In this study we compared two approaches of first thinning: selective and situational. We were interested in the structure of the competitors, the differences in stand stability, and which tree selection criteria are most closely followed in the implementation of tree selection. The study was carried out in the Vrbovec district, GGO Kočevje, in oak-beech forest type stand at an altitude of 520 m to 695 m. The research site was divided into eight 0.04 ha square plots. The first four plots were used for situational thinning, the others for selection thinning. We found no significant differences in the light conditions after the performed thinning. The differences were more pronounced when comparing the candidates with their competitors. In the case of situational thinning the focus was preserving valuable noble broadleaves, and the removal of damaged trees was not carried out. Comparing situational treatment with selective thinning, the intensity of the thinning (i.e. removal of BA) was lower and the release of the targeted trees (i.e. nr. of competing trees per candidate) was stronger. Differences between the two treatments showed in assessed collective stand stability. On the plots with situational treatments, collective stability for trees in the canopy of the stand was more preserved. Comparing the mean values of the collective stability for the candidates, the situation was more favorable in situational treatment, as selected candidates were released more compared to candidates in selective thinning.
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