A research site for long-term monitoring of the thinning effects on the development of beech stands was formed in the Pišece forest management unit. The research site consists of three blocks, each block is divided into three plots (30 x 30 m). A treatment was randomly assigned to each plot: classical selective thinning (A), selective thinning with fixed crop trees (B) and control plot (C). All trees with a breast diameter equal to or greater than 10cm were measured, coordinates of trees within the plots were recorded and tree parameters were assessed (status, crown, and vitality). The study presents an analysis of the stand parameters prior to the thinning. Average growing stock GS (min-max) of the plots was 221 (119-317) m3 ha-1, average number of trees N (min-max) was 1533 (1100-2056). In A stands 274 (178-356) crop trees ha-1 were selected and 530 (367-622) competitors ha-1 were marked for removal. In the B stands there were 89 (78-100) crop trees ha-1 and 326 (267-433) competitors ha-1 respectively. The differences between the blocks were statistically confirmed for a number of stand parameters. Differences between treatments were significant for the number of competitors per crop tree and crown asymmetry index of the crop trees.