Forest biomass used for biofuels consists of waste products that result from logging and forest management, and of inferior-quality timber that is not suitable for industrial use. This includes trunks, crowns, and branches left in the woods or alongside forest roads.
It is noteworthy, that the geographical distribution of these resources in Europe is complementary to that of cereal residues. A previous study (source: FP6 RENEW) has estimated that approximately 90 million tons of wood residues are available in Europe and up to 150 million tons in Asia (source: FAOSTAT) although actual volumes depend on residue harvest intensity.
Forest biomass is an abundant and renewable resource. Its most easily accessible form, that can be used as a biorefinery feedstock, is the byproduct of commercial-grade timber logging.
Energy crop are domesticated energy trees having desirable characteristics for biofuel production. These are regarded as the best route for increasing world biomass resources (Sims et al., 2006). The future ability of EU to produce energy crops (in a sustainable manner) will be about 142 million tons (EEA report, 2006). Among the advantages that are associated with SRC include a favourable energy input/output ratio, enhanced biological diversity (Rowe et al., 2009) and the fact they can occupy marginal and/or polluted lands, not used by food crops. In Europe, Willow and Poplar are the two main species under study. Willow is more suited to Northern European climate, while Poplar can be grown in a vast European zone that covers a large part of western and central Europe. Various data underline the benefits of Poplar. It is well suited to short rotation cropping and is highly efficient for green house gases abatement and carbon sequestration, reaching >200 g CO2e-C·m−2·yr−1 (assuming ethanol production) (Adler et al., 2007).
The main advantage to using forest biomass and energy crop is the carbon neutrality of wood. The volume of carbon or greenhouse gas emitted when wood is burned is the same as that produced when dead wood decays naturally in the forest.