I would like to attempt and heal an old wound on a second hand jpb. It appears that the cambium near the cut site has slightly receded below the hardwood, ~1mm. the wound was likely caused by removing a major branch and the cut was left flush with the trunk. I’m thinking of removing some of the hardwood, eg concave cut , then opening up the cambium a bit to activate healing. Of course I’ll use “putty” to seal. What do you think?