Speaker
Description
The demand for domestic energy wood and pulpwood in Finland has been high due to the increased use of forest chips and the cessation of wood imports from Russia. The forestry operations in the supply chain still face a persistent and long-standing challenge: young, often untreated first‑thinning stands are characterised by high stem densities and small‑sized harvested trees, which result in low hectare-based removals and quality products, generally pulpwood and energy biomass. This, in turn, lowers forest machine productivity and increases harvesting costs, highlighting the need for improved harvesting systems and solutions, and accurate productivity estimates of those systems.
The objective of this study was to examine the time consumption, productivity, and profitability of two harvesting system alternatives for those stands, and namely: separate or integrated harvesting of the two main products (e.g. pulpwood and energy wood). For the test, we used an excavator‑based system (Doosan DX140 LCR‑5) equipped with a TMK‑300 felling head for whole-tree harvesting and Ponsse Ergo 8w/H7, Ergo 6w/H6, and Fox/H5 harvesters adapted for multiple-tree handling through dedicated software.
Time study data were collected from five forest stands. In total, 4,519 stems (309.1 m³ [solid over bark, sob]) were harvested with harvester‑based systems and 3,210 stems (49.4 m³ sob) with excavator‑based systems. The harvesting systems tested were:
1) Whole‑tree harvesting,
2) Delimbed stem wood harvesting,
3) Pulpwood harvesting (using single-tree cutting & multiple-tree handling), and
4) Integrated energy wood (delimbed stem wood) and pulpwood harvesting with two-piles cutting.
When the size of removal was 5–13 cm (diameter at breast height), the effective hour productivity (E0) was 0.3–11.8 m3/h with separate whole-tree cutting and 0.4–19.3 m3/h with separate delimbed stem wood cutting. Correspondingly, the productivity of separate pulpwood cutting using single-tree and multiple-tree handling was 0.3–17.3 m3/h and 0.5–18.3 m3/h, respectively. With integrated delimbed stem wood and pulpwood cutting, using a two-pile method, the productivity was 0.4–17.8 m3/h. Cutting and extraction costs were calculated, and the profitability and sensitivity of different harvesting systems under various stand characteristics were examined and discussed.
| Keywords | costs; first_thinning; multiple-tree_handling; wood_fuels |
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