Name:
A.132
Reference:
EcoArt 2002
Description:
This subalpine forest alliance occurs locally in the mountains of the interior northwestern U.S. and adjacent southwestern Canada from the central and northern Rocky Mountains to the Sierra Nevada, Klamath and Cascades mountains. Elevations range from 2000-3200 m depending on latitude and geography. Landforms include ridgetops, mountain slopes, glacial trough walls and moraines, land- and rockslides, and cirque headwalls and basins. Sites may be nearly level to steep sloping, on all aspects. Subalpine stands typically occur where disturbance such as avalanche or fire has temporarily reduced more shade-tolerant tree species, whereas at treeline are found in mesic, protected pockets away from the extremely harsh environmental conditions. Substrates are generally lithic, well-drained, coarse-textured soils such as shallow, gravelly sands or loams derived from colluvium, glacial till and residuum. These forests are characterized by a coniferous tree canopy, 10-20 m tall, that is dominated or codominated by ~Pinus albicaulis$. Other tree associates, if present, vary by geography and elevation zones. Species include ~Picea engelmannii$ and ~Abies lasiocarpa$ in more mesic stands,~Pinus contorta$ and ~Pseudotsuga menziesii$ in the lower subalpine, ~Tsuga mertensiana$ in the Cascades, and ~Pinus flexilis$ in southern stands. A sparse shrub layer may be present consisting of juvenile trees and other woody species such as ~Juniperus communis, Ribes montigenum, Shepherdia canadensis, Symphoricarpos oreophilus$, and ~Vaccinium scoparium$. The herbaceous layer is typically sparse, but ranges from nearly absent to a moderately dense cover of graminoids with scattered forbs. Characteristic species include ~Achillea millefolium, Antennaria microphylla, Arnica$ spp., ~Carex geyeri, Carex rossii, Festuca idahoensis, Poa nervosa, Potentilla diversifolia$, and ~Solidago multiradiata$. Diagnostic of this alliance is a dense tree canopy dominated by ~Pinus albicaulis$.
Accession Code:
VB.CC.1092.A132
Plot-observations of this Community Concept:
0
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