Optimizing Forest Harvesting Efficiency: A Comparative Analysis of Small-Sized Logging Crews Using Cable-Grapple Skidders

Examination of the technical and economic dimensions of skidding operations is imperative for sustainable forest management, offering invaluable insights crucial for the formulation of sustainable forestry strategies. In many countries, the shift from modified agricultural machinery to purpose-built forest machinery has become apparent in forest operations. However, this transition often accompanies a reduction in logging crew size, raising new questions about productivity, costs, and ergonomics of the introduced harvesting systems. This study investigates two skidding systems utilizing the cable-grapple skidder Welte 115/5L, differing in work team size: one with one skidder operator and two chainsaw operators (WT3) and the other with one skidder operator and one chainsaw operator (WT2). Conducted in natural European beech forests in southern Bulgaria, the research focused on the group shelterwood system within the Natura 2000 network. Both WT3 and WT2 exhibited net skidding productivity of 9.96 m³ PMH⁻¹ over a mean skidding distance of 300 m and a mean winching distance of 20 m, outperforming conventional systems in the area. Despite this, there were notable differences in gross skidding productivity (8.64 m³ SMH⁻¹ for WT3 vs. 7.30 m³ SMH⁻¹ for WT2), affecting skidding cost (EUR 5.41 m⁻³ for WT3 vs. EUR 6.62 m⁻³ for WT2) and unit production cost (EUR 9.33 m⁻³ vs. EUR 11.53 m⁻³). This study highlights that the cable-grapple skidder can be effectively employed by smaller teams, providing higher productivity, lower unit cost, and increased flexibility during piling, primarily due to the presence of the knuckle-boom loader. While WT2 experienced more delays and production pressure, the findings suggest that WT3 represents a balanced option for small logging crews, ensuring sustainable forest operations in the face of workforce challenges.