Mass balance of cadmium in two contrasting oak forest ecosystems.

The mass balance of cadmium in forest ecosystems was parameterized. Soil pH is the main variable controlling retention of Cd in the soil and, hence, determines whether Cd is leached from the system or not. However the extent to which root uptake and biomass accumulation of Cd, or the return of Cd to the soil as internal cycling, influences forest Cd balances is unknown.