Name:
Tsuga heterophylla / Gymnocarpium dryopteris Forest
Reference:
Western Ecology Working Group of...
Description:
This association occurs as small, usually linear patches from Coeur d'Alene National Forest northward to northeastern Washington and northwestern Montana, west of the Continental Divide. This association is generally restricted to conditions of moisture accumulation and low insolation, i.e., sheltered slopes and toeslopes, alluvial bottoms and benches forming part of the meso-riparian zone. It shows no affinity for particular aspects due to sheltered positions and is perhaps subirrigated, at least until early summer. The elevation range is from 555 to 1370 m (1820-4500 feet). In northeastern Washington and northern Idaho, soils generally have an ash component overlying a mixed alluvium or colluvium derived from metasediments and glacial till. In Montana soils are derived from a variety of parent materials, though alluvium from sedimentary rock is common. Textures are silt, silt loam, loams and sandy loams. This mesic forest type varies widely in degree of canopy closure from nearly 100% in younger stands to open (less than 60% canopy cover) in stands that have experienced wind-throw, root-rot or underburns. This type can include all successional stages. Early seral stands can be dominated by other than Tsuga heterophylla or Thuja plicata; however, in late seral to climax stands these two conifers invariably dominate the canopy with specimens approaching 50 m (160 feet) in height. Long-persisting seral tree species include Abies grandis, Picea engelmannii, Pinus monticola (particularly in northern Idaho), Larix occidentalis, Pseudotsuga menziesii, and Betula papyrifera. The shrub layer is often relatively species-rich but not abundant and clearly subordinate to the herbaceous cover. Tall and mid-shrubs with the highest constancy and cover include Acer glabrum, Lonicera utahensis, Paxistima myrsinites, Rosa gymnocarpa, Rubus parviflorus, Taxus brevifolia, and Vaccinium membranaceum. Linnaea borealis is the only subshrub of note. Bromus vulgaris is consistently present in trace amounts. In addition to being 100% constant the herbaceous indicator Gymnocarpium dryopteris ranges in cover from 10 to 90% and averages around 25%. Other forbs of high constancy (>60%) and indicative of mesic or moister moisture levels include Adenocaulon bicolor, Asarum caudatum, Aralia nudicaulis, Clintonia uniflora, Tiarella trifoliata, Galium triflorum, Prosartes hookeri (= Disporum hookeri), Maianthemum stellatum, Trillium ovatum, and Viola orbiculata.
Accession Code:
VB.CC.23548.TSUGAHETEROPHYL
Plot-observations of this Community Concept:
0
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