The U.S. forestry industry, in the process of harvesting and converting wood into consumer products, generates a number of residue and waste materials that could be used for bioenergy and bioproducts. Secondary mills utilize the products from primary mills to produce other products (e.g., convert board lumber into furniture, cabinets, etc.). While primary and secondary mills are typically separate facilities, both primary wood processing and secondary conversion to finished consumer products can occur in the same facility.
Few estimates exist regarding the amount of secondary mill residues that are generated. This type of data is not routinely collected and must be estimated, generally by multiplying the number of employees by a waste generation factor (often lbs of waste/employee). Little data is available regarding appropriate waste generation factors and the quality and type of employment data is often suspect. Use of SIC codes to identify companies often leads to misidentification due either to double counting of companies
listed under more than one SIC code or inclusion or exclusion of companies entering or leaving the industry resulting from delay in compiling SIC data (Buggeln, 2002).
Rooney (1998) estimated that 12.5 million dry tons of secondary mill wood residues are generated, but that only 1.2 million dry tons could be available for bioenergy after correcting for assumed recoverability factors, percent of residues contaminated, etc. No economic analysis was conducted.