Dry-Mesic Calcareous Forests
This group of montane, mixed hardwood forests occupies submesic slopes and crests with warm (southeast to southwest) aspects and fertile soils weathered from underlying limestone, dolomite, calcareous sandstone, and calcareous siltstone. Habitats in western Virginia include valley sideslopes, lower mountain slopes, gentle crests, and ravines up to about 1,150 m (3,800 ft) elevation. Forests of this group are widely distributed in the Ridge and Valley province, more local in the Cumberland Mountains, and rare in the northern Piedmont Triassic Basin. Mixtures of sugar maple (Acer saccharum), black maple (Acer nigrum), white oak (Quercus alba), northern red oak (Quercus rubra), black oak (Quercus velutina), and hickories (Carya spp.) are typical. Another variant features co-dominance by white oak, chinquapin oak (Quercus muehlenbergii), white ash (Fraxinus americana), and hickories. Tulip-tree (Liriodendron tulipifera) is most abundant as an invader of logged stands. Understory and herbaceous vegetation varies from sparse to lush (especially on limestone sites), but is generally dominated by species characteristic of submesic soil moisture conditions, such as white snakeroot (Ageratina altissima var. altissima), hog-peanut (Amphicarpaea bracteata), common eastern bromegrass (Bromus pubescens), and common black cohosh (Actaea racemosa).
Dry-Mesic Calcareous Forests are readily distinguished from Rich Cove and Slopes Forests or Basic Mesic Forests by the absence of prominent mesophytic forbs such as blue cohosh (Caulophyllum thalictroides), broad-leaved waterleaf (Hydrophyllum canadense), or wood nettle (Laportea canadensis). Compared to Montane Dry Calcareous Forests and Woodlands, they occupy more mesic habitats and lack a strong component of xerophytic plants. Many stands of this group have been heavily cut over or destroyed for agriculture. In some cases, it appears that stands of this community result from the invasion of oak-hickory forests by more mesophytic species (especially sugar maple), perhaps as a result of long-term fire exclusion.References: Fleming (1999), Fleming and Coulling (2001), Fleming and Moorhead (1996), Fleming and Moorhead (2000).
Click on the images below to open a larger image in a separate window.
|Dry-Mesic Calcareous Forest on a limestone slope at the foot of Peters Mountain, Alleghany County (George Washington and Jefferson National Forests). Photo: William H. Moorhead III.|
|Enchanter's night-shade (Circaea canadensis ssp. canadensis) covers the forest floor under chinquapin oak (Quercus muehlenbergii) and white oak (Quercus alba) on a limestone ridge in the northern Shenandoah Valley. Near Cedar Creek, Frederick County. Gary P. Fleming / © DCR Natural Heritage.|
|Marginal wood fern (Dryopteris marginalis) dominates the herb layer of a rocky, dry-mesic limestone forest on the lower slopes of Back Creek Mountain near Hidden Valley, Bath County (George Washington and Jefferson National Forests). Gary P. Fleming / © DCR Natural Heritage.|
Three community types are supported by 49 quantitative plot samples (map). This is a modest sample size compared to the apparent extent of the group in the Ridge and Valley province. The full distribution and status of these types in western Virginia is not yet clear and needs additional inventory. Click on any highlighted CEGL code below to view the global USNVC description provided by NatureServe Explorer.
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