Spatio-temporal structure of natural forest: A structural index approach
2012
Balanda, M., Technicka Univ., Zvolen (Slovak Republic). Katedra Pestovania Lesa
The submitted paper deals with the analysis of stand structure of mixed species natural forest located in the Carpathians, Middle Europe. In order to evaluate structural diversity we chose the combination of distance independent and nearest-neighbor indices. The following structural indices were calculated: Shanon-Weaver index (S-W), diameter differentiation index (Td), Gigi coefficient (G), mingling index (DMi) and Clark Evans index (CEd). The permanent research plot (2.5 ha) was established in the National Nature Reserve Hroncecky grun and subdivided into subplots (25 x 25 m). The combination of the indices was calculated for each subplot separately. Regarding the diameter heterogeneity, most of the analyzed structures showed a moderate level of tree size differentiation (S-W value 0.393+/-0.074). The presence of a high number of juvenile individuals which already reached the diameter category "above 2 cm" did not significantly affect the diameter variation of the investigated stand. On the other hand, a massive establishment of subsequent generation led to the creation of a spatial structure characterized by a high level of vertical differentiation (Gini coefficient 0.47 in the structure characterized as the breakdown with successive generation). High climax species richness was confirmed by the calculated values of DMi index (maximum relative presence in the category from 0.3 to 0.4). Each tree was surrounded by two and more different species individuals. Our analysis discovered a negative developmental shift in the DMi values towards less differentiated structures. Regarding the horizontal distribution the analysis of CEd values indicated that the investigated natural forest can reveal a random distribution of individuals regardless of the developmental stage.
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