The chemical composition of wood is important to assess the quality of this raw material for the industry of cellulosic pulp production. The purpose of this work was to determine the chemical composition of Eucalyptus spp. grown for cellulosic pulp production. Ten Eucalyptus spp. clones with six years of age, located in the municipality of Itamarandiba, Minas Gerais, Brazil, were used. Quantification was obtained for extractives, monosaccharides, uronic acids, acetates, lignin, ash and the phenolic composition of the extracts. In average, clones showed around 2.7% extractives, with a predominance of polar compounds soluble in ethanol and water; 27.7% lignin and 0.3% ash. Glucose was the main sugar detected (64.2%), followed by xylose (19.3%). The main components of the extractives were steroids, fatty acids and aromatic acids, followed by smaller amounts of substituted alkanoic acids, fatty alcohols, glycerol derivatives and triterpenes. The ethanol–water extracts presented total phenol contents ranging from 321.4 to 586.6 mg EAG/g of extract, tannins from 28.1 to 65.1 mg catechin/g of extract and flavonoids from 73.6 to 256.9 mg catechin/g of extract. Clones with a higher holocellulose amount and a lower lignin content showed a higher potential for cellulosic pulp production. These findings are important for the development of high-quality wood based on important traits for the pulp and paper sector.

The energy potential of wood biomass is significantly shaped by its chemical composition. Analyzing the chemical composition of wood biomass and understanding the correlations between these parameters and wood combustibility are essential stages in the selection process of Eucalyptus clones tailored for firewood production and energy generation. In this study, we aimed to evaluate the impact of chemical composition on the direct combustibility of Eucalyptus clones. We examined the structural chemical composition and conducted proximate analysis, including fixed carbon, volatile material, and ash, to investigate the relationship between proximate composition and wood combustibility parameters. Our findings revealed significant correlations between wood chemical composition and combustibility parameters. In particular, lignin content, ethanol-soluble extractives, and xylose demonstrated inverse relationships with the parameters of maximum combustion rate, combustion characteristic index, and ignition index. Conversely, holocellulose content, cold-water-soluble extractives, and glucose exhibited direct correlations with the same combustibility parameters. Furthermore, fixed carbon and volatile matter contents demonstrated direct and inverse correlations, respectively, with ignition temperature. These findings have significant implications for enhancing the efficiency and sustainability of biomass energy production.