If hurt means injure or harm, that is really another question. The leaf exists for the life of the tree. It serves to feed the tree, it breathes for the tree, and helps to remove from it the excess water which the roots have sucked up. Of course a tree has many leaves, and so to pluck one cannot hurt the tree much. However, if we were to strip all the leaves off a tree in the sprig, we should soon find that it has harmed the tree. But when winds blows the leaves off a tree in the autumn, the tree is not harmed, for it has already taken what it wanted out of the leaves, and has no use for leaves until the next year.