In carbon cycle research, tree wood density is used to compute forest carbon stock and assess the role of forests in mitigating climate change (Pan et al., 2011;Vieilledent et al., 2016) or evaluate the impact of deforestation on climate (Achard et al., 2014). In community ecology, wood density is a proxy for species performance (Lachenbruch and McCulloh, 2014), reflecting a trade-off between growth potential and mortality risk from biomechanical or hydraulic failure (Díaz et al., 2016). Fast-growing, short-lived species tend to have a lower wood density, while slow-growing, long-lived species tend to have a higher wood density (Chave et al., 2009;Greenwood et al., 2017). In wood technology, most physical and mechanical properties of wood (e.g., strength, stiffness, porosity, heat transmission, yield of pulp per unit volume) are closely related to wood density (Sallenave, 1955;Thibaut et al., 2001;Shmulsky and Jones, 2011). This explains why wood density has been commonly measured in forestry institutes, where wood was principally studied for construction or paper making.Wood density was originally measured at ambient air moisture after air drying (Glass and Zelinka, 2010), but is now measured at a fixed moisture content, such as 15% or the international standard of 12% (Sallenave, 1955). In temperate countries, construction wood is at equilibrium with ambient air at an average moisture close to 12%. Wood density at 12% moisture is the ratio between the mass

Abstract• The vibration damping coefficient (tanδ) of wood is an important property for acoustical uses, including musical instruments. Current difficulties in the availability of some of the preferred species call for diversification, but this comes up against the lack of systematic damping coefficient data.• Keeping in mind the possible factors affecting tanδ, could we predict its variations between species, by using indicators that are either easily measured and/or readily available for many species?• Vibrational properties, equilibrium moisture content and colorimetric parameters were assessed on 94 wood types belonging to 76 species. Experimental results were then related to data on chemical contents and physical properties from the CIRAD database. The "standard" relationship between tanδ and specific modulus of elasticity (E'/ρ) explained only half of the variations. Deviations from this trend were correlated to extractives content, yet effects were not directly quantitative. Damping deviations were also correlated to colour and moisture-related properties, especially so with fibre saturation point.• By taking into account a combination of moisture-related properties, colour -or extractives content, and the "standard" relationship between tanδ and E'/ρ, we could propose simple predictive models which explain up to 89% of observed variations in tanδ between 48 species.

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Pterocarpus erinaceus (Poir) is currently the most exploited and threatened spontaneous tree species in the Guinean-Sudanian and Sudano-Sahelian zones in West Africa. This work analyzed the density and color parameters of P. erinaceus wood in the phytogeographic zones (Sudanian, Guinean and Sahelian) in three countries in West Africa (Togo, Burkina Faso and Niger). The results obtained by studying 451 specimens taken from 95 trees showed significant differences in basic density and color parameter values (P < 0.001) based on phytogeographic zones. Individual tree samples from the Sahelian zone were denser (780 ± 63 kg · m − 3), darker (L* = 48.3 ± 0.6) and redder (a* = 8.2 ± 2) than those in the Guinean zone (basic density = 684 ± 53 kg · m−3; L* = 59.7 ± 0.5; a* = 6 ± 0.2) and the Sudanian zone (basic density = 725 ± 70 kg · m−3; L* = 53.7 ± 0.40; a* = 7.30 ± 0.2). At intra-tree scale, the results did not show a significant variation of basic density according to the number of rings counted from the pith (P > 0.05). This indicated that the age of the trees has little influence on the basic density of P. erinaceus wood.