Vegetation biomass is a crucial ecological variable for understanding the evolution and potential future changes of the climate system and is a larger global store of carbon than the atmosphere. One of the issues of major global concern is the increase in atmospheric carbon dioxide and its potential to change world climate. The study area is located in the Hyrcanian forests and sample plots were selected in the Fagus stands. The logging is done using a method of selecting individual trees. The method presented here is based on existing volume per ha data and volume-weighted average wood density. The total amount of biomass was equal to 421 ton per hectare. The results showed that the rate of deforestation in natural forests in Hyrcanian forest is high. Biomass estimates are critical for many landscape analysis questions. Measurements for biomass should be conducted at least every 5 years. and remote sensing inference should be repeated at least on an annual basis.