I believe JeffL is talking about a normal wrench setup, which is what I use on almost all removals. Set up your wrench as you normally would, then choke the end of your climbing rope off on the tree. Using a carabiner, or a running bowline, whatever, your climbing line terminates on the tree in front of/above you, and you hang off that rope with your rope wrench.
Works especially well with climbing ropes with splices. This is why I love 100' pieces of rope with splices so much - just enough to reach the ground, no hauling extra rope around in the tree, and you are always ready to drop to the ground.