Apple Tree Restoration and Sun Scald / Scorching

Ok, next phase of a project to restore and regraft part of the upper tree is going to kickoff this weekend, and could use some insight. A couple pics of the tree here.

I am trying to understand how much central wood I have to leave, to prevent sun burn to the upper scaffolds. On Alan’s recommendation, I am pruning it to a weep, and will ultimately re-graft a bunch of the upper tree. I can’t figure if it will turn out to be more of an open vase shape (kind of going that way already), or if I have to keep some vegetation in the center.

Can anyone suggest how much central shading of the trunk is needed to avoid bark scald?

In this post Alan shares a lot of comments about sun scalding and making sure there are enough leaf buds to keep the sap moving, though I’m still trying to understand how much coverage is actually needed.

Any insight would be helpful.

Anyone?

I can’t tell you anything about growing conditions in CO. I can tell you that sunscald occurs at least as high as 10’ in central MN