Search this site:

Historical Perspective

To fully understand the ecology of southern terrestrial forested ecosystems today, a brief outline of the evolutionary changes of forested ecosystems in the South during the last 20,000 years is important (Bonnicksen 2000, Buckner and Turrill 1999, Delcourt and Delcourt 1998; also see chapter 2). At the height of the Wisconsian glaciation, southern forest communities were shifted further south than they are today. Oak-hickory, southern pine, and forested wetlands in particular were mostly restricted to the coastline of the Gulf of Mexico and the lower Atlantic Coast. Much of the interior, north of oak-hickory-southern pine dominated areas but south of the ice sheets, was dominated by spruce, fir, jack pine, and northern hardwood forest communities. The exact nature and condition of these forests and disturbance regimes are unknown, but the presence of large grazing herbivores and fire-adapted forest communities suggests that much of this forest land was relatively open and subject to regular disturbances (Bonnicksen 2000).

The distribution of southern forest communities began to resemble what we find today by 10,000 years before present. Spruce, fir, and northern hardwoods became restricted to the highest elevations in the Appalachians, and mixed hardwoods dominated the interior of the South. Southern pine and forested wetland communities spread northward as the glaciers retreated.

Thriving Native American communities existed over virtually all of the South, and they depended heavily on the surrounding ecosystems. Indigenous people impacted the landscape to suit their way of life. They often burned forests to drive game animals, cleared land for rudimentary agriculture, and enhanced habitat for both wildlife and people. Although cultures changed during this 10,000-year period from nomadic people to the larger and more permanent societies, human-induced disturbances were widespread throughout the region at all times during the period up until the first European contact (Bonnicksen 2000). The occurrence of these human-induced disturbances, combined with natural fires, storms, flooding, and grazing suggest the southern landscape was not composed of expansive closed canopied forests as is often suggested (Beilman and Brenner 1951, Hamel and Buckner 1998, Lee and Norden 1996).

Before European settlement, fire was a major force in shaping forest structure. Frost (1998) estimated fire frequencies at 1 to 3 years in Peninsular Florida and the lower Coastal Plain and 4 to 12 years in the Piedmont, upper Coastal Plain, Ozarks, Interior Low Plateaus, and Ouachita Mountains. The frequency of presettlement fire in the Appalachians was 7 to 25 years in most areas but 26 to 100 years in protective coves and in the Cumberland Mountains.

Only recently have scientists fully understood the importance of Native American burning in southern ecosystems. (Buckner and Turrill 1999, Delcourt and Delcourt 1997, Gross and others 1998, Williams 1998). The primary reason for this late understanding is that the Native American population when settlers arrived was vastly underestimated. Pandemics decimated Native American populations soon after Europeans arrived, and their influence on the southern landscape was reduced accordingly. Between 1500 and 1800, cultural disturbance regimes were severely altered. As a result, mosaics of forest and grassland types, including a variety of successional communities, became closed forests (Buckner and Turrill 1999). Pollen analysis of several old-growth forests in New England show that these forests developed after 1700; prior to that, these sites supported frequently disturbed communities (McLachlan and others 2000). The degree to which relict “old-growth” forest communities in the Southeast, especially what are thought to be relict hemlock stands, follow this same pattern is yet to be determined.

Despite the loss of human-induced disturbances from 1500 to 1800, explorers, naturalists, and settlers still reported expansive savannas and open woodlands in the Piedmont, Appalachians, and Interior Low Plateaus (Barden 2000, Bartram 1998, Belue 1996). In western North Carolina, Bartram in 1775 described both “high” forest (presumably closed stands) and expansive open areas, including grassy plains with scattered large trees at over 5,000 feet in elevation. Barden (2000) discusses the map made by the French cartographer Delisle in 1718 depicting the “Grande Savane” covering most of South Carolina's (and some of North Carolina's) Piedmont region. This map corresponds well with settlers’ descriptions in 1752 of “blackjack savannas” and the occurrence of many fire-adapted plants usually associated with prairies (Nelson 1992).

Several large tracts of native prairie existed in the Interior Low Plateaus (south-central Kentucky and adjacent Tennessee) and across the Coastal Plain in what is now Georgia, Alabama, Mississippi, and Arkansas. Two of the largest southern prairies on the Coastal Plain were the Blackbelt Prairie in the Central Gulf Region and the Grand Prairie within the Mississippi Alluvial Plain. All native prairies were perpetuated by fire.

Most of the pinelands on the Coastal Plain were burned periodically, reducing stand density and supporting a rich herbaceous layer of grasses and forbs. The influence of fire on southern forests is covered in detail in chapter 25 of this report. The habitat conditions in Eastern North America supported bison and elk herds, as well as wolves, during the first three centuries after Columbus.

By 1800, however, bison, elk, and gray wolves were extirpated in the South; beaver were nearly trapped out; and the influence of a temporary resurgent Native American influence was waning. As European-Americans spread across the South during the 1800s, they cleared forests for their settlements and agriculture on a larger scale than Native Americans had ever undertaken. Subsequent rapid population growth led to indiscriminate decimation of wildlife populations.

