Mechanized coppice harvesting with new small-scale feller-bunchers: Results from harvesting trials with newly manufactured felling heads in Italy

The revival of coppice management is being considered as one option to satisfy the increasing market demand for wood biomass. Commonly used harvesting systems in coppice forests (CF) are based on motor manual felling, but further mechanization of CF operations is desirable because of increasing labor costs and the high fatality rates associated with motor manual felling.The goal of this study was to determine the machine performance in terms of productivity, cost-effectiveness and cut quality of new feller-bunchers, when used on different types of CF. The study comprised of five tests on different sites in Italy, four of which represented a specific type of CF.Results showed that harvesting productivity varied from 3.1 to 8.6dryt per scheduled machine hour (SMH) in multi-stem coppice stands (4.5-16drym3SMH-1). Productivity reached 16.2drytSMH-1 in a short rotation forestry (SRF) control stand (39.4drym3SMH-1) and it increased with stump mass. Recorded productivities tested in conventional CF were not as high as achieved in single-stem SRF, or in the mechanized felling of comparable softwood stands, but still matched the requirements of commercial mechanized logging. Costs varied between 3.57 and 20.56EURdryt-1 (1.47-14.17EURdrym3-1). Lowest costs were reached in the SRF stand and highest cost in the Mediterranean CF growing on moderate to steep terrain. Shear heads produced poor cuts and single-action shears performed worst. The disc saw produced very low cuts with low damage levels, which might be acceptable even under current cut quality specifications.