In 2016, the third measurement was performed on research plots established in 2005 in the Mežakla's beech stands. Three thinning methods were studied and control with no treatment: conventional thinning with normal cutting intensity (Method 60), thinning with 50 % lower density of crop trees and normal cutting intensity (Method 30), and thinning with 75 % lower density of crop trees and strong thinning intensity (Method 15). For crop trees tree species was determined, their diameter, height and the length of trunk without branches was measured, the number of branches at the first 4 and 8 metres of trunk was counted, and crown asymmetry, damage and growing space were examined. The treatment 15 has shown to be the best for increasing the diameter, decreasing h/d ratio and crown growth. Method 30 was proven best for increasing the height of crop trees and a total number of branches at the first 8 metres of trunk. The smallest decrease in crown size was detected in Method 60. Natural disturbances decreased the number of crop trees by 12.8 % between 2005 and 2016. Method 30 was determined to be the best treatment method, while Method 15 seemed to be the least appropriate.