Productivity and cost of cut-to-length and whole-tree harvesting in a mixed-conifer stand

摘要

A field-based study was performed to broaden our knowledge of harvesting productivity, cost (stump-to-truck), and log value recovery between cut-to-length (CTL) and whole-tree (WT) harvesting working side-by-side in two mixed-conifer stands in northern Idaho. Each site included two replications of each of the harvesting options. Hourly harvesting productivity ranged from 1,163 to 5,428 ft~3 per productive machine hour (PMH) and 1,350 to 6,552 ft~3/PMH for the CTL and WT harvesting machines, respectively. This result suggests that the WT harvesting system was more productive than the CTL harvesting because specific tasks were assigned to each machine. Higher productivity of the WT harvesting system resulted in lower harvesting costs, although the hourly machine rate for the WT harvesting system was slightly higher than for the CTL harvesting system. The CTL harvesting system costs were dollar0.34/ft~3 and dollar0.36/ft~3 while the WT harvesting costs were dollar0.22/ft~3 and dollar0.33/ft~3 at the two sites. Harvesting costs (dollar /ft~3) were highly influenced by skidding or forwarding distance, log length and diameter, and machine combinations. The WT harvesting recovered more sawlogs (large-end diameter > 8 in) and pulpwood (any snag, decayed log or log below mill specified lengths), but less ton-wood (a log of large-end diameter < 8 in and top minimum diameter of 4 in) than the CTL harvesting. Net revenue from the WT harvesting was higher than that from the CTL harvesting.