Rocky's not nuts. That's a pretty fair technique I use regularly when applicable, but as he says, there needs to be an adjacent tree. Tension the rope well, and make sure at the ground level you're not tied off. You go through a friction device, and then tie off. Since the top of the tree to be cut is now bending toward the tie-in tree, a back cut is generally all that is needed, though I've found a face cut, a la Murph keeps the trunk from fully separating, for better control.
Then you cut off firewood chunks from the bottom-up, belaying the tree down as you go. Keeps the mess zone extremely tight.
I doubt, though, I'd do a 50-footer like this. In fact, I rarely use the technique as the overall scenario has to be just right, otherwise it's simply faster to just climb it out. With a 50 footer and an adjacent tree, with a GRCS, you could process a tree like that in mere minutes, probably more quickly than the time taken to rig it.
