Physiognomy and Structure: No Data Available

Floristics: In Pennsylvania, stands of this community type have a closed canopy of Acer rubrum and Picea rubens, with associates of Pinus strobus, Tsuga canadensis, Nyssa sylvatica, Betula alleghaniensis, Betula populifolia, Fraxinus nigra, and Larix laricina. The shrub layer is often dense and may include Ilex verticillata, Vaccinium corymbosum, Viburnum nudum var. cassinoides, Ilex mucronata (= Nemopanthus mucronatus), and Rhododendron viscosum. The herb layer is typically dominated by ferns and graminoids, particularly Carex trisperma, Carex folliculata, Glyceria striata, Osmunda regalis var. spectabilis, and Osmunda cinnamomea; Gaultheria hispidula, Coptis trifolia, and Viola spp. are frequent forbs. Well-drained hummocks may support mesophytes such as Maianthemum canadense and Trientalis borealis. Some pools may be dominated by bryophytes of the genera Sphagnum, Mnium, Fissidens, and Thuidium. Virginia examples are very small (<2 ha or 5 acres) and lack several species of pronounced northern distribution. Canopies are generally codominated by Picea rubens, Acer rubrum, and Tsuga canadensis, with Picea rubens usually the most abundant of the three. Betula alleghaniensis is the only other canopy tree recorded in plots. Shrub layers are very sparse, although Vaccinium angustifolium locally forms dense, low patches on better-drained hummocks and flats. Except in the more deeply flooded pools, herbaceous cover is moderately dense to dense. Variably dominant herbs include Glyceria melicaria, Osmunda cinnamomea, Viola cucullata, Carex leptalea, Impatiens capensis, Glyceria striata, and Packera aurea (= Senecio aureus). Other frequent or locally important herbs are Caltha palustris, Cardamine pensylvanica, Carex baileyi, Carex prasina, Carex stipata, Carex trisperma, Chelone glabra, Cinna latifolia, Platanthera clavellata, Veratrum viride, and Viola macloskeyi ssp. pallens. Well-drained hummocks and mounds may support extensive colonies of Dryopteris intermedia, Lycopodium dendroideum, Maianthemum canadense, Oxalis montana, Thelypteris noveboracensis, and Schizachne purpurascens. Species richness in five plot-sampled Virginia stands ranged from 39 to 55 taxa per 400 m2 (mean = 48).

In West Virginia, canopies are open to closed and dominated by Picea rubens, Tsuga canadensis, and Betula alleghaniensis var. alleghaniensis, with occasional additions of Acer rubrum, Fraxinus nigra, Abies balsamea, Pinus strobus, or Nyssa sylvatica. The shrub layers are characterized by Alnus incana ssp. rugosa, Rhododendron maximum, the regenerating canopy species, and occasionally Ilex verticillata. The herbaceous layer is diverse and variable. Herbaceous species with high constancy include Glyceria melicaria, Impatiens capensis, Osmunda cinnamomea var. cinnamomea, Chrysosplenium americanum, Polygonum sagittatum, Leersia oryzoides, Chelone glabra, Symplocarpus foetidus, Maianthemum canadense, Caltha palustris var. palustris, Onoclea sensibilis, Carex leptalea ssp. leptalea, Oxalis montana, and Dryopteris intermedia. Nonvascular plants are dominated by Sphagnum spp. carpeting the mucky hollows, Rhizomnium appalachianum in the seepy areas, and Hypnum imponens and Dicranum scoparium blanketing the woody hummocks. Mean species richness of all vascular plants and any nonvascular plants with cover >1% ranges from 29-61 (mean = 43) taxa per 400 m2, with nearly 20% of the diversity in the bryophyte layer.

Dynamics:  This is a small-patch woodland/forest community. It is maintained by seepage flow from surrounding upland forest, rainfall, and occasional low-energy stream overflow. Nutrient cycling occurs from the decay of fallen trees, litter, herbaceous vegetation, and overflow deposition/outwash.