Vertical and radial variation in wood acoustical and physical properties of Ailanthus altissima

Abstract

This study investigated the vertical and radial variability of wood acoustical and physical properties in Ailanthus altissima (ailanthus tree), a species with potential applications in musical instrument construction. However, there is limited information about the variation within the stem in these properties, which is essential for assessing its suitability in acoustically demanding applications. In this context, wood density, dynamic modulus of elasticity, damping coefficient, acoustic conversion efficiency, and tangential and radial shrinkage were analyzed across three stem heights and three radial positions. Results revealed significant variation within the stem, with density and dynamic modulus of elasticity increasing from the base to the middle before declining at the top, while acoustic conversion efficiency showed an inverse trend. Radially, acoustic conversion efficiency was highest near the pith and decreased significantly toward the middle and outer parts of the stem, with no significant difference between these outer zones. The damping coefficient was lowest at the bottom logs, increased significantly at the middle, and slightly decreased at the top. Radially, the damping coefficient was lowest near the pith, increased toward the middle, and reached the highest values near the bark. Shrinkage increased significantly from pith to bark but showed minor axial variation, with similar values at the base and middle, and a significant decrease at the top of the stem. Importantly, density could be used as an indicator for acoustic conversion efficiency, enabling indirect assessment of acoustic performance. These variations highlight the potential of selecting specific stem regions to balance sound transmission and structural support, suggesting that Ailanthus altissima (ailanthus tree) could replace traditional woods for the backs and sides of stringed instruments.