Improving large trailer access for biomass recovery in steep terrain

Abstract

Between 30 and 40% of private and state forest lands in the US Pacific Northwest are in steep terrain, making forest harvest residues difficult and costly to obtain. Turnarounds in steep terrain are particularly problematic. In 2010, Hermann Brothers Logging (Port Angeles, WA), in collaboration with Western Trailers (Boise, ID), designed a self-steering chip van to increase large trailer access in steep areas of the Olympic Peninsula (WA). Following a series of mobility tests of the self-steering trailer, Arena Simulation by Rockwell Automation was used to compare the self-steering trailer system cost-effectiveness against a hook-lift truck system on a total system cost BDMt-1 basis. Under a base scenario, the self-steering system had a lower cost ($60.01 BDMt-1) than the hook-lift truck application ($101.27 BDMt-1) with a total system cost, including mobilization, piling, support equipment, and profit and risk. Assuming a 13.72 m (45 ft) standard trailer could reach a percentage of the harvest units, the hook-lift/standard trailer combination system was still not competitive with the self-steering trailer under the base case scenario until the percent allocation for the hook-lift trucks was reduced to 13%. After altering the base case scenario to favor the hook-lift application, the self-steering system was still more cost-effective until the allocation for hook-lift trucks was reduced to 21%.