Investigations were carried out in series of 6 permanent study areas (5 in forests of primeval character, and 1 in a managed stand) with the growing stock ranging from 226 m3ha-1 to 593 m3ha-1. These stands were characterized by a considerable differentiation of the tree d.b.h. and a complex storeyed structure, resembling a selection forest. Only two stands reached the growing stock close to the one accepted as the optimum for the beech selection forests. When carrying out a selection cutting in such forests one should take the lowering of the growing stock to about 220/250-300 m3ha-1 into consideration. It would be more correct, therefore, to carry out in managed beech forests a Swiss irregular shelterwood system, rather than a selection cutting system. The latter one may be used in the beech stands of differentiated structure in protection forests or in forests of a special purpose.