EN
During 1983-1989 late cleanings were carried out in silver fir up-growth. Cuttings based on a positive selection had the most benefical effect on the biomorphological characteristics of silver fir up-growth. They were most intensive and led to increased increment in diamater of the stem and length of the crown, and also to storeyed structure of the up-growrh. Promotion of the most valuable individuals which in future should form the overstorey of the stand is also an important advantage of this treatment. In comparison with the control treatment the negative selection had a statistically significant effect on the height and diameter increment, change in absolute length of the crown and its height above the ground, as well as the number of its whorls. However, the negative selection led to disappearance of height differentiation in the silver fir biogroups.