Instead of the traditional visual and sensory evaluation of the quality of resonance wood of Norway spruce (Picea abies), we analyzed its macroscopic structure and physical, mechanical and acoustic properties. We sampled spruce wood from Pokljuka (1200 m a.s.l., section 64) with narrow annual rings and compared it with a control spruce from a site at a lower altitude (Zavratec nad Idrijo, 650 m a.s.l.). Test specimens (dimensions 20 × 20 × 300 mm) were made from air-dried wood to determine dynamic and static mechanical properties. Polyhedra (75 × 75 × 75 mm) were also fabricated, on which the velocity of ultrasonic waves was measured in all anatomical directions (R, T, L) and planes. Structural properties were determined by stereo microscope; we measured the width of annual rings, the proportion of latewood, and determined the mean wood density. We found that spruce wood with good resonance properties is rare. It has low density (䁤 400 kg/m3), thin (up to 2 mm) and homogeneous annual rings with a low proportion of latewood (up to 23%). Resonance spruce wood is stiffer along the grain and usually has lower vibration damping (tanρ 䁤 0,009). The conversion of mechanical energy into sound is better with resonance spruce wood than with conventional spruce wood (acoustic coeficient R > 14,5 m4/s kg; acoustic conversion efficiency ACE > 1500 m4/s kg).
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