Native American Influences on the Development of Forest Ecosystems
Thomas M. Bonnicksen, M. Kat Anderson, Henry T. Lewis, Charles E. Kay, and Ruthann Knudson. 1999. Native American influences on the development of forest ecosystems. In: Szaro, R. C.; Johnson, N. C.; Sexton, W. T.; Malk, A. J., eds. Ecological stewardship: A common reference for ecosystem management. Vol. 2. Oxford, UK: Elsevier Science Ltd: 439-470.
Selected excerpts:
I INTRODUCTION
Ecosystem management cannot succeed in promoting stewardship if it fails to recognize that humans are an integral and natural part of the North American landscape. Ecosystem management has the potential for widening the gap between people and nature. Subdividing landscapes into ecosystems could create the false impression that ecosystems are real things. This illusion becomes more dangerous when people think that they live on the outside and nature exists on the inside of ecosystems.
Biologists developed the ecosystem model to describe physical, chemical, and biological interactions at a particular time within an arbitrarily defined volume of space (Lindeman 1942). They usually exclude people because the boundaries are sometimes drawn around small parts of the landscape, such as watersheds. Because management decisions come from outside, ecosystems appear as separate entities. Therefore, ecosystem management may reinforce the myth that nature exists apart from people if it does not explicitly state otherwise.
A corollary myth assumes that climate dictated the structure and function of ecosystems. On the contrary, climate provides either a favorable or unfavorable physical environment for certain plants to grow. It does not dictate which plants grow in that environment. Similarly, climate does not dictate human behavior. It only sets temporary limits. Human innovations in technique and technology can and do push back those limits. Therefore, climate is not the sole determinant nor even in many cases the dominate force in guiding the development of particular ecosystems. American Indians selectively hunted, gathered plants, and fired habitats in North America for at least 12,000 years. Unquestionably, humans played an important role in shaping North America’s forest ecosystems.
Interpretations of the impacts made by indigenous people in North America are largely limited to what can be postulated in terms of paleontological, anthropological, and archaeological evidence. None of these approaches have been completely persuasive to skeptics who require more substantial and corroborative evidence before accepting the significance of the environmental changes induced over 12,000 or more years by hunting-gathering societies and, for the last 2,000 years, by indigenous farmers as well. Taken together, however, the evidence shows a clear and convincing pattern of indigenous human influences on prehistoric, historic, and contemporary ecosystems.
In this chapter, we argue that the success of ecosystem management depends on understanding reciprocal relationships between native forests and indigenous peoples. Consequently, we concentrate on the development of forests prior to European settlement. Particular emphasis is placed on American Indians consciously and actively managing landscapes through the selective killing of animals, the cultivation of preferred plants, and the widespread manipulation of habitats with fire.
We also concentrate on what indigenous people did to survive and prosper. We believe it would be inappropriate to use today’s ideas and values as standards for judging their actions. Therefore, our chapter focuses on the management practices of indigenous people that succeeded for them and maybe useful to us (Rides at the Door and Montagne 1996).
Finally, we argue that local knowledge and practices that followed European settlement provide analogues for reconstructing pre-European settlement conditions as well as for suggesting answers to contemporary management problems. Equally important, we believe that ecosystem management cannot succeed unless current human residents of forests become intimately involved in decisions that affect their lives and surroundings.
The romantic 20th century idea of a natural area or wilderness as a place without human influence became meaningless in North America when Paleoindians pushed southward between the continental ice sheets and perhaps along the Northwest coast 12,000 or more years ago. They found two unexploited continents with bountiful game. Their populations grew and by 11,200 years ago there may have been millions of Paleoindians living from coast to coast in both North and South America (Fiedel 1987, Roosevelt et al. 1996).
2.1 Populations at Contact
The earliest European explorers found the southern United States heavily inhabited by American Indians. At the time of European contact, at least 600 tribes or bands consisted of as many as 12 million American Indians, maybe more, who were actively managing or influencing every corner of the continent (Dobyns 1983)…
Estimates of pre-1492 North American human populations range from approximately 2 million (Ubelaker 1988) to 18 million (Dobyns 1983). Ubelaker (1988) relied on a variety of sources of American Indian population estimates to arrive at his conclusion that only 1,894,350 people were spread across the continent at the time of contact. On the other hand, Dobyns (1983) spent over 30 years studying American Indian demography from pre-European to present conditions, building on previous work by Cook (1937) and others. He calculated human population densities based on the availability of natural resources on which archeological evidence shows groups of native people relied (e.g., edible wild plants, cultivated plants, and sources of animal protein). As a result, Dobyns’ (1983) estimate of the 1492 population of North America is 18 million people, with an additional 80 million in Mexico, and Central and South America. Fiedel (1987) used still a different method to derive his intermediate estimate of a 1492 population of 12 million American Indians in North America.
