Przemiana sposobu zagospodarowania lasu na przerębowy na przykładzie jednostki kontrolnej Chełmsko w Nadleśnictwie Kamienna Góra

摘要

Powierzchnia lasów o strukturze przerębowej jest w Polsce marginalna i według materiałów Biura Urządzania Lasu i Geodezji Leśnej (BULiG) obejmuje w Lasach Państwowych niespełna 693 ha w 67 pododdziałach. Ich przeciętna zasobność wynosi 435 m~3/ha. We wszystkich tych drzewostanach gatunkiem panującym jest jodła pospolita.%The study assesses the effect of applied cuttings on the transformation of the species composition, structure and development of the forest towards selection forest type. The described control unit was established in 2000 in the Krucze Mts. (southern Poland) within the programme of silver fir restoration in the Sudety Mts. The working hypothesis was based on the advantageous effect of the selection management system on fir trees. 46 permanent circular sample plots of 0.05 ha each were established and diameter at breast height measured on all trees along with height of 2-3 trees growing closest to the plot center. Measurements were repeated in 2004 and 2013. The greatest share in the growth increment was recorded for the most numerous species (spruce and fir). Only spruce and beech were important in the group of young trees (recruitment), which did not include fir or larch. The timber resources increased from 339 in 2000 to 381 m~3/ha in 2013, which indicates that not whole current increment was harvested. The increase in the growing stock follows the reduction in the number of trees per hectare from 361 to 317. Thus the number of young trees did not compensate for the losses. As a result the investigated unit is not in the state of equilibrium and in the future more work and care should be devoted to the regeneration. Fir turned out to be a species with the greatest production potential. In the first period growing stock of this species amounted to 17%, while the increment was over 26%. In the latter the increment reached 34%. The most important objective of the selection cuttings in this concrete unit should be to tend for regeneration and trees at low diameter sub-classes at the expense of use of trees with target values of diameters at breast height and disturbing the selection cutting structure. It is advisable to increase the share of fir in the structure of analysed unit.