Name:
Pinus contorta Forest Alliance
Reference:
Western Ecology Working Group of...
Description:
This alliance is found in the upper montane and subalpine zone of most major mountain ranges of the western U.S., as well as forested dunes of the Oregon and northern California coast. Pinus contorta occupies the broadest array of habitats of any coniferous species in the western United States. Forests included in this alliance are characterized by a closed to moderately open tree canopy that is dominated by the conifer Pinus contorta. Stands may be even-aged or multi-aged depending on geographic location, edaphic characteristics, and how the stands were established following wildfire. Shrub and herbaceous layers may be present or absent depending on tree canopy. Other tree species, such as Abies grandis, Abies lasiocarpa, Picea engelmannii, Tsuga heterophylla, Tsuga mertensiana, or Pseudotsuga menziesii, may be present to abundant as seedlings and saplings. Associated shrub and herbaceous species vary across the range of this alliance. In the coastal dunes stands important species include Gaultheria shallon, Vaccinium ovatum, Rhododendron macrophyllum, and Morella californica (= Myrica californica). Herbaceous cover is very sparse. Common subalpine and montane shrub species include Arctostaphylos uva-ursi, Arctostaphylos patula, Arctostaphylos nevadensis, Ceanothus velutinus, Linnaea borealis, Mahonia repens, Purshia tridentata, Spiraea betulifolia, Spiraea douglasii, Shepherdia canadensis, Vaccinium caespitosum, Vaccinium scoparium, Vaccinium membranaceum, Symphoricarpos albus, and Ribes spp. The cover of the herbaceous stratum can be dominated by either graminoids or perennial forbs and tends to vary inversely with shrub cover. Important graminoids include Carex pensylvanica, Carex geyeri, Carex rossii, Calamagrostis rubescens, Danthonia californica, Elymus glaucus, or Achnatherum occidentale (= Stipa occidentalis). Important forbs are Arnica cordifolia, Chimaphila umbellata, Orthilia secunda, Osmorhiza berteroi (= Osmorhiza chilensis), Pedicularis racemosa, Xerophyllum tenax, and Thalictrum spp. Diagnostic of this upland forest alliance is the dominance of Pinus contorta in the tree canopy without significant regeneration of Abies lasiocarpa or similar shade-tolerant species.
Accession Code:
VB.CC.17849.PINUSCONTORTAFO
Plot-observations of this Community Concept:
0
|
