Three types of forest stands (chestnut coppice, maritime pine stands, and poplar and willow short-rotation woody crops (SRWC)) were evaluated to determine their potential for energy production. The properties of the main aboveground biomass fractions (wood, bark and crown) and also the whole tree were analysed, thus providing data that could be used for management purposes and for evaluating potential forest, biomass energy yields and atmospheric emissions. Proximate, elemental and energetic analyses of the biomass provided important information for evaluating the fuel potential. The energetic value of the biomass derived from the maritime pine stands was higher than that of the poplar and willow clonal stands and chestnut coppice stands. The high ash content of the chestnut bark, relative to that of the wood and crown material, is also an important consideration in relation to energy production. The proportion of carbon concentration accumulated per tree was very similar in all types of material studied, although the N and S contents were higher in the maritime pine stands than in the other stands. For this reason, selection of species and fractions can help to improve fuel quality and the efficiency of the combustion processes, and to minimize atmospheric emissions.
This work was funded by the TRIBIONOR Project (Reference CTQ2013-45155-R) and the coal mining company HUNOSA GROUP supported by the HUNOSA CHAIR at the University of Oviedo (Project Reference SV-17-HUNOSA-1). The authors acknowledge the helpful co-operation of Hunosa staff in this study. The TRIBIONOR Project (CTQ2013-45155-R) is funded by the National Program for Research, Development and Innovation in Society Challenges, within the framework of the National Plan for Scientific and Technical Research and Innovation 2013–2016 from the State Research Agency (Ministry of Economy, Industry and Competitiveness), co-financed with FEDER Funds. The authors gratefully acknowledge the Government of the Principality of Asturias for supporting Ana Álvarez with a fellowship within the Severo Ochoa Program