We studied physiological characteristics (fluorescence of chlorophyll a, photosynthetic pigments) in shade leaves of beech (Fagus sylvatica L.) trees in dependence on one- and two-week precipitation totals (in mm) before the proper measurement and sampling, in two areas with different pollution load. The leaf characteristics were observed on 15 year old understorey trees. From the results it follows that both short-term and long-term deficit in precipitation were more sensitively responded by the measured fluorescence parameters than by the amounts of the assimilatory pigments. This primarily holds for the two-week precipitation totals. In the locality more loaded by airborne pollutants, the influence of drought in coupling with other negative site factors results in worse physiological state of beech trees.