Cities must undergo a sustainable transformation as they rapidly expand with urban heat and CO2 emissions increasing. Urban development with a detailed digital twin is crucial for managing this multilayered transformation. This paper proposes an approach to integrate urban tree growth in such digital twins. By coupling Geographic Information Systems (GIS) with a tree growth model our methodology predicts the growth of trees for 20 years. This allows the local assessment of future Ecosystem Services from trees and supports their long-term management. The CityTree model is used to simulate tree growth in a 500,000 m2 case study area in Munich, Germany. The derived crown diameter and height increments are implemented in ArcGIS to assess the resulting impact on solar radiation. 20 years of tree growth reduced the solar radiation on the ground by 6.1%, whereas on the building roofs, the reduction was 1.0%. The increase in cooling energy due to tree growth exceeded the reduction of usable solar energy from buildings’ roofs by a factor of almost 50. The methodology for 3D tree growth projection in GIS saves monitoring resources for urban tree management and improves the accuracy of digital twin models.
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