Advances in Cable Yarding: A Review of Recent Developments in Skyline Carriage Technology

Purpose of Review: Carriages are an integral component of cable yarding systems that are used to harvest timber on steep terrain. They provide the mobility component by allowing a payload to be pulled along a skyline that spans a harvest setting, as opposed to a brute force pulling a load along a slope. While yarder machinery and cable yarding systems are extensively studied and reported, this paper provides a first detailed review of recent developments in carriage technology. Recent Findings: There has been significant development in carriage technology in the last decade. In addition to step changes in functionality, they are now also used as technology platforms. This includes integration of geospatial and camera technology to provide for higher levels of automation. There are clear regional drivers that have differentiated carriage development. The need for low mass, versatility, and energy efficiency has generated a demand for electric carriages in the central European market. A focus on safety has driven New Zealand designers to work almost exclusively grapple carriages that no longer need choker setters on the ground being exposed to danger. North American developments include carriages capable of larger payloads to increase productivity and off-set high operation cost. Summary: Carriages have developed over time to become complex systems and provide additional capabilities instead of just providing a mobility and transfer mechanism within the yarding systems. By integrating new technologies that provide for greater efficiency and/or automation, carriage developments will help cable yarding systems remain cost-competitive, with high safety standard and environmentally sound.