. Vegetation of Oregon and Washington. Botany Oregon Ecology; Botany Washington (State) Ecology. Figure 115.—Mountain meadows are common on gentle topography along and near the heads of stream courses in the Abies grandis Zone; they constitute an im- portant grazing resource. are Festuca rubra, Carex spp., Juncus balticus, Aster occidentalis, Polygonum bistortoides, Trifolium spp., and Senecio spp. Most Deschampsia meadows have been overgrazed by domestic livestock (fig. 115) and have deteriorated into other kinds of communities. Reid and Pickford (1946) rec- ognized four major steps in deteri
. Vegetation of Oregon and Washington. Botany Oregon Ecology; Botany Washington (State) Ecology. Figure 115.—Mountain meadows are common on gentle topography along and near the heads of stream courses in the Abies grandis Zone; they constitute an im- portant grazing resource. are Festuca rubra, Carex spp., Juncus balticus, Aster occidentalis, Polygonum bistortoides, Trifolium spp., and Senecio spp. Most Deschampsia meadows have been overgrazed by domestic livestock (fig. 115) and have deteriorated into other kinds of communities. Reid and Pickford (1946) rec- ognized four major steps in deterioration: (1) perennial grass or climax, (2) mixed grass and weed (fig. 117), (3) perennial weed, and (4) annual weed. Serious erosional problems are associated with these changes in community composition. Major dominants in the peren- nial weed stage are Senecio spp., Achillea mil- lefolium var. lanulosum, Wyethia spp., Poten- tilla spp., Aster occidentalis, Taraxacum offic- inale, and Poa pratensis. The annual weed stage is characterized by Bromus mollis, Muh- lenbergia filiformis, Polygonum douglasii, and Madia spp. Development of climax vegetation from these deteriorated communities is usual- ly extremely slow, even if grazing is complete- ly eliminated. "TSUGA HETEROPHYLLA" ZONE Figure 116. —Deschampsia caespitosa, a perennial grass, dominates mountain meadow communities in good Habitats where Tsuga heterophylla or Thuja plicata are climax are encountered on the eastern slopes of the Cascade Range in Washington and northern Oregon. These con- stitute the Tsuga heterophylla Zone. It is es- sentially an eastern extension of the wide- spread coastal Tsuga heterophylla Zone, al- though the composition of serai forests and understory is somewhat altered. This inland Tsuga heterophylla Zone correlates with the Interior Western Hemlock Zone in British Co- lumbia (Krajina 1965, Bell 1965, Smith 1965) and the Tsuga heterophylla series of Dauben- mire and Da
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