You might look for bore bugs on the trunk and base of the tree........try sevin......after the sun goes down...mix 1 teasp liquid hand soap w 1 qt water and spray.........wear old long clothes, goggles, mask, gloves & hat...............keep children & animals away until it is dry............don't spray on windy days....................spray the ground around it...........................you can call your forrester and they might tell you about bores or something else to do............if you decide to cut the top off....you have to put spectricide tree spray repair on it.....I use it when deer use their antlers on our fruit trees.