DIGITALNA ARHIVA ŠUMARSKOG LISTA
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Diameter distribution of Kukavica virgin forest compared to other two beech virgin forests is due to the fact that Kukavica is the youngest forest reserve and the time that has passed since it was declared a reserve was not long enough to develop all structural features of a virgin forest (Fig. 5). The differences in the values of the Gini coefficient are random with a probability of 82% and there is also a small difference in the Coefficients of variation of tree diameters and heights (Tab. 2). The Gini coefficient was in the range from 0.49 to 0.57 in the managed stands and from 0.45 to 0.52 in the virgin stands. Bilek et al. (2011) found an average of 0.22 in five managed stands (even-aged structure) in Central Bohemia, while two virgin stands had the coefficient between 0.67 and 0.75. Significant differences in between the virgin stands of Central Bohemia and Serbia can be affected by the difference in the lower limit of diameter at breast height which was 7 cm in Central Bohemia and 10 cm in Serbia. Coefficient of variation of tree diameters (CVdbh%) is in the range from 50.8 to 59.5% in the managed stands, while it ranges from 47.1 to 57.5% in virgin stands. Bilek et al. (2011) found an average CVdbh% of 21.0% in the managed stands, and between 80.3 and 109.6% in two virgin stands. Coefficient of variation of tree heights (CVh%) is in the range from 21.7 to 41.1% in the managed stands and from 27.4 to 30.8% in virgin stands. The Gini Coefficient and the Coefficient of variation of tree diameters (CVdbh%) show high diameter diversity in all studied stands. Diameter diversity is slightly larger in the managed stands than in the virgin stands. This rule also applies to height diversity. As expected, diameter diversity is much more pronounced than height diversity in all studied stands. The relative ratio of the coefficient of variation of tree diameters (CVdbh%) and the coefficient of variation of tree heights (CVh%) shows a significant deviation in the managed type of stands – from 1.23 to 2.42, while it is more uniform in the virgin type of stands and ranges from 1.53 to 1.87. This relationship shows that diameter and height diversities in beech forests in Serbia aren`t strongly correlated and the knowledge of one of them doesn`t enable estimation of the other one (Fig. 6). This statement is confirmed by correlation analysis which provided a low correlation coefficient of 0.12. Slenderness coefficient – Koeficijent vitkosti The ratio of height to diameter at breast height h / dbh (Slenderness coefficient) have on average higher values in the managed stands than in the virgin stands (Tab. 3). We |