Machine productivity and residual harvesting residues associated with a cut-to-length harvest system in southern Tasmania

Abstract

The cut-to-length method is a preferred method for harvest of pine plantations in Australia. The cut-to-length method studied in southern Tasmania consists of a feller-buncher, processor, forwarder, grapple loader and tractortrailers that were producing only pulp logs for the plantation owner Norske Skog. An elemental time study method was applied to evaluate the productivity of the machines within the flat terrain, Pinus radiata plantation. Multiple regression was used in SPSS to develop the productivity prediction models. The productivity of the feller-buncher and processor averaged 122.20 m³ per productive machine hours excluding all delays (PMH₀) and 84.32 m³ PMH₀ ⁻¹, respectively. The average productivity for the forwarder, grapple loader and truck were 80.90 m³ PMH₀ ⁻¹, 100.80 m³ PMH₀ ⁻¹ and 27.40 m³ PMH₀ ⁻¹, respectively. The average fuel consumption of the feller-buncher, forwarder and processor were also documented. The trial assessed harvest residue left on the site and found 238.7 GMt ha⁻¹ (31% of total biomass above the stump) was left of which 46% was stemwood. These research findings can be used for harvesting planning and improving logging efficiency.