THINNING OF MIDDLE-AGED SCOTS PINE STANDS - KERSKO EXPERIMENT

In order to find out possible effect of thinning on the growth and yield of middle-aged Scots pine (Pin us sylvestris L.) stands, two long-time experiments were established in 33- and 34-yr-old stands in 1962. All experimental plots were situated at an altitude of ca 185 m a.s.l., Polabi region (Central Bohemia). Experiment Kersko I included only two treatments: control and thinning from above. Experiment Kersko II included three treatments: control, thinning from above and thinning from below. Stem diameter and tree height were measured periodically each five years, when the last measurement was done in 2007. Both the stand DBH and the DBH of dominant trees (based on the 100 thickest trees per hectare) were not affected by thinning treatment compared to control one. The development of slenderness quotient was similar in all treatments. 'the differences among the treatments in basal area, stand volume and total volume production was found statistically nonsignificant. The type of thinning application appears to have an ambiguous effect in middle-aged Scots pine stands.