Cradle-to-gate life cycle assessment of forest operations in Europe: environmental and energy profiles

Abstract

Life Cycle Assessment (LCA) has become a common and standardized methodology to evaluate the environmental profiles of forest systems. In this study twelve different European forest systems dedicated to wood production for industrial or energy uses (maritime pine, spruce, willow, poplar and Douglas-fir) were compared in detail from environmental and energy points of view considering a cradle-to-gate perspective. The scenarios included the silviculture of these tree species in Sweden, Germany, France, Italy and Portugal. A database with inventory data was constructed for each scenario. The scenarios considered were standardized using the same methodological life cycle assumptions in order to establish comparisons for an overall analysis. The results show a relatively wide range of variations in terms of biomass productivities as well as environmental and energy profiles. These variations depended on the tree species, management regime (different levels of fertilization, time of harvesting and intensity of forest operations) and the overall conditions of the location of the plantations. However, regardless of the scenario considered, operations related to logging such as harvesting and forwarding were identified as hotspots mainly due to the remarkable fuel requirement. Fertilization activities and fertilizer production (when required), thinning processes (when necessary) as well as weed control related processes reported also notable contributions to the categories under assessment. If these twelve scenarios are compared with other similar studies for the same tree species, significant differences can be found which are mainly linked to different forest management regimes and regional characteristics. The choice and the promotion of a specific forest biomass for industrial applications should not only depend on the biomass yield and the harvesting age but it should be also based on the intensity of forest practices since it considerably affects the environmental and energy profiles.