XVI International Botanical Congess

The autogenic succession of bog moss pine forests under oligotrophic condition in Leningrad region and Karelia has been studied. The dynamic approach to classification of plant communities created on the Dept. of Geobotany and Plant Ecology has been used. The stand of this forests has been discovered to consist of one pine generation or of 2-4 generations, with an interval between them of 40-200 years. Any natural change of the ground cover with respect to the growth of trees ages both in climax communities and in demutation (but not in postdestruction) communities has not been revealed. Fire in this ecotope seems to be a most important factors of the dynamics of stand and ground cover. The ecotopical system of associations has been constructed, which include 4 associations. Climax cycle consists of one association involved the different stages in connection with stand dynamics and changes of generations. Some differences in the ground cover are expressed by greater or lesser abundance of true mosses because of a various degree of the root system development. States of demutation row has been united in 3 associations: demutation proper association which involved the stages of recovering after disastrous destructions and two postfire associations.