Comparative study of temperate Chamaecyparis forests

The objectives of this study include: (1) analysis of Chamae-cyparis lawsoniana, C. taiwanensis, and C. formosensis forests includ-ing the structure, composition, and dynamics of plant communities andtheir environmental relationships; and (2) comparison of the temperateChamaecyparis forests of Taiwan and the Pacific Northwest with emphasison structural and successional characteristics.
One vegetation zone with four communities in Taiwan and threezones with eight communities in the Pacific Northwest are described.
All communities are defined on the basis of their vegetative differenceswhich arise primarily in response to changes in climate and/Or soils.
The Chamaecyparis communities show varying degrees of sitespecificity. The two Taiwan species are sympatric over most of theirranges. Chamaecyparis taiwanensis occurs on high elevation, welldrained landforms and on many aspects. The soils are typically nod-zolized or undifferentiated. Most vigorous forests tend to be in north-western portions of the generic range. Chamaecyparis formosensis isfound at lower elevations, on less well drained and more commonly pod-zolized soils, and is more restricted to north and northwestern aspects.The most vigorous stands are in the southeastern portion of its range.Climatic variation is more pronounced in the Pacific Northwest, andChamaecyparis lawsoniana communities reflect this. In the north, middleand low elevations are occupied by the Tsuga heterophylla-Chamaecyparis lawsoniana/Polystichun munitum-Oxalis oregana community on more nesicareas and by the Tsuga heterophy119.-Chamaecyparis lawsoniana/Rhododendron macrophyllum-Gaultheria shallon community on better drained sites.