itself, thinning and prescribed burning. As we explore below, salvage logging is likely to do much more harm than good. Thinning and prescribed burning, although potentially useful tools for forest restoration, also could cause net ecological harm if misapplied or used in scientifically inappropriate situations.

Salvage logging. Proponents of the "forest health crisis" have advocated increased levels of "salvage" logging as a means of improving "forest health" on federally managed lands. Salvage logging, as traditionally practiced on national forest lands, has involved the widespread removal of dead and dying trees in areas recently affected by fire, insects and disease. The primary motive has been economic -- to harvest the dead trees for a profit before decay set in. Recently, the economic justification for salvage logging has been bolstered by arguments that salvage logging will reduce fire or outbreaks of disease and insects, decrease erosion and improve revegetation rates (Barker 1989, Poff 1989). Accordingly, recent definitions of salvage, such as that which appears in the salvage logging law passed in 1995 (Public Law 104-19), have expanded the definition to include logging of trees "imminently susceptible to fire or insect attack" and even "associated" healthy trees.

Yet there is little scientific support for arguments linking salvage logging to improved forest health. In fact, the opposite is true. Scientific evidence demonstrates that salvage logging typically results in damage to soils, streams and wildlife habitat by:

In short, by compacting soil, removing woody debris, increasing erosion and damaging the ecosystem in the other ways described above, salvage logging and related management activities harm forests already under stress from fire or other natural disturbance and impair their ability to recover (Beschta et al. 1995, Henjum et al. 1994).

While salvage logging has been proposed as a basis for gaining control over insects and disease outbreaks, there is considerable scientific evidence to suggest that salvage operations may actually exacerbate rather than control tree mortality associated with these organisms. For example, forests that were salvage logged have been shown to exhibit increased tree mortality due to root diseases, which multiply in stumps left behind by logging and spread into unlogged trees (Filip 1994, Hagle and Schmitz 1993). Salvage logging can increase the incidence of stem decay fungi and cause remaining trees to be more likely to fall in high winds (Filip et al. 1996). Numerous forests pests, including the gypsy moth, Port Orford cedar root rot, black stain root disease, tansy ragwort and spotted knapweed, have been found to spread along logging roads (Perry 1988, Schowalter 1988, Schowalter and Means 1989). Removal of snags and down wood eliminates habitats necessary to maintain populations of generalist insect and pathogen predators that control pest outbreaks (Schowalter and Means 1989, Mason and Wickman 1994, Filip et al. 1996).

Salvage logging proponents also argue that the practice can reduce the risk of large, high-intensity wildfires by removing dead or dying trees that could serve as fuel in the next fire. However, there is evidence that removing these trees may not significantly decrease fire severity. A number of studies have shown that for some ecosystems, the major factor determining fire intensity and size is weather and not the amount of fuel (Baker 1989, Flannigan and Harrington 1988, Haines and Sando 1969, Rothermel 1995). For example, Bessie and Johnson (1995) found that fire spread and intensity were strongly related to weather conditions and only weakly related to fuel loads in the southern Canadian Rockies. Similarly, many hundreds of the thousands of acres of forests that were intensely burned in the 1994 Tyee Fire on the Wenatchee National Forest had very low fuel loads. The Forest Service and Fish and Wildlife Service concluded that weather patterns and terrain -- not fuels -- were the major reasons why this large fire burned the way it did (U.S. Forest Service 1995, U.S. Fish & Wildlife Service 1994). Such case studies provide little evidence that salvage logging of dead and dying trees will significantly reduce wildfires.

There is also evidence that salvage logging could actually increase fire intensity and size by creating highly flammable logging slash -- small trees, branches and tops -- that is unmerchantable as timber and uneconomical to remove or burn (Gorte 1994, Wolf 1995). After the large, valuable trees are removed by salvage logging, the highly flammable slash is often left where it falls or piled or scattered close to the ground. When fire hits such a concentration of logging slash, it often "blows up," becoming a firestorm that is difficult to suppress (Olson and Fahnestock 1955, Agee 1989).

When recent western forest fire histories are studied, the most damaging fires either started or "blew up" in previously logged areas, especially those where there was inadequate slash reduction or none at all (Huff et al. 1995). A good example of this is the 1994 Tyee Fire that affected more than 130,000 acres of the Wenatchee National Forest in Washington . According to the U.S. Fish and Wildlife Service, this fire was small and of low intensity until it "burned into an area of heavy logging slash, where it progressed quickly, reaching nearly 2,000 acres in size in a day" (U.S. Fish and Wildlife Service 1994). Similarly, clearcuts represented nearly 40 percent of the largest 1994 fire in western Montana (15,000 acres). The fires' speed doubled and tripled when it hit the accumulations of fine, unshaded fuels associated with past clearcuts, causing it to spread into adjacent unmanaged forests (DellaSala et al. 1995b).