Wide variations in population estimates reflect not only different methods for deriving estimates but also different assumptions about the impact of European diseases. That is, low population estimates usually discount the importance or timing of pandemics on American Indians. From the 1930s on, scholars have been reevaluating estimates of pre-Columbian human populations in the Americas to account for the effect of disease. Old World contagious diseases, such as smallpox, measles, influenza, bubonic plague, diphtheria, typhus, and cholera devastated American Indian populations (Ramenofsky 1987). Perhaps the first documented impact of European disease on American Indians can be found in the Narrative of Alvar Nunez Cabeza de Vaca written in 1528 (Hodge 1990). European diseases may have spread rapidly enough to decimate Indian populations in the Pacific Northwest between 1550 and 1600 (Campbell 1990). However, Henry Dobyns (personal communication with Knudson, October 30, 1995) recently found documentation that swine flu may have been transmitted to America as early as 1493 by crew members of Columbus’ second expedition. These diseases spread rapidly because American Indians had regular and extensive trade and exchange systems that covered the continent, and relatively dense populations in some regions. Therefore, low population estimates may be too conservative.
2.2 Modifying Landscapes
American Indians were not passive occupants of the land. Regardless of their population at the time of European contact, the landscapes of North and South America described by the first explorers and settlers had already been shaped by millions of people over thousands of years of use and management (Deneven 1992, Fiedel 1987, Gomez-Pompa and Kaus 1992). American Indians had the incentive, technology, and numbers to modify and maintain forests and other ecosystems. By 11,200 years ago the Monte Alege Paleoindians had already begun cutting and burning tropical rainforests in the Amazon to produce fruits, nuts and other foods (Roosevelt et al. 1996). Paleoindians in North America were equally capable of managing their environment. Therefore, the conclusions drawn by Roosevelt et al. (1996) for South America also hold true for North America:
“Archaeological and ethnobotanical evidence shows that Amazonian forests once thought to be virgin were settled, cut, burned, and cultivated repeatedly during prehistoric and historic times, and that human activities widely altered topography, soil, and water quality. Substantial biodiversity patterning appears to be associated with such human activities.”
Unequivocal evidence now exists from numerous sources that American Indians were deliberately managing the land using a variety of techniques for millennia. This is substantiated by contemporary tribal cultures, studies of museum artifacts, archeological remains, paleoecological findings, fire scar studies, and ecological field studies. Numerous early ethnohistoric and ethnographic studies refer to management practices of Indians in different parts of North and South America. Although much is known about Indian management practices in many areas of North America, further research is needed to cover more areas and to enhance our understanding. Nevertheless, enough evidence exists from written documents alone to build an incontestable case that Indians managed the North American landscape.
During the 12 or more millennia in which people have lived in North America, they fished; herded and hunted game; dug roots; collected berries and nuts; cultivated wild plant foods; built structures of earth, rock, wood (including leaves and bark) and bone; quarried stone for making flaked and ground stone tools, or to be used as building material; mined and smelted minerals; strip-mined for coal; burned forests, prairies and wetlands; cleared fields and planted and harvested domesticated crops; built irrigation canals and roads; and dug wells for water, gas and oil. Some managed the North American continent as scattered bands that moved from place to place. Others concentrated by the thousands in sedentary urban masses. Their management practices and day-to-day activities affected nearly all of America’s ecosystems in some way, especially forests and prairies.
Many people believe that North America’s native forests were all-aged, dense, and self-perpetuating, with a multi-layered canopy that shaded a forest floor strewn with piles of dead trees. Such a view is untenable given the pervasive effects of American Indian use and management. Therefore, only a small proportion of the native forests in the United States fit this image - notably western hemlock (Tsuga heterophylla) forests in the Pacific Northwest, and beech (Fagus grandifolia) and sugar maple (Acer saccharum) forests in the Upper Midwest and East (Daniel et al. 1979, Davis and Mutch 1994). Even all-aged forests burn occasionally, and tornadoes and hurricanes often create large openings in which shade intolerant trees like aspen (Populus tremuloides) and birch (Betula spp.) can flourish, thus temporarily converting these forests into mosaics that included groups of young trees.
Some of North America’s native forests were open and park-like, not dark and dense. For example, Thomas Ashe, an 18th century English traveler, made a statement that was echoed by many other early observers dating back hundreds of years when he said that “The American forests have generally one very interesting quality, that of being entirely free from under or brushwood” (Bakeless 1961). Native forests stayed open because Indian and lightning ignited fires were relatively frequent and extensive. Because these fires were frequent enough to clean up most of the debris on the forest floor in many forest types, fires generally stayed on the ground and burned as surface fires. Some surface fires did reach the canopy and burn small areas of forest, but large crown fires were rare.
