Name:
Acer rubrum - Fraxinus nigra - Betula alleghaniensis / Veratrum viride - Carex bromoides Seep Forest
Reference:
NatureServe Biotics 2019
Description:
This community occupies groundwater-saturated stream headwaters, large spring seeps and runs, and lateral areas in ravine and stream bottoms where groundwater emerges at the base of slopes. It is most frequent and best developed on Catoctin Formation metabasalt (greenstone) of the Northern Blue Ridge and other base-rich substrates. Soil chemistry data indicate moderately high calcium and magnesium levels. Overstory composition is mixed, with <i>Acer rubrum, Fraxinus americana</i>, and <i>Liriodendron tulipifera</i> the most abundant species. <i>Fraxinus nigra</i> is a frequent overstory associate but more abundant and sometimes dominant in the understory, along with young <i>Acer rubrum</i> and <i>Fraxinus americana</i>. With increasing elevation, <i>Betula alleghaniensis</i> becomes increasingly important, codominating most stands above 760 m (2500 feet) in Virginia and in the Catoctin Mountains of Maryland. Minor tree associates include <i>Betula lenta</i> and <i>Tilia americana</i>. Canopy closure is often incomplete (mean stratum cover = 60-80%), most evidently because of blowdowns. Very wet microhabitats that impede the establishment and firm rooting of trees may also contribute to a somewhat open canopy. Shrub stratum diversity is moderately high; <i>Lindera benzoin</i> is usually the most abundant species, and considerable stratum cover is contributed by tree saplings. Other frequently occurring true shrubs are <i>Alnus serrulata, Carpinus caroliniana, Hamamelis virginiana, Ilex verticillata</i>, and <i>Sambucus nigra ssp. canadensis</i>. Except in local areas where shrubs are dense, herbaceous cover is high (mean stratum cover = 90%). One or both of the early-maturing forbs <i>Symplocarpus foetidus</i> (mostly at lower elevations) and <i>Veratrum viride</i> are usually dominant over substantial areas. Because of microtopographic diversity, herbaceous patch-mosaics are typical in this vegetation. More-or-less constant, sometimes locally abundant species include <i>Eurybia schreberi, Caltha palustris, Carex bromoides, Carex gynandra, Carex prasina, Chelone glabra, Chrysosplenium americanum, Cinna arundinacea, Dryopteris carthusiana, Dryopteris goldieana, Glyceria striata, Impatiens capensis, Osmunda cinnamomea, Osmunda regalis var. spectabilis, Ranunculus recurvatus, Saxifraga pensylvanica, Packera aurea, Sphenopholis pensylvanica, Thalictrum pubescens</i>, and <i>Viola cucullata</i>. Moss cover is often significant but only rarely includes <i>Sphagnum</i> spp. (not recorded in Virginia plots). Typical upland mesophytes commonly occur in well-drained hummock microhabitats and contribute to relatively high species-richness values for this type of wetland.
Accession Code:
urn:lsid:vegbank.org:commConcept:36483-{603299A2-59C3-4272-A673-B9553548D623}
Plot-observations of this Community Concept:
36
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