The forests of the Wapiti map area, Alberta, were studied to ascertain relationships among forest growth, plant community distribution, and environmental factors within the western boreal and subalpine forests. Quantitative data on tree productivity, vegetation, and soils were collected from 137 plots. The 16 described forest community types (CTs) of predominantly fire origin were dominated by lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.), white spruce (Picea glauca (Moench) Voss), black spruce (Picea mariana (Mill.)B.S.P.), or aspen (Populus tremuloides Michx.), were floristically simple (111 vascular plants), had tree productivity ranging from 0.4 m3 ha−1 year−1 in the Picea mariana/Ledum groenlandicum/Rubus chamaemorus type to 5.0 m3 ha−1 year−1 in the Populus balsamifera/Rosa acicularis/Thalictrum venulosum type, and occurred on soils representing Luvisolic, Brunisolic, Gleysolic, Regosolic, Podzolic, and Organic orders. Two major successional trends are apparent in the upland boreal forest: lodgepole pine and aspen to the Picea glauca/Rubus pubescens – Maianthemum canadense type on moist sites at low elevations and lodgepole pine and black spruce forest to the Picea spp. – Abies lasiocarpa/Hylocomium splendens type on moist to well-drained sites at higher elevations. The Pinus contorta/Menziesia glabella/Rubus pedatus CT succeeds to the Picea engelmanii – Abies lasiocarpa/Menziesia glabella CT in closed canopy subalpine forests.