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shelf cut is what i'd call it. the cuts absolutely must bypass so bypass cut can work too but i'd call it a shelf because i want the piece to stay right on the "shelf" so i can get out the way and then the crano can take it away.....
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One very important point to mention in the use of the “shelf/bypass” cut is the placement of the cuts. When you have a large leaning leader such as what is shown in the pictures, you usually will have the crane op pre-tension the piece and then make your first cut on the compression side (which could be either on top of the leader or on the bottom of the leader, depending on how much pre-tension is being applied. Your topcut should be closest to the trunk and the undercut is placed 4”-6” out (depending on species and diameter of wood), and the size of the shelf that you want to leave. As oldirty pointed out, the two cuts must bypass eachother to insure proper separation when the crane lifts the piece up.
Remember with crane picks, the pieces usually go up first. If you were using a GRCS to first lift and hold your pieces before you cut the branch, placing the undercut closest to the trunk and the topcut further out on the limb would create the “shelf”. This is just the opposite of crane picks). No need to worry about the kerf’s piece catching and pulling your saw out of your hands, as the piece is still supported by the load line. As the piece is lowered downward, the “shelf” helps keep the branch supported while the climber moves safely away
