Production economics and carbon footprint of an integrated timber harvesting operation in the Northeastern US

Abstract

Woody biomass has tremendous potential to reduce the reliance on non-renewable energy, however, the high cost, uncertain harvesting carbon footprint, and policies may hinder it from becoming a predominant component of the US renewable energy sector, particularly in the Northeast. The objectives of this study were to a) assess productivity (m³ PMH⁻¹) and cost ($ m⁻³) of a stump-to-truck integrated timber harvesting operation; b) identify and evaluate major factors affecting operational productivity and cost; and c) quantify carbon footprint of the harvesting operation. Detailed time and motion studies were conducted in a softwood dominated forest stand in upstate New York, during the summer of 2021. Stump-to-truck life cycle assessment (LCA) of roundwood harvesting and wood chips production was quantified using USLCI and US-EI 2.2 databases and TRACI method in Simapro 9.3.0.3 software. The functional units were 1 m³ of green roundwood (50 % moisture content) and 1 tonne of green wood chips (moisture content 50 %). The results showed that the harvesting cost was $12.98 m⁻³ and $7.40 tonne⁻¹ for roundwood and wood chips, respectively. Grapple skidder had the lowest productivity (m³ PMH⁻¹) and the highest carbon footprint. The carbon footprint of stump-to-truck timber harvesting operation accounted for 0.726 kg CO₂ eq m⁻³ and 0.818 kg CO₂ eq tonne⁻¹ for roundwood and wood chips, respectively. The chipping cost was $7.40 tonne⁻¹. The harvesting cost decreased by 4.5 % when self-loading truck was used instead of a loader. Estimating operating cost and carbon footprint of integrated timber harvesting operations is essential to promote the forest residues as a major contributor of bioenergy in the changing scenarios of climate.