The portion of harvested wood volume entering primary processing mills in North America that is converted to marketable products, or converted to useful energy, is near 100%. In other words, the wood waste at these mills is near 0%; therefore, in terms of wood use, these are zero-waste facilities. Secondary processing plants are similarly diligent in utilization of raw materials. Mill residues, that for much of the past century represented both an environmental problem and unrealized economic opportunity, are today being fully utilized and provide important benefits.