QUALITY OF TIMBER PRODUCTS FROM NORWAY SPRUCE .1. OPTIMIZATION, KEY VARIABLES AND EXPERIMENTAL-STUDY

The overall aim of this study and series of papers is to address the k ey variables for timber quality and to optimize the utilization of Nor way spruce timber with respect to construction purposes. It is the end -user's degree of overall satisfaction that determines the quality of a product. Therefore, the performance of structural timber cannot sole ly be defined by mechanical properties. Geometric performance (warp) m ust be improved if timber is to continue as an important building mate rial. An experimental study of the spatial variation in warp and bendi ng properties of fast-grown Norway spruce is introduced. In this paper , the growth characteristics are presented as a function of stand and location in the tree. The knot area ratio (KAR) was considerably highe r in the core (0.31) compared with timber closer to bark (0.21). The t op log studs had higher KAR (0.38) than the corresponding butt log stu ds (0.31). The average grain angle was 3.5% (approximate to 2 degrees) and appeared not to vary radially. The presence of compression wood w as much more common in the top log timber (75%) than in the butt log ( 44%). However, no consistent radial variation in compression wood was found.