Urban green infrastructure provides a multitude of ecosystem services. Data-based management of green infrastructure is crucial for effective urban climate adaptation and mitigation. City trees are a key component of urban green infrastructure playing an unparalleled role in offsetting heat island effects and capturing anthropogenic carbon emissions. The current, simple tools for the quantification of urban ecosystem services delivered by trees fail to capture the true diversity and complexity of urban trees. Recent advances in laser scanning and detailed 3D modelling techniques can provide virtual city models (so-called digital twins) that can be used to understand and simulate the impact of different urban green infrastructure management strategies. However, the methods and tools to convert the novel 3D information on green infrastructure, and in particular trees, into accurately quantifiable ecosystem services estimates are unavailable today. I have selected two high priority urban ecosystem services delivered by trees that will have the focus in my project: carbon sequestration and the mitigation of the urban heat island effect. This work will use state-of-the-art laser scanning technologies, highly detailed street level images and the great abundance of Google Street View images, to create true digital twins of city trees. I will investigate the potentially large added value of this highly detailed 3D information to accurately quantify ecosystem services.