Tree growth simulation in Geographic Information Systems: Coupling CityTree and ArcGIS for solar radiation analysis

Cities must undergo a sustainable transformation as they rapidly expand with urban heat and CO 2 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 m 2 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. • Methodology for implementing urban tree growth in GIS-based solar radiation studies. • 20 years of tree growth reduce solar radiation on the ground by 6.1%. • 20 years of tree growth reduce solar radiation on the building roofs by 1.0%. • Tree growth increases evaporative cooling more than reducing PV energy. • Cities can update their urban tree database without new measurements.