Name:
Chamaecyparis lawsoniana Forest Alliance
Reference:
Western Ecology Working Group of...
Description:
This coniferous forest alliance occurs in a very restricted range in the Klamath/Siskiyou mountain region of northern California and southern Oregon, but shows wide ecological amplitude within that range. Winters are cool and wet; summers are warm and dry. Coastal stands are usually associated with penetration of ocean fog events, and are particularly well-developed on moist toeslopes and valley bottoms of coastal river drainages. Disjunct inland stands occur at up to 2000 m elevation in the southern Cascades and inner Klamath Mountains where stands occur in moist microhabitats, often in association with streams or springs. Soils are often moist, coarse-textured, ultra-mafic soils with perched water tables derived from alluvium or colluvium. These mixed conifer forests are characterized by Chamaecyparis lawsoniana codominant in the tree canopy. Pseudotsuga menziesii is codominant or common in most stands. Additional codominants include Tsuga heterophylla in northern stands and Picea sitchensis in coastal stands. Other conifers present may include Abies concolor, Abies magnifica, Taxus brevifolia, Picea breweriana, and Chamaecyparis nootkatensis. Northern stands often have a broad-leaved tree subcanopy of Acer macrophyllum, Chrysolepis chrysophylla (= Castanopsis chrysophylla), Lithocarpus densiflorus, or Alnus rubra, and a tall-shrub stratum of Acer circinatum, Rhododendron macrophyllum, Vaccinium parvifolium, or Gaultheria shallon. Shorter shrubs may include Leucothoe davisiae, Mahonia nervosa, Paxistima myrsinites, Chimaphila umbellata, Rubus ursinus, Vaccinium membranaceum, or Rosa gymnocarpa. Herbaceous layers commonly have shade-tolerant species such as Polystichum munitum, Clintonia uniflora, Goodyera oblongifolia, Linnaea borealis, and Oxalis oregana. The tree canopies of southern interior stands may include Lithocarpus densiflorus, Arbutus menziesii, Calocedrus decurrens, and Umbellularia californica. Ericaceous and other shrubs such as Quercus sadleriana, Quercus vacciniifolia, and Morella californica (= Myrica californica) dominate the shrub layer. Important herbs may include Xerophyllum tenax, in addition to the species above. Diagnostic of this forest alliance is Chamaecyparis lawsoniana codominant in the tree canopy.
Accession Code:
VB.CC.17899.CHAMAECYPARISLA
Plot-observations of this Community Concept:
0
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