The study attempts to establish the pattern of the climatic water balance for the Zielonka Forest as a typical example of forested areas in the Wielkopolska region based on a 20-year-long (1986–2005) hydrometeorological record. The period ended with a balance surplus of 229 mm and an annual average surplus of 11 mm. The meteorological conditions were quite favourable for water alimentation in winter half-years. Relatively high air temperatures, stimulating evapotranspiration, were then accompanied by high and stable precipitation. The general pattern of the climatic water balance was rather typical for Wielkopolska. As a rule, the balance was negative in summer half-years and vegetation seasons, and positive in winter half-years. Further studies are needed to explain the impact of the high frequency of warm periods and the wide variability of precipitation in summer half-years and vegetation seasons on the dynamics of evapotranspiration and the climatic water balance.

73-81