Mapping the evidence on the impacts of agroforestry on agricultural productivity, ecosystem services, and human wellbeing in high-income countries

Agroforestry bridges the gap that often separates agriculture and forestry by building integrated systems that address both environmental and socio-economic objectives. Existing research suggests that agroforestry – the integration of trees with crops and/or livestock – can prevent environmental degradation, improve agricultural productivity, increase carbon sequestration, generate cleaner water, and support healthy soil and healthy ecosystems while providing stable incomes and other benefits to human welfare. These claims are becoming more widely accepted as the body of agroforestry research increases, but systematic understanding of the evidence supporting them remains lacking for high-income countries. To address this research need, I developed a systematic map showing the evidence of the impacts of agroforestry practices and interventions on agricultural productivity, ecosystem services, and human well-being in all high-income countries published over the last decade (2008-2018). The results highlight some key evidence gaps and areas where there is a concentration of research. Knowledge on the impacts of specific interventions to promote agroforestry is very limited. The impacts of actual agroforestry practices are more well-studied, but the kinds of practices studied is limited, with most research focusing on shelterbelts, windbreaks, and hedgerows, riparian buffers, and scattered trees on farms with crops and/or livestock. Ecosystem services outcomes are by far the most studied, while evidence on human well-being and agricultural productivity outcomes remains more limited. I also found geographic biases, with little to no evidence for many countries. The results will be useful for informing future research and policy decisions by making the evidence easily accessible and highlighting knowledge gaps as well as areas with enough evidence to conduct systematic reviews. Using the results from the systematic map, I conducted bibliometric and network analysis to better understand the current state of agroforestry research. I performed keyword analysis to demonstrate the study of co-benefits of agroforestry and co-authorship analysis to understand the nature of collaboration among agroforestry researchers. I find that the multiple impacts of agroforestry are highly co-studied and related; however, agroforestry researchers are dispersed as small groups working in isolation from each other. The literature is fragmented and diffuse, but evidence is concentrated in a few key journals. Together, the systematic map and bibliometric analysis present a comprehensive view of the current state of agroforestry research and offer guidance for several possible paths forward to help bring agroforestry more into the mainstream