In summary, many scientists have pointed out that the negative effects of salvage logging are likely to outweigh by far any hypothetical benefits associated with the removal of dead trees. In an open letter sent to President Clinton in 1994, a group of prominent ecologists wrote: "There is considerable scientific reason to believe that salvage logging and the accompanying road building is one of the most damaging management practices that could be proposed for burned areas.... We therefore strongly oppose a general public program of salvage logging and the accompanying roadbuilding in burned areas, simply because they have burned" (Minshall et al. 1994). Similarly, a recent report on western interior forests commissioned by Congress and endorsed by the major professional scientific societies related to wildlife, fisheries and ecosystem research concluded that ÒSalvage cuts that remove a substantial proportion of standing, downed or potential future coarse woody debris are detrimental to most forest organisms" (Henjum et al. 1994).

Thinning. Thinning, generally defined as a reduction in the density of green trees in a given area, has been advocated by some as a silvicultural practice for improving "forest health." When conducted carefully under the appropriate conditions, thinning some of the smaller trees from below the overstory -- particularly in dense stands of dry, fire-prone forest types -- has potential as a tool for improving forest ecosystem health. By removing some of the smaller, shade-tolerant trees, thinning can increase resistance to fire, insects and disease (Mason and Wickman 1994, Harvey 1994), facilitate the reintroduction of fire (Mutch et al. 1993, Arno and Ottmar 1994), and reduce mortality of residual old-growth trees by reducing competition (Pearson 1950, Schubert 1974).

The practice is controversial because it has been traditionally used to increase tree growth rates while maximizing wood fiber production, rather than as a tool to restore forest ecosystem health. Instead of focusing on removal of small-diameter shade tolerant trees, past thinning operations have often targeted the largest trees in a stand and the oldest stands in a forest landscape, focusing on forest types that have not been significantly altered as a result of fire suppression (e.g., the coastal forests of the Pacific Northwest and subalpine forests of the Rocky Mountains). Forest scientists generally agree that thinning must retain larger trees and focus on overly dense stands if it is to be justified on the basis of improving forest ecosystem health (Johnson et al. 1995, Henjum et al. 1994, Kauffman and Agee 1992, DellaSala et al. 1994).

Although thinning offers potential for revitalizing some forests, particularly dry, fire-prone types, its use as a tool for ecological restoration is not without risk. Available evidence indicates that thinning, even when carefully conducted, can significantly harm forest ecosystems, resulting in:

Given the potential for adverse as well as beneficial effects from thinning, many scientists have recommended that previously managed (i.e., logged) areas of dry forest that have been most altered as a result of fire suppression and past logging should be the highest priority for such treatments, at least until the presumed benefits can be better documented (Henjum et al. 1994, Perry 1995, Dellasala et al. 1995, Beschta et al. 1995).

Prescribed fire. Carefully conducted prescribed burning, where fires are intentionally ignited and allowed to burn under controlled conditions, has the potential to improve forest ecosystem health significantly in forest types that have been adversely affected by fire suppression. The objective of prescribed burning is to use surface fires to mimic natural fire patterns in forests that were historically maintained by frequent, low-intensity fires. In addition to restoring forest conditions that more closely resemble those that would occur under natural fire conditions, prescribed fire may decrease fuels and outbreaks of insects and disease organisms, provide germination sites for shade-intolerant species, release nutrients and create wildlife habitat (Brennan and Hermann 1994, Agee 1994b).

While there appears to be scientific consensus that prescribed burning is appropriate for many areas, there are some risks associated with its widespread use. Not much is known about the effects of various fire intensities on sensitive species and other ecosystem components. In addition, current high fuel loads in some areas may increase the probability of crown fires. Ecological damage potentially associated with fires that burn at high-intensity includes erosion, nutrient loss, loss of organic material, damage to tree roots (Thomas & Agee 1986), increased susceptibility to bark beetles (Fellin 1979), smoke hazard and damage from escaped fires.

