Soil conditions, after periods of afforestation up to 45 years, are compared for a series of experimental plots of different tree species at each of 3 localities in Great Britain. The percentage volumes of water, mineral soil, air, C, N and ignition loss down the various soil profiles and the total weights of water, C and N contained in the mineral soil and surface humus are given. Afforestation results in changed soil conditions, the degree of change varying considerably; e.g., woodland soils tend to contain more C and N than comparable non-woodland soils, more soil C being accumulated under conifers than hardwoods. The changed soil conditions are not closely related to differences in plantation productivity.