Natural Resources
Conservation Service
Ecological site F136XY028GA
PROVISIONAL - Triassic Basin Upland Hardpan Forest, Thermic Temperature Regime
Accessed: 04/25/2024
General information
Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
MLRA notes
Major Land Resource Area (MLRA): 136X–Southern Piedmont
This area is in North Carolina (29 percent), Georgia (27 percent), Virginia (21 percent), South Carolina (16 percent), and Alabama (7 percent). It makes up about 64,395 square miles (166,865 square kilometers). (Ag Bulletin 296)
The northeast-southwest trending Piedmont ecoregion comprises a transitional area between the mostly mountainous ecoregions of the Appalachians to the northwest and the relatively flat coastal plain to the southeast. It is a complex mosaic of Precambrian and Paleozoic metamorphic and igneous rocks with moderately dissected irregular plains and some hills. (EPA Ecoregions descriptions)
ADD APPROPRIATE ECOREGION DESCRIPTION(S)
Classification relationships
A PROVISIONAL ECOLOGICAL SITE is a conceptual grouping of soil map unit components within a Major Land Resource Area (MLRA) based on the similarities in response to management. Although there may be wide variability in the productivity of the soils grouped into a Provisional Site, the soil vegetation interactions as expressed in the State and Transition Model are similar and the management actions required to achieve objectives, whether maintaining the existing ecological state or managing for an alternative state, are similar. Provisional Sites are likely to be refined into more precise group during the process of meeting the APPROVED ECOLOGICAL SITE DESCRIPTION criteria.
This PROVISIONAL ECOLOGICAL SITE has been developed to meet the standards established in the National Ecological Site Handbook. The information associated with this ecological site does not meet the Approved Ecological Site Description Standard, but it has been through a Quality Control and Quality Assurance processes to assure consistency and completeness. Further investigations, reviews and correlations are necessary before it becomes an Approved Ecological Site Description.
Ecological site concept
This ecological site occurs on upland sites in the thermic soil temperature regime of the Southern Piedmont MLRA. The site is associated with soils with high shrink-swell clays. The National Vegetation Classification reports that “this community occurs most commonly on mafic igneous rocks found in the Triassic basins in the Piedmont … . Examples may be found on flat uplands where diabase (and related rocks such as gabbro) form dikes or sills close to the surface and subsequent soil development has been affected. Typically, these areas develop dense subsurface "hardpans" and shrink-swell properties that limit plant rooting depth.” As a consequence, these sites are very dry much of the year, but this alternates with periods of saturated soils owing to the shrink-swell character of the clay. Even though the clays derive from base-rich rock, they are generally so highly weathered that pH and cation content tend to be relatively low.
Table 1. Dominant plant species
| Tree |
(1) Quercus stellata |
|---|---|
| Shrub |
Not specified |
| Herbaceous |
(1) Schizachyrium scoparium |
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