RESEARCH INTO THE STRUCTURE OF OLD ER AND OLD STANDS OF COMMON BEECH IN THE MANAGEMENT UNIT OF ĐURĐEVAČKA BILOGORA

Common beech (Fagus sylvatica L.) is the most widely distributed tree species in Croatia. Because of its physiological and ecological characteristics (high shade tolerance, the ability to grow in a broad range of soil types, topographic positions, and climate conditions) common beech in Croatia forms different stands, ranging from pure to mixed stands with different tree species and with different structural characteristics. Beech characteristically occurs in a wide range of different ecological and management conditions and forms stands of diverse structural characteristics. There is increasing deviation of structural element values in managed stands in comparison with the values of identical structural elements that are tabulated in yield tables. Therefore, we need to investigate the structure of beech stands and the applicability of yield tables at the local level for both the common beech and for other species that form beech stands. The aim of this work is to investigate the basic structural elements of managed beech stands and compare them to tabulated valu es in growth-yield tables. Field measurements were conducted in 449 circular plots located in 18 compartments in age class IV and V in the management unit of Đurđevačka Bilogora. Sampling intensity amounted to 5 % of the total area of the selected compartments. As expected, the results in this research show deviations in comparison to the valu es tabulated in yield tables. The results indicate the complexity of the problems occurring in the management with beech stands. In order to improve age structure distribution, product quality and sustainability of revenue on both the local and globallevel, it is necessary to adopt the approach at the local level, bearing in mind the purpose, method and management type of beech stands.