Ocena możliwości rekompensaty miąższości drzew usuniętych ze szlaków zrywkowych zwiększonym przyrostem drzew granicznych

The purpose of the research was to assess the possibility to compensate for the volume and its 10−year increase lost on future crop and trainer trees removed from the strip−roads by the increased growth of trees at their edge. The assessment comprised the estimation of the compensation period length and its percentage value 10 years after cutting the strip−roads. The analysis also comprised 5−year−long wood volume growth periods. The research was conducted in Scots pine stand, located in the eastern part in the Notecka Forest, the area managed by the Oborniki Forest District (western Poland). The strip−roads 2.5 m and 3.5 m of width were cut every 30 m in the 31−years−old stand. The measurements covered trees growing directly at the strip−roads as well as 2−4 m and 8−10 m away from them. The volume increase was calculated on the basis of tree− ring widths, on the cross−sections cut from the mid−points of 2−meter−long sections. The simulation of the possibility to compensate for the volume loss on future crop and trainer trees removed from strip−roads was conducted by calculating the difference of the average annual volume increments in a 10−year−long period for single trees from the 0−1 and 8−10 m zones, and for the sum of differences in annual increments between these zones as well as between the 2−4 m and 8−10 m zones. The results showed that the trees growing directly at the strip−roads had the largest periodic volume increments, and in case of the wider strip−roads the largest volume increments were also found on trees growing in the 2−4 m zone away from the strip−road. Simulations of the volume loss compensation period length and of 10−year volume increment showed that the compensation was possible in the variants with the wider strip−roads. 10 years after cutting the strip−roads, the compensation for the volume loss and for the lost 10−year volume increment, resulting from the increased increment on trees form the 0−1 m and 2−4 m, was 30% and 14%, in tree stands with wider and narrower strip−roads respectively.