Southeastern Interior Longleaf Pine Woodland

This system encompasses the fire-maintained non-Coastal Plain woodlands and forests where Pinus palustris is a dominant or codominant canopy species. Its current range includes the outer Piedmont of Georgia and the Carolinas and various parts of Alabama, including the Talladega upland region (quartzite-slate transition) and the Cumberland Plateau, as well as, at least historically, the intervening Ridge and Valley. Examples occur on rolling to somewhat mountainous upland slopes in North Carolina, South Carolina, Georgia, and Alabama. They are believed to naturally be open woodlands with grassy ground cover, but many are now closed forests with dense shrubs or with little ground cover. Pinus palustris is either dominant, codominant, or present in circumstances that indicate former dominance or codominance. Pinus echinata, Quercus coccinea, Quercus falcata, Quercus marilandica, Quercus montana, Quercus stellata, and Quercus velutina are frequent associates, often codominating. Carya pallida and Sassafras albidum are also frequent trees. Some of the most frequently encountered grasses include Andropogon spp., Chasmanthium laxum, Danthonia spicata, Dichanthelium commutatum, Panicum virgatum, Piptochaetium avenaceum, Schizachyrium scoparium, and Sorghastrum nutans. Important forbs include Coreopsis major, Euphorbia corollata, Helianthus microcephalus, Pityopsis graminifolia, Solidago odora, Tephrosia virginiana, and the fern Pteridium aquilinum.

Vegetation consists of open woodlands or forests. Pinus palustris is either dominant, codominant, or present in circumstances that indicate former dominance or codominance. Pinus echinata, Pinus taeda, Quercus falcata, Quercus stellata, Quercus montana (= Quercus prinus), Quercus coccinea, and Quercus velutina are frequent associates, often codominating. Alteration of fire regimes and universal logging have made the natural condition of the vegetation somewhat uncertain. Almost certainly Pinus palustris was more abundant than it usually is at present, but very likely some component of other pines and oaks was present. Under conditions of frequent fire, understories and shrub layers were sparse and the grassy herb layer dense. Some of the most frequently encountered grasses include Andropogon spp., Chasmanthium laxum, Danthonia spicata, Dichanthelium commutatum (= Panicum commutatum), Panicum virgatum, Piptochaetium avenaceum, Schizachyrium scoparium, and Sorghastrum nutans. Some frequent forbs include Tephrosia virginiana, Solidago odora, and Pteridium aquilinum (Andrews 1917, Peet 2006). Other frequently dominant species, such as Piptochaetium avenaceum and Danthonia spicata, are not characteristic of Coastal Plain longleaf pine systems. Many other grasses and forbs are shared with the upland longleaf pine systems of the Coastal Plain. There is no evidence that Aristida stricta or Aristida beyrichiana were present in stands of this system, as these species are confined to the coastal plains. In remnant examples, where fire suppression has affected vegetation structure, the ground cover is often shrubby, with dense ericaceous shrubs leaving little space for herbs. Examples that have been burned recently often have ground cover dominated by shrubs and hardwood sprouts, with somewhat increased herb cover.

This system occurs in upland settings, which may range from gently rolling to rugged and mountainous. Geologic substrates vary. Most portions are dry, but occasional moist areas and seepage wetlands occur. The primary influence on the system is frequent fire, associated with a location near a fire-prone portion of the Coastal Plain or with other factors. Apparently once widespread along the Fall-line, remnants are now largely limited to two clusters, in eastern Alabama and adjacent Georgia and in south-central North Carolina. There are also examples on the Piedmont portion of the Sumter National Forest, on the Long Cane Ranger District and possibly on the Enoree Ranger District. The former occurs on rugged terrain associated with the extension of geologic belts of the Blue Ridge. The latter is on gently to moderately rolling topography of metasedimentary and volcanic rocks. Most common on the poorest soils in the Piedmont of eastern Alabama, Pinus palustris was "a prominent constituent of the upland forests of nearly every county" but, by the first half of the twentieth century, "grew too scattered to be logged economically" (Harper 1943). About 35% of the original forest there was estimated to have been evergreen; the most common pines were Pinus taeda, Pinus palustris, and Pinus echinata (Harper 1943). However, this estimate is likely to have been low, since much Pinus palustris logging, turpentining and regeneration failure had already occurred prior to Harper's time (J.M. Varner pers. comm.). Today, montane Pinus palustris occurs mainly on ridgelines and south to southwesterly slopes (USFWS 2005), but was previously found on nearly all upland sites surveyed in Coosa County, Alabama (Reed 1905). In northwest Georgia, Pinus palustris occurs above 300 m (1000 feet) elevation, and it occurs up to nearly 600 m (2000 feet) in Talladega County, Alabama (Harper 1905).

The dynamics of this system are strongly dominated by fire. The needles of Pinus palustris are an important fuel source for low-intensity fires. Fires probably once occurred at frequencies similar to those in the Coastal Plain but more frequently than in any other Piedmont ecological system. Evidence suggests fire frequencies of once every two to four years, with some annual fires (Bale 2009). Modern fire suppression has allowed Pinus taeda and Quercus spp. to increase in density, along with shrubs, and has resulted in the decrease in cover and diversity of the herb layer. Reproduction of Pinus palustris has been largely eliminated by the lack of fire, and the rooting of feral hogs (Sus scrofa). Where the canopy was also logged, Pinus palustris has often been completely eliminated, leaving the system indistinguishable from logged examples of Southern Piedmont Dry Oak-(Pine) Forest and Woodland (CES202.339). Because Pinus palustris and some of the canopy species naturally associated with it are fairly resilient to fire, and many have the ability to sprout, reintroduction of fire can return this system to its natural composition and structure, but this must be done gradually. Despite frequent fire, canopy dynamics were probably naturally dominated by gap-phase regeneration, with trees reproducing in small to medium-sized gaps created by wind storms and hot spots in fires. Pinus palustris is a long-lived tree, which continues to produce greater numbers of cones after age 100.

Lack of fire is probably the biggest threat. Without fire, the development of a closed forest canopy can lead to declines in the native herbaceous ground cover vegetation, reducing their contribution to the surface fuels which are needed for frequent fires. Feral hogs (Sus scrofa) have been known as a threat to Pinus palustris seedlings for over a century (Reed 1905). Conversion of Pinus palustris sites via harvesting is another clear threat. Clearcut logging of Pinus palustris and subsequent succession to mesophytic hardwood forest and conversion to intensively managed Pinus taeda plantations are common at extant sites. Often when sites have been replanted with Pinus taeda, the sites are no longer burned for forest management.

This system once occurred in parts of the mostly outer Piedmont, from central North Carolina to Alabama, where it extends into the adjacent Ridge and Valley in northeastern Alabama and northwest Georgia. More extensive areas are now largely, if not exclusively, restricted to south-central North Carolina (outer Piedmont) and eastern Alabama (Talladega upland), as well as the Cumberland Plateau and at least historically, the Ridge and Valley of Alabama. Smaller remnants are found in very limited areas of South Carolina and Georgia (such as Pine Mountain).