Name:
Tsuga heterophylla Forest Alliance
Reference:
Western Ecology Working Group of...
Description:
This alliance occurs in all the maritime-influenced regions of the Pacific Northwest, from north coastal California to the Kenai Peninsula in Alaska and eastward to the Continental Divide in northwestern Montana. Throughout the range of this alliance, much of the annual precipitation occurs as rain. Where snow does occur, it can generally be melted by rain during warm winter storms. In all settings, this type occurs where environmental conditions are moderated by the marine influence, with moderate drought and frost. Stands of the alliance generally occur on all slopes and aspects, except for wet bottomland sites. It occurs on a wide variety of soil types across its range, but growth of Tsuga heterophylla is decreased on heavy soils, or soils with poor drainage. The geographic and environmental range of this type is wide and associated vegetation is correspondingly diverse. Along with Tsuga heterophylla, Pseudotsuga menziesii commonly shares the canopy, and Pinus monticola, Pinus contorta, Abies grandis, Abies lasiocarpa, Taxus brevifolia, or Picea engelmannii may be present. Thuja plicata is commonly present in these forests and can be codominant at sites which are wetter or drier than optimum for Tsuga heterophylla. In the interior (northern Rockies) stands, Paxistima myrsinites, Vaccinium membranaceum, Acer glabrum, and Spiraea betulifolia are common shrub species. In Cascades or Coast Range stands, Acer circinatum, Mahonia nervosa, Arctostaphylos nevadensis, Holodiscus discolor, and Oplopanax horridus are common associates. The composition of the herbaceous layer reflects local climate and degree of canopy closure. In moist stands with dense tree canopies, Polystichum munitum, Trientalis borealis ssp. latifolia (= Trientalis latifolia), Achlys triphylla, and Linnaea borealis are common forbs. In drier habitats, such as south-facing slopes, Pteridium aquilinum, Adenocaulon bicolor, or Xerophyllum tenax become more frequent.
Accession Code:
VB.CC.18125.TSUGAHETEROPHYL
Plot-observations of this Community Concept:
0
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