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A.552 | EcoArt 2002
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Name: A.552
Reference: EcoArt 2002
Description: This widespread coniferous woodland alliance occurs across the western U.S., typically on relatively poor sites for tree growth. Environmental factors, such as harsh substrate, desiccating winds or frequent disturbances that limit the tree canopy density, vary geographically. Stands are typically restricted to hot, dry slopes with southern and western exposures at higher elevations and latitudes. At lower elevations and latitudes stands are found on relatively mesic northern aspects. Where there is adequate moisture to develop a closed tree canopy, shallow rocky soils, talus and scree have so little moisture-holding capacity that these sites are effectively very dry for plant growth. Other harsh substrates, such as serpentine, or frequent disturbance from fire may also limit tree canopy development. Substrates are typically shallow, lithic, course-textured and well-drained. Woodlands included in this alliance have a sparse to moderately dense canopy, or may occur as patchy stands that are dominated by ~Pseudotsuga menziesii$. Other trees in the canopy and subcanopy may include ~Pinus ponderosa, Tsuga mertensiana$ or ~Quercus chrysolepis$ in Oregon, and ~Pinus flexilis$ or ~Juniperus scopulorum$. Typically sparse tall-shrub/small-tree layer may include ~Acer circinatum$ or any of the above trees depending on the species range. Shrub cover is scattered to patchy. Common shrubs include ~Cercocarpus ledifolius, Cercocarpus montanus, Holodiscus dumosus, Purshia tridentata$, or ~Toxicodendron diversilobum$. The herbaceous layer is often dominated by perennial graminoids such as ~Festuca campestris, Festuca idahoensis, Leucopoa kingii (= Festuca kingii), Piptatherum micranthum (= Oryzopsis micrantha), Pseudoroegneria spicata$, or ~Schizachyrium scoparium$. Forbs important in this layer include ~Aspidotis densa$ and ~Penstemon fruticosus$. Annual grasses and forbs may be present, especially on disturbed sites. Diagnostic of this alliance is the ~Pseudotsuga menziesii$-dominated tree canopy with less than 60% cover on average. 
Accession Code: VB.CC.2196.A552
Plot-observations of this Community Concept: 0
      Party Perspective according to: NatureServe (organization)
Perspective from: 26-Nov-1997 to: 17-Mar-2005
     
  • status: accepted
  • Community's Parent: II.A.4.N.b
  • This Community's Level: Alliance
  • This Community's Children: [none]
Names:   Scientific: PSEUDOTSUGA MENZIESII WOODLAND ALLIANCE
  Code: A.552
  Common: Douglas-fir Woodland Alliance
(convergence) and Synonyms:
(undetermined) Pseudotsuga menziesii Woodland Alliance