Abstract.The soil has been investigated at a long‐term experiment examining the silvicultural and site‐related effects of four tree species (Scots pine, Norway spruce, oak, common alder), planted pure or in mixtures. The experiment is located in Gisburn Forest, Yorkshire, and commenced in 1955. After 32 years, small significant differences were found for soil properties relating to soil organic matter accumulation and incorporation; the soil under the conifers and alder was slightly more acid than that under oak and grass control plots, and the conifers had thicker F and H but thinner A horizons. There was also some evidence that the conifers and alder has retarded the formation of a grey iron‐deficient B horizon. Some mixed plots were differentiated from pure ones by canonical variate analysis. Soil pH has declined under all plots since 1954; the effect of mixing species on this property is disc