Tachigali vulgaris energy forests: understanding spacing, age, and stem type effects on tree growth patterns and wood density

Reforestation with species of the Eucalyptus genus provides the main biomass source for energy purposes in Brazil. However, the country’s northern region lacks such crops to meet the demand of the second-largest national steel pole. The species is a promising source of biomass, as it is native to the region and grows at high rates. Thus, this research aimed to evaluate the effect of planting spacing (4.5, 6.0, 7.5, 9.0, 10.5, and 12 m 2 per plant), tree age (87 and 102 months) and stem forking on dendrometric variables and wood basic density of T. vulgaris trees from a trial plantation located in Eastern Amazonia. The commercial volume, basic density, form factor, and dry wood mass of trees were determined. The forked trees had a higher volume (0.2492 m 3 ) and dry wood mass (112.88 kg) than non-forked trees (average volume of 0.1573 m 3 and 73.66 kg of dry wood mass). At 87 months, wood basic density was found higher in wide spacings (9 and 12 m 2 plant − 1 ). At 87 months, the non-forked and forked trees presented basic densities of 0.505 and 0.474 g cm − 3 , respectively. The forked trees at 102 months spaced by 9 m 2 had a basic density > 0.500 g cm − 3 , a desirable parameter for charcoal production. Thus, this study confirmed the relevance of planting spacing, age, and stem type on the basic density of T. vulgaris , supporting future studies to define the best silvicultural practices and decision-making on the species by forest companies located in Amazonia.