Some also believe that native forests consisted of mostly large old trees that covered the landscape like a blanket. Most native forests were dramatically different from this popular image. Instead of a blanket of old trees, native forests consisted of a dynamic mosaic containing patches of young and old trees, interspersed with patches of grass and shrubs. American Indians played a key role in creating and maintaining this mosaic by favoring early successional stages that produced the resources they required. They cleared old forests to make room for crops and new forests, removed fallen trees and debris, thinned overstory and understory trees, and created a diverse landscape of forests, brushlands, and prairies. Indian cultivation and timber harvesting, Indian and lightning fires, and other natural forces such as tornadoes, hurricanes, insect infestations and disease interacted to sustain the mosaic structure of most North American forests. Thus, old trees could only occupy a small part of the landscape in most forest mosaics, but the proportion varied with the frequency and severity of disturbances (Bonnicksen 1994a; Bonnicksen and Stone 1985; Cooper 1960, Teensma et al. 1991).
In short, historical evidence paints a picture of native forests and indigenous peoples that differs markedly from the sentimental views we often nurture today. The management practices of American Indians helped to shape the development of North America’s native forests. Understanding native forests and the management practices of American Indians that helped to create and sustain them provides essential lessons for ecosystem management.
3 FIRE: CREATING AND MAINTAINING HABITATS
American Indians modified many North American plant communities to meet their needs. They not only engaged in widespread burning but they also cut trees for agriculture, fuel, and building materials. This habitat modification benefited many species, mostly those associated with disturbance, but adversely impacted others, such as those dependent on late successional vegetation or old-growth forests. Most extinctions on Pacific Islands, for example, are thought to have been more the result of habitat alteration than hunting (Olsen 1989). On the other hand, some species that are now in danger of extinction were common in pre-European settlement times because they prospered under various aboriginal land management systems (Blackburn and Anderson 1993).
Fire was the most powerful tool for managing habitats available to American Indians. American Indians used fire to modify forests, brushlands, and grasslands. Missionaries’ diaries, settlers’ journals, and explorers’ and surveyors’ field notes document the intentional burning by American Indians as a universal practice. For example, many early explorers commented about Indian burning in southern forests. In 1528, Alvar Nunez Cabeza de Vaca recorded in his narrative that in Texas “The Indians of the interior … go with brands in the hand firing the plains and forests within their reach, that the mosquitoes may fly away, and at the same time to drive out lizards and other like things from the earth for them to eat. In this way do they appease their hunger, two or three times in the year…” (Hodge 1990).
American Indians also burned forests in California, the Northeast, northern Rocky Mountains, the Southwest, the Northwest, and the Midwest. They burned to stimulate the production of edible wild plants for seeds, leaves, fruits, bulbs and stems; to promote young adventitious and epicormic shoots of shrubs for basketry; to discourage insects, diseases and weeds; to increase palatable grasses and browse for animals; to increase visibility; to facilitate travel; to decrease. dense brush and promote more open country; to enhance waterfowl habitat; to create firewood; to use as a weapon of war; to eliminate rubbish and pests in villages; to open and maintain trails; to signal one another; to create fuel breaks; to open meadows along forest trails that attract animals and provide living food reserves during travel; to clear the ground for gathering acorns; to reduce competition for mast trees; to cook insects or seeds before harvesting; to clear fields for planting; to flush and surround game; to clear underbrush that could hide their enemies; and for many other reasons. Some Indian-set fires also went out of control, and signal fires and campfires often were left to burn (Barrett 1980a, b; Barrett and Arno 1982; Blackburn and Anderson 1993; Day 1953; Lewis 1978, 1980; Pyne 1982)…
3.2 Management Fires
If human-set fires had a goal, it was (and in parts of Australia still is) to establish and then maintain significantly different conditions than those found to exist naturally. The maintenance of such conditions was not the simple replication or even only the intensification of natural fire regimes; to a very large measure it involved their replacement.
Given the composition and characteristics of particular habitats, and especially the culturally defined resources therein, the distinguishing features of cultural fire regimes include: (1) the alternate seasons for burning different kinds of settings, (2) the frequencies with which fires are set and reset over varying periods of time, (3) the corresponding intensities with which fuels can be burned, (4) the specific selection of sites fired and, alternately, those that are not, and (5) a range of natural and artificial controls that humans employ in limiting the spread of human-set fires, such as times of day, winds, fuels, slope, relative humidities, and natural fire breaks. (Lewis 1982).
The considerable literature on hunter-gatherer uses of fire shows that the seasonality of setting fires varied from habitat to habitat. Natural fires primarily derive from late summer or late dry-season lightning storms. They occur at the peak or end of growing seasons, and at times when fires can be highly disruptive and invariably destructive in areas dominated by old growth and detritus. In contrast to natural fire regimes, hunting-gathering peoples set fires that were relatively easy to control and less disruptive, and that initiated plant growth weeks or even months before new growth occurs naturally. A goal of human-set fires was to induce the early emergence of plant growth. Thus, fires were set during the spring in northern and more temperate regions, or in late summer and early autumn in areas where growth took place during much of the winter (e.g., the semi-arid parts of California and in other similar Mediterranean-type regions).
