Evaluation of competition indices to assess the effect of management interventions on oriental beech (Fagus orientalis Lipsky) forest of Lavij- Noor region, Mazandaran province

Tree to tree variation in growth results from compositional complexity, stand structure and competition. Therefore, it is essential to know how trees respond to competitive interactions. This study aims to evaluate of competition indices in order to assessment of management interventions effects in pure beech (Fagus orientalis Lipsky) stands (with 36 hectares) in Lavij- Noor region of Mazandaran province. For this purpose, the positions of all 58 marked trees were recorded as cored trees. Competition plots centered on the cored tree with radius of 3.5 × the cored tree crowns were established. The following attributes were measured for each tree (≥ 7.5 cm diameter at breast height (DBH)) within the plots: X and Y coordinates (m), total height, DBH, crown diameter at the base of the living crown in different directions and crown length. In order to quantify the competition level by each of the cored trees, 4 different distance-independent indices including Gerrard, Bella, Hegyi and Braathe were used. The results showed that the studied stands were middle-aged, the major interventions were in the middle DBH classes, and there was no significant change in the amount of competition indices following the interventions. Accordingly, the management interventions (marking) were not targeted and the process of individual tree competition changes was not measured. Therefore, the process of competition changes is necessary to be considered in stand management due to the high importance of the competition factor and its relation to the stand parameters.