Development of Seeded Scots Pine Stand from Precommercial Thinning to First Commercial Thinning

1990

29 S.

17 Abb., 5 Tab., 44 Lit. Ang.

Bandaufführung

2628

37249

The aim of the study was to examine the effects of precommercial thinnings carried out in seeded Scots pine stands at the dominant height of 7 meters. The material was obtained from 64 samples plots in three thinning experiments. The sample plots were measured at the dominant heights of 7, 9.5 and 12 meters (age 19, 25 and 30 years). The last measurements were made at the dominant height of 12 meters at a time when the first commercial thinning was carried out on 20 sample plots. The height growth of the trees was independent of the thinning intensity, but precommercial thinning increased the mean diameter especially when the density was under 2200 stems/ha. The increase in total volume was the greater, the higher the growing stock level. If mortality is excluded, the total volume incremend is highest when the density is 3000-4000 stems/ha. If large-sized merchantable wood is preferred in the first commercial thinning, then the density after precommercial thinning should be 2000-2200 stems/ha. The quality of the timber depends on the stocking density. The best results were achieved when the density was 3000-4000 stems/ha, although the diameter of the thickets branches remained under 30 mm also on the plots with a density of under 1000 stems/ha. Even at very low densities after precommercial thinning good quality if obviously attainable of the precommercial thinning is carried out not earlier than when the dominant height is 6-7 meters.