Abstract\ud Purpose Social life cycle assessment (S-LCA) method lacks\ud of standard and code of practice. The aim of the study is to\ud classify the wide variety of contributions on S-LCA for tracking\ud the development of different themes and for defining and\ud classifying the main approaches in a systematic and reproducible\ud way.\ud Methods The research addressed to study a collection of 51\ud articles published between January 2006 and November 2014\ud using statistical criteria. We used automatic text analysis\ud (ATA) tools related to lexicon analysis to identify keywords\ud useful in tracing the main topics covered in articles published\ud in different periods. We conducted principal component analysis\ud (PCA) to classify the different approaches in the literature\ud and to outline the orientations of the various research groups.\ud Results and discussion The results from lexicon analysis\ud showed a rapid succession of different topics covered in\ud the analyzed period. This alternation is strongly affected by\ud the introduction of UNEP/Society of Environmental\ud Toxicology and Chemistry (SETAC) S-LCA guidelines\ud and methodological sheets. PCA analysis enabled to synthesize\ud the information related to the numerous\ud approaches. Results did not show a clear division into\ud groups which indicates the absence of a dominant position\ud on the subject in the literature.\ud Conclusions This study attempted to map the state of art in SLCA\ud integrating literature review with multivariate statistical\ud techniques. The analysis showed a highly fragmented field.\ud These results confirm the existence of a variety of approaches\ud that in part have already been identified by literature reviews\ud on S-LCA. Alignment with the results in the literature confirms\ud ATA to be a suitable instrument for the realization of\ud reviews. Moreover, being systematic and reproducible allows\ud ATA to be applied repeatedly, expanding the number of articles\ud and topics analyzed

a b s t r a c t An extended Life Cycle Assessment (LCA) is performed for evaluating the impacts of a woody biomass supply chain for heating plants in the alpine region. Three main aspects of sustainability are assessed: greenhouse gas emissions, represented by global warming potential (GWP) impact category, costs and direct employment potential. We investigate a whole tree system (innovative logging system) where the harvest of logging residues is integrated into the harvest of conventional wood products. The case study is performed in Valle di Fiemme in Trentino region (North Italy) and includes theoretical and practical elements. The system boundary is the alpine forest fuel system, from logging operations at the forest stand to combustion of woody biofuels at the heating plant. The functional unit is 1 m3 solid over bark of woody biomass, delivered to the district heating plant in Cavalese (Trento). The relative sustainability of traditional and innovative systems is compared and energy use is estimated. Results show that the overall GWP and costs are about 13 kg CO2equivalent and 42 euro per functional unit respectively for the innovative system. Along the product supply chain, chipping contributes the greatest share of GWP and energy use, while extraction by yarder has the highest financial costs. The GWP is reduced by 2.3 ton CO2equivalent when bioenergy substitutes fuel oil and 1.7 ton CO2equivalent when it substitutes natural gas. The sensitivity analysis illustrates that variations in fuel consumption and hourly rates of cost have a great influence on chipping operation and extraction by cable yarder concerning GWP and financial analysis, respectively. This is confirmed by sensitivity analysis. Better technologies, the use of biofuels along the product supply chain and more efficient systems might reduce these impacts. Replacing the traditional system with the innovative one reduces emissions and costs. A low energy input ratio is required for harvesting logging residues. The direct employment potential is a conflicting aspect and needs further investigations. IntroductionInternational and national policies support the utilization of renewable energy and bioenergy for several purposes i.e. climate change mitigation, energy supply security and energy source diversification. The Kyoto protocol agreement (United Nations, 1998), the European Union target of a 20% reduction in greenhouse gas emissions (GHG) emissions, energy consumption and energy based on fossil fuels (European Union, 2009), and the assumption of carbon neutrality for biomass (International Energy Agency, 2007) are the main drivers behind the implementation of bioenergy production. Along the Alps, local communities show high levels of awareness regarding renewable energy sources, while provincial policy-makers have a keen concern for environmental protection, and are open to the use of bioenergy for mitigating the effects of global warming.

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