A cost-benefit analysis of pre-sorting using a feller-buncher in underdeveloped short rotation poplar plantations

ABSTRACT

Underdeveloped tree crops (⩽ 30 bone-dry tons ha⁻¹) offer a main harvest of biomass-trees, which lack the size and the form for producing a log. However, about 1/3 of the available stems may yield at least one log, which could significantly increase the overall value of the harvest. Under those circumstances, it may make sense to sort log-trees from biomass-trees at an early stage, rather than having a harvester or a processor go through all of the treesonly to toss almost 70 out of 100 trees into the biomass pile. The Authors set up a controlled experiment to quantify the eventual benefit obtained by early pre-sorting, performed by the feller-buncher. Pre-sorting resulted in a 15% productivity loss for the feller-buncher, which was repaid by a 100% productivity increase for the processor. Considering the different hourly cost of the two machines, three Euros were saved for each additional Euro invested in pre-sorting. Pre-sorting made whole-tree harvesting (WTH) a significantly cheaper option than cut-to-length (CTL) , whereas the two systems would be almost equally expensive when no pre-sorting was applied. Pre-sorting would also facilitate multiple-tree delimbing, implemented through the introduction of a chainflail; that is likely to further reduce harvesting cost, returning financial viability to the harvesting of underdeveloped plantations.

KEYWORDS:

• Productivity
• cost
• log recovery
• Multi-tree
• CTL
• WTH

Acknowledgements

This study was funded by the Bio Based Industries Joint Undertaking under the European Union’s Horizon 2020 research and innovation program 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 authors.

Additional information

Funding

This work was supported by the Horizon 2020 Framework Programme [BBI JU 745874 »Dendromass for Europe« (D4EU).];Pahernik Foundation;