Dear Gardeners Mailbag, I have an oak tree with a cavity. Can I use some type of wood filler to fill it and even the surface out?
Certified arborists advise against that. Filling cavities adds no strength to the tree trunk, and it encapsulates any decay that might be present.
You are really better off to just allow the tree to form new bark across the open wound.
If you see a roll of bark forming uni…
