| Abstract: | Flux balances and current rates of change of heavy metal stores in forest ecosystems of the Soiling The inventory of the heavy metals Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb is calculated for a beech and a spruce forest ecosystem in the Soiling mountains on the basis of measured concentrations in the vegetation and soil compartments and their dry mass per hectare. The inventory is compared with measured heavy metal fluxes coupled with precipitation above and below the canopy, with seepage water fluxes below the rooting zone (50 cm depth), with litterfall, and with the current increment to biomass. The ratios between heavy metal stores in the forest floor layers (table 3) and the annual flux with litterfall (table 4) show decreasing tendency for liberation of the elements by decomposition of organic matter (OM) in the following order: Mn>OM>Ni>Cd>Cu>Cr ≈? Zn>Co ≈? Fe ≈? Pb Manganese is set free faster than total organic matter. The flux balances for the total ecosystems (table 4) show input > output in the case of Cr, Fe, Cu, Cd, and Pb; input ≈? output for Ni and Zn; input < output for Mn and Co. Heavy metal stores in mineral soil are decreasing by percolation losses and increment to biomass (mainly wood) in the case of all elements investigated, except Zn (under beech), Cd and Pb (table 4). The concentrations of Cu and Pb in the forest floor layers have reached levels at which deleterious effects on microorganisms and litter decomposition are to be expected. |
