Trends in changes of water storage in upper soil layers were analyzed. The observations were carried out from 2002 to 2016 hydrological year in a small forest catchment in the district of Siemianice Forest Experimental Farm (LZD). The samples were taken from the upper soil layer of profiles located in different forest habitats, both at the beginning and at the end of hydrological half-years. Water storage was evaluated separately for two layers at the depths of 0–15 cm and 15–100 cm. Changes in water storage determined using the Mann-Kendall test were found to indicate multi-year trends. Results of the study are inconclusive. There were no statistically significant long-term trends in water storage changes in soil profiles in moist mixed broadleaved and coniferous forest and also in the soil profiles of fresh habitats. However, it is worth noting that statistically significant downward trends of water storage in two soil profiles located in ash alder swamp forest and moist broadleaved forest were observed. To some degree, they can be accounted for by long-term downward trends of ground-water levels in the area.