aerial burr knots

diligentduck starts with ...
What is the best way to remove aerial burr knots? How can I deter further rootstock sprouts from my Ballerina apple tree?

california dude says...
Jimmy: I'm curious. I've looked all over the net for information on removing burr knots and have found only this thread so far. My apple trees are almost all on M111 which is notoriously productive of burr knots. No one told me to that and some are planted too high, so I have quite a few of them that I would like to remove. I was just out experimenting and I can see the specks that are the root growths in the wood of the tree after cutting out off the burr knots with a saw. Should I actually hollow the burr knot out until absolutely all of these are removed from the wood? Or is it sufficient to make sure there are none in the bark/cambium zone? I just don't want to carve that deep if I don't have to. My trees are several years old, so its going to be very disruptive to their growth. Thanks. Hope you're still out there since you seem to be like the only human in the internet universe that knows how to remove burr knots :)