File:Vegetation of Oregon and Washington (1969) (20580509641).jpg

Title: Vegetation of Oregon and Washington
Identifier: CAT92272720 (find matches)
Year: 1969 (1960s)
Authors: Franklin, Jerry F. cn; Dyrness, C. T
Subjects: Botany Oregon Ecology; Botany Washington (State) Ecology
Publisher: Portland, Or. : Pacific Northwest Forest and Range Experiment Station, U. S. Dept. of Agriculture
Contributing Library: U.S. Department of Agriculture, National Agricultural Library
Digitizing Sponsor: U.S. Department of Agriculture, National Agricultural Library

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Figure 155. — Ultramafic rock outcrops in Washington typically consist of open woodlands and barren slopes; left, landscape mosaic on ultramafic slopes and, right, local outcrop of serpentine showing the extremely barren openings (Teanaway River drainage, Wenatchee National Forest; photos cour- tesy A. R. Kruckeberg). pentine sites from 300- to 2,000-meter eleva- tion (Whittaker 1960; Waring 1969). Pinus jeffreyi is typically the only tree species pres- ent in these open woodlands (fig. 154) along with a rather sparse growth of grasses (e.g., Stipa lemmoni, Sitanion jubatum, Melica gey- eri, Elymus glaucus, and Festuca ovina) and occasional Arctostaphylos viscida. Forests, in- termediate in elevation and moisture regime, are typified by a sparse and xerophytic ap- pearance and dominated by a mixture of sev- eral conifers — Pseudotsuga menziesii, Libo- cedrus decurrens, Pinus jeffreyi, P. monticola, P. lambertiana, and P. attenuata (Whittaker 1960). Associated with them is a dense layer of sclerophyllous shrubs such as Quercus vac- cinifolia, Lithocarpus densiflora, Vaccinium parvifolium, Garrya buxifolia, and Umbellu- laria californica. Herb coverage is generally low but rich in species. Whittaker (1954b, 1960) has commented at length on the "two- phase" or patchwise distribution of the shrub cover in these forests with essentially closed shrub patches alternating with herbaceous openings. On more mesic sites the shrubs form the matrix, but on more xeric sites the herbaceous openings are dominant. Other community types described on Siski- you serpentines include: Chamaecyparis lawsoniana-Pinus monticola-Pseudotsuga men- ziesii stands, with a dense shrubby understory in ravines and draws, and higher elevation for- ests dominated by Abies concolor and Pseu- dotsuga menziesii and Pinus monticola, singly or collectively, over a Xerophyllum tenax and Arctostaphylos neuadensis understory. Whittaker (1960) has provided a list of more useful serpentine indicator plants in the Siskiyou area. These include: (1) some domi- nants— Pinus jeffreyi, P. monticola, P. at- tenuata, Quercus chrysolepis, Ceanothus cu- neatus, and Arctostaphylos neuadensis; and (2) species which are of more frequent occur- rence on smaller serpentine areas — Galium ambiguum, Pyrola dentata, Lomatium macro- carpum, Cheilanthes siliquosa, Rhododendron macrophyllum, and Darlingtonia californica. Xerophyllum tenax is considered the most useful single indicator of small serpentine out- crops. WASHINGTON SERPENTINES Most ultramafic outcrops in Washington occur within forested zones, and communities consist of open woodland with barren slopes between the scattered stunted trees (fig. 155) (Kruckeberg 1964, 1967). In the Wenatchee 179

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