Chemical and fuel properties of stumps biomass from Eucalyptus globulus plantations

Eucalyptus globulus Labill. is managed in commercial plantations for the pulp and paper industry as a coppice system. For stand reforestation the stumps are uprooted and at present used as biofuel. In this study, the biomass of stumps collected in six eucalypt stands in Portugal was evaluated in terms of physical, chemical and fuel properties. Stumps had basic density between 0.55 g cm−3 and 0.71 g cm−3, and the chemical composition showed 15.1% total extractives (mainly ethanol soluble extractives, 10.5%), 24.8% lignin and 67.0% holocellulose. In terms of thermal properties the stumps presented 18.9 MJ kg−1 for higher heating value (HHV) and 0.6%, 81.1% and 18.3% respectively for ash, volatile matter and fixed carbon. The elemental composition (C = 51.0%; H = 5.8%; O = 45.3%; Cl = 0.04%) has adequate values for use as woodfuel.

► Stumps biomass has a high content in extractives principally in ethanol and water soluble compounds.
► The higher heating value (HHV) is similar to that of E. globulus wood and forest residues.
► Stumps biomass presented suitable properties to be used as a fuel for heat and power generation.
► No variations for fuel and chemical properties were found across sites in this study.