Although managers are beginning to recognize the importance of reintroducing fire, prescribed fire is not used commonly in many forests where it is appropriate, except for removal of logging slash (Agee 1996). Many scientists have indicated that prescribed fire programs will need to be increased substantially in order to return dry forests to a more resilient condition. For example, Mutch et al. (1993) recommend a ten-fold increase in the number of acres presently burned each year in the Blue Mountains of northeastern Oregon , and Agee (1994a) indicates that about 830,000 acres per year would need to be burned to reintroduce fire on a 15-year rotation in ponderosa pine forests. In mixed conifer forests in the inland Northwest, a 30-year rotation would be needed. Underburning may not be sufficient in all ecosystem types to restore historic fire patterns and large, stand-replacing fires may be necessary to restore some forest landscapes to their historical patterns (Baker 1992, 1994, Turner & Romme 1994).

Robert L. Peters is a Defenders of Wildlife conservation biologist and co-author of the Defenders report, Endangered Ecosystems: A Status Report on America 's Vanishing Habitat and Wildlife.

Evan Frost is a staff ecologist with the Northwest Ecosystem Alliance, specializing in biodiversity and forest issues in the Pacific Northwest .

Felice Pace is executive director of the Klamath Forest Alliance, specializing in issues pertaining to preservation of biodiversity in the Klamath-Siskiyou Bioregion.

 

Managing for Forest Ecosystem Health:

A Reassessment of the " Forest Health Crisis"

by Robert L. Peters, Evan Frost, and Felice Pace

Recommendations for Maintaining and Restoring Forest Ecosystem Health

The foregoing review of forest ecosystem health leads us to conclude that human-caused disturbances are the primary threats to sustaining ecosystems on federal lands and the numerous goods and services that they provide. Instead of focusing "forest health" treatments on areas influenced by insects, disease and fire, we believe that the way to maintain and restore ecosystem health is to decrease adverse human impacts while allowing natural disturbances to play their historical roles in maintaining the diversity and productivity of forest landscapes. With the objective of protecting our healthiest forest ecosystems while also attempting to restore forests that have suffered damage, we make the following recommendations.

Restore the role of fire. Fire must be reintroduced into those forest ecosystems from which it has been excluded. This means allowing natural fires to burn in remote areas when conditions are favorable and where there is no threat to human life, as well as setting prescribed management fires to mimic natural fire effects. The National Park Service has been using prescribed fire effectively for many years and has recognized its value in maintaining or restoring forest ecosystem health (U.S. DOI 1992, Bancroft et al. 1985, Parsons et al. 1986). In 1995, the Interior and Agriculture Departments released a report on federal wildland fire management in which they recommended several progressive changes in fire policy, including recognition of wildland fire as a critical ecological process that must be reintroduced to many forest ecosystems. Decisions about how and where to reintroduce fire "will be accomplished across agency boundaries and will be based upon the best available science" (U.S. DOI and USDA 1995).

Some Forest Service personnel know how to use prescribed fire appropriately, but these specialists have not been provided with the resources needed to implement prescribed burning programs at levels that current conditions require. The forest conservation community in northern California has had some success in obtaining increased funding from Congress for "natural fuels treatment." The 1995 Federal Wildland Fire Management Report highlighted the need to develop policies for training and retaining experts in prescriptive burning within the agencies.

Thin some managed dry forest stands. Some areas of forest -- particularly those dry forest types that have been most altered as a result of past logging, livestock grazing and fire suppression -- have become so dense with smaller trees that fire cannot be safely or successfully reintroduced without first reducing fuel loads. In overly dense stands, thinning some of the smaller trees from below the tree canopy has potential to facilitate fire's return and thereby improve forest ecosystem health. However, even when carefully conducted, thinning can result in undesirable environmental impacts to soils, water and wildlife. Since the use of thinning specifically as a tool for ecological restoration rather than timber extraction has not been widely tested, it must be used judiciously and in ways that minimize ecological risks.

Given the potential for adverse as well as beneficial effects from thinning, we recommend limiting this practice primarily to areas of dry forest that have been subjected to past logging activities, where the greatest potential benefits can be gained while minimizing risks to soils, water quality and biodiversity. There are millions of acres of such forests on federal lands in the United States -- the legacy of a century of logging, livestock grazing and fire suppression.

Research and experience have shown that retaining appropriate levels of crown closure and structure with the largest trees provides important habitat for sensitive wildlife (FEMAT 1993, Verner et al. 1992), reduces risks from fire and insect outbreaks (Mason and Wickman 1994, Mutch et al. 1993), and accelerates the development of forest conditions that are compatible with natural disturbance regimes (Everett et al. 1994). For western forests, we recommend use of a set of standards and guidelines for thinning based on these concepts that has been developed by a group of forest scientists and forestry practitioners (Pace and Frost 1995).

