This thesis is focused on the physiological quality of long-term stored beech seedlings (Fagus sylvatica L.). In the first part of the thesis we dealt with the problems of physiological quality of seed material, long-term storage and dormancy as an important factor for long-term storage. Furthermore, we describe the Šariš nursery center as an object in which the seedlings were stored long term, observed and measured. Differences in physiological quality between seedlings stored at three temperatures (-3, 0 and 3 ° C) were investigated and the effect of root treatment was also examined in an attempt at root growth potential. Physiological quality was assessed by water potential factors, water content in seedling parts (terminal, main root, third order roots to finest roots, and soil roots) and growth root potential. Water potential and water content were determined during storage and growth root potential at the end of storage. We have processed and evaluated the values. We used variance analysis for processing root growth potential values. Larger differences in physiological quality appeared only at the water potential, where average values of -1.5 MPa were measured at the end of storage at 3 ° C, which is the lower limit of very strong water stress. For other factors, no significant differences in values were found.