Southern Coastal Plain Dry Upland Hardwood Forest

This is one of three hardwood-dominated systems found in the East Gulf Coastal Plain and adjacent areas of central Florida. This type is found in the Southern Coastal Plain and Southeastern Plains (EPA Level III Ecoregion 75 and parts of 65). Examples attributable to this type are typically deciduous or mixed evergreen oak-dominated forests, often with a pine component present. Although the southern portion of the range of this system overlaps Southern Coastal Plain Oak Dome and Hammock (CES203.494), the latter is dominated by evergreen oak species, and the two should not be confused. The core range of this type extends northward to the approximate historical range of Pinus palustris; although most deciduous species do not mimic this range, this boundary does appear to be a reasonable demarcation boundary north of which Quercus alba becomes more abundant and south of which Quercus hemisphaerica is more diagnostic. Like all hardwood systems of this region, examples occur within a landscape matrix historically occupied by pine-dominated uplands and consequently this system only occurred in fire-sheltered locations in naturally small to large patches. Examples of this system tend to occur on sites intermediate in moisture status (mostly dry to dry-mesic), although occasionally very dry (xeric) stands may also be included. Toward the northern range limits of this system, it may have been less restricted to small patches in fire-protected locations, and may have been formerly more prevalent on the landscape even in areas heavily influenced by fire.

Important tree species vary geographically and according to previous disturbance. Quercus hemisphaerica is a typical species in many examples, with Quercus stellata, Quercus falcata, and Quercus alba less frequently encountered, but dominant in some stands. The overstory of some examples may be quite diverse, with hickories and other hardwood species often present. Typically mesic sites, as indicated by species indicative of these conditions (e.g., Fagus grandifolia), are covered under other systems. Pinus taeda is sometimes present, but it is unclear if it is a natural component or has entered only as a result of past cutting. Pinus glabra or Pinus echinata may also be present in some examples. Stands may be found on slopes above rivers and adjacent to sinkholes, as well as other fire-infrequent habitats including narrow bands between mesic slopes below and pine-dominated flats above.

Vegetation consists of forests dominated by combinations of upland oaks, particularly Quercus alba, Quercus falcata, Quercus stellata, Quercus margarettae, and other species. There is some variation between the composition of northern versus southern examples in which evergreen species such as Quercus nigra and Quercus hemisphaerica become more prominent. Carya tomentosa (= Carya alba) and Carya glabra may be present. There is some variation in composition with aspect and degree of exposure to fire. More mesophytic species such as Fagus grandifolia and Magnolia grandiflora are absent or are confined to the understory. Pinus echinata may be present in some stands, particularly on drier south- and west-facing slopes, but is typically not dominant. Pinus taeda is sometimes present, but it is unclear if it is a natural component or has entered only as a result of past cutting. Some examples of this system will have pine (Pinus echinata, Pinus glabra, Pinus taeda) as a natural component, where occasional fires may allow them to regenerate. In most examples, the understory is well-developed. A well-developed shrub layer may be present, with Vaccinium spp. and Gaylussacia spp. most typical. The herb layer is generally sparse; species richness tends to be low but may be richer if fire has played a role in shaping the structure and composition of the stand. The most likely grass taxa (found in open-understory examples) are Schizachyrium scoparium, Andropogon spp., Chasmanthium spp., Dichanthelium spp., and Danthonia sericea.

Topographically, these sites tend to occur on upper to mid slopes, but occasionally on broader uplands with reduced fire frequencies. A range of soils may be present from loamy and clayey to coarse sands, but are generally well-drained but not excessively drained. Soils are generally acidic, though calcareous soils occur occasionally. Sites are somewhat protected from most natural fires by steep topography and by limited flammability of the vegetation.

Sites where this system occurs almost invariably grade upslope into pine-dominated systems, especially stands containing Pinus palustris and, to a lesser extent, Pinus echinata. If these sites were burned more frequently, the vegetation would likely be replaced by more fire-tolerant southern pines. Fires that penetrate stands of this type are generally low in intensity and have fairly limited ecological effect. In general, more frequent or intense fire would move the vegetation on the site toward more fire-tolerant components. Conversely, with the prolonged complete absence of fire, less fire-tolerant species could invade, causing the vegetation to resemble the more mesic slope forests below.

Frequent surface fires occurred on a 4- to 8-year return interval from both lightning and Native American ignitions. These frequent light surface fires maintained the grassy understory and kept more fire-tolerant hardwoods and shrubs from capturing the understory and forming a midstory layer. Lightning fires occurred primarily during the spring dry season (April and May) with a secondary peak of Native American and settler burning during the fall (October and November) (Landfire 2007a). Occasionally, during extensive droughts, mixed-severity or stand-replacement fires did occur, especially in drier Pinus echinata-dominated stands. Local thunderstorms created gaps on a small but continual basis. More extensive regional disturbances included tropical storms during the growing season and ice storms during winter (in the northern part of the range). Dense stands of middle to older aged Pinus species (where present) were susceptible to periodic mortality from bark beetle epidemics (Landfire 2007a).

The most critical anthropogenic threats include removal of the characteristic dominant hardwoods and a lack of fire. Removal of the characteristic dominant hardwoods (primarily Quercus species and Carya species) through logging may result in a stand dominated by wind-blown or bird-dispersed tree species, including Acer rubrum, Celtis spp., Fraxinus americana, Juglans nigra, Juniperus virginiana, Liquidambar styraciflua, Liriodendron tulipifera, Prunus serotina, Robinia pseudoacacia, Sassafras albidum, Ulmus americana, and the exotics Albizia julibrissin, Vernicia fordii (= Aleurites fordii), and Melia azedarach. Sites may also be converted to Pinus species plantations. Lack of fire in the system leads to a closing of the subcanopy and consequent loss of ground layer diversity. Feral hog (Sus scrofa) activity, combined with invasion of exotic species, are also major threats. Another major threat is conversion to human-created land uses, including residential development, quarries, industrial development, and infrastructure development. The most significant potential climate change effects over the next 50 years include periods of drought, interspersed with more intense storms, which will affect the health and survival of the trees.

This system is found in the East Gulf Coastal Plain and adjacent areas of central Florida ranging northward into central Mississippi and Alabama.