Abstract: This study aimed to model and identify the most productive cutting methods of tree plantations by comparing a forward felling technique (C) with sideways techniques outside (A and D) or inside cutting edge (B and E). Drone video material of each tree was analyzed by comparing time distribution of work phases. The relation between this input data and harvester production data was analyzed by regression models. A quadratic model predicted productivity precisely (R² = 0.95) and explained the effective-hour productivity in cutting cycle with dummy variables of harvesting conditions. The productivity was explained by tree size and cutting cycle time, while effects of operator and harvester were eliminated by statistical analysis. In loblolly pine (Pinus taeda L.) plantations on flat terrain, cutting method B was 4.8 m³/E₀h (effective working hour) more productive than method A, and 6.7 m³/E₀h than method C. In Sydney blue gum (Eucalyptus saligna Sm.) plantations, cutting method E was 1.8 m³/E₀h more productive than cutting method D on sloping terrain. Of the time-cycle variables, time consumption of the “moving of tree” changed significantly between the cutting methods, of which the ones that used the sideways felling technique inside cutting edge were most efficient. This quadratic modeling structure can be recommended for precise studies in similar harvesting conditions.

Key words: Time and motion study, Effective-hour productivity, Felling technique, Work-phase analysis, Cut-to-length method