Origin of Biomes and Succession 



269 



Original soil 



Sphognum debris 



Water 



Fig. 120. Diagram of community succession from an open lake through the 

 sphagnum bog series to tamarack forest. 



and converted to soil, oak, pine, or spruce seedlings spring up, 

 gradually displace the larch, and become the dominants of the 

 final stage in the succession, the climax forest of the general area. 

 The estimated time involved in this succession is at least several 

 thousand years, varying with the initial depth of the pond. 



The same mechanisms of succession occur in all of these ex- 

 amples. Throughout any one series of community successions, the 

 seeds of all plants from all the communities reach or fall on the 

 area occupied by all the communities. Seeds of climax species fall- 



