Introducing urban food forestry: a multifunctional approach to increase food security and provide ecosystem services

We examine the potential role of perennial woody food-producing species (food trees) in cities in the context of urban sustainable development and propose a multifunctional approach that combines elements of urban agriculture, urban forestry, and agroforestry into what we call urban food forestry (UFF). We used four approaches at different scales to gauge the potential of UFF to enhance urban sustainability and contribute to food security in the context of urbanization and climate change. First, we identified 37 current initiatives based around urban food trees, and analyzed their activities in three categories: planting, mapping, and harvesting, finding that the majority (73 %) only performed one activity, and only 8 % performed all three. Second, we analyzed 30 urban forestry master plans, finding that only 13 % included human food security among their objectives, while 77 % included habitat for wildlife. Third, we used Burlington, Vermont as a case study to quantify the potential fruit yield of publicly accessible open space if planted with Malus domestica (the common apple) under nine different planting and yield scenarios. We found that 108 % of the daily recommended minimum intake of fruit for the entire city's population could be met under the most ambitious planting scenario, with substantial potential to contribute to food security even under more modest scenarios. Finally, we developed a Climate-Food-Species Matrix of potential food trees appropriate for temperate urban environments as a decision-making tool. We identified a total of 70 species, 30 of which we deemed highly suitable for urban food forestry based on their cold hardiness, drought tolerance, and edibility. We conclude that substantial untapped potential exists for urban food forestry to contribute to urban sustainability via increased food security and landscape multifunctionality.