Along with seasonality of burning, hunter-gatherers set fires in terms of different, invariably much greater frequencies than those that occur as a result of lightning storms. In addition, because lightning strikes are partly a function of altitude and are less likely to ignite grasslands, open prairies and brushlands, huntergatherers regularly, in some cases annually, set fire to areas as small as forest glades to those constituting large sections of open prairies (Boyd 1986; Lewis 1973, 1982; Morgan 1978; Stewart 1955). In a work summarizing historical accounts of Indian and natural fires on the Northern Great Plains, Higgins (1986:7) stated that,
“The pattern of seasonality of lightning-set fires … showed that 73% of the lightning-set fires occurred in July and August. This pattern was different from the two seasonal periods of Indian-set fires reported here-March through May with a peak in April, and July through November with a peak in October. Therefore, it seems that the northern plains Indians did not pattern their use of fire according to lightningfire pattern but for some other reason.”
Other reasons concerned the influence of Indians on local and seasonal movements of bison to induce them to graze in tall-grass areas near their winter encampments along the ecotones separating forests and prairies (aspen parklands and riverine valleys). Then, in burning the tall-grass ecotone areas in early spring, bison were alternately drawn onto the short-grass prairies which had been burned the previous autumn. In these areas new growth emerged earlier and more lush in the spring than it did in unburned areas. The scale of fires set by Indians on the short-grass plains was much greater than in nearby parklands and far greater still than what has been estimated for adjacent boreal and montane forest regions (Lewis 1982)…
4.2 Limiting and Protecting Game Populations
American Indians protected habitats and promoted biodiversity in plant and animal communities by keeping ungulate numbers low (Wagner and Kay 1993, Zimov et al. 1995). Prior to the early 1800s, for example, millions of beaver (Castor canadensis) occupied lush riparian zones throughout the West. Beaver were so abundant that in 1825, Peter Skene Ogden’s party trapped 511 beavers in only five days on Utah’s Ogden River. In 1829, Ogden also reported that his fur brigade took 1,800 beaver in a month on Nevada’s Humboldt River (Kay 1994). Yellowstone too once contained large numbers of beaver, but that species is now extinct on the park’s northern range. Without American Indian hunters, the park’s burgeoning elk population has nearly destroyed the willow and aspen communities that beaver need for food and dam-building materials (Kay and Platts 1997). So American Indian hunting benefited all species by preventing habitat destruction by large populations of ungulates.
Many people believe that before the arrival of Europeans, North America teemed with wildlife, especially ungulates like elk (Cervus elaphus), moose (Alces alces), and bison (Bison bison). Although wildlife were abundant in many places, historical records show that game populations fluctuated in response to local weather, and the hunting and habitat modifying activities of American Indians. Thus American Indians limited game populations in some areas by hunting, and increased populations in other areas by using fire to improve habitats. Changes in weather, predators, and other factors in a particular area aided or interfered with their success. The overall effect of American Indian hunting, however, was to maintain game populations within the carrying capacity of their habitats.
Hunting pressure necessarily depressed game populations in certain places. Birkedal (1993) reported that American Indians armed with no more than spears and hunting dogs once kept Alaskan grizzly bear (Ursus arctos) populations at very low levels. In the Intermountain West, early fur trappers seldom reported seeing or killing a moose. When Peter Skene Ogden’s fur brigade killed three moose near presentday Philipsburg, Montana, in 1825, he noted that it was the first time any of his men had seen a moose despite having spent a total of nearly 300 man-years in the West during the early 1800s. Kay (1997) concluded that native hunting controlled the numbers and distribution of moose throughout western North America - often keeping moose populations at exceedingly low levels because the species was so easy to hunt.
Although not as rare as moose, elk were also historically uncommon in parts of the Rocky Mountains. Between 1835 and 1872, for example, 20 parties spent a total of 765 days traveling through Yellowstone on foot or horseback, yet reported seeing elk only once every 18 days - today nearly 100,000 elk live in that ecosystem (Kay 1990). The same was true in the Canadian Rockies where early explorers reported seeing elk only once every 31 days (Kay and White 1995). During the 1800s, elk also were rare in parts of Utah, Arizona, New Mexico, as well as other regions of the Intermountain West (Kay 1995, Truett 1996).
Moreover, deer (Odocoileus hemionus and O. virginianus), antelope (Antilocapra americana), and bighorn sheep (Ovis canadensis) were also rare in many places when the Rocky Mountains were first visited by Europeans. Accounts of starvation and killing horses for food are common in early journals (Kay 1990). Except for Idaho’s Snake River Plain and surrounding areas, few bison were ever seen west of the Continental Divide. Today in Yellowstone National Park there are approximately 4,200 bison, but between 1835 and 1872, early explorers encountered bison only three times despite spending 765 days there (Kay 1990). Game populations also were low on many parts of the Columbia Plateau and in the Great Basin at historical contact (Daubenmire 1985).
