Name:
Betula occidentalis Shrubland
Reference:
Western Ecology Working Group of...
Description:
This shrubland occurs on stream benches and floodplains in narrow to moderately wide valleys and hillside seeps in the mountains and foothills across much of the western U.S. Surface water is present for extended periods during the growing season. The water table, after flooding ceases, is variable, extending from saturated to well below the ground surface. Substrates are typically alluvial and range from fairly shallow, finer-textured soils to gravel and boulders. Soils usually have signs of saturation (mottles). The vegetation is characterized by a nearly continuous tall-shrub to small-tree canopy dominated by Betula occidentalis along the streambank. Other shrub species include Alnus incana, Cornus sericea, Dasiphora fruticosa ssp. floribunda (= Pentaphylloides floribunda), Salix exigua, Amelanchier utahensis, Prunus virginiana, and Salix monticola. Along narrow valleys at higher elevations, conifers may overhang the stream edge. Herbaceous undergrowth can be limited because of the dense shrub canopy. However, if the shrub canopy is open and the stand is on relatively well-drained yet mesic site (for example, elevated river benches), the herbaceous layer can be abundant. It is often a diverse mixture of grasses and forbs that is dominated by disturbance-induced species, including most commonly Agrostis stolonifera, Cirsium arvense, Phleum pratense, and Poa pratensis. Native forb species include Maianthemum stellatum, Heracleum sphondylium, Thalictrum fendleri, and Rudbeckia laciniata. Graminoid cover is highly variable and can include the following species Carex utriculata, Carex pellita (= Carex lanuginosa), Carex microptera, Carex nebrascensis, Glyceria spp., Juncus balticus, and introduced hay grasses. Diagnostic of this association is the Betula occidentalis-dominated tall-shrub layer and a variable, weedy, herbaceous undergrowth that occurs on sites that are flooded for extended periods during the growing season.
Accession Code:
VB.CC.23688.BETULAOCCIDENTA
Plot-observations of this Community Concept:
0
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