Name:
Abies lasiocarpa - Picea engelmannii / Clintonia uniflora Forest
Reference:
Western Ecology Working Group of...
Description:
This association is broadly distributed across the inland northwest and northern Rocky Mountains, where it is associated with a maritime component of climate. It occurs as far east as the Continental Divide in northwestern Montana and Alberta, extending only a few air miles to the east of this strongest of topographic breaks. This community occupies relatively moist (mesic) and cool sites having free air drainage and lacking frost pocket conditions. Elevations range from 1066 to 1710 m (3500-5600 feet). It occurs on slopes of all degrees of steepness and aspect orientation, though it is more likely to occur from toeslope through midslope positions (predominantly collecting positions). At the dry extremes of its distribution it is more strongly associated with protected positions such as concave slopes, moist depressions in gently sloping plateaus, stringers along perennial stream bottoms, toeslopes and northeastern aspects. It occurs on a variety of parent materials, as varying as granite, limestone, glacial-fluvial material, and volcanic ash caps. <i>Abies lasiocarpa</i> and <i>Picea engelmannii</i> dominate the tree canopy. The most important seral species are <i>Pseudotsuga menziesii, Larix occidentalis</i>, and <i>Pinus contorta</i>, however, their cover seldom exceeds 10-15%. Total tree canopy cover is generally in excess of 55% ranging to 75%. <i>Abies lasiocarpa</i> dominates the tree regeneration layer, whereas <i>Picea engelmannii</i> reproduction is more sporadic. The shrub layer ranges from low diversity and cover to extremely diverse and high in cover; the shrubs present are judged largely seral. Those of highest constancy include <i>Acer glabrum, Ribes lacustre, Lonicera utahensis, Rubus parviflorus, Symphoricarpos albus</i>, and <i>Vaccinium membranaceum</i>. The low-shrub component is well-represented by <i>Linnaea borealis, Spiraea betulifolia, Paxistima myrsinites</i>, and, in the northern portion of the type's range, <i>Vaccinium myrtillus</i>. The only graminoids consistently present are <i>Bromus vulgaris</i> and <i>Calamagrostis rubescens</i>; the latter species may be relatively abundant on early seral stands but with an increase in tree canopy cover it is less abundant. The forb component is relatively species-rich and abundant; cover of the diagnostic species <i>Clintonia uniflora</i> or <i>Tiarella trifoliata</i> generally does not exceed 20%. There are many other forbs with high constancy and the potential to have appreciable cover, including <i>Maianthemum stellatum, Arnica cordifolia, Thalictrum occidentale</i>, and <i>Eucephalus engelmannii (= Aster engelmannii)</i>; forbs merely with high constancy include <i>Orthilia secunda, Galium triflorum, Goodyera oblongifolia, Osmorhiza berteroi</i>, and <i>Viola orbiculata</i>.
Accession Code:
VB.CC.32215.CEGL005912
Plot-observations of this Community Concept:
0
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