New Zealand's potential forest composition was predicted from regressions relating the distributions of major canopy tree species to environment. Environmental variables, chosen for their correspondence to major tree physiological processes, included annual and seasonal temperature and solar radiation, soil and atmospheric water deficit, soil leaching, slope, and soil parent material and drainage. Environmental values were estimaged both for a large set of irregularly distributed plots describing forest composition, and points on a 1-km grid across New Zealand. Regressions were fitted to the ploy data species by species, with those for the four Nothofagus species also including terms to correct for the effects of their geographic disjunctions. Predictions of species abundance were then made for the grid data set, and the resulting matrix was classified to derive groups of similar composition. This data is expected to provide a context for both the assessment of the biodiversity value of surviving forest remnants and for the subsequent management and/or restoration of these sites.