Name:
Tsuga heterophylla Giant Forest Alliance
Reference:
Western Ecology Working Group of...
Description:
This giant forest alliance occurs within the maritime climate-influenced region of the Pacific Northwest from northern California to southern Alaska, primarily west of the Cascade Crest. Stands of this alliance are best represented in areas of the coastal ranges with high precipitation, frequent fog, long frost-free periods, low fire frequencies, with only moderate drought and the majority of the annual precipitation arriving as rain. Annual precipitation is among the highest in temperate North America. Soils can vary widely, but growth is decreased on heavy soils or soils with poor drainage. These forests are characterized by a multi-tiered, mixed-species canopy over 50 m in height that is dominated by Tsuga heterophylla. Pseudotsuga menziesii is usually present and may approach 1000 years or more in age. Thuja plicata is commonly present in these forests and can be common on valley bottom sites with poorly drained soils. A secondary forest stratum of Acer macrophyllum or Taxus brevifolia may be present, especially at moist sites. In southern Oregon stands, Lithocarpus densiflorus or Chrysolepis chrysophylla (= Castanopsis chrysophylla) often occur. The tall-shrub layer may be dominated by Acer circinatum, Acer glabrum, Mahonia nervosa, Rhododendron macrophyllum, Rhododendron albiflorum, Vaccinium ovalifolium, Vaccinium membranaceum, Vaccinium ovatum, Gaultheria shallon, Holodiscus discolor, Rubus spectabilis, or Oplopanax horridus. The herbaceous layer is highly variable, often dominated with a rich mix of shade-tolerant, mesic forbs or ferns species such as Polystichum munitum, Oxalis oregana, Trientalis borealis ssp. latifolia (= Trientalis latifolia), Achlys triphylla, Gymnocarpium dryopteris, and Linnaea borealis. However, young stands are often understory depauperate. Diagnostic of this forest alliance is an upper tree canopy over 50 m tall that is dominated by Tsuga heterophylla.
Accession Code:
VB.CC.18401.TSUGAHETEROPHYL
Plot-observations of this Community Concept:
0
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