This article summarizes the results of four studies on changes that occurred over the 1970-1996 period in the chemical content of forest soils in North Eastern France. These changes were quantified by twice sampling and analyzing soils from identical locations at different dates. Nitrogen concentrations are increasing in the upper horizons and the carbon/nitrogen ratio is decreasing in the lower horizons. Cation content (potassium and particularly calcium and magnesium) is decreasing in most of the soils studied, especially in acid soils or at high elevations. It is still difficult to quantify the respective impact of anthropogenic environmental changes (atmospheric exchange, changes in forest uses) and of natural changes arising from the growth of tree populations on soil variation.