Name:
Pseudotsuga menziesii Middle Rocky Mountain Dry-Mesic Forest & Woodland Alliance
Reference:
NatureServe Biotics 2019
Description:
Stands of this alliance are <i>Pseudotsuga menziesii</i>-dominated forests and woodlands occasionally with <i>Juniperus osteosperma, Juniperus scopulorum, Pinus flexilis</i> (on calcareous substrates), <i>Populus tremuloides</i> (on disturbed sites), and <i>Pinus contorta</i> (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 shrubs such as <i>Cercocarpus ledifolius, Juniperus communis, Mahonia repens, Purshia tridentata, Spiraea betulifolia, Symphoricarpos albus</i>, and <i>Symphoricarpos oreophilus</i>. Common graminoids include <i>Calamagrostis rubescens, Carex rossii, Leucopoa kingii</i>, and <i>Pseudoroegneria spicata</i>. Forbs are variable, but typical taxa include <i>Arnica cordifolia, Thalictrum occidentale, Viola adunca</i>, and species of many other genera, including <i>Antennaria, Arenaria, Erigeron, Eriogonum, Lathyrus, Lupinus, Penstemon</i>, and <i>Vicia</i>. This alliance occurs on relatively dry to mesic sites throughout 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 often occurs at the lower treeline immediately above valley grasslands, or sagebrush steppe and shrublands. Stands are found on all aspects 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. Lower elevation stands typically occupy cooler, less xeric northern exposures often on steep slopes. At higher elevations, these forests occur primarily on southerly aspects or ridgetops and plateaus. 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 are typically well-drained and well-aerated. They can be derived from moderately deep colluvium or shallow-jointed bedrock, and are usually gravelly or rocky.
Accession Code:
urn:lsid:vegbank.org:commConcept:38747-{D3E17FCC-4D00-42B4-BD3F-F490F90E51B2}
Plot-observations of this Community Concept:
0
|
