If you cut that tree and it falls into other trees, he will be launched from the tree when it comes to a stop. He could be very badly injured, or so frightened by the fall that he just runs right up another tree. I'd call a tree service guy to come out and climb the tree to retrieve him. Or get a hose and wet him down good, maybe that could chase him back down. Do this in the morning though so he has a chance to dry in case it does not work.