Habitat relationships of Chamaecyparis nootkatensis in southern Washington, Oregon, and California

Chamaecyparis nootkatensis is uncommon south of Mount Rainier, Washington. It occurs almost exclusively above 1100 melevation and occasionally reaches timberline. Populations are generally adjacent to open habitats such as meadows, rockyridges, avalanche tracks, bogs, and lakeshores. The species rarely grows in extensive tracts of closed-canopy forest. In 75sample plots, 387 vascular species occurred, including indicators of both very wet and dry environments. Judging from theaccompanying flora, the topographic locations occupied, and water potential data, C. nootkatensis can grow throughout muchof the range of moisture conditions present at high elevations in the Cascade Mountains from central Oregon north. Chamaecy-paris nootkatensis varies in growth form from a shrub to a tree 50 m tall. Layering produced the majority of small stems onmost sites; it facilitates expansion both on open sites and of shrub-form plants in the forest. Chamaecyparis nootkatensisestablishes some seedlings and is shade tolerant enough to survive under moderately dense canopies, but forest-grownseedlings fail to develop a strong upright trunk. Most trees on forest sites appear to have established following disturbance.