Investigating the Wind Regulation Mechanisms of Tree Crown Morphology and Layout at Different Heights

Urban heat islands (UHIs) are intensifying in hot–humid regions under climate change, making tree configuration crucial for optimizing urban wind environments. This study, based on computational fluid dynamics (CFD) simulations in Macau, systematically assessed three crown morphologies (ellipsoidal, cylindrical, conical) and six planting layouts (single tree, contralateral, single row, double row, enclosure, curved) at pedestrian height (1.5 m) and canopy height (5 m). Results show that crown morphology strongly influences vertical wind differentiation: ellipsoidal crowns produced the weakest attenuation at 1.5 m but the strongest obstruction at 5 m; conical crowns induced the greatest near-surface reduction yet the fastest recovery aloft; cylindrical crowns displayed intermediate effects. Planting layouts further modulated these outcomes: single and contralateral plantings showed similar patterns; single and double rows of ellipsoidal crowns balanced ventilation at 1.5 m with shelter at 5 m; enclosure layouts caused pronounced intra-area wind differences; curved layouts yielded morphology-dependent responses, with ellipsoidal crowns causing stronger near-surface reduction but slower recovery. Overall, the coupling of crown form and spatial configuration determines wind attenuation and recovery across vertical layers, providing scientific guidance for climate-responsive greening in dense subtropical cities.