Integrated in-stand debarking with a harvester in cut-to-length operations–processing and extraction performance assessment

Abstract

Climate change fostered one of the most destructive spruce pests, the Eurasian spruce bark beetle. One measure to control bark beetle outbreaks could be debarking by a harvester. To assess the difference in harvesting and forwarding productivity between cut-to-length (CTL) and CTL with integrated debarking, a detailed time and motion study was carried out. The study covered two stands (2.1 ha) divided into sample plots, whereby 19 were treated as CTL and 20 as CTL debarking. The harvesting head H415 attached to a John Deere 1270G was modified with special feed rollers and adjusted hydraulic settings. A John Deere 1210E forwarder extracted the logs. Trees were measured and video recordings of the operation allowed a post hoc time and motion study. Linear and mixed models were applied to develop prediction functions. Altogether 400 spruce trees were harvested whereof 163 trees with an average stem volume of 0.45 m3 were processed CTL and 237 (0.40 m3) were treated with CTL debarking. Harvesting productivity reached 26.4 m3 PSH0−1 in CTL debarking, which was 25% lower than CTL causing €2.40 m−3 additional costs. Forwarding productivity with 18.8 m3 PSH0−1 did not differ.