A 70 ft. white oak is missing 1 ft. X 6 ft. section of bark at the very bottom. A lightning strike knocked it off 5 years ago. The tree is recovering nicely and new growth is starting to cover the bare wood where the bark is gone. A portion of the bare wood is rotting so badly you can pull rot out with your fingers. The majority is good, hard, weathered oak. If I pull out all the rot now is there a chemical to treat the area so it will not rot anymore? I'm thinking of a spray.