Metla Project 3354

Factors for the wood and timber quality of Scots pine

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Duration: 2002-2007   Keywords: pine , sawing, small-sized timber, thinning wood, variation of wood quality, visual properties, wood quality
Research Programme: Potentials for the utilisation of roundwood and wood raw materials in relation to the wood product markets

Objectives

Specific wood and timber properties and their variation for Scots pine raw materials interesting in further processing of wood product industries are studied and verified for selected parts of Finland, and their potential of utilisation for manufacture and argumentation for marketing are evaluated. For pine from thinnings, wood and timber properties, technical and economic suitability and criteria for selecting into wood procurement strategy are determined for different thinning stands from the viewpoint of manufacturing sawn timber and, furthermore, specific materials for further processed wood products. In particular, the effects of saw log lengths on the technical and economic suitability as well as the recovery of different timber assortments are studied for different thinning stands of pine. In addition, the relationships between the external and internal knottiness of pine stems cut in the thinnings are determined, and the quality and value of wood and timber from the future final cuttings growing from the current thinning stands of pine are estimated. Along with pine, the suitability of Siberian larch from thinnings for special products of wood industries is studied.

Results

In the research on Scots pine from final cuttings, specific wood and timber properties and their variation for Scots pine raw materials interesting in further processing of wood product industries are studied and verified in three regions in Finland and two regions in Sweden, and their potential for utilization in the manufacture and marketing argumentation of wood products are evaluated. As a specific issue, pine from Finnish Lapland and the district of Koillismaa is evaluated in relation to pine from Central Finland (inland) and South-Eastern Finland (the district of Lake Saimaa). Due to the winter 2004, comparisons have been made on the technical quality of and different defects limiting the yield of saw timber in the stems, and on the distribution to different timber assortments when different combinations of assortments are aimed in bucking the stems (high-grade butt logs, conventional saw logs, small-diameter logs, short logs, pulpwood). In addition, fast laboratory tests on the decay resistance of heartwood and sapwood, on the knottiness structure of lumber for billet manufacture for technically and visually demanding uses, and pre-tests on the colour, its homogeneity and changes under UV-A radiation for interior uses.

Scots pine from thinnings has been studied in several sub-projects. In the large collaboration project of Metla, VTT and several firms in the wood product sector, Development of procurement and saw milling of Scots pine from thinnings, wood and timber properties, technical and economic feasibility and criteria for selecting as raw materials of saw milling and, further, as specified materials for further-processed, value-added products were studied. In particular, the effects of cutting and using small-diameter and short-length logs on the yield of different timber assortments, their volume and grade distribution and the commercial value of the removal were determined, as well as on the technical and economic suitability to saw timber concluded from the yield, product distribution and value recovery of sawn goods and on the harvesting costs and mill price of the timber. In addition, regression models were generated for determining the criteria for the main external characteristics of the standing stock in thinning stands when aiming to the desired yield of saw timber by using different combinations of timber assortments. These models were generated after establishing the relationships of external and internal knottiness of thinning pines.

In the second project on pine thinnings, the quality and value of timber that could be expected in the stands in the final cutting stage was studied. Simultaneously, the effects of strip roads and their locating on the recovery and technical quality of the removal and the remaining stock were studied, especially in relation to the ditch network on drained peatlands. In the third project, technical quality and timber assortment distributions were compared in the first thinning stands of Scots pine and Norway spruce between drained peatlands and mineral forest lands, and conclusions were made on the potential of the remaining stock for saw timber in the final cutting stage and on the feasibility for the procurement of small-diameter saw logs or small-diameter round construction timber. The ongoing studies concentrate on the physical and mechanical properties of wood and timber of thinning pine, in order to justify the knowledge of the potential end-products as well as the opportunities and objectives to develop the mechanical processing of young, small-diameter pines.

Project leader: Verkasalo, Erkki
The Finnish Forest Research Institute, Joensuu Office, PL 68, FI-80101 JOENSUU, FINLAND
Phone: +358 10 211 3020 Telefax: +358 10 211 3001
E-mail: erkki.verkasalo@metla.fi

Other researchers: Grekin, Mika (2003-05), Kannisto, Kari, PA (2005), Kilpeläinen, Harri, JO (2004-06), Korpunen, Heikki, PA (2005), Lukkarinen, Antti (2003-06), Nevalainen, Seppo, JO (2003-07), Stöd, Reeta (2003,2007), Wall, Tapio, JO (2003-05)


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Updated 31.12.2010
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