Diversification of the urban forest—Can we afford to exclude exotic tree species?

•From a European perspective, the study aim to curate a set of necessary considerations for current and future discussions on native and non-native plant material in sustainable urban development.•Using examples from Northern and Central Europe the study illustrate that in some regions the catalogue of native tree species may be too limited to fulfil ecosystem services and resilience in harsh urban environments.•A main message from our line of arguments is that we cannot afford to generally exclude non-native tree species from urban greening.