High-Elevation Cove Forests
Protected, concave slopes and ravines at elevations from 1,070 m (3,500 ft) to about 1,460 m (4,800 ft.) on the highest mountains of Virginia support the mixed mesophytic hardwood or coniferous-deciduous forests of this ecological group. The elevation range extends somewhat lower, to around 900 m (3,000 ft), in the Allegheny Mountains. This is a group of very localized communities that are restricted in Virginia to the Mount Rogers - Whitetop Mountain area of the southern Blue Ridge, the highest elevations of the Ridge and Valley and Cumberland Mountains, and Allegheny Mountain in Highland County. Similar communities are found throughout higher elevations of the North Carolina and Tennessee Blue Ridge. Habitats are characterized by cool, moist microclimates and frigid, organic-rich soils. Soil fertility is variable and relates strongly to compositional variation within the group. Soils with moderately high levels of calcium, magnesium, and/or manganese support communities that are transitional between northern hardwood forests and rich cove forests of the lower elevations. Soils with low base status and somewhat higher organic matter content support species-poor forests dominated by acidiphiles.
Overstory dominants in richer high-elevation cove forests include sugar maple (Acer saccharum), yellow birch (Betula allegheniensis), basswoods (Tilia americana var. americana and var. heterophylla), American beech (Fagus grandifolia), white ash (Fraxinus americana), and yellow buckeye (Aesculus flava). Stands typically have lush herb layers with patch-dominance of mountain black cohosh (Actaea podocarpa), ramps (Allium tricoccum), filmy angelica (Angelica triquinata), evergreen wood fern (Dryopteris intermedia), two-leaf toothwort (Cardamine diphylla), blue cohosh (Caulophyllum thalictroides), Goldie's wood fern (Dryopteris goldiana), Canada waterleaf (Hydrophyllum canadense), wood nettle (Laportea canadensis), fringed phacelia (Phacelia fimbriata), clustered snakeroot (Sanicula odorata), southern red trillium (Trillium sulcatum), sweet white violet (Viola blanda), Canada violet (Viola canadensis var. canadensis), and other nutrient-demanding species.
High-elevation acidic cove forests typically have overstories of yellow birch (Betula alleghaniensis), eastern hemlock (Tsuga canadensis), and sometimes red spruce (Picea rubens), with dense shrub layers of great rhododendron (Rhododendron maximum). The herb layer is sparse and contains a number of northern species that are restricted to the higher elevations in Virginia.
References: Adams (1991), Fleming and Coulling (2001), Fleming and Moorhead (1996), Rheinhardt and Ware (1984).
Click on the images below to open a larger image in a separate window.
|High-elevation acidic cove forest along Laurel Fork in the Allegheny Mountains of Highland County (George Washington and Jefferson National Forests). Gary P. Fleming / © DCR Natural Heritage.||High-elevation acidic cove forest along Fox Creek, in the valley between Mount Rogers and the Iron Mountains, Smyth County (George Washington and Jefferson National Forests). Yellow birch (Betula alleghaniensis) dominates the overstory, while great rhododendron (Rhododendron maximum) forms a nearly continuous shrub layer. Gary P. Fleming / © DCR Natural Heritage.||A lush herbaceous assemblage species covers the floor of a high-elevation rich cove forest on Whitetop, Smyth County (George Washington and Jefferson National Forests). Photo: Gary P. Fleming.|
Three community types have been classified, based on analysis of 26 plot samples (map). All types in this group could benefit from additional inventory, quantitative sampling and analysis, in order to better identify their within-state distribution and range of compositional variation. Click on any highlighted CEGL code below to view the global USNVC description provided by NatureServe Explorer.
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