Evaluation of technical and organizational approaches for directly loading logs in mechanized cut-to-length harvesting

Abstract

In the mechanized cut-to-length system, a harvester fells and cuts trees into logs that are stored on the ground until a forwarder picks them up and carries them to landing sites. A proposed improvement is to place logs in the load space of the transporting machine as they are cut. Two approaches for this integration of work tasks are available: technical, using a single machine (a harwarder), and organizational, using a harvester to place cut logs directly into the bunk of a waiting forwarder. Here, the theoretical potential of the two approaches is evaluated using a developed methodological framework. In static modeling, the same type of work took equally long times for variants of both approaches. The results indicate that harwarders (first conceived more than 50 years ago) have substantial theoretical potential and may finally become competitive if key innovations are developed. Conversely, there was very limited theoretical potential for organizational integration, using either a manned or unmanned harvester, because the interacting machines are not affected by the same environmental factors. Hence their interdependency generates waiting time under most stand conditions, and the reduced costs of an unmanned harvester are insufficient to compensate for the increased time consumption. © 2012 by the Society of American Foresters.