ELEMENT OUTPUT APPRAISAL FROM FOREST ECOS YSTEMS OF NORTHEASTERN BAVARIA, UNDER STRESS FROM ATMOSPHERIC DEPOSITION, BY HYDROCHEMICAL SPRINGWATER ANALYSIS

In the mountainous regions of northeastern Bavaria (F. R. G.), 400 for est springs in the Fichtelgebirge and the Frankenwald were sampled bet ween 1989 and 1991. The resulting hydrochemical data characterize the variability of spring water chemistry in space and time. Springs are r egarded as output of forest ecosystems which can indicate deposition c limate and ecosystem reaction to acidic deposition. In both areas high sulfate concentrations (SO4 mean = 200 muMol/l) in spring waters indi cate the impact of acidic deposition. The highest sulfate concentratio ns (SO4 max = 965 muMol/l) were reached in the northern parts of Frank enwald and the eastern parts of the Fichtelgebirge. The springs of the Fichtelgebirge, which is dominated by granites and phyllites, are gen erally for more acidified (pH(mean) = 5.13) than those of the Frankenw ald (pH(mean) = 6.31), which consists mainly of schists and does not r eceive comparable precipitation amounts. Acidification in the Frankenw ald is concentrated at higher elevations close to the former East Germ an border. In the Fichtelgebirge low pH is common to upper regions abo ve 800 m altitude and, accompanied by high concentrations of aluminium , reaching 189 muMol/l. Due to the comparatively base-rich parent mate rial, the Frankenwald springs reach higher concentrations of calcium a nd magnesium but lower concentrations of potassium than those of the F ichtelgebirge. From the large number of investigated forest springs a detailed geographical picture of spring water acidification can be con structed. Forest springs can be used to identify sensitive forest ecos ystems before damages become obvious in forest canopies.