Name:
Populus tremuloides - Populus balsamifera ssp. trichocarpa / Osmorhiza occidentalis Forest
Reference:
Western Ecology Working Group of...
Description:
This association has been described from the foothills of the eastern slope of the Rocky Mountains in northwestern Montana. It is found on the bottoms of narrow mountain valleys, intra- and inter-morainal depressions, areas possibly underlain by clay lenses, and fringing kettle lakes, from 1372-1678 m (4500-5500 feet) elevation. These sites have gentle slopes and occur on all aspects. Sites on southerly aspects are typically moist mountain slopes where soil moisture is probably augmented by subsurface flow. Soils are derived from alluvium (some deposited by slopewash), colluvium, or aeolian materials derived from sedimentary rock types and layered over morainal drift. Soils are seasonally saturated and have relatively high organic matter. This forest association is dominated by the broad-leaved deciduous tree Populus balsamifera ssp. trichocarpa (= Populus trichocarpa), with Populus tremuloides usually present. Where both species are present, Populus balsamifera ssp. trichocarpa has at least 1-5% cover, and is the indicator species for this association. Occasional individuals of Picea engelmannii and Pseudotsuga menziesii occur, but seedlings of these species are rare. The understory is characterized by a low-shrub layer composed of patches of Symphoricarpos albus. Amelanchier alnifolia and Mahonia repens (= Berberis repens) occur in most stands, but are typically not abundant. The herbaceous layer is diverse, well-developed and composed of species indicative of mesic conditions. Important perennial forbs include Osmorhiza occidentalis, Heracleum maximum (= Heracleum lanatum), Actaea rubra, Galium triflorum, Viola canadensis, and Angelica arguta. Other forbs of high constancy are Thalictrum occidentale, Fragaria virginiana, Maianthemum stellatum (= Smilacina stellata), Geranium viscosissimum, Geranium richardsonii, and Packera pseudaurea (= Senecio pseudaureus). On sites that are transitional to those with permanently saturated soils, Equisetum arvense, Streptopus amplexifolius, and Calamagrostis canadensis become more important.
Accession Code:
VB.CC.27192.POPULUSTREMULOI
Plot-observations of this Community Concept:
0
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