Prediction of Basic Wood Density from the Apparent Density of Growth Rings of Tachigali vulgaris in Plantations in the Amazonia

Tachigali vulgaris is a fast-growing species adapted to different environmental conditions and has the potential to meet the demand for energy biomass in Amazonia. However, research is needed to guide its management and expand understanding of silvicultural aspects and wood quality. This study aimed to (i) develop an equation to estimate the basic density of wood from the apparent density of T. vulgaris growth rings in the Amazonia, and (ii) apply the generated equation to estimate the average and annual basic density along the stems and evaluate the variation of these densities. The research was carried out in Pará, Brazil, in two experimental plantations (without and with P and K fertilization), established in sandy loam and very clayey soil. 32 trees (non-forked and forked) were sampled. Discs approximately 5 cm thick were removed along the stems and divided into duplicates of approximately 2.5 cm. One duplicate was used to determine the wood basic density (WBD) and the other the wood apparent density (WAD). WAD was the only significant explanatory variable of WBD, with a correlation = 0.84, coefficient of determination = 0.71, root mean square error = 9.31, and mean absolute error = 7.28. The generated equation (WBD = 0.7492WAD + 0.0632) overestimated the WBD by 1.09% on average. Non-forked trees had a higher proportion of wood with density ≥ 0,500 g cm− 3. The study suggests that different regions of the tree can be used for different bioenergetic uses. The developed equation can be recommended to convert the apparent density at 12% moisture content into basic density, both for future studies and for application in the forestry sector.