The Effect of Yarding Technique on Yarding Productivity and Cost

Raffaele Spinelli,Natascia Magagnotti,Gernot Erber,Eric R Labelle,Giulio Cosola,Rien Visser

doi:10.5552/crojfe.2021.886

Abstract

Cable yarding is a well establish technology for the extraction of timber in steep terrain. However, it is encumbered with relatively low productivity and high costs, and as such this technology needs to adapt and progress to remain viable. The development of biomass as a valuable byproduct, and the availability of processors to support yarder operations, lend themselves to increasing the level of whole-tree extraction. Double-hitch carriages have been developed to allow for full suspension of whole-tree and tree-length material. This study compared a standard single-hitch to a double-hitch carriage under controlled conditions, namely in the same location using the same yarder with downhill extraction. As expected, the double-hitch carriage took longer to load up (+14%), but was able to achieve similar productivity (10–11 m3 per productive machine hour) through increased inhaul speed (+15%). The importance of this study is that it demonstrates both the physical and economic feasibility of moving to whole-tree extraction using the double-hitch type carriage for longer corridors, for settings with limited deflection, or areas with lower tolerance for soil disturbance.

Highlights

For timber extraction during harvesting, cable yarders use winches and wire rope to lift stems or logs off the ground and extract them out of the forest
On steep terrain, harvesting with cable yarding systems typically avoids the need to build a dense network of skidding trails and lowers the level of soil impact compared to ground-based logging (Spinelli et al 2010)
This is valuable in environmentally-sensitive areas, where the added cost of environmental compliance makes cable yarding more attractive than ground-based harvesting, even where the latter would be technically feasible (Huyler and LeDoux 1995)

Summary

Introduction

For timber extraction during harvesting, cable yarders use winches and wire rope to lift stems or logs off the ground and extract them out of the forest. On steep terrain, harvesting with cable yarding systems typically avoids the need to build a dense network of skidding trails and lowers the level of soil impact compared to ground-based logging (Spinelli et al 2010). This is valuable in environmentally-sensitive areas, where the added cost of environmental compliance makes cable yarding more attractive than ground-based harvesting, even where the latter would be technically feasible (Huyler and LeDoux 1995). Cable yarders can have many different attributes that affect their capability and performance, including overall size and power rating, number of drums, capability of the wire ropes, height of tower, carriage and rigging types (Samset 1985, Harrill et al 2019)

Methods

Results

Discussion

Conclusion