Conserve remaining old-growth forests and large, old trees. One of the primary factors lying at the root of current ecosystem health problems is the extensive loss of old-growth forests. Ecological research conducted in a wide variety of forest types has found that these communities provide unique and essential habitats for plants and animals and carry out important ecological functions not associated with younger forests (Norse 1990, Moir 1992). Because of the high timber values associated with old growth, these forests have been the focus of commercial logging activity for nearly a century and are now much reduced from their historic abundance.

The remaining old-growth forests are invaluable as reservoirs for genetic diversity, seed sources for forest regeneration, refugia for old-growth dependent wildlife, and examples for forest restoration in the managed landscape. Continued logging of old growth, as is currently planned, will increase the number of endangered fish and wildlife species, further degrade streams and watersheds, and jeopardize many of the ecological values and products (including timber) associated with public forests. At present, only a small fraction of the old-growth forests that remain are protected from logging. Given what we do and do not know about how western forest ecosystems function, we conclude that all remaining old-growth stands are ecologically significant, and recommend that they be protected from logging.

In addition, management guidelines should be developed that prohibit the removal of large, old trees remaining in previously logged areas, including areas where there is a perceived "forest health emergency." Because such a large proportion of large, old trees have already been logged from U.S. forests, those that still remain have enormous ecological value. They serve as reservoirs of genetic diversity and irreplaceable seed sources for forest regeneration; they replenish the depleted supply of large snags and fallen logs, providing nest and den sites for many animals; and they furnish unique historic records. As stated by forest entomologist Boyd Wickman, "These trees are living examples of our long-term objectives" (Wickman 1992). We agree with previous scientific assessments for western forests that have recommended that no trees be logged that measure greater than 30" diameter at breast height west of the Cascade/Sierra Crest and 20" east (Henjum et al. 1994; Verner et al. 1992; FEMAT 1993).

Reduce roads and protect roadless areas. Roads by themselves are one the largest contributors to the deterioration of forest ecosystem health. Although they are intended to act as innocuous corridors for human transportation, roads fragment habitat, alter the hydrological processes of watersheds, discharge excessive sediment to streams, increase disturbance to forest animals and facilitate the spread of non-native species (Noss and Cooperider 1994). In contrast, remaining roadless regions include the least human-disturbed forests and streams -- important reservoirs of biological diversity -- and are the primary benchmarks for restoring ecosystem integrity (Henjum etal. 1994, Wissmar et al. 1994). Furthermore, roadless areas often contain steep slopes with unstable or highly erosive soils.

We therefore recommend that the Forest Service and other federal land management agencies:

  1. move aggressively to close and decommission roads down to levels that do not result in excessive resource damage. This reduction in roads should be accomplished using an ecologically based decision process in which roads are given priority for closure on the basis of the magnitude of their current impacts and future risks to ecosystem health.
  2. Avoid construction of roads within roadless areas, particularly if they are contiguous with national parks, wilderness areas or other roadless areas or represent rare or unique habitats. Building new roads into these areas will only make our forests less biologically diverse and less resilient to undesirable change.

Protect riparian areas, unstable lands, and fragile sites. Managers should ensure that any activity, including livestock grazing, mining or logging, does not degrade riparian areas, water quality or soil integrity. Livestock grazing should be greatly reduced or eliminated in degraded riparian areas on public lands to prevent additional damage of riparian forests, water quality and wildlife. Unstable areas prone to landslides or accelerated erosion should be identified and mapped so that logging, grazing and other disturbances can be excluded from these areas. Examples include low-elevation forest sites transitional to grasslands or desert shrublands, high-elevation forests, rocky areas, steep slopes, wetlands, areas with high water tables and frost pockets. Ground-disturbing activities should not be permitted in areas identified as unstable unless the proposed activities are peer-reviewed, scientific study conclusively demonstrates that they will not degrade soils or release sediment into streams, and forest regeneration after logging is assured.

Reduce fire risk where rural areas meet wildlands. As the United State 's rural population continues to grow, more people will live in or near the national forests. As a result, we can expect more forest fires in the vicinity of residential areas, along with increased demand for fire suppression. Because such fire suppression may harm forests, we should explore opportunities to minimize fire danger with a minimum of suppression.

One solution is to shift fire-fighting efforts away from fighting large fires in remote areas to defending human life and property in the zone where rural populations and wildlands meet. This shift not only would free up resources to prevent or fight fires in rural areas but also would have the ecological benefit of allowing natural fire patterns to reestablish themselves in more remote wildlands. A useful preventative measure is to create firebreaks -- areas cleared of fuel -- near residential communities to protect them from fires burning in adjacent wildlands. Proposals for firebreaks of this kind put forward by several community groups in northern California , have gained the support of the forest products industry, conservation groups, state agencies and local government.

