Browsing by discipline "Metsävaratiede ja -teknologia (metsäteknologia ja logistiikka)"

To achieve the appointed goals set in the national climate and energy strategy it is important to launch biomass into markets more effectively. In addition to biomass from clearing sites energy wood needs to be procured from young stands. First thinnings have been neglected to great extent in Finland mainly because of low profitability. The targets have been achieved only once during last decade. Expanding energy wood procurement to young stands increases the need for resources. Therefore more effective operating machines should be developed. The challenge is in launching these prototypes into testing and commercial markets. Fixteri Ltd. has developed a whole-tree bundler in order to enhance harvesting of small-diameter energy wood from young stands. This method is meant to reduce transportation costs through load compaction. The aim of this research was to study the productivity of cutting and bundling of whole-trees using Fixteri FX15a bundling unit and to clarify the competitiveness of the whole production chain compared to rival methods. The harvesting was studied trough video analyze in order to detect factors limiting the productivity. 35 whole-tree bundles were produced in young Scots pine stand. An average weight and volume of the bundle were 502.5 kg and 463 dm³. It took 3.38 min to produce one bundle. FX15a bundling unit was fitted to Logman 811FC base machine. Accumulating Nisula 280E+ felling head was used. An average performance per effective working hour of 9.74 m3 was recorded when average volume of removal was 37.3 dm3. The operator used multi-tree cutting effectively in average 3.1 whole-trees per work load. The share of multi-tree cutting was 96 percent. The performance of prototype FX15 was significantly lower than the performance of FX15a. The performance of 5.07 and 5.86 m³/h0 were recorded when average volumes of removed trees were 28.4 and 41.1 dm³. It was observed that the productivity of FX15a was higher compared to the harvesting of undelimbed trees when average volume of removed trees was less than 70 dm3. Harvesting and off-road transportation of whole tree bundles was more profitable when average volume of removal was under 95 dm3. Total costs of wood chip supply chain were lower compared to harvesting of undelimbed trees when average volume of removal was less than 85 dm3. Total costs of wood chip supply chain were higher compared to harvesting of undelimbed trees regardless of average volume of removed trees when FX15 bundling unit was used. When includung the possible energy subsidies (max 30 %) for whole-tree bundling and pre-clearance-related additional costs for harvesting of undelimbed trees into account the potential number of harvesting sites increases significantly. Drying the bundles plays an important role since high moisture content in the bundles after road side storing may endanger the competitiveness of the whole supply chain when bundles are burned to produce energy. Although bundling whole-trees seems to be a competitive alternative in harvesting small-diameter energy wood there are still several questions unanswered. The method should be studied in greater depth by varying harvesting conditions and machine operators. Also the potential of on-road transport and bundle features needs further study.