Investigating the impact of gaps created by single-tree selection system on beech tree ring width (Fagus orientalis Lipsky) (Case study: Alandan forest-Sari)

The present study was conducted to explore the effects of harvest-created gaps by single-tree selection system in beech stands in Alandan Forests-Sari on the ring widths of beech trees located at the edge of gaps and unmanaged stands eight years before and after the gap formation. For this purpose, the cores facing towards 16 gaps in four area classes as well as the adjacent un-harvested stands were extracted in diameter at breast height (DBH) and measured from 110 overstory trees. The results indicated significant differences among gap classes in terms of ring widths eight years after their creation (P<0.01). Moreover, various positions within gaps showed significant differences regarding to ring width (P<0.01). Ring widths of the studied beech trees were also different for each year within the eight year period (P<0.01). There was significant difference among gaps eight years before and after cutting (P<0.01). Gaps were also significantly different from the unmanaged stands regarding to ring width (P<0.01). In general, it can be stated that the applied single-tree selection have influenced tree ring width of beech trees eight years after gap creation.