I have used redirects while working in a tree by wrapping a small dynema sling around the branch thru a binner holding a small pulley. The rope follows along the pulley and it moves fairly easy. It works well in some instances but like Moss mentioned you will have to go back and remove it before being able to get down from the tree. It works but it is not that practical in general. In this set up I used screw _link_ biners or self locking it does not matter because the rope never touches the binner but instead moves along the mini-pulley.

Edited: rapping vs wrapping