Spatial structure of managed beech-dominated forest: applicability of nearest neighbors indices

High structural diversity is often attributed to old-growth forests, usually established naturally and unmanaged. Forest diversity should be considered not only in terms of species diversity and richness but also the variation in trees dimension and their spatial distribution have to be taken into consideration. The main goal of this paper was the answer if nearest neighbor indices are suitable for spatial forest structure description. To answer this question results obtained from 3 managed beech-dominated forests from natural regeneration are presented and discussed. The following indices were calculated: Clark-Evans aggregation index (R), DBH and height differentiation indices (TD and TH, respectively) and mingling index (DM) analyzing horizontal and vertical spatial structure of the forest. Results indicated that managed beech forests demonstrated rather homogenous spatial structure in both aspects. Living trees as well as future crop trees were mostly regularly distributed. Spatial variation in DBH and height between living nearest neighbors was rather low. The lowest variation in sizes was demonstrated by future crop trees. Mature beech forests revealed single species structure and other tree species – if present – were spatially segregated from beech. It can be supposed that high homogeneity structure of these forests results from biological characteristics of this species as well as thinning treatments conducted by foresters.