Name:
Pinus contorta - Populus tremuloides Forest Alliance
Reference:
Western Ecology Working Group of...
Description:
This mixed evergreen-deciduous forest alliance has been described on mountain slopes and plateaus in Utah. Sites occur on gentle to steep slopes on all aspects. Soils are derived from alluvium and colluvium. Seral forests included in this alliance are characterized by an open to moderately closed, mixed evergreen-deciduous tree canopy that is codominated by Populus tremuloides and Pinus contorta. Several other species of conifers may be scattered within the stands, including Pseudotsuga menziesii, Abies lasiocarpa, Picea engelmannii, Picea pungens, and Pinus flexilis. Younger stands typically have dense Populus tremuloides with Pinus contorta mixed in. As stands age, Populus tremuloides cover is slowly reduced until Pinus contorta becomes dominant. The understory is moderately dense to sparse and becomes sparser as Pinus contorta becomes more dominant. The short-shrub layer is often dominated by Juniperus communis or Symphoricarpos oreophilus. Other shrubs may include Arctostaphylos uva-ursi, Artemisia tridentata, Mahonia repens, Paxistima myrsinites, Rosa woodsii, Shepherdia canadensis, and Symphoricarpos albus. Scattered tall shrubs Amelanchier alnifolia and Prunus virginiana may be present. The relatively sparse herbaceous layer is a mixture of graminoids and forbs and is often dominated by Calamagrostis rubescens, Carex geyeri, Lathyrus lanszwertii, or Thalictrum fendleri. Other common graminoids include Bromus carinatus, Carex rossii, Elymus glaucus, Elymus trachycaulus, and Achnatherum occidentale (= Stipa occidentalis). Forbs, such as Achillea millefolium, Arnica cordifolia, Balsamorhiza spp., Fragaria vesca, Geranium spp., Lupinus argenteus, Osmorhiza berteroi (= Osmorhiza chilensis), and Potentilla spp., may be present. The exotic species Poa pratensis and Taraxacum officinale are common in livestock-impacted stands. Diagnostic of this forest alliance is the codominance of Pinus contorta and Populus tremuloides in the tree canopy.
Accession Code:
VB.CC.23827.PINUSCONTORTAPO
Plot-observations of this Community Concept:
0
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