Precision Modeling of Fuel Consumption to Select the Most Efficient Logging Method for Cut-to-Length Timber Harvesting

The fuel consumption of a harvester–operator system was modeled to select logging methods by comparing the forward felling technique (C) and the sideways techniques at the logging edge (A and D) or inside of the stand (B and E). To that end, trees’ logging cycle process data were collected using a drone for time consumption analysis. The fuel consumption data were recorded automatically from the harvester’s digital monitoring system. The fuel consumption averaged 0.22 L during the logging cycle process of trees on flat terrain and 0.25 L for those on sloping terrain. In stands on flat terrain, logging method C consumed 7.9 L E0h−1 more fuel than method A and 4.9 L E0h−1 more fuel than method B, meaning method A consumed 3.0 L E0h−1 less fuel than method B. On sloping terrain, logging method D consumed 1.4 L E0h−1 less fuel than method E. There was a large variation in fuel consumption between the logging methods, which was explained most efficiently (R2 = 0.70) by the stem processing speed (m E0h−1), the tree’s stem length (m), and effective hours of tree logging cycle processes (E0h). The results reveal that logging methods A and D were the most efficient. This precision modeling structure is recommended for the development of working techniques for harvester operators and for environmental efficiency comparisons of logging methods in different timber harvesting conditions.