The thesies represents the results cariied out in the mountain chain of Kum onsites overgrown by phytocenosis arrayed into Isopyro-Fagetum syntaxon. We analysed the beech stands in optimal development phase. In the stands structure we were examining tree structure, diameter and height structure, structure of stands to the social tree layer and stem quality structure. In the five sample plots size of 30 x 30 m stands in optimal phase have been analyzed. We carried out the trunk analysis of 271 trees with the intension of ascertaining the diameter and height growth and presence of red heart. On the basis of site indicies it was established that the productivity in the site unity Isopyro-Fagetum ranges from 4,2 to 7,4 m3/ha/year (timber ? ? cm without bark) or 4,5 to 8,0 m3/ha/year (timber ? ? cm with bark) respectively.