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Limestone Valleys and Coves

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About the Limestone Valleys and Coves

The Limestone Valleys and Coves are a small region consisting of several disjoint pieces, located within the Blue Ridge of the Appalachians, towards the west of the southern end of that region. These areas begin in southwestern Virginia and extend well into Tennessee. Although this region is very small, it is markedly different from its surroundings in terms of topography, ecology, and present land use. This region was formed when the top layers of rocks were eroded, revealing limestone and dolomite underneath; these soluble rocks weathered much more quickly, forming a lower, flatter landscape than the surrounding mountains.

This region ranges from flat to rolling valleys and coves; approaching the surrounding mountains, there are broad, long footslopes, and broad alluvial fans where rivers and streams flow into this area. This region is underlain by limestone and dolomite, soluble rocks high in calcium. Soils here are formed on clay residuum resulting from these rocks being dissolved by rainfall. Both the flatter landscape and more neutral and nutrient-rich soils lead this area to be better-suited to Western agriculture than the surroundings.

This area was originally mostly forested, although there were also extensive wetlands in some of the valleys, such as Shady Valley, TN. Original forest cover here is not well known, but has been mapped as Appalachian oak forest, including mixed oaks, hickory, pine, tuliptree (Liriodendron tulipifera), birch, and maple. As with other areas formed on limestone soils, calcium-loving species such as maple and hackberry were probably more common, and others, such as beech, absent or uncommon.

Presently, this area is mostly utilized for agriculture, mostly small farms with pastureland or hay production. There is a small amount of tobacco production. Some forest remains, mostly on hills and slopes. This forest consists mostly of a mix of oaks, with some eastern white pine (Pinus strobus), eastern hemlock (Tsuga canadensis), tuliptree, sourwood (Oxydendrum arboreum), and dogwood. Drier sites, as well as early-successional communities on abandoned fields, often support pitch pine and Virginia pine. Fields here are often dominated by introduced grass species including fescue and witch grass.

In the north, this region is surrounded by the Southern Sedimentary Ridges, which have higher elevations, steeper topography (mostly in the form of long ridges), and more acidic, nutrient-poor soils. In the south, this region is surrounded by the Southern Metasedimentary Mountains, also higher-elevation and steeper, but more geologically diverse and with fewer long, unbroken ridges.

References

1. Griffith, G.E.; Omernik, J.M.; and Azevedo, S.H. "Ecoregions of Tennessee (Poster)", U.S. Geological Survey, Reston, VA (1998) Web.