Common (Translated Scientific) Name: Western Red-cedar / Wild Sarsaparilla Forest

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This is a late-seral evergreen conifer forest found in the mid elevations in the Okanogan Highlands east of the Kettle Mountain crest in Washington and British Columbia, with outliers in Montana. It appears on stream terraces representing xero-riparian conditions and on lower slopes and benches, mostly below 1065 m (3500 feet) in Washington and 1220 m (4000 feet) in Montana. Its name reflects a potential vegetation. The existing vegetation is dominated by a closed canopy of Picea engelmannii, Thuja plicata, and Pseudotsuga menziesii trees. The undergrowth can contain scattered tall deciduous shrubs such as Acer glabrum and Alnus viridis ssp. sinuata. The short and dwarf-shrub layers have both greater diversity and cover than the tall-shrub layer, with Linnaea borealis and Cornus canadensis being the most constant and having appreciable coverages. The herbaceous component is characterized by a rich assortment of mesic site forbs, such as Aralia nudicaulis, Clintonia uniflora, Galium triflorum, Maianthemum stellatum, Tiarella trifoliata, and Prosartes hookeri; graminoids, with the exception of the highly constant Bromus vulgaris (or Bromus ciliatus), are a minor element.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Currently there are at least two conceptions of this type, one is that of a potential vegetation type identified by the mere presence and successful reproduction of Thuja plicata (Pfister et al. 1977, Williams et al. 1995); Williams et al. (1995) also recognize the type based on at least 10% cover of Thuja and less than 10% cover of Tsuga heterophylla. A modified cover type approach (as encouraged by the USNVC) is reflected by the approach taken in Waterton-Glacier International Peace Park (IPP); Thuja must comprise at least 25% of the cover of the upper canopy and Tsuga less than 25% of this stratum. Under the potential-vegetation concept a considerable number of seral tree species are capable of dominating the site, whereas with the IPP concept, primarily mature to late-seral and climax stages are recognized. In Montana this association was formerly recognized as a phase of the Thuja plicata / Clintonia uniflora Habitat Type (Pfister et al. 1977), but with accumulating compelling information linking this phase with particular environmental parameters, it is appropriate to recognize it at the association level, as exemplified by Williams et al. (1995). However, following intensive field sampling in IPP, it is deemed prudent to recognize Aralia nudicaulis as an indicator only at 1% or greater canopy cover; this contrasts with Pfister et al. (1977) and Cooper et al. (1987) who recognize its mere presence not confined to microsites as indicative. In contrast Williams et al. (1995) stipulate that 5% be present to recognize the type. Pfister et al. (1977) and Williams et al. (1995) also use Gymnocarpium dryopteris, Athyrium filix-femina, Asarum caudatum, Actaea rubra, and Cornus canadensis as alternative indicators for this association. All of these species are also used as indicators of other plant associations (both with and without Thuja as overstory indicator), and the first three are clearly indicative of more mesic environments or at least a more maritime climatic regime than reflected by the presence of Aralia nudicaulis.

Similar NVC Types: No Data Available

note: No Data Available