Name:
Betula alleghaniensis - Tilia americana var. heterophylla / Acer spicatum / Ribes cynosbati / Dryopteris marginalis Forest
Reference:
NatureServe Biotics 2019
Description:
This association includes boulderfield forests of the Southern Appalachians, with abundant <i>Betula alleghaniensis</i>, but in habitats that allow for more diverse canopies, including other species such as <i>Aesculus flava, Betula lenta</i>, and <i>Tilia americana var. heterophylla</i>. This community occurs in a cool, humid climate, on steep, rocky, northwest- to northeast-facing, middle to upper concave slopes, or in saddles between ridges, at moderate to high elevations (610-1220 m [2000-4000 feet]) of the Blue Ridge and possibly ranging into the Cumberland Mountains and adjacent Ridge and Valley and Appalachian Plateau provinces. It grows on bouldery talus and is often associated with small streams and seepage. <i>Betula alleghaniensis</i> in the canopy are often stunted and gnarled, with roots that may have grown to encircle the boulders. The canopy is much more open than the surrounding forest and tree windthrow is common, leaving patches of exposed mineral soil and gaps in the canopy. A woody layer of shrubs and vines is usually well-developed. Rooting opportunities for most herbaceous plants is limited because of the development of this community on periglacial boulderfields of blocky talus, thus herbaceous cover is only sparse to moderate. Typical shrubs and vines which are more abundant in this type than in other associations in this alliance include <i>Acer spicatum, Aristolochia macrophylla, Hydrangea arborescens, Parthenocissus quinquefolia, Toxicodendron radicans, Vitis</i> spp., <i>Ribes cynosbati</i>, and <i>Ribes rotundifolium</i>. <i>Dryopteris marginalis</i> is often an abundant herb. This type is conceptually similar to <i>~Betula alleghaniensis / Ribes glandulosum / Polypodium appalachianum</i> Forest (CEGL006124)$$, which is more restricted to more extreme boulderfield situations at high elevations (1370-1615 m [4500-5300 feet]). The association described here generally occurs at lower elevations in less extreme environmental situations and lacks species characteristic of high elevations. However, it ranges to higher elevations than the typical rich cove forests with which it shares canopy species. Similar <i>Betula alleghaniensis</i>-dominated forests occur on glaciated rocky slopes in the upper mid-Atlantic and in the northeastern United States. The <i>Betula alleghaniensis</i>-dominated periglacial boulderfields of the southern Appalachian Mountains are distinguished from the northern forests by the occurrence of Southern Appalachian endemic species, better developed shrub layers and slightly less species diversity.
Accession Code:
urn:lsid:vegbank.org:commConcept:33750-{7CEA006C-0547-4817-B406-04E909AFF194}
Plot-observations of this Community Concept:
21
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