Dear all - I planted this tree about 4 years ago, and it has grown into a fine specimen. A couple of years ago, I noticed hole(s) in the trunk and distended, cracked bark at the base. I went postal and sprayed both places with Captain Jack's deadbug. It helped, and these have healed, but this hole in the trunk has not been filled up. I worry that insects may be getting in there and destroying my tree. What can I do? I was thinking of filling it up with vaseline to deter insects.