This study assessed the cable tensile forces of a Falcon Winch Assist machine tethering a track feller-director. Peak tensile forces at the harvesting machine reached 400 kN, mainly while
moving downhill. Depending on the working task, tensile forces were higher at the harvesting machine or at the anchor machine, but the most critical values were always recorded at the
harvesting machine, with differences in local peaks up to 55%. Local variations in the tensile forces exceeded 50 kN in just a few hundredths of a second, mainly during movements of the
harvesting machine. Exceedance of the safe working load of the cable at the harvesting machine was limited to a short time but concentrated in local spikes which reached 48% of
the minimum breaking strength of the cable. Implementation steps for safer winch-assist harvesting operations are discussed.