Name:
Acer saccharum - Tilia americana / Staphylea trifolia / Dryopteris marginalis - (Impatiens pallida) Forest
Reference:
NatureServe Biotics 2019
Description:
This association occurs in the Central Appalachians of Pennsylvania, Maryland, northern Virginia, and probably northeastern West Virginia, extending eastward locally in the Piedmont. It is associated with steep, usually stream- or river-fronting slopes covered by rocky colluvium weathered from various calcium-bearing sedimentary, metasedimentary, and igneous bedrock, including the Sykesville metasedimentary melange, hornblende tonalite, metapyroxenite, metabasalt, mica schists, phyllite, calcareous shale, limestone, and dolomite. Substrates vary from stable, large-block boulderfields to fine talus and unstable, loose scree. Surface substrate in 16 plots averaged 15% bedrock cover and 42% cover of boulders and large rocks. North and east aspects prevail among these plots. Colluvial soils are strongly calcareous and frequently restricted to interstices among rocks but may form deeper deposits where microtopography permits. Vegetation is a rich mesophytic forest with the overstory consisting largely of <i>Tilia americana</i> (mostly <i>var. americana</i> but occasionally <i>var. heterophylla</i>), <i>Fraxinus americana</i>, and <i>Acer saccharum</i>. <i>Acer nigrum</i> is also codominant in a few localities. Minor overstory associates include <i>Carya cordiformis, Ulmus rubra, Celtis occidentalis, Quercus rubra, Liriodendron tulipifera, Quercus montana</i>, and <i>Quercus muehlenbergii</i>. Because of frequent blowdowns and canopy gaps induced by the continuous, often unstable substrates, stands tend to be somewhat open to very open. <i>Staphylea trifolia</i> is constant and abundant in the shrub layer. Other characteristic small trees, shrubs, and vines that may achieve high cover are <i>Asimina triloba, Ostrya virginiana, Toxicodendron radicans, Parthenocissus quinquefolia</i>, and <i>Hydrangea arborescens</i>. Density of herbs varies seasonally, as well as with rock cover and available microhabitats. Spring ephemerals, especially <i>Cardamine concatenata</i> and <i>Dicentra canadensis</i>, are fairly common in most stands, while dense colonies of <i>Impatiens pallida</i> overwhelmingly dominate the late-season aspect of some stands. Other herbs that occurred in half or more of plot samples are, in descending order of constancy, <i>Dryopteris marginalis, Eurybia divaricata, Arisaema triphyllum, Asarum canadense, Polystichum acrostichoides, Solidago flexicaulis, Maianthemum racemosum ssp. racemosum, Hydrophyllum virginianum</i>, and <i>Actaea racemosa</i>. Less constant herbs that may be important locally include <i>Arabis laevigata, Cystopteris bulbifera, Pilea pumila, Polymnia canadensis, Sanguinaria canadensis, Symphyotrichum cordifolium</i>, and <i>Thalictrum dioicum</i>.
Accession Code:
urn:lsid:vegbank.org:commConcept:35109-{3E1386CC-901E-4E32-871E-CBEF2627D6ED}
Plot-observations of this Community Concept:
16
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