Name:
Pinus contorta - Populus tremuloides Rocky Mountain Forest Alliance
Reference:
NatureServe Biotics 2019
Description:
This mixed evergreen-deciduous forest alliance has been described on mountain slopes and plateaus in Utah, Colorado and Wyoming. Seral forests included in this alliance are characterized by an open to moderately closed, mixed evergreen-deciduous tree canopy that is codominated by <i>Populus tremuloides</i> and <i>Pinus contorta</i>. Several other species of conifers may be scattered within the stands, including <i>Abies lasiocarpa, Picea engelmannii, Picea pungens, Pinus flexilis</i>, and Pseudotsuga menziesii. Younger stands typically have dense <i>Populus tremuloides</i> with <i>Pinus contorta</i> mixed in. As stands age, <i>Populus tremuloides</i> cover is slowly reduced until <i>Pinus contorta</i> becomes dominant. The understory is moderately dense to sparse and becomes sparser as <i>Pinus contorta</i> becomes more dominant. The short-shrub layer is often dominated by <i>Juniperus communis</i> or <i>Symphoricarpos oreophilus</i>. Other shrubs may include <i>Arctostaphylos uva-ursi, Artemisia tridentata, Mahonia repens, Paxistima myrsinites, Rosa woodsii, Shepherdia canadensis</i>, and <i>Symphoricarpos albus</i>. Scattered tall shrubs <i>Amelanchier alnifolia</i> and <i>Prunus virginiana</i> may be present. The relatively sparse herbaceous layer is a mixture of graminoids and forbs and is often dominated by <i>Calamagrostis rubescens, Carex geyeri, Lathyrus lanszwertii</i>, or <i>Thalictrum fendleri</i>. Other common graminoids include <i>Achnatherum occidentale, Bromus carinatus, Carex rossii, Elymus glaucus</i>, and <i>Elymus trachycaulus</i>. Forbs, such as <i>Achillea millefolium, Arnica cordifolia, Balsamorhiza</i> spp., <i>Fragaria vesca, Geranium</i> spp., <i>Lupinus argenteus, Osmorhiza berteroi</i>, and <i>Potentilla</i> spp., may be present. The invasive species <i>Poa pratensis</i> and <i>Taraxacum officinale</i> are common in livestock-impacted stands. Sites occur on gentle to steep slopes on all aspects. Soils are derived from alluvium and colluvium.
Accession Code:
urn:lsid:vegbank.org:commConcept:38061-{A15DCCFB-7662-462D-85AC-C38C785C7C0A}
Plot-observations of this Community Concept:
0
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