Name:
Betula alleghaniensis / Ribes glandulosum / Polypodium appalachianum Forest
Reference:
Southeastern Ecology Working Gro...
Description:
This association includes high-elevation boulderfield forests of the southern Appalachians, strongly dominated by Betula alleghaniensis, with few or no other species in the canopy, and with other species indicative of high elevations. 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 elevations of 1370-1615 m (4500-5300 feet). It is known from the high elevations of the Blue Ridge from West Virginia south to eastern Tennessee and western North Carolina. This forest is distinguished by a closed to somewhat open canopy dominated by Betula alleghaniensis, occurring over angular rocks (0.25-1 m diameter) covered by thin soil, lichens, mosses or vines. The rocks may be almost totally covered by moss. Betula alleghaniensis in the canopy are often stunted and gnarled, with roots that may have grown to encircle the boulders. Tree density is typically less than that of the surrounding forests. Other species that may form a minor canopy component include Aesculus flava, Prunus pensylvanica, Sorbus americana, Acer spicatum, Picea rubens, Tilia americana var. heterophylla, Sambucus racemosa var. racemosa (= Sambucus racemosa var. pubens), or Quercus rubra. Tree windthrow is common, leaving patches of exposed mineral soil and gaps in the canopy. The shrub density is typically high but may vary between occurrences. Herbaceous cover is generally sparse because of thin, rocky soil, but herbs and mosses may cover the rocks and boulders. Characteristic species include, in the herb stratum, Oclemena acuminata (= Aster acuminatus), Eurybia chlorolepis (= Aster chlorolepis), Aconitum reclinatum, Cardamine clematitis, Carex aestivalis, Actaea podocarpa (= Cimicifuga americana), Claytonia caroliniana, Clintonia borealis, Dryopteris campyloptera, Dryopteris marginalis, Huperzia lucidula, Oxalis montana, Polypodium appalachianum, Streptopus amplexifolius, and in the shrub stratum, Acer pensylvanicum, Acer spicatum, Amelanchier arborea var. austromontana, Diervilla sessilifolia, Hydrangea arborescens, Ilex montana, Lonicera canadensis, Ribes glandulosum, Ribes rotundifolium, Rubus canadensis, Sambucus racemosa var. racemosa, Vaccinium erythrocarpum, and Viburnum lantanoides. Seepage areas are common, producing wet microhabitats with unique species assemblages (Chelone lyonii, Chrysosplenium americanum, Circaea alpina, Rudbeckia laciniata, Impatiens pallida, and Monarda didyma). This association is distinguished by being strongly dominated by Betula alleghaniensis, with few or no other species in the canopy, and with other species indicative of high elevations (e.g., Abies fraseri, Dryopteris campyloptera, Ribes glandulosum, Rugelia nudicaulis, Streptopus amplexifolius, Prunus pensylvanica, and Sorbus americana. On less extreme sites, generally at lower elevations in the Blue Ridge and adjacent montane ecoregions, a similar boulderfield forest is Betula alleghaniensis / Acer spicatum / Hydrangea arborescens - Ribes cynosbati / Dryopteris marginalis Forest (CEGL004982). Similar Betula alleghaniensis-dominated forests occur on glaciated rocky slopes in the upper mid-Atlantic and in the northeastern United States. The Betula alleghaniensis-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:
VB.CC.21884.BETULAALLEGHANI
Plot-observations of this Community Concept:
0
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