The dynamics of linear growth and annual productivity of Sphagnum cuspidatum, S. fallax, S. majus, S. obtusum, S. riparium, and S. subsecundum were studied in 2006–2013 in natural and transformed mire sites in the Kindasovo forest-mire research station of the Karelian Research Centre RAS (61°48ʹN, 33°35ʹE). Sphagnum mosses demonstrated the greatest linear increment and productivity in years with a warm spring and warm moist summer, when the water regime in their habitats was favourable. In the summertime air temperature influenced the growth of Sphagna more significantly than precipitation amounts. In natural mire sites linear increment variations among years with different climatic parameters were two-three-fold (S. subsecundum, S. majus) to four-five fold (S. riparium, S. fallax, S. obtusum). The productivity of the cenopopulations of the studied species in natural habitats varied among years from 1.5 to 15 g / dm2. The greatest annual production was demonstrated by Sphagnum riparium – 4 to 15 (12.4 on average), the index in other species being twice or thrice lower. It was shown in this study that the linear increment of peatmosses of the section Cuspidata in transformed mires in overgrown drainage ditches was two or three times that of the same species in natural habitats, whereas their annual production was only 20–30 % higher than in natural mires, since the density of the moss cenopopulations in the ditches was low.