Historical photographs also indicate that ungulate populations were low in many places. In Yellowstone, for example, 1870 photographs show that aspen, willows (Salix spp.), and other preferred forage species were not as heavily browsed in the early years of the park’s existence as those plants are today. Because many plants were 70 to 100 years old when they were first photographed, this means that the enormous numbers of elk that inhabit the northern range today did not exist from the late 1700s through to the 1870s. The same is true in other parts of Intermountain North America.
Archaeological evidence reinforces the idea that ungulates were rare in heavily populated parts of North America before Europeans arrived. Elk presently dominate ungulate communities in most western national parks, yet elk are seldom recovered from archaeological sites. Of over 52,000 ungulate bones excavated from more than 200 archaeological sites in the western United States only 3% were elk and only one moose bone was identified (Kay 1990,1995).
Both carnivore predation and native hunting limited ungulate numbers (Waiters et a1.1981). The age of their respective kills, however, shows that American Indians were more efficient predators than carnivores such as wolves (Temple 1987). The more difficult it is for a predator to capture a particular prey, the more that predator will take weakened individuals and young. So, if two or more predators are preying upon the same species, the least efficient predator will tend to kill fewer prime-age animals. Although wolves (Canis lupus) and other carnivores kill primarily young-of-the-year and old animals, American Indians killed mostly prime-age ungulates. For example, ungulates recovered from Intermountain archaeological sites are dominated by prime-age animals, thus suggesting that American Indians were more efficient predators than wolves or other carnivores.
Killing mostly prime-age animals is contrary to a maximum sustained yield strategy (Hastings 1983, 1984). The impact of American Indian hunting was further increased because they killed primarily females (Kay 1994a). Furthermore, because American Indians could prey-switch to small animals, plant foods, and fish, they could take their preferred ungulate prey to low levels without having an adverse effect on human populations. Thus, American Indian hunting probably sustained wildlife habitats by limiting game numbers and preventing large fluctuations in populations.
According to predator-prey theory, prey populations will increase if they have a refugium where they are safe from predation (Taylor 1984). Ungulates that could escape aboriginal hunters in time or space were more abundant. Moreover, refugia do not have to be complete to be effective. Partial refugia will also enable prey populations to survive. This explains why there were larger numbers of ungulates on the Great Plains and in Arctic regions. By undertaking long-distance migrations, bison and caribou (Rangifer tarandus) could outdistance most of their human and carnivorous predators (Kay 1994a).
Ungulates also were able to survive in buffer zones between warring tribes (Hickerson 1965). Lewis and Clark (1893:1197), for example noted that, “With regard to game in general, we observe that the greatest quantities of wild animals are usually found in the country lying between nations at war.” Thus, American Indians sustained a diverse post-Pleistocene fauna by (1) limiting game populations to what could be supported within the available habitat, (2) using fire to create new habitat, and (3) providing refugia…
CULTIVATION: HARVESTING AND ENCOURAGING WILD PLANTS
North American Indians practiced plant husbandry for prolonged periods, causing positive, negative, and benign effects on the biota in a multitude of vegetation types (White 1984). Detailed observation and experimentation with the natural environment over many generations led to in-depth, native knowledge of how natural systems work. It also improved their understanding of the basic reproductive biology of plant and animal populations crucial to subsistence economies (Uhser 1987, Anderson and Nabhan 1991).
Anthropologists and ecologists have not sufficiently explored aboriginal harvesting strategies and manipulation of wildlands, which contain plant resources for fuelwood, weapons, clothing, basketry, cordage, foods, tools, dyes, and medicines. Yet vegetation manipulation to augment wild plant populations and sustainable resource-gathering strategies for these needs is seldom considered. Nevertheless, the use of fire as a vegetation management tool, plant harvesting strategies, and other horticultural techniques enabled humans to alter systematically the natural environment on a long-term basis, cumulatively affecting vast areas (Gomez-Pompa and Kaus 1992, Blackburn and Anderson 1993)…
6.1 Disappearing Ecosystems
… Pre-European settlement ponderosa pine (Pinus ponderosa) savannas throughout the West are becoming denser and shading out the grass underneath the trees (e.g., Cooper 1960). Ponderosa pine forest density on the G.A. Pearson Natural Area near Flagstaff, Arizona, increased from 25 trees per acre in pre-European settlement times to 1,182 trees per acre today. Similar changes are occurring elsewhere in southwestern ponderosa pine forests (Covington and Moore 1994). Mixed-conifer forests in the Sierra Nevada and the Southwest are being replaced by shade-tolerant white fir (Abies concolor) trees (Bonnicksen and Stone 1982a,b). Pine trees formerly made up 70 percent of the Boise National Forest in Idaho, but today they only represent 30 percent of the forest. Fir trees replaced pine on the forest. Sugar maple is taking over northern and eastern hardwood forests and oak (Quercus spp.) forests are disappearing. Old-growth Douglas-fir (Pseudotsuga menziesii) forests set aside in reserves in the Pacific Northwest are gradually being replaced by shade-tolerant western hemlock (Bonnicksen 1994a). Lodgepole pine (Pinus contorta) forests also are being replaced by shade-tolerant spruce (Picea spp.) and fir in the Rocky Mountains.
