CLASSIFICATION OF NATURAL FOREST COMMUNITIES OF COASTAL BRITISH-COLUMBIA, CANADA

In comparison to countries with a tradition of vegetation studies, a c omprehensive, hierarchical classification of plant communities in the province of British Columbia has not yet been developed. Such a classi fication is needed for systematic ecological studies and coordinated c onservation of vegetation. As the culmination of fifty years of detail ed surveys, tabular and multivariate analyses of 3779 releves of natur al, old-growth, submontane, montane and subalpine forest communities i n coastal British Columbia were used to develop a hierarchy of vegetat ion units according to the Braun-Blanquet approach. At the highest lev el, we distinguished seven orders: Quercus garryana, Pseudotsuga menzi esii-Mahonia nervosa, Tsuga heterophylla-Rhytidiadelphus loreus, Tsuga mertensiana, Thuja plicata-Tiarella trifoliata, Populus trichocarpa, and Pinus contorta-Sphagnum. Diagnostic table, ordination, and climati c and edaphic regimes were used to show floristic affinities among the orders and to interpret their relationships to regional environmental gradients. Plant communities of each order were briefly characterized by their floristic composition, physiognomy, succession, and environm ent. The synopsis for all delineated vegetation units (order, suborder , alliance, and association) of coastal British Columbia is included.