Energy wood harvesting productivity of three harvesting methods in first thinning of scots pine (Pinus sylvestris L.)

Abstract

Abstract Energy wood harvesting in young forests presents an economical challenge and has been dependent on subsidies in Finland. Whole-tree harvesting systems have proved to be most productive when carrying out energy wood harvesting in cleanings and early thinnings in young forests. The application of integrated energy wood and pulpwood harvesting is less common. It was hypothesized that multi-tree harvesting (MTH) with the OM-Waratah 745 single grip harvester head could change harvesting logistics and improve productivity for integrated energy wood and pulpwood thinnings. Two variations of MTH were compared with single-tree harvesting (STH). The logging methods studied were: (1) conventional single-tree harvesting with pulpwood and energy wood processed at the strip road; (2) multi-tree harvesting with pulpwood and energy wood processing along the strip road (MTH1); and (3) multi-tree harvesting at the stump where the aim was to leave the logging residues distributed evenly over the harvesting area and not on the strip roads (MTH2). MTH methods were 28–35% more productive than the single-tree harvesting. The biggest differences in work stages were found in the felling and delimbing stages. In single-tree harvesting felling was 9–26% and delimbing 14–27% slower than in multi-tree harvesting. MTH2 distributed 13% of residues further than 7 m from the strip road center. With STH and MTH1 only a good 1.2–1.7% was placed this far, and 74.4 and 62.0% respectively within 3 m.