A falling tree does not make noise. The falling tree displaces air that human ears detect as noise. If no one is around to detect it, the air is still displaced. So as to whether or not no one is there to hear it depends on your strength of hearing, natural amplification of the environment, and disruptions to the signal. e.g. a golf ball landing on grass does not roll as far as a golf ball landing on ice.If a tree falls in the woods, and no one is there to hear it, does it make any noise?