engleski

The Influence of the Number of Trees on Crown Diameter for Common Oak in the Carpino betuli-Qercetum roboris Anić ex Rauš 1969 Community

Research was carried out on six trial plots, in the community of common oak and common hornbeam (Carpino betuli-Quercetum roboris Anić ex. Rauš 1969), that belong to the development stage of older stand (from 81 to 100 years, ) and are 1 ha large. Although the trial plots were laid out in the same age group, the number of common oak trees on particular plots differs significantly. The trial plots are divided into three groups: group 1 - plots with a smaller number of trees and bigger d.b.h. (less dense stands) ; group 2 - plots with a medium number of trees and d.b.h. (medium dense stands) ; group 3 - plots with a bigger number of trees and lower d.b.h. (denser stands). Regression analysis was performed for all three groups. Crown diameters of particular groups were levelled by straight line equation, (crown diameter is a function of d.b.h.): D=f(d1, 30), and D=b0+b1*d1, 30 ; where D is a levelled crown diameter, d1, 30 is d.b.h. and b0 and b1 are parameters. Significant difference in a crown diameter and number of trees of particular groups is evident from the obtained results. Group 1 (less dense stands) has bigger crown diameters up to d.b.h. of 45 cm, and from d.b.h. of 45 cm less than groups of plots 2 and 3. Crown diameters of group 2 (medium dense stands) and group 3 (dense stands) do not reveal significant changes in crown diameters as related to d.b.h. Differences are dependent on line inclination (regression coefficient b1) which is at less dense stands considerably lower and is 0, 118 and 0, 211. It is significant that the levelling lines at all three groups of plots (less dense, medium dense and dense) meet at d.b.h. of 45 cm, and further from this d.b.h. the number of trees does not play an important role. Medium crown diameter is bigger for less dense stands and is 8, 11 with a medium d.b.h of 50, 99, for medium dense stands it is 7, 44 with a medium d.b.h. of 45, 10, while the crown diameter for dense stands is the lowest and is 6, 82 with d.b.h of 41, 86. Correlation coefficient (crown diameter and d.b.h.) is almost identical for all groups of plots and ranges from 0, 759 for less dense stands, 0, 810 for medium dense stands and 0, 720 for dense stands. In concord with the above mentioned, the determination coefficient, which explains the measurement unit for the interpretation of the variability by this correlation connection, amounts to 0, 562 for denser, 0, 656 for medium dense and up to 0, 518 for dense stands.

stand; stand elements; structural elements; measurement; dendrometry; silvicultural and managerial works; common oak; species distribution; number of trees; d.b.h.; d.b.h. distribution; tree height; height curves; sequence of rates; basal area; bas-relief

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