About the time they were shredding the last pile of debris, it hit me: I should have dragged the huge piles of limbs I had in the backyard down the driveway and let them chip those, too. (I generated a bunch of stuff I was going to have to saw up and cord when I pruned the hedges and cut down some saplings last week.) I decided to drag down at least one load of the biggest limbs, so I wouldn't have to deal with them. When I got to the chipper, Manuel and Felix saw what I was up to and asked if there was more. Then they went up and dragged the rest down for me!
The lesson: A simple gracias and a smile (and un poco de Español) can get you far in today's world. :)