I have a mature black walnut growing on my front lawn. This year I noticed a sizable bare patch on the trunk (see photo). I have also observed branches that are dead at the top. I called an arborist who thought its roots were most likely damaged in a renovation we did not too long ago. He wanted to give it a deep fertilization as well as trim the dead branches. Do you have any further suggestions as to what I can do for this tree? The arborist did not address the bare patch.
The arborist provided standard recommendations for good tree health. As to the bare patch on the trunk, if less than 25% of the bark around the trunk has been damaged, the tree will probably recover. When fresh wounds occur on the trunk, the injured bark should be removed carefully, leaving healthy bark that is sound and tight to the wood. A wound dressing (tree paint) is not necessary, and is not recommended.