If the rainforest increases in size, then carbon is removed from the atmosphere. If the rainforest decreases in size, it is released. As you pointed out, if the

If the rainforest increases in size, then carbon is removed from the atmosphere. If the rainforest decreases in size, it is released. As you pointed out, if the rainforest is the same constant size, it doesn't matter if a tree is oxidized after it dies - that means a new tree replaced it. The steady state is that the rainforest is a constant size. It is constantly absorbing and releasing carbon dioxide, but they must sum to zero if the size of the forest is constant.