Hi all, I think that bark obtained from coppicing was used in the tanning industry. The bark from willow birch and oak was ground up and soaked to release the tannin, and the skins were soaked in the solution to cure them. I reckon a twig peeler was someone who stripped the bark.
Having said that, "peel" sounds like removing it in strips, so it could be that willow bark etc was being used for fibre ie for tying hurdles or similar. Dad often used to use willow bark on the farm for emergency repairs in the days before plastic baler twine.
Fred.