Apple – Burr Knot on Trunk

Q: I have black warty growths all over my Fuji apple tree. I think it’s “burr knot”. I’ve removed most of the knots with chisel. Can I save my apple tree?

A: I think you have diagnosed the problem exactly right. I’ve seen these galls on apple trees before but never knew what they were called.

All the references I see say to chisel or somehow physically remove the gall and hope the tree heals over the wound.