Stem¯ow of beech (Fagus sylvatica L.) represents a signi®cant input of water and elements to the soil and might in¯uence the spatial patterns and the rate of seepage ¯uxes at the stand scale. We investigated the soil solution chemistry at dierent depths and distances from the stem and the element ¯uxes with stem¯ow, throughfall and seepage in proximal and distal stem areas of a 130-year-old beech/oak forest in Steigerwald (northern Bavaria, Germany). The proximal stem area (in total 286 m 2 ha À1 ) was de®ned as a 1 m 2 , 60 cm deep cylinder around the beech stem. Seepage ¯uxes were calculated by a soil hydrological model for 1996 using measured soil matrix potentials and tree xylem ¯ow data for calibration. Stem¯ow represented 6 . 6% of the annual soil water input. With the exception of H ¯uxes, less than 10% of the total element ¯uxes with throughfall and stem¯ow reached the soil via stem¯ow. The volume-weighted concentrations of H , K and SO 4 2À in stem¯ow were higher than those in throughfall, while other elements had similar concentrations. Soil solution K concentrations decreased with stem distance, but the Na , Mg 2 , Cl À and SO 4 2À concentrations increased. Gradients for other elements were not statistically signi®cant. Stem¯ow had a strong in¯uence on the spatial patterns of element ¯uxes with seepage. The water ¯uxes through the soil of the proximal stem areas at a depth of 60 cm contributed 13 . 5% to the total seepage at the stand scale. Proximal to the stems about 20% of total seepage for K , Mn 2 , Al n , dissolved organic N and dissolved organic C were concentrated, but only 8±10% for Na , Mg 2 and Ca 2 . The loss of acid-neutralizing capacity calculated from the ¯ux balance was about four times higher proximal to the stems compared with distal areas, indicating high rates of soil acidi®cation proximal to the stems.
Our results con®rm the concept of a microsite around beech stems, characterized by high element and water ¯uxes in comparison with distal stem areas. Calculations of seepage ¯uxes and element budgets in beech stands have to consider the spatial heterogeneity of ¯uxes induced by stem¯ow.