Summary:

The Wielkopolski National Park is located in the mid-part of the Warta river basin, in central part of Wielkopolska region, near Poznań city. The area is placed in the western part of the Wielkopolska-Mazovian climatic region. The natural landscape is of glacial type of Pleistocene and Holocene formation. Scot pine (Pinus silvestris) is the dominant species but also Common oak (Quercus robur), Silver birch (Betula pendula), alder (Alnus glutinosa) and Red beech (Fagus silvatica) are present there. The predominant habitats are: fresh broadleaved forest, fresh mixed broadleaved forest and fresh nixed coniferous forest. In paper the original method of potential water storage coefficient estimated for The Wielkopolski National Park has been presented. The idea of the method is as follows – for each elementary area (a square cell of 0.5 km side) exclusive potential water storage coefficient is assigned. This coefficient focuses converging influence of 8 parameters: area slope, soil thickness, infiltration coefficient of soil, distance from watercourse network, distance from pond and lake network, dominant forest site, dominant species of species composition and class of tree stand age. The next step in the course of calculation is division of the variability range of 8 above-mentioned parameters into 3 classes corresponding to “small” – code “1”, “medium” – code “2” and “large” – code “3” potential water storage capacities. After summation of these codes for each cell and reducing sums to range 1-3 the spatial distribution of the potential water storage coefficients are obtained. The potential water storage capacities of The Wielkopolski National Park are characterized by relatively significant spatial variability. As far as categories of small and large potential water storage coefficient are concerned following distribution regularities are observed – the areas of small potential water storage capabilities agree with these parts of the Park where afforestation of farmland was performed. The areas, as a rule, consist of Scotch pine (Pinus silvestris) monoculture stands of younger age classes on poorer forest sites. The areas of large potential water storage capability are largely present in these parts of the Park, where older class age Common oak (Quercus robur) and Red beech (Fagus silvatica) stands occur on fertile forest sites