This study evaluated the operational performance and cost of an integrated harvesting system that harvested sawlogs and biomass (i.e., energy wood chips) in stand conversion clearcut operations. Douglas-fir ( Pseudotsuga menziesii ) trees were processed into sawlogs while whole trees of tanoak ( Lithocarpus densiflorus ), and sub-merchantable materials (small-diameter trees, tops and limbs) were fed directly into a chipper to produce biomass for energy production. A standard time study method was used to determine productivity and costs. Over 26 working days, the integrated system produced 1,316 bone-dry metric tonnes (BDTs) of sawlogs, and 5,415.89 BDT of chips, with an average moisture content of 43.2%. Using the joint products allocation costing method, the costs of the integrated system were $29.87/BDT for biomass and $4.26/BDT for sawlogs. Chipping utilization was as low as 41%, directly affecting production and cost of chipping operation. Single-lane, dirt, spur roads were the most costly road type to transport whole trees to a centralized processing site: transportation costs for biomass and sawlogs were increased by $0.08/BDT and $0.02/BDT, respectively, for every 50 meter increase in traveling distance. Diesel fuel price could raise total system cost for each product by $0.78/BDT and $0.08/BDT for each $0.10/liter increase.
Harrill, H., & Han, H.-S. (2012). Productivity and Cost of Integrated Harvesting of Wood Chips and Sawlogs in Stand Conversion Operations. International Journal of Forestry Research, 2012, 1–10. https://doi.org/10.1155/2012/893079