Name:
Pseudotsuga menziesii Middle Rocky Mountain Mesic-Wet Forest Alliance
Reference:
NatureServe Biotics 2019
Description:
Stands are <i>Pseudotsuga menziesii</i>-dominated forests and woodlands; occasionally <i>Populus tremuloides</i> may codominate on disturbed sites ,and <i>Pinus contorta</i> may be present at higher elevations. True firs, such as <i>Abies concolor, Abies grandis</i>, and <i>Abies lasiocarpa</i>, are absent, but occasional <i>Picea engelmannii</i> can occur in some stands. <i>Pinus ponderosa</i> is also not common in this group. Understory components include relatively mesic species such as the shrubs <i>Acer glabrum, Amelanchier alnifolia, Linnaea borealis</i>, and <i>Physocarpus malvaceus</i>, and herbs and grasses such as <i>Achillea millefolium, Bromus carinatus, Eucephalus engelmannii, Fragaria vesca, Geranium viscosissimum, Lathyrus</i> spp., <i>Osmorhiza berteroi</i>, and <i>Piptatheropsis micrantha</i>. This alliance is restricted to mesic to wet sites in the middle Rocky Mountains of central and southern Idaho, the Greater Yellowstone region, and the Wind River, Gros Ventre and Bighorn ranges of Wyoming. It extends north into Montana on the east side of the Continental Divide, to the McDonald Pass area, and also into the Rocky Mountain Front region and central "sky island" ranges of Montana. This alliance occurs in the Central Rockies where the southern monsoon influence is less and maritime climate regime is not important. Climate is drier and more continental than at higher elevations or in the Pacific Northwest. Annual precipitation ranges from 50-100 cm with moderate snowfall and a greater proportion falling during the growing season. Monsoonal summer rains can contribute a significant proportion of the annual precipitation in the southern portion of the range. Elevations range from less than 1000 m in the central Rocky Mountains to over 2400 m in the Wyoming Rockies. Stands typically occupy cooler northern exposures in relatively moist sites such as lower slopes, benches and valley bottoms. Lower elevation stands occupy mesic ravines and canyons on northerly aspects. Soils are highly variable and derived from diverse parent materials, including extrusive volcanics in the Yellowstone region, and sedimentary rocks elsewhere in the Rockies. The soils can be derived from moderately deep colluvium or shallow-jointed bedrock, and are usually gravelly or rocky.
Accession Code:
urn:lsid:vegbank.org:commConcept:38748-{9AE8B2B3-A48C-420D-9EAF-5992FE1691B2}
Plot-observations of this Community Concept:
0
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