The first link isn't working... I see what you mean though, using the rope for a harness. Or usually, those are Nylon Straps now. Those are generally used with spikes on the shoes, and can get you up any kind of tree safely and easily. You can probably shimmy up quicker if you're good, but if you're doing it for a living you probably don't want the skinned up shins and forearms that go along with it. Plus, the harness is about the only way to get up a large trunked tree, if there are no low-laying branches.

I thought you were talking about a long length of climbing rope, which is usually taken up with the climber, so you can tie off at the top, belay down, then use it to pull the tree when falling, or for lowering branches you've cut. You could also that rope to climb up the tree again, if you're not falling it.

I worked as an arborist in South Carolina, trimming hardwoods, and that is how we climbed trees most of the time, with a harness and spikes. I was never that patient though, so I would just shimmy up small trees without equipment, like a 'coon hunter, is how people described it.

When I moved to the Islands (the Florida Keys) though, I never saw anybody climb a coconut palm with a harness. They are slimmer trees, so shimmying up just seemed the natural thing to do. Of course, coconuts aren't harvested commercially there. We just grab 'em to make drinks out of, and sell to tourists.