In the era of climate change, there is an increased interest in including different types of green infrastructure in building legislation as a strategy to improve the built environment. Among these different types, trees on buildings have received little attention, and there is limited literature and policies to guide their design and implementation. Therefore, this research aims to explore trees on buildings from various perspectives to enrich the scholarship and policies and to enable their implementation. To achieve this, the research includes a four-stage mixed method using qualitative and quantitative approaches.