Urban Tree Information in the Built Environment Process—Current Status and Possible Improvements

The European Union adopted the Nature Restoration Law (NRL) in 2024 to protect and restore ecosystems across the EU, including specific targets for urban ecosystems (Regulation (EU) 2024/1991). One objective is to safeguard urban trees, which provide important ecosystem services, including the mitigation of urban heat island effects. Implementing the NRL requires Member States to monitor urban tree metrics, such as urban tree cover (UTC). This study investigates the potential to monitor UTC and related metrics throughout the built environment process, from early planning to maintenance, through three case studies. The first examines how urban trees are represented in current planning and construction instruments and evaluates how UTC can be estimated from these instruments in a study area in Stockholm, Sweden. The second investigates the requirements for an urban tree information model applicable from planning to maintenance, based on an extensive literature review and interviews with 14 experts as well as developing such an information model. The third case study implements a knowledge graph-based workflow for information exchange among actors in the built environment process, demonstrating a potential technical approach for sharing urban tree information. The results show that urban tree information, including UTC, cannot currently be consistently followed throughout the planning and construction process. This constrains the ability to determine whether operational decisions and realized outcomes align with policy-level decisions, thereby limiting vertical alignment. Improving vertical alignment requires a better representation of urban trees in planning and construction instruments, a common information model, and technical solutions for sharing urban tree data, such as knowledge graphs, which is demonstrated in the third case study.