Classification of young Corymbia genotypes for steelmaking charcoal production based on their wood properties

Abstract

Background: The continuous assessment of new genotypes is essential to boost industries such as that for charcoal production. This is because wood properties can significantly change among different genotypes. The aim of the present study is to assess the wood quality of different Corymbia genotypes to identify those with desirable features and to improve the ability to classify and select the best genotypes for charcoal production.

Methods: Different Corymbia genotypes were assessed, including two progenies and nine clones. Trees in the age group 3 and 4 years were collected from two trial crops in Minas Gerais State, Brazil, in collaboration with a company from the steel sector. Genotype assessment demanded several wood analyses focused on physical, chemical, energy and anatomical parameters. The collected data were subjected to multivariate analysis to cluster the genotypes. This procedure allowed classifying the genotypes presenting the most desirable features for charcoal production.

Results: The study revealed significant variations in Corymbia genotypes’ wood density, bark features, chemical composition, energy and anatomical features. Genotypes were categorised into different groups based on wood and bark density, bark thickness and content, and heartwood content. Notably, genotype influenced parameters such as ash, volatile matter and fixed carbon content. Total extractives, lignin and holocellulose content showed significant variability across genotypes. Genotypes did not significantly affect energy composition, except for energy density. Principal component analysis highlighted key wood properties that contribute to data variability in order to help genotype classification.

Conclusions: The study provides understandable insights into the wood quality of Corymbia genotypes, and points out that wood properties work as reliable indicators to classify and select superior Corymbia genotypes for charcoal production. These properties reasonably predict the impact of raw material features on charcoal quality in a quite accurate way. All assessed genotypes emerged as having promising initial potential for charcoal production or for other energy applications, and it also indicates that Corymbia wood properties were comparable to, or even better than, those of genus Eucalyptus.