The Puszcza Zielonka and the Wielkopolski National Park are a big forest complex near the Poznan city. Is taken as the reference meteorological data for the Puszcza Zielonka and the Wielkopolski National Park based on data from the Poznan gauge station. The climate in the Puszcza Zielonka and in the Wielkopolski National Park shows relatively high stationarity. Air temperature (T) for these forest areas, from 1848-2016, shows in vegetation seasons, the positive trend of 0.004 0C/year (Sen's slope) on the significance level α = 0.05. While precipitation (P) and Sielianinov's hydrothermal coefficient (HTC) do not exhibit statistically significant changes. Fourier analysis of periodicity of air temperature indicates the dominant cycles: 84.5-; 56.3-; 15.4-; 3.5- and 3.3-years. An analogous analysis indicate the periodicity of precipitation: 7.0-; 4.0-; 3.6-; 3.3- and 2.8-years. Very similar, periodicity dominant was obtained for Sielianinov's hydrothermal coefficient ie.: 7.0-; 3.9-; 3.3-; 2.8- and 2.1-year. You can indicate that in Poznan, and therefore also in the Puszcza Zielonka and in the Wielkopolski National Park, in vegetation seasons, between 1848-2016 (almost 170 years) air temperature has increased by about 0.7 0C, while precipitation remained on unchanged level. Sielianinov's hydrothermal coefficient, which is a comprehensive assessment of the conditions falls ...
