Read here. It now appears that the vast majority of scientists have been wrong in their conclusion that old rain forests naturally become carbon 'sources' in old age. (Imagine that, the scientific "consensus" wasn't correct, amazing.)
The new research has discovered these old trees to be sucking up the excess CO2, much to their liking and new growth. Scientists now estimate these old forests might account for up to 50% of the infamous, global "missing carbon sink."