Carbon impacts of hardwood lumber processing in the northeastern United States.

Carbon emission from hardwood lumber processing in different-sized sawmills under varying energy sources, man- agement strategies, and potential carbon offsetting capacity through useful life (service life) of lumber in the northeastern United States was analyzed using analytical statistics such as analysis of variance (ANOVA), mixed-effect model, principal component analysis, and Monte Carlo simulation. Data obtained from a regional sawmill survey (Pennsylvania, New York, Ohio, and West Virginia), energy audit of sawmills, public databases, and relevant literature were analyzed for the gate-to-gate life cycle inventory framework. Results showed that mean carbon emission (megagrams (Mg) per thousand cubic metres (TCM)) for lumber processing significantly differs among sawmill sizes. The total carbon emission from electricity consumption and wood residue of lumber processing was approximately 62.5%, 80.3%, and 66.2% of carbon stored in lumber processed for small, medium, and large sawmills, respectively. Efficient management and potential opportunities of improvement in sawmills can significantly reduce carbon emission (10.96% ± 1.57%) from hardwood lumber processing. Carbon stock from lumber production could be enhanced by either reducing carbon emission from energy consumption or decreasing lumber export quantity. The carbon emission-loss ratio (CELR) suggested that after 100 years, nearly 50% of carbon stored in lumber would be still available for carbon accountability. Electricity generation from either a single resource (natural gas) or mixed resources as is the case in RFC EAST (eGrid subregion) would be beneficial in lowering carbon emission from sawmill processing.