Common (Translated Scientific) Name: Western Larch / Bride''s Bonnet - Common Beargrass Forest

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: 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, Pedicularis racemosa, Orthilia secunda, Thalictrum occidentale, Trillium ovatum, and Viola orbiculata.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This association defines an extremely broad environmental range due to the relatively recent approach stipulated by the USNVC of defining as unique associations that would formerly have been subsumed within a number of different climax or potential vegetation types; in the case of this association it is a successional stage in environments as mild and wet (defining a Pacific maritime climatic influence) as those supporting Thuja plicata or Tsuga heterophylla / Clintonia uniflora associations (and permutations) to those of the lower subalpine zone characterized by Abies lasiocarpa / Clintonia uniflora, Abies grandis / Clintonia uniflora, Tsuga mertensiana / Clintonia uniflora, and even Picea engelmannii / Clintonia uniflora forest associations; however, by far the greatest proportion of this type is seral to ~Abies lasiocarpa - Picea engelmannii / Clintonia uniflora - Xerophyllum tenax Forest (CEGL005892)$$. That this association in fact occurs in the states and USFS sections listed derives from this writer''s interpretation of constancy/cover tables of various authors/publications; where Larix occidentalis is listed as a major seral species, the inference has been made that stands quite likely occur on the landscape where this species strongly dominates the upper canopy (often observed by this author throughout northern Idaho and western Montana). It should also be noted that this type is probably less common in zones where Thuja plicata and Tsuga heterophylla are the climax dominants because following disturbance in these environments the climax trees are quick to reclaim the site, i.e., they comprise a significant cover of the earliest forested successional stages. Considering Xerophyllum tenax and Vaccinium membranaceum as ecological analogues may be questionable when applied across the geographic ranges of these species; Vaccinium membranaceum is more broadly distributed, and thus this type could be recognized for northeastern Oregon, where little or no Xerophyllum occurs. The crosswalking for this type is incomplete, and it may well eventually be documented west of the Cascade Crest in Oregon, Washington and British Columbia.

Similar NVC Types: No Data Available

note: No Data Available