Elsewhere in the West, juniper (Juniperus spp.) is spreading within pinyon-juniper woodlands and replacing grasslands in the Colorado Plateau and southern Rocky Mountain regions of northern Arizona and northern New Mexico. Because of increases in the density of pine and other conifers, aspen forests in Arizona and New Mexico have decreased by 46 percent since 1962, and they are rapidly disappearing as a distinctive forest type throughout their range (Johnson 1994). This is particularly serious because aspen provides habitat for many species of birds and mammals. Unless something is done now to reverse the deterioration, aspen and many other forest types may cease to exist.
In no other area are the changes in native forests more dramatically displayed than within the mixedconifer forests of Sierra Nevada national parks. Bonnicksen and Stone (1982a,b) compared a reconstruction of a pre-European settlement giant sequoia/mixed conifer forest with the same forest as it exists today. The results showed that the area of the forest mosaic covered by patches of sapling-size trees and shrubs declined dramatically. On the other hand, a dramatic increase occurred in patches of pole-size trees and mature trees. Thus, today’s forest is thicker and older than the pre-European settlement forest. Shrubs, black oak (Quercus kelloggii) trees and wildflowers are less abundant, white fir is gradually becoming the dominant tree species, and biodiversity is declining. Even more ominous is an increase in the fire cycle from 129 years to 348 years (Bonnicksen 1994a). This means that the forest will shift from a surface fire regime to a massive fire regime. Heavy cutting will be needed to reduce the density of trees that are choking the understory and to create openings to reproduce trees that require full sunlight. Continued cutting and prescribed burning will be needed to maintain the restored forest or it will simply return to its current deteriorated state.
The decline in forest health is also reducing wildlife and fish habitats, water yields, and biodiversity. The loss of aspen in the Southwest and throughout the Rocky Mountains, especially in Yellowstone and Banff National Parks (Kay 1990, Kay and White 1995), is particularly serious because such forests provide unique wildlife habitat. Today’s dense forests also are infected with disease and infested with insects. In 1988-1989 pine bark beetles killed 15,000 acres of pine trees in five East Texas wilderness areas. Tree mortality in the United States increased 24 percent between 1986 and 1991, and forest growth declined by 2 percent during the same period. Competition for water, nutrients, and sunlight among densely packed trees explains some of the decline.
6.2 Dangerous Fires
Unlike most of the original native forests, many of today’s forests have become dangerous fire hazards. Heavy logs and dead trees clutter these forests and provide massive amounts of fuel. They also are choked with several layers of trees that allow fires to climb easily into the canopy. Fires also can move freely across vast areas because the mosaic structure is disappearing as patches of trees grow to similar sizes. In 1988, a lightning fire that was declared a “prescribed fire” in Montana’s Scapegoat Wilderness escaped and burned 240,600 acres, including 40,000 acres outside the wilderness area. Millions of board feet of timber, ranch buildings, fence and hay were lost, and 100 cattle were killed (USDA Forest Service 1989). Wildfires blackened 1.5 million acres in eastern Oregon, eastern Washington, Idaho, Montana and portions of Utah and Nevada during the Summer of 1994. Two million more acres burned in 1996. Many of these fires burned hotter than would have been the case under natural conditions.
The mammoth wildfires that scorched nearly one-half of Yellowstone National Park during the summer of 1988 were significantly larger than any fire that occurred in Yellowstone in the past 350 years. Huge blocks of young trees regenerating on the burned areas, intermixed with dead trees, will grow older and thicker as a unit, becoming a vast unbroken mass of highly flammable fuel. This could create a new cycle of massive wildfires…
6.3 Endangered Species
The changes occurring in North America’s landscapes because of the removal of Indian management also affects endangered plants. The loss of biodiversity in the United States in some cases may be directly tied to past fire suppression policies of federal and state agencies (National Research Council 1992, Leach and Givnish 1996). Researchers who have recently conducted studies on rare and endangered animals and plants in different geographic regions are concluding that frequent fire is necessary to the health and maintenance of habitat for certain endangered biota (Boyd 1987, Soule and Kohm 1989). Fire suppression policies on public lands were based on a perception of fire as a destructive force without an understanding of the dynamics of fire and its ecological role in ecosystems, and therefore, constituted a real threat to the very resources they were intended to protect. Fire is now a universally accepted management tool in conservation biology (National Research Council 1992). Yet when prescribed burning programs are implemented, they are done with an inadequate understanding of the earlier role of American Indians in setting these fires and creating other kinds of human disturbances. For example, wildfires in the West often occur on a larger scale and are more destructive than the fires in aboriginal times.
