Analiza zmian stanów wód gruntowych po wycięciu drzewostanu w siedlisku lasu mieszanego wilgotnego na przykładzie Leśnictwa Laski

The paper presents the results of researches carried on averages about precipitation sums, 2003/2004 (before cutting) and 2006/2007 (after cutting) hydrological years in catchment of pond No 5 located in Laski forestry. Discussing forestry is situated at Siemianice Experimental Forest Farm of Poznań University of Life Sciences located about 15 km south-east from Kępno. The forests of this forestry are within range of Nizina Południowo-Wielkopolska, on Wysoczyzna Wieruszowska, which is differential morainic plain, cut with the river Prosna headwaters. Area of the pond’s catchement is about 20 ha and it’s an afforested catchment, with predominance of fresh habitats, in smallest step in area adjacent to pond No 5 occurrence moist broadleaved forest and moist mixed broadleaved forest. Predominant species of tree stand in analyzing catchment there is pine about 100 years. In the soil cover the largest area is dear brown soil, and the most common type of soil is loamy sand. From february to october 2006 carried on analyzed catchment cutting forest stand, which included habitats moist broadleaved forest, moist mixed broadleaved forest and partially fresh broadleaved forest. To analysing choose wells No 1.1 and 1.2 which were situated at cutting area. The researches carried out confirmed, that ground-water levels shows some cycle and depend of meteorological conditions. Maximal levels occurred at the end of winter researches half-year. Whereas minimal ground-water levels, causes higher air temperature and influence with them transpiration forest stands, were in analyzing habitat at the end of summer half-year. The researches indicated also, that without meteorological conditions, large influence at form ground-water level (increase) in afforested catchments, particularly in moist habitats, have carried cuttings. Carried out researches indicated that execute cutting at area analysis habitat moist mixed broadleaved forest causes increase ground-water levels. Ground-water level at cutting area in 2006/2007 hydrological year was closer to land surface, average about 61 cm.