Cooling high-density historic districts with strategic greening in the “port-opening area” of Shantou city

This study addresses summer thermal comfort optimization in high-density historic districts, exemplified by the “port-opening area” of Shantou city—an area of renowned for its well-preserved arcade architecture and rich cultural heritage of south east China. Integrating field measurements and ENVI-met simulations, we analyzed how street morphology (orientation, height-to-width ratio) and green infrastructure affect thermal conditions. Results identified peak heat stress (PET > 43 °C) at 14:00–15:00. The 75% tree canopy coverage scheme achieved maximum cooling, reducing PET by 0.45–11.10 °C while generating a Cool Island Spillover Effect that improved adjacent streets. In narrow streets, 2m-high shrubs reduced PET by 0.17– 3.73 °C. Strategic recommendations include deploying decentralized tree greening (50–75% coverage) in open spaces and modular 1–2 m shrubs along pedestrian corridors to synergize shading, ventilation, and heritage preservation. The research provides a data-driven framework for climate-resilient design in heritage-intensive urban contexts.