A mature forest is a perfectly balanced carbon sink, with carbon released through death and decay, equal to the amount of carbon fixed by its growth – a climax ecosystem. Once it has reached this state it does not fix additional carbon. There it is, a giant store that would release a huge amount of carbon if burned, but while alive,it simply maintains itself. You can call the Amazon rain forest the lungs of the world if you like, because it does indeed respire. But don’t fool yourself that it is producing any net reduction in atmospheric CO2. For that …