Name:
Tsuga heterophylla - Pseudotsuga menziesii / Rubus spectabilis Mesic Forest Alliance
Reference:
NatureServe Biotics 2019
Description:
These forests are characterized by a mixed canopy of <i>Tsuga heterophylla</i> and <i>Pseudotsuga menziesii</i> and can have a complex, multi-tiered structure of multiple age classes. <i>Thuja plicata</i> may codominate with <i>Pseudotsuga</i> and <i>Tsuga</i> on valley bottom sites with poorly drained soils, and <i>Tsuga heterophylla</i> is generally the dominant regenerating tree species. Other common tree associates include <i>Abies amabilis, Abies grandis, Alnus rubra, Picea sitchensis</i>, and <i>Taxus brevifolia</i>. Understory species are generally intolerant of drought. The shrub layer is commonly composed of <i>Acer circinatum, Cornus sericea, Gaultheria shallon, Mahonia nervosa, Menziesia ferruginea, Oplopanax horridus</i>, and/or <i>Rubus spectabilis</i>. The herbaceous layer is dominated by ferns, including <i>Athyrium filix-femina, Blechnum spicant, Gymnocarpium dryopteris, Polystichum munitum</i>, and /or <i>Pteridium aquilinum</i>. Moisture-loving forbs include <i>Oxalis oregana, Achlys triphylla</i>, and <i>Tiarella trifoliata</i>. This coniferous forest alliance occurs at low elevations (0-1500 m) in all the maritime-influenced regions of the Pacific Northwest, from north coastal California to the northern end of Vancouver Island, British Columbia. 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 alliance occurs where environmental conditions are moderated by the marine influence, with moderate drought and frost. Stands are best represented on lower slopes of the coastal ranges of the Pacific Northwest with high precipitation, long frost-free periods, and low fire frequencies. Stands of the alliance generally occur on very moist, water-receiving slopes, usually north-facing or otherwise protected sites that are subirrigated but well-drained. Soils remain wet year-round, but are not saturated, and are not wetland or riparian in nature. Diagnostic of this alliance is an upper tree canopy dominated by <i>Tsuga heterophylla</i> and <i>Pseudotsuga menziesii</i> and moist, well-drained sites.
Accession Code:
urn:lsid:vegbank.org:commConcept:38664-{BE6A0B4A-E66F-4DFC-93AF-8C65618D95AD}
Plot-observations of this Community Concept:
0
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