Seasonal Variability of Ground Water Levels in the Puszcza Zielonka Forest

Abstract

Abstract The paper presents results of studies on seasonal variability of ground water tables recorded in long-term observations of water levels in the Puszcza Zielonka forest complex. The Puszcza Zielonka Forest is located in the middle part of the Warta basin in the central part of the Wielkopolska region. Its western boundary is located approx. 6 km north-east of Poznań. The area is situated in the western part of the Wielkopolska-Mazovian climatic region. The natural landscape is of young glacial type of Pleistocene and Holocene formation. For this reason parent materials for soils in this area were mainly postglacial drifts, deposits coming from the Poznań stage of the Würm glaciation. In terms of granulometric composition these were mainly low clayey sands deposited on loose sands with an admixture of gravel and eroded sandy clay. Scots pine is the dominant species. Oaks, alders, larches and scarce spruces are also found in this area. Predominant sites include fresh mixed forest, fresh mixed coniferous forest, fresh broadleaved forest and alder swamp forest. Seasonal variability in groundwater levels depends mainly on abiotic factors. Characteristics of stands have only a modifying effect on the dynamics of changes in groundwaters. Slightly greater fluctuations in water levels were recorded in the fresh broadleaved forest site in comparison to the alder swamp forest. There are no marked dependencies of fluctuations in groundwater tables on age classes of the tree stands. Generally a negative correlation was found between variability in groundwater levels and the depth of its table below ground surface (b.g.s.). However, in the conducted studies the hypothesis on the marked delay in the variability of groundwater levels between sites, tree species, age of tree stands or depth of ground water tables was not confirmed.