Spatial structure – case study on experimental plots of beech (Fagus sylvatica L.) and scots pine (Pinus sylvestrisL.) in Olovo, Bosnia and Herzegovina

Spatial structure is the horizontal and vertical arrangement of individual trees. It affects many processes in the stand such as stability, production and regeneration. Stand structure parameters are used to describe spatial structure on experimental plots. The paper presents methods that describe the stand structure through three levels of diversity related to position, species and size. Research has been conducted on two experimental plots from the area of Olovo. Referent trees and their competitors were selected on both experimental plots, and competitors were defined by referent tree distance. The aim of this paper is to describe the spatial structure on experimental plot of European beech (Fagus sylvatica L.) and experimental plot of European beech and Scots pine (Pinus sylvestris L.). Indicators of spatial diversity, dimensional diversity and diversity of tree species have been determined to achieve that aim. For each experimental plots are described: horizontal tree distribution (Poisson Distribution, Clapham's Variance – Mean Ratio and Morisita's Index of Dispersion), diameter differentiation (Diameter Differentiation by Füldner and Dominance Index by Hui et al.), species diversity and structural diversity (Species Profile Index by Pretzsch) and species intermingling (Species Intermingling Index by Füldner). Obtained results show that the stand structure of both experimental plots deviates from random distribution. Dimensional diversity parameters indicate stronger intensity of competition for beech trees. Analysis of species diversity showed that beech trees occur in groups or patches, and the other represented species mix more intensive.