Common (Translated Scientific) Name: Laurel Oak - Willow Oak - Loblolly Pine Wet Flatwoods Group

Colloquial Name: Hardwood - Loblolly Pine Nonriverine Wet Flatwoods

Hierarchy Level:  Group

Type Concept: These are nonriverine wetland hardwood or pine-hardwood forests and woodlands of the Atlantic and Gulf coastal plains and the Mississippi River Alluvial Plain, ranging from southeastern Virginia to Texas. Stands occur in a variety of flat, wet habitats and are most frequently dominated by Quercus spp. (including Quercus laurifolia, Quercus phellos, Quercus pagoda, Quercus similis, and Quercus stellata). In the Atlantic Coastal Plain, Quercus michauxii, Quercus nigra, and Quercus virginiana are important components, In addition, particularly in the Gulf Coastal Plain, Pinus taeda is dominant or codominant. Pinus glabra may be present within its range. Other hardwoods, including Fraxinus pennsylvanica, Nyssa biflora, and Ulmus americana, may be present as well. Acer rubrum and Liquidambar styraciflua, which are often increased by timber removal or other soil disturbance, may be prominent in some examples. Sabal minor is abundant in the lower strata of some stands within its range. In the Mississippi River Alluvial Plain, which is outside of the typical range of pine, hardwoods are the sole dominants. These communities are generally known as "flatwoods," and are found on a variety of sites which are generally flat to very gently sloping, primarily Pleistocene terraces. These sites typically have poor internal drainage, often from strata in the soil that limit permeability (claypans, hardpans, etc.). This limited permeability of the soil contributes to shallowly perched water tables during portions of the year when precipitation is greatest and evapotranspiration is lowest. Conversely, during the dry season, there is very little available water, leading to seasonal droughtiness. The hydrologic regime is primarily influenced by rainwater (and groundwater in included depressions), rather than overbank flooding. In some cases the flatwoods are within the current floodplain, but the hydrology, soils and vegetation are dominated by flatwoods, rather than floodplain, characteristics. Soil moisture fluctuates widely throughout the growing season, partly as a result of included impermeable layers. Hydrologic conditions vary from saturated to very dry, a condition sometimes referred to as xerohydric or hydroxeric. Soils are primarily mineral but may have some organic matter or muck. In some areas (e.g., in the youngest Pleistocene terraces in the Upper West Gulf Coastal Plain of Arkansas), the local topography is a complex of ridges and swales, often in close proximity to one another. Ridges are typically drier than swales, which may hold water for varying periods of time. Within both ridges and swales, there is vegetation variability relating to soil texture and moisture and disturbance history. As a result of dry (xeric) conditions during the dry season (summer-fall), most sites with these communities burned frequently, and the characteristic physiognomy was woodland. In today''s landscapes, with reduced fire, most occurrences are forested.

Diagnostic Characteristics: The hydrology is nonriverine, with water coming from rainwater and (in depressions) groundwater rather than from overbank flooding. The environmental setting is wet flats with included depressions. Frequently burned sites have a woodland physiognomy, while most examples today are forested from lack of fire.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This group encompasses a range of hydroperiods, as is traditional for the vegetation commonly called "flatwoods." It is drier than basin swamps, which can occur in similar topography, and wetter than mesic or upland groups. The placement and classification of vegetation commonly called "flatwoods" depend on the length of the hydroperiod. Forests in this group represent this hydrologic variation, which helps define the component alliances. Some other flatwoods included in this group are wetter than most flatwoods but not as wet as basin swamps. The relative abundance and ecological role of Pinus taeda in examples of this group is dependent on its importance in the particular region. In the West Gulf Coastal Plain, Pinus taeda (with some Pinus echinata) may be a primary dominant in stands of this group. The description of NVC associations in this group is probably incomplete, and more information is needed. On the lower terraces of the East Gulf Coastal Plain, the most western parts of the region contain flatwoods vegetation dominated primarily by Quercus spp., whereas in the more central part of the region (sometimes called the "Louisiana Florida Parishes Spruce Pine Flatwoods Forest"), the vegetation is dominated by a mixture of hardwoods with Pinus glabra and Pinus taeda. Characteristic hardwoods include Magnolia grandiflora, Quercus laurifolia, Quercus michauxii, Quercus nigra, Quercus pagoda, and Quercus virginiana. Some important understory trees and shrubs include Crataegus opaca and Sabal minor (which may often be very abundant or dominant), with Arundinaria tecta (Smith 1996b).

Similar NVC Types: No Data Available

note: No Data Available