Name:
Pinus contorta / Vaccinium cespitosum Forest
Reference:
NatureServe Biotics 2019
Description:
This association is found in the upper montane and subalpine zone of the Rocky Mountains from north-central Colorado to southern Alberta. It is more common near and east of the Continental Divide, but occurs in the Uinta Mountains of northern Utah and in Idaho. Elevations range from 2950-3120 m (9700-10,240 feet) in northern Colorado down to 950-1800 m (3100-5900 feet) in the northern Rocky Mountains. It typically occurs on cold, dry-mesic sites where cold air accumulates causing high diurnal temperature fluctuations often with frequent summer frosts and high daily maximum temperatures. Topography is flat to gently undulating or moderately sloping terrain typically occurring on valley bottoms, terraces, lower slopes, and benches with variable aspects, but also on steep canyon slopes and benches, plateau tops and adjacent upper slopes in the Uinta Mountains. Soils are typically well-drained, moderately deep, acidic, gravelly or non-gravelly sandy loam, loam, silt loam, silt or less frequently clay that are typically derived from a variety of noncalcareous parent materials. Ground cover is mostly litter, often with duff over 3 cm deep. The vegetation is characterized by a <i>Pinus contorta</i>-dominated tree canopy with <i>Vaccinium cespitosum</i> dominating or codominating the patchy to continuous dwarf-shrub layer. The tree canopy varies from moderately dense to nearly closed (40-90% cover) and is often composed solely of <i>Pinus contorta</i>. However, in some stands scattered <i>Abies lasiocarpa, Larix occidentalis, Picea engelmannii, Pinus albicaulis, Populus tremuloides</i>, or <i>Pseudotsuga menziesii</i> trees may be present, especially in the subcanopy. Some stands have tree saplings and scattered shrubs. <i>Vaccinium cespitosum</i> (indicator species) is usually dominates or codominates the dwarf-shrub layer. Other dwarf-shrubs may include low cover of <i>Arctostaphylos uva-ursi, Paxistima myrsinites, Ribes</i> spp., <i>Linnaea borealis</i> (on more mesic sites), or <i>Juniperus communis</i> and <i>Vaccinium scoparium</i> (drier sites). The herbaceous layer is sparse to moderately dense (to 30% cover) and is typically dominated or codominated by perennial graminoids such as <i>Calamagrostis rubescens, Danthonia intermedia, Deschampsia cespitosa, Carex geyeri, Carex rossii</i>, or <i>Festuca</i> spp. Forbs are generally have sparse cover but may be diverse. Mosses and lichens are common (5-20% cover) on some sites.
Accession Code:
urn:lsid:vegbank.org:commConcept:29077-{CDFB2BFD-2ED0-4D92-9ACB-6E3D5D5629FD}
Plot-observations of this Community Concept:
10
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