A quantitative gradient study in a central Himalayan mixed Quercus forest ( Q. semecarpifolia and Q. lamellosa ) was made to evaluate the relationships between environmental variables and species composition at different scales. The data (91 taxa x 120 sub-plots) were sampled at three sites, where groups of four sub-plots (2.5 m x 2.5 m) were sampled within 10 m x 10 m. The species data were analysed together with the environmental data (altitude, relative solar radiation and soil variables) using Correspondence Analysis and its constrained version (CCA). The environmental variables used in CCA were chosen by forward selection. Altitude was the overriding complex gradient (2000-3000 m), with loss-on-ignition, total nitrogen, and RI covarying. The most important factors independent of altitude were available phosphorus and tree canopy cover, whereas pH and nitrogen had minor independent influences. The overall species environment correlation was highest for the largest plot size. The species environment correlation increased with spatial extent for the largest plot size. The field-layer and shrub-tree strata did not consistently differ in their concordance between species and environment. The field-layer species had a stronger relationships with the soil variables, which may relate to rapid changes over a short spatial extent both for the field-layer species and for the soil variables.