The effect of sanitation measures on slimness coefficient of 9 years old spruce plantations were observed on two semi-practice experimental plots, which were established in 1996 on clearings after calamity decayed spruce stands (District forests of Nálepkovo, Slovenské rudohorie Mts). The research was done separately in four differently treated parts of both experimental plots. Results achieved from these plots, despite they reflect the same sanitation measures (liming by dolomite limestone powder and application of phosphate and boron fertilisers), are different in values of slimness coefficient.