I've been wanting to get a good look at the guys while cutting. I can't imagine they cut this palm without some kind of guide to stop them from wandering all over. Maybe they just snap a chalk line? The guys that built my palapa did the same thing but I wasn't interested in the wood cutting process then.
These palms are in a very old mango orchard and both the mangoes and palms were damaged in Hurricane Patricia. They've cut and cleaned up many of the mangoes so they can get in for the wood. Still many people cook on an open fire so the mangoes will get used someday.