Under the “new management,” the frequency of burning increased. Many areas were burned annually to provide spring forage for ranging livestock. Especially in the Appalachians, the combination of increased frequency of fire and livestock grazing had many undesirable effects. Trees failed to regenerate and erosion increased on steep slopes (Ayers and Ashe 1905).

By the early 1900s, most old-growth longleaf pine had been logged. Most upland hardwoods outside the steep Appalachian Mountains had been logged and cleared for farming. Control of large predators to protect livestock severely reduced populations of several large predators, including mountain lions, black bears, and red wolves. Hunting and selling wildlife was common and had detrimental effects on white-tailed deer, bison, wild turkeys, passenger pigeons, Carolina parakeets, waterfowl, and others (chapter 1). Introduced plant diseases eradicated plant species from much of their native range, drastically reducing carrying capacity for many wildlife species (Diamond and others 2000) (chapter 3). Land was cleared for plowing over much of the South. Rice, tobacco, and cotton were major cash crops. Especially on marginal sites, farming led to massive and widespread soil erosion (Reynolds 1980).

As steam and gasoline powered machinery became available, large-scale drainage and flood control projects were completed. With flooding controlled and wetlands drained, over 30 million acres of bottomland hardwood forests were cleared for agriculture. By the 1940s, the last great bottomland forests, which were in the Mississippi Alluvial Plain and in Florida, were logged over in support of the War effort. Effects on wildlife were profound. For example, the last population of ivory-billed woodpeckers in the United States was destroyed. These changes impacted not only wildlife populations but also ecosystem resiliency. Immediately after clearing, these “new lands” were highly productive for agriculture, but many sites were depleted of nutrients after several years of cropping and erosion. Before agriculture and water control, these former forested wetlands benefited from annual soil nutrient deposition from flooding and high organic content from forest biomass. Draining and clearing compromised the natural soil recharge mechanisms. It has been demonstrated that bottomlands previously in agriculture are not as productive for forest growth as those that have remained in forests (Baker and Broadfoot 1979).

Due to difficult access, most steep mountain slopes were spared until the beginning of the 20th century. Then technology and transportation advances made steep mountainous slopes economically accessible. Logging practices changed from commercial high-grading, which was changing tree species composition, to commercial clearcutting, with little attention to sustainable practices. Between 1900 and 1930, most of the steep mountain slopes were logged, dramatically changing the nature of Appalachian forests.

During the first half of the 1900s, the amount of forested acreage was at its all time low; but the Great Depression, the boll weevil, diseases like tobacco mosaic virus, and the introduction of high-yield agriculture led to wide-scale abandonment of unprofitable farms. Through tree planting and natural seeding, abandoned agricultural fields and logged-over lands reverted to forest during the 1950s and 1960s. Southern forests recovered much of their lost acreage. As part of recovery efforts, use of fire was restricted and fire was suppressed. The use of prescribed fire, even where appropriate, became rare in the South (Croker 1987, Frost 1993). As a result, hardwood encroached into prairies and pinelands, and forests became denser all across the South. Fire suppression, extensive and unregulated clearcutting, and losses of important species like American chestnut to exotic diseases and pests, greatly altered forest conditions throughout the South.

Now, there is a growing realization that limiting fire use across the South has been detrimental to biotic diversity (Buckner and Turrill 1999; Frost 1995, 1998). However, increasing urbanization and increasing density of major roads create liability risks that may doom widespread prescribed burning for silvicultural purposes. In addition, recent industrial forest economic studies indicate that frequent burning causes some slowing of true growth rates.

Today there are more forested acres in the South than in the early 1900s. These forests, however, are greatly altered from forests encountered by European settlers. And the forests cleared by European settlers differed from those used for thousands of years by Native Americans. The common theme for the last 10,000 years is that forests were managed to meet human needs, including those of Native Americans.

Many of the forest wildlife and plant species now listed as endangered or threatened are suffering from the effects of changes in the last 500 years in conditions that existed for the previous 10,000 years. Lost forest acreage has been recovered over the last 50 years, but the new forests are not the same as those that existed for 10,000 years. Development activities and some management practices are not favorable for maintaining many species or for maintaining the integrity of southern terrestrial ecosystems.

One important lesson from the last 10,000 years of southern history, along with recent research results, is that “hands-off” management of extensive areas of southern wildland must be viewed and implemented with caution. Preservation of pristine and functioning ecosystems is an important conservation goal, but such situations are now very rare in the Southeast. Attempts to remove all human influences from some wildlands in the Southeast may appear to be an attractive conservation strategy. They certainly promote other nonconservation values, such as solitude and unique recreational opportunities. We should recognize, however, that removal of all human disturbances will have profound effects on the region's biota. Certainly, “hands-off” management in one area will not necessarily counterbalance intensive management elsewhere. To avoid regional population declines and species losses, land managers must have the flexibility to promote active management. This region's biota does not thrive in a static system, and intentional neglect does nothing but promote additional extinctions and endangerment to species at risk (for example, see Askins 2001, Barden 2000, Buckner and Turrill 1999, Cook 2000, Gross and others 1998, Holmes and Sherry 2001, Hunter and others 2001, Saenz and others 2001). This flexibility should not extend to the other extreme of promoting intensive forestry for wildlife conservation, but it does suggest that some level of active management will be necessary to maintain many still extant but imperiled species, including many found on present or proposed set-aside lands.