Current issue: 53(3)

Under compilation: 53(4)

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Silva Fennica 1926-1997
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Acta Forestalia Fennica
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Articles containing the keyword 'cut-to-length harvesting'.

Category: Research article

article id 454, category Research article
Paula Jylhä, Olli Dahl, Juha Laitila, Kalle Kärhä. (2010). The effect of supply system on the wood paying capability of a kraft pulp mill using Scots pine harvested from first thinnings. Silva Fennica vol. 44 no. 4 article id 454. https://doi.org/10.14214/sf.454
The efficiencies of wood supply systems based on cut-to-length (CTL) harvesting, the harvesting of loose whole trees, and whole-tree bundling were compared using the relative wood paying capabilities (WPC) of a kraft pulp mill as decisive criteria. The WPCs from mill to stump were calculated for three first-thinning stands of Scots pine (Pinus sylvestris L.) with mean breast-height diameter of the removal of 6, 8, and 12 cm. Pulp price had a strong effect on the WPC, and the CTL system resulted in the highest WPC per m3 at stump. The savings in procurement costs and gains in energy generation from additional raw material acquired with the harvesting of loose whole trees did not compensate the losses in pulp production. Considering removal per hectare, loose whole trees gave the highest WPCs at stump in the two stands with the smallest trees and the highest proportion of additional raw material. Decrease in pulp price and increase in energy price improved the competitiveness of the whole-tree systems. In the case of whole-tree bundling, savings in transportation costs did not balance the high cutting and compaction costs, and the bundling system was the least competitive alternative.
  • Jylhä, Finnish Forest Research Institute, Kannus, Finland ORCID ID:E-mail: paula.jylha@metla.fi (email)
  • Dahl, Aalto University School of Science and Technology, Department of Forest Products Technology, Espoo, Finland ORCID ID:E-mail:
  • Laitila, Finnish Forest Research Institute, Joensuu, Finland ORCID ID:E-mail:
  • Kärhä, Metsäteho Oy, Helsinki, Finland ORCID ID:E-mail:
article id 437, category Research article
Raffaele Spinelli, Philip M. O. Owende, Shane M. Ward, Maximiano Tornero. (2004). Comparison of short-wood forwarding systems used in Iberia. Silva Fennica vol. 38 no. 1 article id 437. https://doi.org/10.14214/sf.437
Time studies were conducted to quantify the productivity and the operational cost of mechanized wood extraction in the Iberian Eucalyptus plantations. The key objectives were: to determine the significant variables that influence machine productivity and extraction costs in shortwood transport within the forest and to find the basis for optimization of shortwood transport with respect to Eucalyptus forest stands. Three machines were selected for study, each representative of the different log forwarding regimes that are used in Iberia and that could be extended to most of Southern Europe. These were: 1) a modified articulated dumper, 2) a purpose-built forwarder and 3) a farm tractor paired to a twin-axle forestry trailer. It was observed that the productivity and the cost of shortwood extraction may vary from 6 to 15 fresh tonnes/SMH and 3.5 to 6.5 Euro/fresh tonne, respectively. It was estimated that the optimal extraction route network covered approximately 10% of the forest surface. It was also observed that the modified dumper is the most-productive unit, and given its higher speed (> 5 km/h) and larger payload (16 tonnes), it is the economic choice for extraction distances in excess of 1000 m. However, it also generates the most severe rutting, hence it should be used with caution. For extraction distances below 1000 m, the light purpose-built forwarder compares favourably with the modified dumper, while generating less than half the site disturbance. The tractor-trailer combination is economically inferior to the modified dumper and the light forwarder, and should be regarded as a complement to the main extraction fleet and where short-haul operations are required. Under the assumptions of the study, light forwarders (8-tonne payload) may become competitive with heavier ones when road density is at least 6 m/ha, so that extraction distance does not exceed 1 km. This study provides a model for estimating the productivity and the cost of timber forwarding under varying conditions.
  • Spinelli, CNR - Timber and Tree Institute, Via Madonna del Piano - Pal. F, 50019 Sesto Fiorentino, Italy; University College Dublin, Ireland ORCID ID:E-mail: spinelli@ivalsa.cnr.it (email)
  • Owende, Dept. of Agricultural and Food Engineering, University College Dublin, Earlsfort Terrace, Dublin 2, Ireland ORCID ID:E-mail:
  • Ward, Dept. of Agricultural and Food Engineering, University College Dublin, Earlsfort Terrace, Dublin 2, Ireland ORCID ID:E-mail:
  • Tornero, Servicios Forestales SA, Ctra. SE-184 Km 0.63, E-41970 Santiponce, Sevilla, Spain ORCID ID:E-mail:

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