Name:
Pinus albicaulis Forest Alliance
Reference:
Western Ecology Working Group of...
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 Mountains and Cascade Range. 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.23779.PINUSALBICAULIS
Plot-observations of this Community Concept:
0
|
