Common (Translated Scientific) Name: Douglas-fir / Thinleaf Huckleberry / Common Beargrass Forest

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This large-patch to matrix type is manifested as both a seral and climax type from central Idaho north to northern Idaho, eastern Washington, western Montana and southwestern Alberta, and it very probably will be identified for British Columbia. As a climax type this association is most prominent in west-central and central Montana forests. This association''s elevation range is rather broad, ranging from 1030 to 2015 m (3100-6600 feet). Virtually the whole of this appreciable elevation range can be realized in a given geographic area due to the type''s presence as both a seral and late-successional type. It occupies primarily south- through west-facing, moderate to steep slopes and is usually found on midslope to slope-shoulder positions. It also occurs on benches associated with broad ridges. Soils are well-drained and derived from a broad spectrum of parent materials, including glacial till and drift, both calcareous and noncalcareous sedimentary types, intrusive and extrusive igneous rock and metamorphic types, particularly quartzite. Ground surfaces have little or no bare soil or rock exposed. The canopy structure ranges from moderately open to closed (>60% cover) with Pseudotsuga menziesii being the dominant canopy tree, often joined by lesser amounts of Larix occidentalis and Pinus contorta (sites are beyond the cold limits of Pinus ponderosa for the most part). At its mid to upper elevation limits Abies grandis, Abies lasiocarpa, and Picea engelmannii may be minor components of the overstory and major components of the subcanopy. A tall-shrub layer is absent and even scattered individuals are rare. The short-shrub layer dominates the undergrowth with Vaccinium membranaceum being dominant, often exceeding 50% canopy cover. Spiraea betulifolia, Lonicera utahensis, Paxistima myrsinites, Amelanchier alnifolia, and Rosa gymnocarpa are the other high-constancy species of this layer. Dwarf-shrub layer species that occur with consistence include only Vaccinium scoparium and Mahonia repens. The herbaceous layer is generally relatively depauperate with the diagnostic species Xerophyllum tenax being strongly dominant (average cover reported by various studies ranging from 25 to 61%). Only two graminoids occur consistently and are well-represented in cover, Calamagrostis rubescens and Carex geyeri. Other forbs with moderate to high constancy include Arnica cordifolia, Arnica latifolia, Chimaphila umbellata, Orthilia secunda, Thalictrum occidentale, and Viola orbiculata; not all of these forbs have high constancy throughout the range of the type.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This association is the result of elevating to plant association status the Xerophyllum tenax Phase of the Pseudotsuga menziesii / Vaccinium membranaceum Habitat Type (Pfister et al. 1977); and, by recognizing Pseudotsuga menziesii dominance in the canopy layer, many seral stands of existing potential-based classifications have been drawn into this syntaxon (including those of the Tsuga mertensiana, Abies lasiocarpa, and Abies grandis Series) and considerably broadened the environmental parameters for the type.

Similar NVC Types: No Data Available

note: No Data Available