I'm not sure if I killed the branch, or not. I'm thinking that now that I've taken the twine off that branch, I'll give it a few days to see if it starts getting some color back. If not, I may have to prune that branch off. I'm hoping it's not fire blight, but it can't be a coincidence that the branch loses its color right where I had the twine. I'm hoping that I didn't do any permanent damage, and that the branch will come back to life. Maybe I should water the tree a bit, to get the sapwood to pump some nutrients up to that branch. Am I doing the right thing?

I guess I need to find something softer to wrap around the tree. The guy at the gardening store told me that this gardening twine would be perfect, but I think I may need something softer, at least at the point where it wraps around the trees. Does anyone have any suggestions on what to use?

I tie down using cotton twine. But the key is don't wrap around the branch. Tie a short loop in the twine at appropriate height, say half way to branch. Then place loose end over the branch and tie off to the loop. This means twine touches the branch only on top side.

Wait till spring to do this. The branch only assumes new position when growing. It's when growing that new wood is laid down in proper position. Not wrong to do now but won't be any better than spring.