Common (Translated Scientific) Name: Virginia Pine - Post Oak / Running Serviceberry / Poverty Oatgrass / Pincushion Moss Woodland

Colloquial Name: Appalachian-Northern Piedmont Riverside Outcrop Woodland

Hierarchy Level:  Association

Type Concept: This community occupies exposed, xeric outcrops along high-gradient stretches of the New River in West Virginia and the Potomac River in Maryland and northern Virginia. It has an open to nearly closed canopy dominated by a mixture of evergreen conifer and deciduous tree species over a diverse understory of shrubs and herbs often with heavy ground cover by mosses and lichens. In West Virginia stands, the open canopy is dominated by about equal amounts of Juniperus virginiana var. virginiana and Pinus virginiana. Associated deciduous tree species include Quercus stellata, Fraxinus americana, Celtis occidentalis, Ulmus americana, and Cercis canadensis. The dense shrub layer includes Amelanchier stolonifera, Rhus copallinum, Rosa carolina, and Viburnum prunifolium. Vines include Toxicodendron radicans, Parthenocissus quinquefolia, and Vitis aestivalis. The exotics Ligustrum vulgare, Rubus phoenicolasius, Lonicera japonica, and Rosa multiflora may also be present. The herbaceous layer has high representation of grasses; species include Andropogon virginicus, Danthonia spicata, Leersia virginica, Melica mutica, and Piptochaetium avenaceum. The fern ally Selaginella rupestris may also contribute significant ground cover. Cover by mosses and lichens is variable and may approach 90%. The Potomac Gorge stands are woodlands or open forests of stunted trees (usually 7 m tall or less). The overstory may be strongly dominated by Pinus virginiana or by a mix of Pinus virginiana, Carya glabra, Quercus montana, Quercus rubra, and Quercus stellata. Fraxinus americana and Juniperus virginiana var. virginiana are minor, but constant, associates and are most often limited to the subcanopy, where Juniperus virginiana var. virginiana is often abundant. A sparse tall-shrub layer is present, with Chionanthus virginicus, Viburnum prunifolium, Amelanchier arborea, and Rhus copallinum most frequent. A short-shrub layer is often present and dominated by Vaccinium pallidum; Hypericum prolificum, Rosa carolina, and Amelanchier stolonifera are less frequent. The herbaceous layer is somewhat sparse to moderately dense, with Danthonia spicata the most abundant species, and Carex umbellata, Carex tonsa var. tonsa, Carex nigromarginata, Helianthus divaricatus, Comandra umbellata, Solidago ulmifolia, Eupatorium hyssopifolium var. laciniatum, Potentilla canadensis, Silene caroliniana, Stylosanthes biflora, Symphyotrichum patens, Dichanthelium laxiflorum, Dichanthelium depauperatum, Dichanthelium commutatum, Dichanthelium sphaerocarpon, Dichanthelium villosissimum, Houstonia caerulea, and Houstonia longifolia often present. Vines are occasional; Smilax glauca and Vitis aestivalis are the most frequent species.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This community was first described by Rouse and McDonald (1986) as a part of the "Appalachian river flatrock" community, by McDonald and Trianosky (1995) as sub-mesic Virginia pine woodland, and by Suiter (1995) and Suiter and Evans (1999) as Pinus virginiana - Juniperus virginiana - Quercus stellata woodland. McDonald and Trianosky (1995) identified communities described from other eastern states which are superficially similar to the community described here, but their ecology is related to fire and/or edaphic regimes rather than flooding. They suggested this community may be most similar to xeric Pinus virginiana woodlands in the vicinity of Great Falls on the Potomac River in Maryland. The community at Great Falls has been described as Pinus virginiana - Carya glabra - Quercus (rubra, stellata) / Chasmanthium latifolium (Thomson et al. 1999) and Pinus virginiana - Quercus stellata / Vaccinium pallidum / Helianthus divaricatus Forest (Lea 2000). In a previous report (Vanderhorst 2001b), this association was divided into a woodland type and a sparsely vegetated type, however, floristic similarities, small size of openings, and constant co-occurrence of these physiognomic expressions support recognition of just one woodland association. Two separate community types within this association at Camp Brookside were also recognized and described by Mitchem (2004). In 2007, as part of the NCR parks vegetation mapping project, ecologists at VDNH and WVNHP compared classifications of the New River and Potomac Gorge stands. They agreed that, both compositionally and environmentally, the vegetation of the two areas was very similar and should be treated as a single USNVC association. Plots of the Potomac Gorge vegetation were examined in a large regional dataset assembled for the NCR project and performed as a discrete group. However, the Maryland plots sampled by Lea (2000) are much more species-rich (n = 72) and contain more species typical of the adjacent oak-hickory forest ~Carya glabra - Quercus (rubra, montana) - Fraxinus americana / Viburnum rafinesqueanum Forest (CEGL006209)$$ than the Virginia plots sampled by VDNH (n = 35), in which Juniperus virginiana var. virginiana is also much more important. These differences may have resulted from the different purposes and protocols of the two studies.

Similar NVC Types: No Data Available

note: No Data Available