Productivity and cost assessment of two harvesting methods for medium-rotation poplar plantations

ABSTRACT

The study compared the cut-to-length (CTL) and the whole-tree-harvesting (WTH) methods under two alternative log length specifications (2 m vs. 4 m) as deployed in the new medium-rotation poplar plantations. The goal of this study was to determine if any of the four combinations of harvesting method and log length incurred lower cost and/or better log yield than the others. The test was conducted in a 6-year-old plantation with a stocking between 30 and 60 bone-dry tons (BDT) per hectare. Each treatment was repeated 8 times – each repetition consisting of one sample plot with a 700 m² surface area (115–130 trees). Researchers determined the mass obtained from each sample plot, as well as the time necessary to turn standing trees into logs and biomass piled at the landing. A calculator was developed for estimating harvesting costs as a function of variable machine rates. Under the conditions of the study, CTL harvesting into 4-m long logs was the most effective solution, because it offered a better log yield compared with WTH (60% vs. 50%) and incurred the same harvesting cost (∼ 33 € BDT⁻¹). Shortening log length to 2 m determined a 25% increase of harvesting cost.

KEYWORDS:

• Logging
• efficiency
• operations
• harvester
• forwarder
• economics

Acknowledgements

This project has received funding from the Bio Based Industries Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 745874 »Dendromass for Europe« (D4EU). Additional support was provided by the Pahernik foundation – University of Ljubljana. https://www.uni-lj.si/news/news/6498/.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This project was supported by the European Union’s Horizon 2020 Research and Innovation Framework Programme under grant agreement no 745874 »Dendromass for Europe« (D4EU). Additional support was provided by the Pahernik Foundation – University of Ljubljana.