Loss of the Original Ecosystems
Southern pine savannahs and open woodlands once dominated the southeastern United States, and may have totaled over 200 million acres at the time of European colonization. Longleaf pine communities characterized the Atlantic and Gulf coastal regions, and covered an estimated 60 to 92 million acres. Roughly one quarter of the longleaf communities also supported other pines such as loblolly, shortleaf, slash, and pond pine in various proportions depending on soil conditions, especially in transitional zones between the coastal plains and other physiographic regions.
Today, longleaf forests have declined to less than 3 million acres, of which roughly 3 percent remains in relatively natural condition. Little old-growth remains, and virtually no longleaf forest has escaped changes in the natural fire regime. Shortleaf pine was prevalent outside the range of longleaf, especially on dry slopes and ridges in the Interior Highlands and Oklahoma, and has declined considerably. In the precolonial forests, loblolly was present as a minor component of riparian hardwoods or in association with shortleaf in some upland interior forests.
Southern pine forests today are very different from precolonial communities not only in extent, but also in species composition, age, and structure. Original pine forests were old, open, contained a two-layered structure of canopy and diverse grass and forb groundcover, and were dominated by longleaf in the coastal plain, longleaf/shortleaf/loblolly in the Piedmont and interior highlands, and slash pine in south Florida. Much of today's forest is young, dense, and dominated by loblolly pine, with a substantial hardwood component and little or no groundcover.
Original longleaf communities in the Atlantic and Gulf coastal plains were first heavily impacted by exploitation for naval stores and then virtually eliminated by widespread logging and subsequent reproductive failure of longleaf pine. Naval stores industries harvested pine resin for the production of tar, pitch, and turpentine-commodities in high demand during colonial times. Pine woodlands were logged for lumber and conversion to agricultural fields. Impacts to easily accessible areas began with the arrival of Europeans, but technological developments of the 1800's, such as the copper still, steam power, and especially railroads, dramatically increased the rate and area of loss. In the late 1800's logging operations moved to the previously inaccessible interior forests of longleaf, shortleaf, and loblolly pines. For over a decade these operations removed a reported 3 to 4 billion board feet per year, and an estimated 13 billion board feet of longleaf was extracted in 1907 alone. This especially intense period of logging from 1870 to 1930 resulted in the loss of virtually all remaining old-growth forest in the southeast.
A common logging practice before the late 1800's was to leave a fair number of residual trees, including small trees, some of those infected with red heart fungus, and some that had been boxed for resin production. Cavity trees of red-cockaded woodpeckers probably were left in much higher proportion than their numbers, due to the likelihood of red heart infection and the abundant resin coating. These residual pines enabled the red-cockaded woodpeckers to survive the original devastation. Loss of residual trees in the twentieth century has been a major factor in the decline of woodpecker populations.
Fire Suppression
Precolonial fire frequencies in the southeast have been estimated at 1 to 3 years for the Atlantic and lower Gulf coastal plains, 4 to 6 years for the Piedmont and upper Gulf coastal plain, and 7 to 25 years for the southern Appalachians and interior highlands. Fire frequency increases with size of fire compartments, and natural firebreaks in the southeastern coastal plains were rare. Historically, fires were ignited by Native Americans and by lightning. Lightning was the primary ignition source shaping the evolution of these fire-maintained ecosystems, but Native Americans may have played a substantial role in maintaining them. Such maintenance vanished, of course, as Native Americans were all but eradicated by the diseases and aggression of incoming Europeans. Natural fire frequency also declined as fires were reduced in area because of roads, plowed fields, and other human-made firebreaks.
Europeans brought their perceptions of fire with them as they colonized North America. In Europe, fire was an integral part of traditional swidden agriculture (i.e., shifting cultivation) and was celebrated by peasants as a source of renewal. In contrast, urban intellectuals and authorities viewed fire as a destructive force. This view was rooted in a social context: controlling the use of fire could facilitate control of the populace by discouraging the nomadic system. Such socially constructed perceptions of fire impacted natural fire regimes in all of Europe's colonies.
In North America, after European settlement and prior to the mid 1800's, farmers burned the woodlands regularly to improve forage for free-ranging livestock. Burning the open woods decreased with the fencing of livestock in the mid to late 1800's, although many people continued to use fire in agricultural fields well into the 1900's. In the twentieth century, the rise of mechanical and chemical agriculture has replaced fire-based agricultural methods.
Active fire suppression began to be institutionalized in the southeastern United States between 1910 and 1930. Several factors influenced its rise. First was the existing bias against fire brought to this continent by European intellectuals. Then, in the late 1800's, fire suppression grew in response to the extreme intensity of fires burning the logged-over slash across the entire eastern United States. Fires in pine resin orchards were similarly intense and had been suppressed for some time to protect resin production. Fire was denounced by many ecologists as detrimental to southern pines rather than an integral or useful component of the natural system. Suppression of fire increased with the rise of pine plantations, a land use which began in the 1930's and 40's and continues to increase today. Fire suppression has severe and numerous impacts on southern pine ecosystems, including changes in tree species composition and forest structure. Longleaf pine cannot reproduce without access to the mineral soil, and will be replaced under fire suppression by other species of pines and hardwoods. Structure changes from two layers, a canopy and a diverse groundcover, to a multi-layered midstory and canopy and little or no groundcover. With increasing hardwood midstory, arthropod communities change in species abundance, species composition, and distribution on the substrate. Red-cockaded woodpeckers are directly and adversely affected by each of these changes.
Reproduction of longleaf pine has been severely restricted since the precolonial era, first because of the impacts of free-ranging hogs and more recently because of the absence of fire. A short period of reproduction took place after hogs were fenced and before fires were suppressed. Most second-growth longleaf in existence today is 70 to 100 years in age and reproduced naturally during this short period of opportunity. Reproduction of longleaf in the twentieth century has been, and still is, constrained by hardwood midstory developed as a result of fire suppression.
Detrimental Silvicultural Practices
Several silvicultural practices have been detrimental to red-cockaded woodpeckers, including short rotations, clearcutting, and conversion to sub-optimal pine species. Cutting of second-growth longleaf pines began during World War II and continues today. Removal of second-growth longleaf has exceeded growth by over 40 percent, and much of the remaining longleaf is aging without replacement.
The years following World War II also saw the rise of plantation forestry. Plantations of dense slash or loblolly pines covered over 12 million acres by the mid 1960's and over 15 million acres at present. Plantations typically have been under rotations of 35 to 70 years for sawtimber production and 20 to 40 years for pulp production, and industry has continued to shift from logs and poles to pulp. With technological developments such as chainsaws, the practice of leaving 'cull' pines that were infected with red heart fungus or boxed for resin production declined. These two practices-short rotations and the removal of all trees-had substantial negative impacts on the woodpecker populations that remained after the initial logging.
