A very acidic soil under an adult spruce (Picea abies) stand, in the Basses-Vosges (North-eastern France), was analysed in 1986, and ten years later in 1996. The chemical composition of the mineral horizons did not show much variation, but the sum of exchangeable Ca and Mg in the mineral horizons and their total contents in the OL, OF and OH horizons decreased significantly. In ten years, the M...