Economic evaluation of a roll-off trucking system removing forest biomass resulting from shaded fuelbreak treatments

Shaded fuelbreak treatments involve removal of understory brush and small-diameter trees to reduce fire hazards by disconnecting the continuity of fuels. As a result of these treatments, woody biomass (referred to as slash) is piled throughout the treated stand and later burned. Mechanical removal of slash has not been successfully implemented in many areas due to limited accessibility to sites and the high costs associated with collection and transportation of slash. To address these issues, a roll-off truck paired with a small skid-steer loader was used to collect and transport slash to a centralized processing site where slash was ground as hog fuel for energy production. “Roll-off truck” refers to a straight frame truck configuration in which a 30.6-m3 container is rolled onto and off the straight frame truck by means of a truck-mounted winch system. This study was designed to quantify the operational performance and costs of removing slash piles using a roll-off trucking system in mountainous conditions in northern California. The overall cost to collect and haul hand-piled slash was $26.81/tonne with 22% average moisture content or $34.37/bone dry metric ton. The roll-off trucking system should be used primarily for short hauling distances since trucking costs significantly increase with small increases in hauling distance due to slow traveling speeds and low slash weight being hauled. Financial analysis indicated that contractors can receive high rates of return on their invested capital after accounting for inflation and income taxes, but limited work opportunities are a concern for them.