BENDING PROPERTIES OF NORWAY SPRUCE TIMBER - COMPARISON BETWEEN FAST-GROWN AND SLOW-GROWN STANDS AND INFLUENCE OF RADIAL POSITION OF SAWN TIMBER

The primary objective of this work was to study one aspect of improvin g timber quality. The aim of this paper is to supplement previously pu blished results in Wood Science and Technology. Bending strength and s tiffness of Norway spruce (Picea abies) from three stands in southern Sweden, two fast-grown and one slow-grown, were measured. Radial varia tions were studied using six studs (45 mm x 70 mm x 2 900 mm) per log cut along a diameter, with a total of 500 studs. The bending strength of studs from the slow-grown stand was 57 % higher and the modulus of elasticity 54 % higher than that of the fast-grown stands. The bending strength of studs from mature wood (near the bark) was 47 % higher an d modulus of elasticity 30 % higher than that of the core studs. The i mprovement in mechanical properties from pith to bark was far more sig nificant for the studs from the slow-grown stand than from the fast-gr own ones. ((C) Inra/Elsevier, Paris.).