You have to go to the sawmill to get a load of bark, which could well be in town (wrong side of the tracks, however). One would waste his time collecting bark "down river" because it would be rotten; full of fungus and bacteria. For use, the bark must be fresh.
Nowadays, one can go the the materials section of a plant nursery where they have it nicely bagged and sized for use as mulch or ground cover, as well as bags of selected bark from west coast sawmills for those of us who raise orchids.