The results of studying long-term dynamics of the Darwin State Nature Biosphere Reserve forests happened to be in changed environmental conditions due to the influence of the Rybinsk reservoir are presented. Multi-year reservoir influence has significantly changed the environment of coastal areas, which resulted in necessity of studying the state of coastal forests. Dynamics studies of the forests were based on the principles of dynamic typology tested by I.S. Melekhov under study of early stages of anthropogenic forest life. The data we have obtained for mature and old growth forests bring in the significant changes to a concept of forest type stability at a stage of mature forest stand or formed type of forest. The studied forests do not remain their uniformity even throughout a single generation. The study object was waterlogging berry green moss pine forest growing in the indirect reservoir influence zone. Detailed description and analysis of various components of the studied forest type have been carried out for the purposes of studying the direction and speed of growth and development processes. The main attention was paid to the changes of forest live cover as an indicator of soil and hydrological conditions, forest stand, undergrowth and understorey. Conclusions on the direction and speed of changes in soils, their hydrological regime, the phytocenosis were drawn on the basis of data analysis obtained for the 70-year period on dynamics of different components of waterlogging berry green moss pine forest at the initial stage. It is essential in terms of dynamic typology to consider the studied forest type as a stage of relatively accelerated formation of blueberry green moss sphagnum pine forest at the middle waterlogging stage with a well-defined tendency to replacement of pine with spruce in new generation. These conclusions confirm the principles of I.S. Melekhov’s dynamic typology and have a significant meaning for forest science and practice, as well as carrying out the monitoring researches in the reserve. For citation: Mukhin A.K. Long-Term Dynamics of Waterlogging Pine Forests under the Reservoir Influence. Lesnoy Zhurnal [Forestry Journal], 2019, no. 3, pp. 17–31. DOI: 10.17238/issn0536-1036.2019.3.17