Sustainability assessment of forest biomass supply chain at local scale: carrying capacity of the system for energy valorisation

Evaluation of the trade-off between the benefits coming from forest resources’ use and the conservation of forest ecosystems is needed. Considering the use of biomass for energy purpose, on one hand the use of wood resources should be based on an evaluation of the “carrying capacity” of the forest ecosystem and site-specific characteristics; on the other hand, the role of biomass valorisation has to be assessed considering the socio economic benefit or drawbacks due to the further development of the supply chain. In the context of a site –specific sustainability assessement of a wood energy supply chain, the research focuses on development of an expeditious methodology to obtain georeferred quantity of biomass at local scale for mountain forest areas, in order to facilitate energy planning that considers the local system carrying capacity and the potential of substitution of fossil fuels. Methodology developed for the site-specific assessment of the biomass availability, with respect to carrying capacity, consists of quantification and spatial distribution (using Geographic Information System) of forest biomass that considers local features as reported in local territorial plans and it applies Life Cycle Assessment for supporting the overall environmental assessment. Biomass value calculated has been converted from volume to mass, considering species features and water content. The result is compared with current utilization of wood, and waste products from forestry processing are estimated, in order to quantify the mass available for energy valorisation. Then, the energy potential is estimated, from biomass quantity and from wood features, principally the lower calorific value and water content for each species. Finally, the potential of substitution of fossil fuels is calculated, knowing energy potential from available biomass for energy use. The methodology is applied to two mountain areas, Comunità Montana Lario Intelvese (CMLI) and Comunità Montana Triangolo Lariano (CMTL), in northen Italy (Como Province). The proposed methodology evaluates the possibility that forests can provide the supply of raw material for energy production among ecosystem services. In addition, this assessment aims to integrate considerations to protect the other ecosystem services. Moreover, the proposed methodology is useful for a preliminary assessment of the possibility to considering woody biomass in energy planning at local level.