Acoustic properties of resonance wood and distribution of inorganic components of the cell wall

Acoustic properties of spruce resonance wood can be thoroughly measured by the ultrasonic technique. It is possible to measure six ultrasonic velociti es and to deduce the corresponding elastic constants on a small cubic speci men. However, as previously stated (Bucur 1995), spruce resonance wood has a very high ultrasonic velocity in fiber direction (>5500 m/s) and a very s mall shear velocity (400 m/s) in the transversal plane. This very high anis otropy of the resonance wood is the most important quality of this material . The inorganic content shows a wide variability depending on the origin of the wood. The distribution of inorganic compounds in resonance wood was ve ry homogeneous while in common spruce the distribution is inhomogeneous.