Trees can be used as technical solutions to urban problems, but they are also highly unique landscape elements that create important aesthetic and atmospheric characteristics. These qualities are valued differently by engineers, architects, and landscape architects. Often, these differences are exposed when converting the qualities of trees into digital models, where the effect of underlying disciplinary assumptions can limit how living materials are used in a digitally informed design. This research uses a detailed case study of the workflow of a large multidisciplinary urban design project to explore how trees are valued in different ways in a digital design process. Using interviews with designers and engineers the case study reveals distinctive disciplinary perspectives on working with trees. Further, where disciplinary assumptions impact how trees are incorporated into digital models of environmental performance. These examples expose how attitudes and values directly influence methodological decisions within a project workflow, but also the significant effect on the designed outcome.