Abstract for CNVC00030


Pseudotsuga menziesii - Tsuga heterophylla (Thuja plicata) / Paxistima myrsinites - Vaccinium membranaceum / Rhytidiopsis robusta

Douglas-fir - Western Hemlock (Western Redcedar) / Oregon Boxleaf - Mountain Huckleberry / Pipecleaner Moss
Douglas de Menzies - Pruche de l'Ouest (Thuya géant) / Pachistima myrte - Airelle à feuilles membraneuses / Rhytidiopsis robuste

This mature to old, coniferous forest association is found within the coast / interior climatic transition of the middle to leeward valley systems of the Coast and Cascade Mountains of British Columbia. The canopy is co-dominated by western hemlock (Tsuga heterophylla) and Douglas-fir (Pseudotsuga menziesii), with less cover of western redcedar (Thuja plicata). Pacific silver fir (Abies amabilis) and/or subalpine fir (Abies lasiocarpa) are often present in the canopy. Along with conifer regeneration, the shrub layer features Oregon boxleaf (Paxistima myrsinites), mountain huckleberry (Vaccinium membranaceum), and red huckleberry (V. parvifolium). The sparse herb layer typically includes common pipsissewa (Chimaphila umbellata), twinflower (Linnaea borealis), one-sided wintergreen (Orthilia secunda), Menzies' rattlesnake-plantain (Goodyera oblongifolia), and pink pyrola (Pyrola asarifolia). Stairstep moss (Hylocomium splendens), pipecleaner moss (Rhytidiopsis robusta) and red-stemmed feather moss (Pleurozium schreberi) along with some common freckle pelt lichen (Peltigera aphthosa) comprise most of the cover on the forest floor. Two subassociations are recognized: typic and Rhododendron macrophyllum (Pacific rhododendron). Pacific rhododendron dominates the understory in the subassociation of this name, occurring primarily in the Skagit River valley. CNVC00030 is distinguished from similar associations in this climate by its dry to mesic and nutritionally poor to medium soils occurring mostly on either steep slopes or coarse-textured glaciofluvial or fluvial materials. Fire and forest harvesting are the most prevalent stand disturbance agents.