Answer:
It depends on what you mean by "destruction". If they are burned, the carbon sequestered in the trees' tissue will combine with oxygen to form carbon dioxide, which some say causes global warming. But the same thing will happen if trees die naturally and rot in the forest. If, on the other hand, the trees are harvested and converted to lumber, and in some cases treated to prevent decay, the carbon in the tree tissue will remain sequestered indefinitely. If, when the trees are harvested, more trees are planted in their place, and eventually harvested and converted to lumber, more carbon will be sequestered. The most effective use of forests, in terms of carbon sequestration, is to continually plant and harvest trees on a regular cycle.