Name:
Larix occidentalis / Clintonia uniflora - Xerophyllum tenax Forest
Reference:
Western Ecology Working Group of...
Description:
This wholly seral, large-patch to matrix type occupies the relatively cold and dry environments across a number of climax tree series and associated geographic regions; the species defining these series include, but are not limited to, Thuja plicata, Tsuga heterophylla, Tsuga mertensiana, Abies grandis, Abies lasiocarpa, and Picea engelmannii. Thus this mesic type is found throughout the northern Rocky Mountains and may extend as far west as the Cascade Crest on environments characterized as foothills and montane to lower and even mid-subalpine. This association's possible elevation range is from 915 to 1800 m (3000-5900 feet), and regardless of the climax series in which it is found, it consistently occurs on south- through west-facing exposures. The range of parent materials is, with the exception of highly unusual substrates like serpentine, literally as great as possible types occurring in the northern Rocky Mountains and northernmost middle Rocky Mountains and may include some ultramafics east of the Cascade Crest. It is difficult to characterize the soils as well, but they are uniformly well-drained and have a low coarse-fragment content, except those sites within the lower to mid-subalpine zone. The overstory is dominated by Pseudotsuga menziesii with a whole host of tree species capable of playing a subordinate role; on warmer sites these include Thuja plicata, Tsuga heterophylla, Abies grandis, and on colder or higher elevation sites are found Abies lasiocarpa, Tsuga mertensiana, and Picea engelmannii. However the most frequent canopy codominants or associates are the seral species Larix occidentalis, Pinus contorta, and in a restricted portion of the type's range, Pinus monticola. The tall-shrub component is relatively unimportant, only Alnus viridis ssp. sinuata and Amelanchier alnifolia approach 50% constancy (and have low cover values). The short-shrub layer exhibits greater cover and diversity than the other shrub components with Vaccinium membranaceum, Paxistima myrsinites, Rosa gymnocarpa, Rubus parviflorus, and Spiraea betulifolia being consistently present. Linnaea borealis and Chimaphila umbellata have high constancy in the dwarf-shrub layer. Bromus vulgaris (or Bromus ciliatus) are the only graminoids of note. The diagnostic forbs Clintonia uniflora, Xerophyllum tenax, and Tiarella trifoliata naturally have high constancy and/or cover; however, a number of other forbs also exhibit high constancy, including Arnica latifolia, Aralia nudicaulis, Adenocaulon bicolor, Coptis occidentalis, Cornus canadensis, Galium triflorum, Goodyera oblongifolia, Maianthemum stellatum, Osmorhiza berteroi (= Osmorhiza chilensis), Pedicularis racemosa, Orthilia secunda (= Pyrola secunda), Thalictrum occidentale, Trillium ovatum, and Viola orbiculata.
Accession Code:
VB.CC.28076.LARIXOCCIDENTAL
Plot-observations of this Community Concept:
0
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