LOL
Look in the videos section and a member called brainfart put up a German video where they are using that technique, no pun intended but they call it the box cut.
Over here we call it the bar was not long enough relief cut.
As Jim was up against a fence a standard felling bore in and go round for a shorter bar wasn't going to happen, easiest way was to take off the sides so the bar was long enough for the fell. I also done this on some bottle bottomed palms coz they get a bulge, neat trick, keep it in mind next time you may have the need for it.