Load security of crosswise- and lengthwise-loaded 8' roundwood, as well as 16' and tree lengths was assessed from the various standpoints of tie-down systems, load and haul equipment and techniques, trailer type and trailer suspension characteristics. Static and dynamic computer simulations were done to identify rollover threshold and handling characteristics of a typical haul unit. A hydraulic tilt table was used to measure the rollover threshold and changes in the centre of gravity for a loaded trailer. Two different loaded trailers were instrumented for on-the-road testing to measure load sway, cable tension, trailer flex and vibration of trailer and cargo.