The longleaf pine ecosystem is a temperate coniferous forest ecosystem found within the Southern United States. Spanning pine savannas, sandhills and montane forests, it includes many rare plant and animal species, and is one of the most biodiverse in North America. Once one of the largest ecosystems in North America, from Virginia south to Florida and west to Texas, it now occupies less than a quarter of the original range. Degradation of the ecosystem is partially due to excessive timber harvesting, urbanization, and fire exclusion. Although the ecosystem is heavily fragmented at present, it still carries a great diversity of plant and animal species, many of which are endemic. A range of techniques, including planting longleaf pine seedlings, introducing prescribed burning regimens, managing native ground cover, and controlling invasive species within the ecosystem, are used in attempting to preserve this threatened ecosystem.
Original range During the Ice Age, when the North American continental glaciers extended as far south as parts of the Ohio River, the climate was colder and drier; longleaf pine and associated species grew in coastal regions away from the ice, from Florida to Mexico. During the Holocene, the ice retreated, the climate became warm and dry, and the longleaf pine ecosystem established itself in its historical range. The longleaf pine ecosystem was first described in the early 1500s by the Spaniard Hernando de Soto, and in accounts by Native Americans recorded in journals of European explorers as well. Prior to intensive settlement this ecosystem consisted of 70 million acres (280,000 km2) of pure and 20 million acres (81,000 km2) of mixed longleaf pine stands; all together the total was 90 million acres (360,000 km2). The ecosystem extended from southeastern Virginia down to northern Florida over to eastern Texas, forming the dominant land cover in the coastal plain of these states. There is some doubt about the original extent due to lack of systematic data from the coastal regions of Florida to Mexico. There is, however, extensive literature from various explorers of southeastern North America dating as far back as 1608, when Captain John Smith recorded his accounts of the forest and the first exports of products from pines close to the new settlement in Jamestown, Virginia.
Role of fire The longleaf pine ecosystem is a fire climax community, that is "a plant and animal community that is limited by and adapted to an early successional stage by frequent fire disturbances". Fire destroys other pine species and hardwoods which would outcompete the longleaf pines. Before Europeans established themselves in the area, Native Americans set fires regularly in order to encourage the growth of plants eaten by game animals and to clear undergrowth for ease of occupation and movement in the forest. Wildfire, ignited by lightning from summer thunderstorms, also played a role in the ecosystem. Once lit by humans or lightning, fires burned across the landscape for days, weeks, and even months due to the lack of habitat fragmentation by roads, railroads, or cities.
Animal and plant diversity
The longleaf pine ecosystem is one of the richest habitats in North America, and its forest floor is one of the most diverse of its kind in the world. As of 2001, there are an estimated 27 federal endangered species and 100 species of concern that reside in the ecosystem. Some of the species in this ecosystem have limited range due to topography and climate of some regions of the system. The most notable species of the ecosystem are the longleaf pine, wiregrass, and red-cockaded woodpecker, all of which were found throughout the historic range. The longleaf pine (Pinus palustris) is characterized as having bushy clusters of 10 inches (25 cm) long needles and large 6 to 12 inches (15 to 30 cm) long pine cones. These pines are capable of growing 80 to 100 feet (24 to 30 m) tall with a diameter of 2.5 feet (80 cm) across, only in well suited soil. The longleaf pine is notable for its thick bark, which aids in the species' resistance to fire and to southern pine beetle outbreaks.
The grass species Carolina wiregrass (Aristida stricta), which is found in the northern portion, and southern wiregrass (Aristida beyrichiana), which is found in the southern portion, are the dominant grass species of the habitat. These grass species occur in clumps which measure 6 inches (15 cm) across and have flat leaves that reach 20 inches (51 cm) long. These wiregrass species play a key role in the reproduction and spread of the longleaf pine, as they help to carry fire across the land. The red-cockaded woodpecker (Picoides borealis) was once a common inhabitant of this habitat, but since the decline of the ecosystem it has been placed on the federal endangered species list. The woodpecker adults are characterized by being 7 inches (18 cm) long, with a black head, white cheek patch, and barred back with black and white stripes that give the appearance of a latter. In males, a red strip atop the head is only visible when young or up close. This woodpecker carefully selects longleaf pine, or associated pine species of the area, for heart rot disease. Once a tree is selected, excavation of a cavity is achieved usually taking 2 years to complete.
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