Woodland: comparative dynamics of average diameters of coniferous tree stands of different forest types

The growth rates by average diameter of different types of conifers forest stand aggregates are analyzed in the paper. Three predominant Siberian stone pine Pinus sibirica Du Tour forest types have been studied. It was found that their growth is essentially different. The growth rate of the Siberian stone pine stand of green moss­red bilberry (Pinetum sibiricae vacciniosum) forest type is especially impressive. The Siberian stone pine stand of bergenia (Pinetum sibiricae bergeniosum) forest type shows the lowest growth rate. An intermediate place occupies the Siberian stone pine stand of low herb­dwarf shrub (Pinetum sibiricae nanaherbosa­fruticosum) forest type. Two types of the Siberian stone pine stand are remarkably growing up to 140–200 years. It has been revealed that standard yield tables for different age generations are not stable models. In the Siberian fir Abies sibirica Ledeb. Stands, low growth rates are registered at bergenia (Abietum sibiricae bergeniosum) and mountain rocky (Abietum sibiricae montani­lithosum) (due to severe site conditions) forest types, but stands of gramineous­herbaceous (Abietum sibiricae poacea­geteroherbosum) forest types grow well up to 100–140 years. The Siberian spruce Picea obovata Ledeb. stands of high (wide) herbaceous (Piceetum sibiricae latiherbosum) forest type grow intensively up to 130–160 years, and have principal water conservation value. The pioneers of alpine zone – forest types of mountain pine Pinus pumila (Pallas) Regel stands (Pinetum pumilae montani­lithosum, var. fruticosum) grow slowly in severe conditions of highlands, but their principal role is the stabilization of mountain ecosystems. Mutual comparison of all types of coniferous stands of the woodland shows the better than average growth of the Siberian stone pine and the Siberian spruce stands, and worse growth of the Siberian fir and mountain pine stands. Comparison of average diameters of the Siberian stone pine and the Siberian fir stands with similar characteristic for different mountain regions of Siberia according to the yield tables have been done