Name:
Pinus ponderosa Temporarily Flooded Woodland Alliance
Reference:
Western Ecology Working Group of...
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.17905.PINUSPONDEROSAT
Plot-observations of this Community Concept:
0
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