High Mountain Stony Loam (mixed conifer)

Description

The Reference State is a description of this ecological site just prior to Euro-American settlement but long after the arrival of Native Americans. The description of the Reference State was determined by NRCS Soil Survey Type Site Location information and familiarity with relict areas where they exist. At the time of European colonization, what would have been observed on these sites would have primarily depended on the time since the last wildfire occurred. If fire had not occurred for about 100 years, a stand of mixed conifers including subalpine fir (Abies lasiocarpa), Douglas-fir (Pseudotsuga menziesii), and white fir (Abies concolor) would have been the dominant species occupying the site (1.1). The particular tree dominants would also sort out based on aspect exposure (Alexander 1985, 1988). The understory would have been relatively sparse under mature trees due to tree competition, overstory shading, and duff accumulation. Wildfire or insect outbreaks on particular tree species (1.1a) would have replaced these stands with a rich diversity of herb-dominated vegetation (1.2). In the absence of any major disturbance (1.2a, 1.3a, 1.4a, 1.5a), the vegetation would have progressed into more of a shrub-herb co-dominance (1.3), followed by the increasing presence of aspen (Populus tremuloides) first as seedlings and saplings (1.4), and later as mature aspen with mixed conifer seedlings (1.5). Ultimately the conifers would have outcompeted aspen, returning the climax vegetation (1.1). Wildfire (1.1a, 1.5b) would have been the primary disturbance factor prior to colonization, although periodic outbreaks of insects destroying particular tree species could reset the successional clock. Early successional stages were shorter in duration. A more complete list of species by lifeform for the Reference State is available in the accompanying tables in the “Plant Community Composition by Weight and Percentage” section of this document.

Submodel

Submodel

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