Hakkuutähteiden laadunhallinta: PUUT09

The effects of different storage methods on drying and quality control of logging residue from final fellings were studied. The research concentrated on the fore-part of energy wood procurement chain - the storage of the residues on a clear-cut area in harvester made heaps and on roadside landings in large piles. The storage of both fresh and dry logging residues were studied. The objective was to study the storage logistics, by which it is possible to reduce the moisture content of the logging residues below 40%, and to maintain the quality gained during the storage. Drying of logging residue on the clear-cut area in harvester made heaps has clear advantages: material will dry effectively and the nutrient-rich needles will largely fall off and be retained on the site. The optimum length of a drying period on the clear-cut area is 1-3 weeks depending on the weather conditions. Moisture content of stored material will decrease down to 25-30%. After drying the material should be transported to roaside as soon as possible for storage in large piles. If logging is carried out in winter time and if the goal is not to dry logging residue over the next summer, it should be transported from the logging site to the roadside storage immediatelly after roundwood logging. When logging residues are stored in piles at the roadside the result can be improved by covering the piles. This will result in a decrease moisture content by 10-15% lower moisture content in comparison with the uncovered piles. The transportation of elements from needles to branch wood was not observed during one summer's drying period on the clear-cut area. However, because of the considerable decrease in the needle mass during storage, the chlorine content was also cut in half. Both heavy metal and ash contents of logging residues were very low. Also neither the storage area nor the storage method seems to have significant effect of the concentrations. The amount of microbes, mostly fungi, occurring in the chips was so high that it has to be taken into account when evaluating possible health risks among people handling the material. During the chipping of logging residues it is advisable to use class P3 respirator.