Wood density of 38 Dalbergia and 29 Diospyros Malagasy species and its relationship with climate and tree diameter

Abstract

Several Malagasy Dalbergia and Diospyros species are highly valued, in the furniture industry despite limited understanding of their wood technological properties. This study contributes to address this gap by assessing the wood density (WD) of 38 Dalbergia and 29 Diospyros species, their radial WD variation, and the influence of climate and tree size on WD. WD was measured on 297 wood cores using X-ray computed tomography. One-way analysis of variance revealed that Diospyros genus (1.070 ± 0.165 g∙cm⁻³) has significantly denser heartwood compared to Dalbergia (0.961 ± 0.142 g∙cm⁻³). Heartwood density also showed greater between-species variation, allowing the identification of eleven groups of Dalbergia and seven groups of Diospyros, each with significantly different heartwood density ranges. For radial density profile assessment, each of the 52 cores having the pith-to-bark part of the wood, was divided into ten equal length segments. Anova between mean WD of the core segments, combined with correlation tests between the average density of each segment and its distance from the pith, showed that radial wood density profile varied among species. Most species exhibited a decreasing radial WD profile. Correlation tests between tree diameter, climatic factors, and wood density demonstrated that, for both genera, wood density increases with rising temperature and decreasing precipitation at the growth site, while tree diameter has no significant effect on density. These findings significantly enrich the wood density database for Malagasy precious wood species, which previously existed for only a very few species.