Abstract
Achieving urban sustainability goals, and improving the quality of life in cities, are aided by the careful selection of tree species for public green spaces. Numerous trade-offs and synergies are necessary to consider when selecting tree species for successful public green spaces and there is little data on effective species mixes. In this transdisciplinary research we consider the relative impacts of nine different tree planting scenarios, as modelled with i-Tree, in three piazzas of Bolzano, North Italy. The scenarios consider the opinions of the general public gathered from focused workshops and data collected via a purposefully created smartphone application in addition to data from local urban tree inventories. Shade provision and aesthetics were the primary factors that influenced citizen tree preferences. Scenarios which included larger tree species generally performed the best due to the greater provision of ecosystem services that arises with larger tree dimensions. Ecosystem disservices also increase with larger trees but can be minimised by careful species selection. Public participation in the planning of urban green spaces can be a beneficial activity which ensures new planning outputs will be well-received whilst providing opportunities for education of citizens about the multiple ecosystem services and disservices in urban contexts. Model outputs revealed that different tree species choices can have greatly different impacts in terms of ecosystem service and disservice provision.