Abstract
Growing demand for renewable energy from biomass has prompted exploration of timber transportation concepts. This study evaluated the operational and regulatory boundaries of whole-tree hauling using a modified log trailer in the southeastern United States. Two designs, a swinging gate and an extendable bolster, were developed to accommodate full-length, unprocessed loblolly pine (Pinus taeda) and contain tree crowns. The swinging gate was selected for field testing due to its lower cost, lighter weight, and structural reliability. Field testing included nine loads evaluated under unprocessed, trimmed, and delimbed trees. Axle weights and net payloads were evaluated with tandem and tridem axle regulations. The modified trailer increased biomass recovery, while processed biomass represented 14% of total load weight. However, the mean trimmed loads exceeded tandem-axle allowances reviewed for the eleven southeastern states considered. Pulpwood-sized timber required less trimming and allowed better crown containment than chip-and-saw timber. Overall, the modified trailer can improve biomass recovery, but practical implementation is strongly constrained by timber characteristics, axle configuration, and state-specific weight regulations.