Evaluating the Potential of Non-commercial Eucalyptus spp. and Corymbia spp. for Bioenergy in Brazil

Wood energy plantations are important sources of feedstock for bioeconomy, given their potential to replace fossil fuels, which would ultimately result in the reduction of greenhouse gas emissions. Eucalyptus and Corymbia woods have been widely used for the production of firewood, wood chips, and charcoal for the steel industry in Brazil. The present study aims to assess the properties of non-commercial Eucalyptus and Corymbia woods for energy purpose in Brazil. Six years after planting, the chemical, physical, energy, and thermal properties of Corymbia citriodora, Corymbia variegata, Corymbia henryi, Corymbia torelliana, Eucalyptus amplifolia, Eucalyptus longirostrata, Eucalyptus major, and Eucalyptus urophylla were analysed. The results showed significant variations in basic density (480–662 kg·m−3), total extractives (1.03–4.56% db), lignin (28.33–34.25% db), holocellulose (61.54–69.07% db), higher heating value (19.22–20.33 MJ·kg−1), syringyl/guaiacyl ratio (2.20–3.36), energy density (9.45–12.51 GJ·m−3), ash content (< 1% db), and pyrolysis activation energy (247–468 kJ·mol−1). Compared to E. urophylla’s wood, the most used species in the steel industry in Brazil, the wood from E. major, E. amplifolia, and C. torelliana had properties that favoured the production of high-quality charcoal for use in steel industry. C. citriodora, C. variegata, C. henryi, and E. longirostrata presented a high potential for use in energy cogeneration systems.