Quantification of beech stands structure in the stem exclusion phase

Evaluating the forest stands structure in different development stages is one of the ways for better understanding the forest dynamics and its response to natural disturbances. This study was carried out in the compartment 319, Kheiroud forest in order to quantify the structure properties of mixed beech stands in the stem exclusion phase. For this purpose, three one-hectare sample plots were selected in which stand structure characteristics were measured. The quantitative characteristics of two beech trees closest to grid intersection (30×30 m) as reference trees, were also measured along with three nearest neighbors to reference trees. The distance and angle between reference tree and neighbor ones and also the distance among neighbor trees were calculated. The results indicated that the average value of uniform angle index and species mingling were 0.53 and 0.51, respectively which implies random distribution of trees and tending beech to being mixed with other tree species and inter-species competition of this species with hornbeam. The average value of tree to tree distance was 4.7 m. Meanwhile diameter and height differentiation were 0.44 and 0.57, respectively indicating high density and competition in this phase to access the sources and better growth conditions.