Name:
A.565
Reference:
EcoArt 2002
Description:
This alliance occurs on low-elevation, semi-riparian localities scattered throughout most of the Rocky Mountains, and west into the Columbia Basin of Washington and Oregon. Valleys vary from V-shaped to trough-shaped or broad and flat, and stream gradients are typically moderate. These woodlands can occur as broad, extensive stands on wider floodplain terraces or as narrow, long ribbons. Sites include mountain valleys, foothill ravines, terraces and alluvial benches of major streams and rivers. In southern Arizona, stands occur along smaller perennial streams and washes. Soils are cobbly, coarse-textured and derived from alluvium. Vegetation included in this semi-riparian alliance is characterized by an open canopy of the conifers ~Pinus ponderosa$ and often ~Pseudotsuga menziesii$. Other trees occasionally present include ~Populus balsamifera ssp. trichocarpa, Populus angustifolia, Acer negundo, Quercus$ spp., ~Juniperus deppeana, Juniperus scopulorum, Pinus edulis$, and ~Pinus discolor$ in southern stands. Composition and structure of understory vegetation vary greatly by geographic region. Typically a tall-shrub layer is present, with species such as ~Alnus$ spp., ~Betula occidentalis, Cornus sericea, Crataegus douglasii, Juglans major, Prunus virginiana, Quercus garryana$, or ~Salix$ spp. Some stands have a short-shrub layer that includes species such as ~Frangula betulifolia (= Rhamnus betulifolia), Holodiscus discolor, Rhus aromatica, Ribes$ spp., ~Physocarpus malvaceus, Rosa woodsii$, or ~Symphoricarpos$ spp. Woody vines are important in some stands, including ~Toxicodendron rydbergii$ or ~Vitis arizonica$. The herbaceous layer can be dominated by either graminoids or forbs. Graminoids can include ~Panicum bulbosum, Bromus ciliatus var. richardsonii (= Bromus richardsonii)$, and ~Pascopyrum smithii$. Forbs can include ~Geranium caespitosum, Galium$ spp., ~Pteridium aquilinum, Thalictrum fendleri, Potentilla$ spp., ~Achillea millefolium$, and ~Maianthemum stellatum$. Diagnostic of this semi-riparian alliance is ~Pinus ponderosa$-dominated woodland stands with brief seasonal flooding during the growing season.
Accession Code:
VB.CC.2209.A565
Plot-observations of this Community Concept:
0
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