Energy Potential and Age-Related Variation in Wood Properties of Eucalyptus Clones Grown in Mato Grosso, Brazil

The growing demand for energy in agro-industrial systems has increased the need for forest biomass in regions of expanding commercial forestry, such as Mato Grosso State, Brazil. However, information on how genetic material and harvest age influence the energy properties of eucalyptus wood under local edaphoclimatic conditions remains limited. This study evaluated the energy potential of wood from different eucalyptus clones and harvest ages intended for industrial combustion in Mato Grosso. Clones H13, VM01, and H15 were assessed at 54 months of age. To investigate the effect of harvest age, clone VM01 was also evaluated at 54, 108, and 144 months. All samples were collected from a commercial plantation located in Brasnorte, Mato Grosso, Brazil. Morphological, physical, chemical, and energy-related wood properties were determined. Among the evaluated clones, VM01 showed the highest energy potential, with energy production reaching 674.62 Gcal ha−1, approximately 53% higher than H15. Clone H13 presented the highest lignin and fixed carbon contents, while H15 exhibited the highest extractives content. Regarding harvest age, wood maturation led to increases in basic density (15.9%), extractives content, and fixed carbon content, along with reductions in ash content, volatile matter, and the elemental ratios H/C, N/C, and O/C, indicating a gradual improvement in biomass energy quality with increasing harvest age. These results provide technical support for clone selection and harvest age optimization, contributing to more efficient use of eucalyptus wood as a renewable energy source in tropical regions where commercial forestry is expanding.