Name:
Pinus contorta Seasonally Flooded Forest Alliance
Reference:
Western Ecology Working Group of...
Description:
This forest alliance occurs in upper montane, riparian or wetland areas in the Rocky Mountains and eastern Cascades, and on deflation plains of sea-level coastal dune systems in Oregon. Sites are flat, wet, relatively cold floodplain and basin landforms. Stands occur in forested margins of meadows, lake or forest basins, along valley bottoms and also occurs adjacent to or within open bogs. In all cases, the sites are flat to gently sloping. This coniferous forest alliance is characterized by a moderately closed to closed tree canopy composed primarily of Pinus contorta. Other conifers sometimes present may include Abies grandis, Abies lasiocarpa, Abies X shastensis (= Abies magnifica ssp. shastensis), Picea engelmannii, or Tsuga mertensiana. In most stands, only Pinus contorta is successfully reproducing, and cover of mature trees of the other species is low. The short-shrub layer, if present, is usually continuous and dense. Vaccinium uliginosum is the most frequent and dominant species in such a shrub layer, but other shrubs often present include Ledum glandulosum, Vaccinium caespitosum, Dasiphora fruticosa ssp. floribunda (= Pentaphylloides floribunda), Lonicera caerulea, or Spiraea douglasii. Herbaceous species are not abundant in shrubby stands. Associate species often present can include Carex angustata, Ligusticum grayi, Fragaria spp., Thalictrum occidentale, Geum macrophyllum, Maianthemum stellatum, and Trifolium longipes. In stands with no dense short-shrub layer, the herbaceous layer is typically lush and dominated by tall graminoids such as Calamagrostis canadensis or Carex obnupta. Diagnostic of this lowland forest alliance is the dominance of Pinus contorta in the moderately dense to dense tree canopy without significant regeneration of other tree species, and the extended flooding and high water tables during the growing season.
Accession Code:
VB.CC.18627.PINUSCONTORTASE
Plot-observations of this Community Concept:
0
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