Although the Forest Service can take actions that may reduce fire danger immediately adjacent to rural communities, people living in high fire risk areas should be encouraged, if not required, to carry out fire prevention measures around homes and other structures. Incentives for increasing cooperation and coordination between national forests and intermingled private lands should be expanded.

Reduce logging slash. Large amounts of slash left by logging operations in managed areas pose a risk of high-intensity fires and should be removed. Steps should be taken to assure that future timber sales do not leave behind excessive concentrations of slash. Slash abatement should be required in all timber sale contracts. The objective of slash abatement should be to reduce small fallen branches and other fine, highly combustible material while retaining large branches, snags and down logs on all sites to provide for wildlife habitat and soil nutrient replenishment. Appropriate levels of large woody material that should be left is a forest-specific issue that should be determined through the project planning process.

Practice ecosystem management and adaptive management. Project planning should evaluate the potential adverse environmental impacts of proposed management actions on entire forest ecosystems, not just tree health. The hypothetical benefits of any logging or other proposed action should be carefully weighed against the risk of degrading water quality, soil integrity, fisheries and biological diversity. Project implementation should incorporate adaptive management Ñmodification of management activities as indicated by results of ongoing monitoring studies (Walters and Holling 1990). Adaptive management is particularly important in applying ecosystem health measures because our existing scientific understanding of the overall short- and long-term effects of such actions is poor. Unfortunately, scientifically sound monitoring programs have not been developed for many national forests, and where such programs do exist, they are often the first to be cut when budgets are reduced. A federal mandate and support for a comprehensive monitoring program are essential if ecosystem health is to be maintained and restored.

Because all forest ecosystems are different and respond differently to human-caused disturbances, management must be carefully tailored for each forest. Even within a single forest there can be large differences in species composition, physical structure and response to disturbance, dependent on which way a slope is facing, how much moisture the soil can hold or the nutrient content of the soil. The message for managers and politicians is that blanket prescriptions, such the large-scale salvage logging mandated by Public Law 104-19, are not appropriate.

Robert L. Peters is a Defenders of Wildlife conservation biologist and co-author of the Defenders report, Endangered Ecosystems: A Status Report on America 's Vanishing Habitat and Wildlife.

Evan Frost is a staff ecologist with the Northwest Ecosystem Alliance, specializing in biodiversity and forest issues in the Pacific Northwest .

Felice Pace is executive director of the Klamath Forest Alliance, specializing in issues pertaining to preservation of biodiversity in the Klamath-Siskiyou Bioregion.

 

Managing for Forest Ecosystem Health:

A Reassessment of the " Forest Health Crisis"

by Robert L. Peters, Evan Frost, and Felice Pace

Conclusion

Recent congressional and Forest Service initiatives aimed at solving the purported "forest health emergency" are likely to further degrade, rather than restore, forest ecosystems. At best, these initiatives are driven by major ecological misconceptions that include: (1) reliance on a narrow definition of forest health biased toward timber production that fails to recognize or address declines in biodiversity, soils, water quality and other ecological values not directly associated with tree health; (2) exaggeration of the severity and geographic extent of problems with fire, insects and disease and mischaracterization of these problems as a "crisis"; and (3) promotion of widespread salvage logging as a means for restoring "forest health," despite the fact that salvage logging damages soils, water quality and wildlife habitat and has yet to be shown effective at reducing fire risks on a landscape scale.

To the contrary, we conclude that: (1) long-term sustainability of forest ecosystems requires adopting a definition of health that recognizes the need to maintain all components of the ecosystem; (2) insects, disease and fire are integral parts of forest ecosystems, and while there may be increased activity of these agents in some specific areas, these disturbances are not so widespread or severe as to constitute a "crisis"; and (3) while thinning and prescribed fire offer some potential for improving ecosystem health in some areas, salvage logging is usually not appropriate because it is likely to result in more environmental damage than would be caused by wildfire, insects or disease. What is needed is a clear set of objectives for maintaining and restoring ecosystem health and a coordinated strategy to achieve those objectives that minimizes risks to the numerous values and services provided by federal forests.

Robert L. Peters is a Defenders of Wildlife conservation biologist and co-author of the Defenders report, Endangered Ecosystems: A Status Report on America 's Vanishing Habitat and Wildlife.

Evan Frost is a staff ecologist with the Northwest Ecosystem Alliance, specializing in biodiversity and forest issues in the Pacific Northwest .

Felice Pace is executive director of the Klamath Forest Alliance, specializing in issues pertaining to preservation of biodiversity in the Klamath-Siskiyou Bioregion.