Soils were collected from different depths (0–2.5 cm, 2.5–5 cm and 20–40 cm) one month, two years, and four years after clearfelling of a mature, mixed species, coastal Eucalyptus forest in East Gippsland, Australia. Soil carbon, effective cation exchange capacity (CECe), amount of salt-extractable cations, and the chemical composition of equilibrium soil solutions from a number of sequential batch experiments were measured. For batch experiments, four different solutions were used (2 mM HCl, 2 mM NaOH, 2 mM KCI, and 1 mM CaCl 2). Surface soil decreased in soil carbon, CECe, acid neutralisation capacity (ANC), and buffering capacity with time after clearfelling. A decrease in these soil properties indicates a long-term reduction in the ability to retain bases and to buffer input of protons. A coupled equilibrium model was used to describe soil chemical changes. The model included a solubility product of Al(OH) 3, selectivity characteristics of two different cation exchangers, and inorganic complexation of cations. The model explained the decrease in ANC of the soil when a decrease in the buffer capacity of a second exchanger (exchange of Al from carboxyl sites on organic matter) was incorporated. Model predictions for sorption experiments were fairly good when measured amounts of salt extractable cations were used as exchangeable amounts. Some differences between modelled and experimental values were found for Al and large differences were found for NH 4 +. One month after clearfelling, an imbalance in the adsorption/desorption of cations was found in the sorption experiments, indicating a need to include metal-organic complexes when describing the soil solution chemistry. Four years after clearfelling, no imbalance was found and the model satisfactorily described the sorption curves of all cations, except for NH 4 +. The data, especially the decrease in ANC, indicate that clearfelling should be avoided in a sustainable forest management.