Dynamics and Structural characteristics of a natural unlogged oriental beech (Fagus orientalis Lipsky) stand during a 5-years period in Shast Kalate Forest, Northern Iran

Investigation on structure and dynamics of natural forest ecosystems is an important issue for silvicultural decisions. The aim of this study is to analysis dynamics and structure of a beech stand during 5-year period in the Shast Kalateh forest in the Caspian region, North of Iran. Data were collected from a 16.9ha permanent research plot established in a natural unlogged stand in 2006. All living trees with a diameter at breast height of ≥7.5cm were measured. The analysis of results showed that the total living stand density and volume was fluctuated between 302 and 287Nha-1 and 504 to 472m3ha-1 over a 5-year period, respectively. Results also showed that the total density of deadwood increased from 21 to 27.7Nha-1 over the 5 years. During the study period the volume of died trees was 15.3m3ha-1, that was equal to 3% mortality compared to the living trees volume in 2006. The maximum proportion of stem numbers were found in the small diameter class (≤30cm), whereas the maximum volume of trees was found in the largest diameter class (>75cm). Another remarkable change was related to the amount of total volume in the diameter class (35-50 cm), which was 37.4 and 40.3 m3ha-1 from 2006 to 2011, respectively. The results showed that the highest mortality rate happened among young trees with diameter ≤30cm. It can be concluded that Shast Kalateh forest as a part of beech forests is passing through a degradation phase, due to the significant number and volume of dead wood.