Name:
Populus tremuloides - Pseudotsuga menziesii Forest Alliance
Reference:
Western Ecology Working Group of...
Description:
This mixed evergreen-deciduous forest alliance has been described on lower montane slopes and plateaus in western Wyoming, Idaho, Utah, and eastern Nevada. Sites occur on gentle to steep slopes on any aspect. Soils are derived from alluvium, colluvium and residuum from a variety of parent materials. Forests included in this seral alliance are characterized by an open to moderately closed, mixed conifer and deciduous tree canopy that is codominated by Pseudotsuga menziesii and Populus tremuloides. Several other species of conifers may be scattered within the stands, including Abies concolor, Abies lasiocarpa, Picea engelmannii, Picea pungens, Pinus contorta, Pinus flexilis, and Pinus ponderosa. Younger stands typically have dense Populus tremuloides with Pseudotsuga menziesii mixed in. As stands age, Populus tremuloides cover is slowly reduced until the conifer species become dominant. The sparse to moderately dense understory may be structurally complex and includes tall-shrub, short-shrub and herbaceous layers, or simple with just an herbaceous layer. If present, the tall-shrub layer may be dominated by Amelanchier alnifolia, Prunus virginiana or Acer grandidentatum, and short-shrub by Symphoricarpos oreophilus, Juniperus communis, or Mahonia repens. Where dense, the herbaceous layer is often dominated by graminoids such as Bromus carinatus, Calamagrostis rubescens, Carex geyeri, Elymus glaucus, Poa spp., and Stipa spp. The sparser herbaceous layers are generally a more even mixture of forbs like Achillea millefolium, Arnica cordifolia, Eucephalus engelmannii (= Aster engelmannii), Erigeron speciosus, Fragaria vesca, Geranium viscosissimum, Lathyrus spp., Lupinus argenteus, Osmorhiza berteroi (= Osmorhiza chilensis), and Thalictrum fendleri. Diagnostic of this forest alliance is the codominance of Populus tremuloides and Pseudotsuga menziesii in the tree canopy.
Accession Code:
VB.CC.20721.POPULUSTREMULOI
Plot-observations of this Community Concept:
0
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