The poplar bark from which the shingles are made is salvaged from timber operations, and otherwise would be burned, mulched, or left to rot. Among the benefits of top manufactured bark shingles: They contain no chemicals, having been processed solely with sanitizing kiln heat. Bark's insulating heft keeps heating and cooling bills low. Bark requires no paint, stain, or other treatments. And shingles can last 75 years or more without maintenance.