Description

ANNOTATION: This study focuses on two harvesting methods for utilization of understory biomass that were tested against a conventional harvesting method to determine relative costs. The conventional harvesting method tested removed all pine 6 inches diameter at breast height (DBH) and larger and hardwood sawlogs as tree length logs. The two intensive harvesting methods were a one-pass and a two-pass method. In the one-pass method, all material 1 inch DBH and larger was simultaneously harvested. With the two-pass method, the energy wood (same description as in the one-pass) was harvested in a first pass through the stand, and the commercial size wood being removed as tree length logs was harvested in a second pass. ABSTRACT: Two harvesting methods for utilization of understory biomass were tested against a conventional harvesting method to determine relative costs. The conventional harvesting method tested removed all pine 6 inches diameter at breast height (DBH) and larger and hardwood sawlogs as tree length logs. The two intensive harvesting methods were a one-pass and a two-pass method. In the one-pass method, all material 1 inch DBH and larger was simultaneously harvested. Pines 1 to 6 inches DBH and hardwoods 11 inches DBH and less were chipped for energy wood and all other stems were logged tree length. With the two-pass method, the energy wood (same description as in the one-pass) was harvested in a first pass through the stand, and the commercial size wood being removed as tree length logs was harvested in a second pass. The conventional harvesting system recovery averaged 52 percent of the standing biomass while the one-pass and two-pass methods recovery averaged 85 percent and 76 percent of the standing biomass, respectively. The conventional system had an average harvesting cost of $8.75 per green ton onto the log truck while the one-pass and two-pass methods had average costs onto log trucks and chip vans of $7.60 and $8.85 per green ton. Both the one-pass and two-pass methods produced energy chips into vans at a cost which was well below the value of the material as a fuel source at the mill.