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.