A global analysis of 403 tropical and temperate tree species, showing that for most species mass growth rate increases continuously with tree size. Thus, large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon. At the extreme the annual fixing of carbon by a single large tree can equal the entire carbon content of a smaller tree.
Stephenson, N.L. et al.
2014
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Forest Ecology and Conservation Group 