Laitila, J. 2008. Harvesting technology and the cost of fuel chips from early thinnings. Silva Fennica 42(2): 267-283.This study compared and analyzed the procurement cost of whole tree chips when using supply chains based on comminution at the roadside landing or at the terminal. It also identified the bottlenecks of the most common logging systems used in Finland. The study was done by using existing and published productivity parameters and models. The procurement cost calculations were made for a stand where the forwarding distance was 200 metres, removal of whole trees was 60 m³ per hectare and the area of the stand was 2.0 hectares. The average size of the removed whole trees was 30 litres. The direct transport distance from the stand to the terminal or to the end use facility was 40 km while the secondary distance from the terminal to the end use facility was 10 km. A stumpage price for the harvested raw material was not included in this study. According to the study the cost of whole trees chips were 31.9-41.6 €/m³ at the plant, or 14.9-19.4 €/MWh when the moisture content of chips was estimated to be 40%.The two-machine system was found to be the most cost competitive logging system in precommercial thinnings thanks to both efficient cutting and, especially, forwarding work. In the manual worker based logging, the costs of felling bunching were the same as the mechanised system, whereas in forwarding the costs were almost double. Using the harwarder system the logging costs were found to be the highest, but in the larger tree volumes and removals the costs were almost equal to the manual worker based logging. The supply chain based on chipping at the roadside landing was more cost efficient compared to the chipping at the terminal system. The lower comminution cost at the terminal was not enough to cover the higher transportation cost of unprocessed material to the terminal, handling cost of chips at the terminal or the delivery cost to the end use facility.

The EU should produce 20% of their energy from renewable sources, including bioenergy, by 2020. Each member state has their own target, for example, Finland should produce 38% and Sweden 49% of their energy from renewable sources by 2020. In this context, the development of forest energy utilization and more effective and economic supply systems plays an important role in both countries. The Nordic countries are the world leaders in the utilization of forest biomass for energy production. This paper provides a short overview of the driving forces behind the current technical solutions of forest energy procurement systems in Finland and Sweden and some perspectives on possible future developments. At the moment, the by-products from forest industries (e.g., sawdust, black liquor) have a high degree of utilization in both countries. Additional raw materials for energy production include logging residues, stump and root wood, small diameter wood, and other wood not in demand by the traditional forest industries. Forest energy supply chains may be characterized based on the location of comminution into roadside comminution, terminal comminution, or comminution at a plant. The productivity of the generally highly sophisticated and costly procurement machinery is, to a large extent, dependent on the operator's skills and thus new technological solutions should be developed to improve their usability and consequently efficiency. C 2012 John Wiley & Sons, Ltd.

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