Natural regeneration of mixed broad leaves in different sized gap and wıld cherry (Cerasus avium (L.) Moench ) plantations in Western Black Sea region

With high biodiversity and multilayered structure, the Black Sea Region (BSR) forests have a significant place in Turkish forestry. Practicing the ?close-to-nature? principles in the region?s mixed hardwood forests is critical for sustainability and multi-functionality of these forests. Developing silvicultural prescriptions that will govern the natural processes most efficiently to sustainably produce wood in a cost-effective manner and to enhance biodiversity is an increasing necessity for the region?s forests. Gaps created naturally or artificially in the stand canopy supports a highly heterogeneous micro-environment and vegetation underneath. There is a big information gap in Turkish forestry on practicing the gap regeneration techniques including determining appropriate gap sizes for certain stand types. Mixing wild cherry (Cerasus avium) ? a tree species with great ecological (enhanced biodiversity, stand stability, wildlife support), economic (valuable wood), and social (apiculture) uses ? into the region?s oriental-beech-dominated (Fagus orientalis Lipsky) mixed hardwood forests will enhance the multi-functionality of these forests further.32 gaps of two different sizes (16 with 12 m and 16 with 25 m radius) were created in the beech-dominated mixed hardwood forests, which were subject to continuous forest management, of Zonguldak Kdz. Ereglisi Kocaman Forest Sub-Directorate in 2006. One-year old wild cherry seedlings of a native origin were planted in 3 x 3 m spacing under each gap at the end of the year. One year after planting, seedling growth were compared by gap size and ecotone in the gap (center, transitory zone, and neighboring closed forest). Natural regeneration in different gaps and ecotones in a gap were also compared in May 2008.No significant instantaneous solar radiation difference was found between the large (0.2 ha) and small (0.05 ha) gaps. However, substantial differences in solar radiation within the gap were apparent. The center of gaps received a significantly greater mean in the amount of solar radiation when compared the transitory zone and in the neighboring closed forest. The amount of solar radiation reaching the forest floor increased as the size of the gap increased. Wild cherry ? a typical light-demanding tree species - seedlings tended to grow greater in the large gaps when compared to those planted under small gaps, although the difference was nonsignificant.One year after gaps were created, semi-shade tolerant Anatolian chestnut (Castanea sativa), which requires shelter in early ages - regenerated most (70%) in the transitory zone in gaps. Similar amount of regeneration was found in the center and transitory zones under small gaps for beech. For large gaps, significantly greater mean number of natural seedlings (1.5-fold) was found in the transitory zone when compared to natural beech seedlings in the center zone. Tolerating shade and requiring shelter when they are very young, beech seedlings preferred the transitory zone of the large gaps. Small gaps provided shelter and were ideal for beech regeneration. Also, this result is attributable to the seed dissemination distance of relatively heavy beech seed. Scarce wild cherry natural regeneration tended to come more under the large gaps. These results were in line of the cherry?s ecology.Small gaps can be employed to regenerate mixed stands composed of shade-tolerant tree species whereas large gaps are required to establish the natural regeneration of light-demanding tree species such as wild cherry in mixed stands.Key words: close to nature forestry, gap regeneration, samall and big gaps, shade rolerant species, light species, mixed stand, wild cherry