Metla Project 3355
Novel upgraded products of mechanical wood processing
Keywords: engineered wood products, further processing, modified wood products, side products, wood product industries, wood quality
Research Programme: Potentials for the utilisation of roundwood and wood raw materials in relation to the wood product markets
Objectives This project concentrates on the wood resources suitable for engineered wood products (EWP) and modified wood products (MWP), esp. regarding thinning wood, small-diameter timber, and hardwoods. Market potentials and competitive abilities of these products are studied, as well. Simultaneously, the segments of demand at the global markets are studied.
Results The sub-project “Small-diameter Scots pine and birch timber as raw materials for engineered wood products” was finished in 2003. The purpose of this study was to investigate the possibilities to utilize small-diameter Scots pine and birch timber for production of EWPs that are reconstituted of strands. The wood technological characteristics of the tree species used in these products world-wide were studied based on the literature, and the findings were compared to the characteristics of domestic woods. In addition, test specimens were manufactured from domestic raw materials of Scots pine and birch species, and tested in order to examine the differences between woods from young trees from the first commercial thinnings and top sections of mature trees from final cuttings as a raw material. According to the literature review, the average basic density and, consequently, many mechanical properties of pine and birch grown in Finland do not markedly differ from those of the numerous foreign species used for EWPs.
The sub-project dealing with the quality of native aspen and hybrid aspen, will be final reported in the beginning of year 2006. In this project, we studied the technical properties, possibilities for mechanical processing and applicability of certain modification methods for aspen timber from final fellings. The results indicated obvious differences between native and hybrid aspen regarding, e.g., the growth, branchiness, and susceptibility for decay. The growth of hybrid aspen decreases already at the age of ca. 20 years, whereas native aspen continues its slow but steady growth until ca. 50-year-age. We noticed lots of decolouration and decay in 20-25-year-old hybrid aspen stems, sometimes even in younger stems. Although the average quality of aspen lumber is poor due to large knots that spread colour defects, the quality can be improved using, e.g., finger-jointing technique. The mechanical and physical properties of aspen wood can be influences by drying-related modifications. It is obvious that especially the naturally-born aspen stands but also the cultivated hybrid aspen stands provide logs in addition to pulpwood. By sawing or veneering the logs can be transformed into high-quality furnishing, furniture, etc.
The Finnish Forest Research Institute,
PL 68, FI-80101 JOENSUU, FINLAND
Phone: +358 29 532 3037
Jouhiaho, Aki (2002), Junkkonen, Reijo (2003-04), Tammiruusu, Vesa (2002), Verkasalo, Erkki, JO (2002,2005), Wall, Tapio, JO (2003)
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