Structural diversity of mixed beech stands in regeneration and decay phases of Darabkola forests, Mazandaran province

Forest structure is one of the most important key components in the description of forest ecosystems and its biodiversity. In order to properly forest ecosystems management, indicators are required to obtain the most information about the current condition of the forest structure and monitoring its changes with the least cost and time. The purpose of this study was to investigate the structural diversity of beech stands using a set of quantitative indicators based on the closest neighbor including uniform angle indicators, mingling, distance to neighborhoods, and diameter and height differentiation in the regeneration and degradation phases were carried out in Darabkola forest, Mazandaran. Six one-hectare sample plots were established in regeneration and degradation phases (three sample plots in each phase). In each plot, nine subplots (each 900 m2 ) were dispersed at a distance of 30 m. The diameter at breast height, tree height, the distance and angle among trees were measured for the nearest beech tree to the center of the sample plot as the control tree and three neighboring trees at the nearest distance to the control tree. The mean of uniform angle indices, species mingling, diameter and height differentiation, and distance index were 0.54, 0.51, 0.38, 0.54, and 4.13 in the regeneration phase, while these values were 51.0, 33.0, 43.0, 35.0 and 44.5 in the degradation phase, respectively. Therefore, using data from structural quantization of untouched beech stands, it is possible to assess their development stages and the results of forest management activities.