Good example of tree healing a wound

Q: A few years ago my neighbor hit this tree with his car. He covered the damaged spot with tar and we thought everything was fine until a few days ago when I noticed a patch of raised bark on the tree. Is there anything I can do to fix this? Is this tree save-able?

A: It looks like the tree is doing a great job healing itself! You can’t see it, but immediately after the injury, the tree put a layer of dense cells underneath the wound to keep fungi away from the center of the tree.

Tar should not have been applied: it slowed the healing process.

The rounded, ropey callus tissue around the edge of the damage is the tree’s attempt to seal the bark edge and to put fresh tissue on top of the wound. Over the next year, the hole in the bark will gradually get smaller and you won’t see inside the wound anymore.