Wood quality of Corymbia hybrids for kraft pulp production

Brazil is the world's largest hardwood pulp producer and, despite the results achieved through the cultivation of eucalyptus, other crops such as species and hybrids of the Corymbia genus are being studied in breeding programs. In this context, this study aimed to evaluate the wood quality and rank ten hybrid clones of Corymbia torelliana and Corymbia citriodora for kraft pulp production, using a commercial clone of Eucalyptus saligna as a control. Wood quality was assessed for its chemical composition, basic density, and pulping performance. The following were evaluated regarding kraft pulping: screened pulp yield, kappa number, rejects content, and specific wood consumption. All the hybrid clones of the Corymbia genus had a higher basic density than the control treatment, with results ranging from 509 to 607kg/m(3). The Corymbia hybrids had total extractives ranging from 2.53 to 8.16%, total lignin from 25.84 to 28.42%, ash from 0.5 to 1.17% and holocellulose from 65.35 to 70.84%. The Corymbia hybrid with the best pulping performance had a screened pulp yield of 53.24%, a Kappa number of 22.2, a rejects content of 0.91%, and a specific consumption of 3.11 m(3)/tsa. The study ranked and indicated the clones with the best wood quality for kraft pulp production.