An investigation of wood fibre recovery and related economics of four harvesting systems common to northwestern Ontario.

摘要

Wood fibre recovery levels of harvesting systems have increased steadily since the advent of mechanized logging in northwestern Ontario. Although wood utilization levels are commonly better than the legal specifications there remains room for improvement. Better knowledge of wood utilization levels can lead to a more efficient choice of harvesting systems and/or the improvement of elements within given harvesting systems. More efficient harvesting systems can be used to meet management goals of lower wood costs, greater fibre recovery, and/or less extensive cutting. The objectives of this study were to: (1) determine the relative amounts of wood fibre recovery of various harvesting systems currently being employed in northwestern Ontario, (2) quantify the amount of waste wood produced at each elements of those harvesting systems, and (3) determine the overall economic impact of achieving better recovery.; Sampling of wasted wood fibre from each element of three common harvesting systems; full-tree chipping (FT-CH), full-tree to roadside with shortwood to mill (FT-SW), and cut-to-length (CTL), occurred over two summers of typical operations. Detailed models of fibre recovery were developed for these three harvesting systems. As well, logical extrapolations were used to develop a fibre utilization model for a fourth system; full-tree to roadside with tree-length to mill (FT-TL). A wood flow analysis was conducted on a case study area using a raster based geographic information system. Results indicate that the most efficient systems in terms of fibre recovery are the FT-CH and the CTL system. The geographic wood flow analysis revealed that significantly less area would be required to be harvested if more efficient harvesting systems were used. Marginal cost analysis revealed that the CTL system should not be used to replace the FT-SW system. Slight reductions in the cost of the CTL system would, however, make the system more cost advantageous in the long term.