The concepts of sustainability and climax of native spruce forests from the standpoint of successional dynamics of the forest community

The concepts of climax and sustainability of forest communities were considered using forests of native spruce formations of the taiga zone of European Russia as an example. Objects and methods. Native spruce forests of different ages, different dynamic states and evolutionary formations were selected by a random sample from the general database of spruce communities of the taiga zone of the European North. A total of 30 spruce forests from all taiga subzones were selected. Results and discussion. The structure of age series and analysis of different generations’ trees volumes in forest stands were studied to determine the successional position of spruce forests. Biogeocenoses with no more than two excesses of tree volumes (50 % or more of the forest stand wood stock) in adjacent age generations cannot be considered forests of the climax dynamic state, but are treated as communities of transitional phases of dynamics. Spruce forests with relatively uniform distribution of tree volumes within generations of adjacent positions in the age series of the forest stand correspond to a stable state to the greatest extent, which significantly increases the time period of their stable structural position, close to the climax state. Statistical analysis of the relationship between age and volume of trees in biogeocenoses of different successional positions confirms these expectations: the relationship between predictors is “high, close” — R² > 0.8. Conclusion. A forest community can reach a climax stable state with a relatively uniform distribution of tree volumes in age generations, constituting more than half of the age series of the forest stand.