Chemical, Energetic, and Thermal Characteristics of Corymbia Hybrid Progenies and Clones for Sustainable Charcoal Production

Abstract

Many countries are seeking to reduce their dependence on non-renewable energy sources, particularly fossil fuels. This study evaluated the chemical, energetic, and thermal characteristics of wood from non-commercial hybrid progenies and clones of Corymbia torelliana × C. henryi, C. torelliana × C. maculata, C. torelliana × C. citriodora × C. maculata, and C. torelliana × C. citriodora, at 3 and 4 years of age, to assess their potential for energy production. The genotypes exhibited variation in wood density, chemical composition, and energetic properties. Higher heating values ranged from 19.0 to 19.6 MJ kg^-1, although differences among genotypes were not statistically significant. Energy density ranged from 9.15 to 11.8 GJ m^-3, with clone CTC2 exhibiting the highest value (11.8 GJ m^-3) and the highest basic wood density (616 kg m^-3). Clone CTM2 stood out for its high extractive, lignin, and fixed carbon contents, supporting its potential for charcoal production. Thermogravimetric analysis showed that clone CTC6 had the highest residual mass (31.0%), indicating greater thermal stability under the tested conditions. Fourier-transform infrared spectroscopy identified functional groups associated with the main wood constituents, while X-ray diffraction revealed the highest crystallinity index in clone CTCM (38.4%). Overall, clones CTC2 and CTM2 showed promising wood properties for metallurgical charcoal production, highlighting the potential of non-commercial Corymbia genetic materials for energy applications.