In many cases natural disturbance alone, such as lightning, is not sufficient for reestablishing and perpetuating pre-European settlement vegetation patterns (Bonnicksen and Stone 1982a,b, 1985). The removal of American Indians from traditional economic and land management roles in the United States has created its own set of ecological consequences. To assess accurately the health of different ecosystem types requires a thorough understanding of the ecological role of aboriginal people in the dynamics of wild plant populations, communities and ecosystems. This may provide invaluable information for management of now rare and endangered plant and animal species. For example; rare and endangered animals such as the red-cockaded woodpecker (Picoides borealis), the northern spotted owl (Strix occidentalis caurina) and the great gray owl (Strix nebulosa) live in habitats that are no longer being maintained with indigenous burning regimes.
Indigenous burning regimes created a highly suitable habitat (forest structure and valuable food sources from insect and mammal populations) for the California spotted owl (Strix occidentalis), which is listed as a sensitive species (Verner et a1.1992). Its primary prey in the Sierra Nevada mountains is the northern flying squirrel (Glaucomys sabrinus), which lives in older stands within a forest mosaic, but the owl preys almost exclusively on dusky-footed woodrats (Neotoma fuscipes) in Southern California and lower elevations, which live in younger forests. In the Sierra Nevada, 82 percent of the spotted owl sites were found in mixed-conifer forests (Verner et al. 1992). This forest type cannot be maintained without frequent fires, many of which were set by American Indians during pre-European settlement times (Bonnicksen and Stone 1982a,b, 1985). Thus, the historical forests in which the owl lived were maintained, in part, because of the sophisticated ecological knowledge and management practices of American Indians…
9.3 Reintroduce Traditional Fires
The use of fire as a tool is the most dramatic way by which American Indians and other indigenous peoples influenced local environments. However, it was only one albeit critically important dimension of the overall strategies by which hunter-gatherers managed environmental resources - and in the process maintained what Europeans naively assumed was an “untouched wilderness.” As Pyne (1982:71) pointed out,
“It is often assumed that the American Indian was incapable of greatly modifying his environment and that he would not have been much interested in doing so if he did have the capabilities. In fact, he possessed both the tool and the will to use it. That tool was fire … without which most Indian economies would have collapsed.”
Traditional management practices are important today in a number of ways. They represent alternative examples of how people managed and, in a few cases and in more limited ways, still manage local resources - examples which cannot be automatically assumed as either appropriate or inappropriate to today’s concerns. In almost all instances they show how such strategies changed over time, particularly throughout recent historical times when placed under great external pressures. In a number of instances they provide comparative examples of how people in like regions acted on the environment (e.g., as hunting-gathering societies in temperate rainforests), as well as how unlike traditions acted (e.g., prairie bison hunters and, later, cattlemen). In addition, there are still aspects of traditional knowledge to be found (e.g., hunting strategies, varying uses of fire, fishing practices, plant cultivation) which remain locally important today.
It must be stressed that traditional technology, as with modern technology, is preeminently knowledge and not merely the sum total of tools and techniques that people now or in the past employed. Technology is thus knowledge used for both practical and scientific purposes. Complimenting this, traditional ecological knowledge concerns peoples’ understandings of environmental relationships, both those related to natural phenomena (e.g., weather, soils, animal behavior, and plant growth) and those influenced by human activities (e.g., hunting, trapping, burning, collecting plants, and other forms of cultivation). The only question in relating indigenous and scientific knowledge is whether such understandings can be shown to parallel or, in different but testable ways, challenge those of environmental science and practice.
Had American Indians not employed fires they would probably not have adapted at all. Academic as that question may be today, it is clearly the case that they would not have existed in such great numbers, and adaptations would have been far more precarious.
California provides one of the best records on both the extent and variability of burning practices in terms of the types of habitats and preferred resources involved (Blackburn and Anderson 1993; Lewis 1973). As on the Great Plains, California’s Central Valley was regularly, in some cases annually, burned during late summer and fall to influence the diversity and productivity of plants and animals. Similar frequencies and seasonal patterns of burning were carried out in adjacent and higher-elevation oak-grasslands. On the other hand, coastal and interior stands of chamise and mixed chaparral were burned to create and maintain a mosaic of young to mature stands of brush, most of which were burned in the late fall and others in early spring, depending upon the preferred resources and kind of plant-animal communities therein.
Sierra-Cascade forests were subjected to regular understory burning, which provided new growth, highly attractive to game, and which at the same time prevented the build-up of dense undergrowth, such as have threatened sequoia and ponderosa forests in this century. In contrast, coastal redwood forests were managed in quite different ways involving the much more limited burning of forest corridors, ridge tops and forest openings, or prairies. In similar ways, these patterns of burning were much more characteristic of what was carried out in the temperate rainforest regions of Washington and British Columbia - as well as functionally similar practices found in the western Canadian boreal forest.
