Name:
Tilia americana var. heterophylla - Aesculus flava - Acer saccharum / Cystopteris bulbifera - Asarum canadense Forest
Reference:
Description:
This association is currently known only from carbonate rock districts in the west-central and southwestern Virginia portions of the Ridge and Valley province, extending into peripheral areas on the flanks of the Southern Blue Ridge and Cumberland Mountains. Occurrences in limestone valleys of West Virginia, Kentucky, and Tennessee seem likely. Sites are restricted to mesic, fertile slopes underlain by limestone or dolomite, small outcrops, and loose talus which is often exposed. Habitats are usually situated on lower to middle slopes subtending streams in low-elevation (<700 m [2200 feet]) montane valleys, coves, and gorges. Slopes are steep to extremely steep (mean = 33°), usually with north to east aspects. Bedrock outcrops are frequent, and significant subsurface lateral seepage may occur seasonally at some sites. Substrate varies from site to site, but generally consists of a mosaic of deep colluvial soil and fine talus or scree that is somewhat to very loose and unstable. Soils collected from plot samples are circumneutral, with very high calcium, magnesium, and total base saturation levels. Stands have a variable overstory composition, with <i>Tilia americana var. heterophylla, Aesculus flava, Acer saccharum</i>, and <i>Fraxinus americana</i> consistently important. Other less constant or abundant trees that may be important in some stands include <i>Ulmus rubra, Carya cordiformis, Liriodendron tulipifera, Quercus muehlenbergii, Quercus rubra, Acer nigrum, Thuja occidentalis</i>, and <i>Celtis occidentalis</i>. On several unusually sheltered, north-facing slopes, <i>Tsuga canadensis</i> is a codominant in the canopy mix. The understory and shrub layers of this community tend to be open or sparse, but patches of <i>Staphylea trifolia</i> and <i>Lindera benzoin</i> are frequent, along with climbing lianas of <i>Aristolochia macrophylla</i>. The herb layer is lush and diverse, with an array of patch-dominants that vary both among and within stands. On rockier substrates, <i>Cystopteris bulbifera</i> is consistently abundant, often covering up to 50% of an individual plot sample. More-or-less constant herbs that achieve >10% in one or more plots include <i>Asarum canadense, Solidago flexicaulis, Osmorhiza claytonii, Actaea racemosa, Caulophyllum thalictroides, Laportea canadensis, Impatiens pallida, Polymnia canadensis, Hydrophyllum canadense, Jeffersonia diphylla, Thalictrum dioicum, Viola canadensis, Phacelia bipinnatifida, Dicentra canadensis, Dicentra cucullaria, Trillium grandiflorum, Delphinium tricorne, Stellaria corei</i>, and <i>Meehania cordata</i>. Other characteristic herbs that usually occur at low cover are <i>Arisaema triphyllum, Sedum ternatum, Cardamine concatenata, Polystichum acrostichoides, Hepatica nobilis var. acuta (= Hepatica acutiloba), Mitella diphylla, Asplenium rhizophyllum, Adiantum pedatum, Uvularia grandiflora, Prosartes lanuginosa, Prosartes maculata, Podophyllum peltatum, Carex albursina, Hybanthus concolor, Trillium sulcatum, Synandra hispidula</i>, and <i>Stylophorum diphyllum</i>.
Accession Code:
VB.CC.36549.CEGL006472
Plot-observations of this Community Concept:
28
|
