Name:
Abies lasiocarpa - Picea engelmannii Forest Alliance
Reference:
Western Ecology Working Group of...
Description:
These upper montane or subalpine conifer forests occur in many of the mountainous areas of western North America, where they are often the matrix forests of the subalpine zone. They occur above the warmer and drier montane forests of the West, which are typically mixed-coniferous forests, but may extend down into the montane zone where there is cold-air drainage. Parent materials and soils are variable. Typically, soils are not deep, poorly developed and rocky. Tree canopy characteristics are remarkably similar across the wide distribution of the alliance. Abies lasiocarpa and Picea engelmannii generally are codominant, usually with higher density of Abies lasiocarpa in the smaller size classes, and with fewer, larger Picea engelmannii. In some stands, Picea engelmannii may be absent altogether, or Abies lasiocarpa may only occur as seedlings and saplings. Picea engelmannii will often be prominent on more moist sites or in more mature stands. Pinus contorta and Populus tremuloides are important seral species. Forest understories are highly variable across the range of this alliance and can be dominated by grasses, dry sedges, mesic forbs or shrubs (typically ericaceous). Important shrubs include Vaccinium spp., Menziesia ferruginea, Oplopanax horridus, Physocarpus spp., Linnaea borealis, Rubus parviflorus, Symphoricarpos albus, Spiraea betulifolia, Mahonia repens, Shepherdia canadensis, Acer glabrum, and Juniperus communis. Herbaceous layers are highly variable. Species that are important in individual associations include Arnica spp., Actaea rubra, Calamagrostis rubescens, Carex spp., Clematis columbiana, Clintonia uniflora, Cornus canadensis, Erigeron eximius, Coptis occidentalis, Xerophyllum tenax, Valeriana sitchensis, and Thalictrum occidentale. Diagnostic of forests in this alliance is that they are upland forests (non-flooded) with average tree canopy cover greater than 60%, and with Abies lasiocarpa being the predominant conifer in the tree-regeneration layer.
Accession Code:
VB.CC.17827.ABIESLASIOCARPA
Plot-observations of this Community Concept:
0
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