How does Life Cycle Assessment capture the environmental impacts of agroforestry? A systematic review

In this paper, a systematic review approach was used to evaluate how environmental Life Cycle Assessment (LCA) has been applied in agroforestry in the context of food systems. This review was used as the basis for discussing methodological issues in the LCA framework for agroforestry systems (AFS) and relevant environmental outcomes in the agroforestry literature. A total of 32 LCAs in 17 countries identified in four databases and spanning a decade form the basis for this paper. Studies were selected based on pre-defined inclusion criteria and followed established guidelines and a review protocol. Qualitative data were extracted and categorized into multiple themes. Results were quantitatively synthesized for the four phases of the LCA for each individual agroforestry practice (i.e., based on its structural composition). Results showed that around half of the selected studies are located in tropical climates, the rest being in temperate climates, predominantly in Southern Europe. Studies primarily used a mass functional unit and rarely included post-farm gate system boundaries. Almost half of the studies account for multifunctionality, and most allocation methods were based on physical properties. Climate change had the greatest coverage from all impact categories with some variations within milk, meat, and crop production systems. Methodological issues were related to limited system boundaries, few impact categories, and differing functional units and multifunctionality approaches. The identified effects of AFS on biodiversity, climate change mitigation, water, soil, pollination, and pest and disease were only partially documented or not analyzed in the LCA studies or the LCA framework. Gaps in knowledge and limitations of the present review were discussed. Further methodological improvements remain necessary to determine the net environmental effects of food products resulting from individual AFS, especially within the area of multifunctionality, carbon sequestration, and biodiversity.