Name:
Picea engelmannii Forest Alliance
Reference:
Western Ecology Working Group of...
Description:
This forest alliance occurs in the upper montane or subalpine zone from the Oregon Cascades and Rocky Mountains, south into Arizona and New Mexico. Overall, this alliance is found in similar elevational ranges as Abies lasiocarpa, but occurs on sites either too cold or too dry for Abies lasiocarpa dominance. Sites include gentle to very steep mountain slopes, ridgetops, plateaus, basins, alluvial terraces and benches. All aspects are represented, but northerly and easterly aspects predominate, and southerly aspects are found only at higher elevations. Soils are variable, but often gravelly or rocky, relatively shallow with thick duff layers and sometimes high moss or lichen cover. Forests included in this alliance are dominated by Picea engelmannii. In early to mid-successional stands, other conifers can be dominant or codominant, but Picea engelmannii (or Picea engelmannii X glauca hybrids in western Montana) are the most abundant seedlings and saplings. Associates vary geographically. Common associated conifers can include Pseudotsuga menziesii, Larix occidentalis, Pinus contorta, Abies lasiocarpa, Pinus albicaulis, and Pinus flexilis. Pinus aristata, Pinus strobiformis, Picea pungens, and Abies concolor are common in southern stands. The shrub layer is often absent, but when present is often dominated by species of Vaccinium. Other common shrub species may include Acer glabrum, Cornus canadensis, Holodiscus dumosus, Juniperus communis, Linnaea borealis, Lonicera utahensis, Physocarpus malvaceus, Ribes spp., Shepherdia canadensis, Spiraea betulifolia, or Symphoricarpos albus. The herbaceous layer is often dominated by perennial forbs. Graminoids are generally sparse. Diagnostic characteristics of these forests are that the average tree canopy is greater than 60% cover with Picea engelmannii often codominant in the tree canopy as well as being the predominant conifer in the tree-regeneration layer alliance.
Accession Code:
VB.CC.20253.PICEAENGELMANNI
Plot-observations of this Community Concept:
0
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