Whereas today fire is generally viewed by the public as only destructive, it is recognized by environmental scientists - as it was by American Indians - as a multidimensional tool with one of its most important benefits being that it can be used to limit major conflagrations…
For American Indians it was not in the belated actions of “fighting fire with fire” but, rather, in the preemptive acts of using fire to preclude its most dangerous effects, whether natural or man-made. This is a new perspective - we need more fire rather than less - that the general public, conservation groups, and elected officials are finding extremely difficult to accept.
Again, Indigenous fire regimes were particularly significant in that they were not mere replications of natural fire regimes but involved important differences that we have already discussed in terms of seasonality, frequency, intensity, control, and the purposeful rather than the random selection of sites. Natural fires (i.e., primarily lightning ignitions) helped to create and maintain coarse grained mosaics, being variably important in different biomes. The additive effects of indigenous burning practices, however, created and maintained fine grain mosaics in many forest types. They also reduced the most disruptive effects of natural fires, as is especially evident in semi-arid environments, such as California which today is regularly subjected to fire storms in the absence of either indigenous or management fire regimes.
Because we have accumulated a body of scientific knowledge about the ecology of fire, we can now interpret the environmental significance of what has been learned from historical and ethnographic descriptions of indigenous uses of fire. At the same time, there are still knowledgeable people in parts of Alaska, western and northern Canada, northern Mexico, and isolated areas of the American West who still have understandings about the uses and consequences of managing resources by hunting, gathering, and burning. And, without trying to replicate overall systems within which fire was an important tool for American Indians at the end of the last century, we can consider and perhaps use those features which best suit conditions in the coming centuries…
9.5 Use Timber Harvesting to Simulate Historical Disturbances
The wildfire hazard already is extreme in parts of North America and it is likely to become worse. We must break up blocks of dense trees and heavy fuels by restoring forest mosaics like those that existed during pre-European settlement times. Thus, restoring the historical forest mosaic will reduce the size and destructiveness of wildfires while creating a variety of wildlife habitats that enhance biological diversity.
Without American Indian burning, lightning fires alone cannot be relied upon to restore and maintain native forest mosaics because they occur too infrequently to prevent fuels from building up and causing catastrophic fires (Bonnicksen 1990). The human agents of disturbance are no longer operating, so the effects of American Indian burning must be simulated using either prescribed fire or mechanical methods. As Dr. Leopold said in his 1983 letter to the U.S. Park Service, “A chain-saw would do wonders.” Sciencebased timber harvesting is the safest and most effective way to mimic Indian and lightning fires within an occupied landscape where prescribed fire is too dangerous. It can also be used to meet contemporary resource needs while still restoring an approximation of the historical forest ecosystem. That is, timber harvesting has the added advantage of creating jobs, producing wood, and generating revenue to pay for ecosystem management.
The deterioration of native forests caused by eliminating Indian fires and suppressing lightning fires during the past century demonstrates that diverse and healthy forests can only be sustained by active management. Prescribed fires can be used in many areas and lightning fires in a few areas. However, safety and liability concerns, especially in massive fire regimes, may prevent the widespread and frequent use of prescribed burning to thin forests and restore forest mosaics. A recent interest by Congress and the Environmental Protection Agency in regulating PM 2.5
(particulate matter less than 2.5 microns in diameter) under the Clean Air Act may further reduce opportunities to use prescribed burning. In addition, the density of understory trees is too high and the fuel loading too great in many forests to risk the use of prescribed fire.
Restoration-oriented timber harvesting is the safest and most effective way to restore the effects of fire in these forests. The need to retain living and dead parts of the current forest is an important part of timber harvesting and prescribed burning to mimic historical fires. It is especially important where native forests developed within a massive fire regime. Although massive fires in native forests killed most of the trees, they rarely destroyed all of the trees. Some dead trees were left standing after the fire and others lay in heaps on the ground. During the fire, winds often drove the flames along narrow paths, leaving behind stringers of scorched living trees. Occasionally the flames would leap over, or skip around, protected areas and leave groups of trees untouched. As a result, snags, fallen logs, and patches of live trees usually remained on the site after the fire passed. These remnants of the former forest provided habitat for wildlife and the foundation for a new forest.
Even-aged timber harvesting can mimic natural fires by leaving snags and fallen logs behind, and by creating openings shaped to look as if they were formed by fire. Patch cuts and group selection timber harvesting can mimic surface fires by producing small scale mosaics. Single tree selection can mimic single tree falls in uneven-aged forests composed of shade-tolerant trees. Snags and fallen logs should also be left behind when using these techniques. Thinning and prescribed burning also can keep the forest clear of debris and small trees. Low intensity prescribed fire may also be required following timber harvesting to more closely approximate the ecological effects of natural fires…
