Name:
Pseudotsuga menziesii Giant Forest Alliance
Reference:
Western Ecology Working Group of...
Description:
This giant conifer forest alliance occurs in maritime climate-influenced mountains from northern California to southern British Columbia. This region has mild winter temperatures, hot summers, and receives winter rain followed by summer drought. Drought stress is ameliorated somewhat by fog events in coastal stands and by summer rains in the north. Sites include mountain slopes and valley margins, with an increasing affinity for moist topographic positions away from the coast and southward. Elevations range from 0-1300 m. These forests are characterized by a multi-tiered canopy of Pseudotsuga menziesii, which is typically over 50 m in height. Other coniferous trees, such as Sequoia sempervirens, Abies concolor, Tsuga heterophylla, Thuja plicata, Pinus lambertiana, Pinus ponderosa, and Chamaecyparis lawsoniana, may be present in the upper tree layer, depending upon location and stand history. Common associates in the subcanopy are broad-leaved deciduous and evergreen trees, such as Umbellularia californica, Lithocarpus densiflorus, Chrysolepis chrysophylla (= Castanopsis chrysophylla), Cornus nuttallii, Betula papyrifera, Quercus garryana, Quercus kelloggii, Acer macrophyllum, and Taxus brevifolia. The forest understory is usually well-developed and species-rich, and can be dominated by either shrubs or a mixture of ferns and forbs. Common shrubs include Gaultheria shallon, Toxicodendron diversilobum, Rhododendron macrophyllum, Quercus sadleriana, Holodiscus discolor, Mahonia nervosa, Acer circinatum, Symphoricarpos albus, Lonicera hispidula, and Corylus cornuta var. californica. The herbaceous layer is usually dominated by shade-tolerant forbs and ferns, including Achlys triphylla, Trientalis borealis ssp. latifolia (= Trientalis latifolia), Asarum caudatum, Trillium ovatum, Oxalis oregana, Polystichum munitum, Adiantum pedatum, Maianthemum stellatum, and many others. Common graminoid species include Festuca occidentalis, Elymus glaucus, Bromus vulgaris, Luzula parviflora, and Xerophyllum tenax. Mosses and lichens can be abundant, covering trees, logs, or the forest floor. Diagnostic of this forest alliance is a tree canopy over 50 m tall that is dominated by Pseudotsuga menziesii.
Accession Code:
VB.CC.17959.PSEUDOTSUGAMENZ
Plot-observations of this Community Concept:
0
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