The Impact of Plant Community Spatial Configurations on Summer Microclimate: A Simulation Study of Urban Parks in Zhejiang, China

The intensifying Urban Heat Island (UHI) effect exacerbates urban heat stress. While vegetation is a key mitigation strategy, the quantitative effects of its spatial configuration are not fully understood. This study employed ENVI-met simulations to systematically evaluate how three design parameters—tree spacing (8–18 m), canopy structure (single/multi-layer, sparse/dense), and horizontal layout (enclosed, semi-enclosed, linear)—regulate summer microclimate in urban parks. Results demonstrated that reduced spacing and denser canopies significantly enhanced cooling and humidification. The multi-layer dense canopy and an enclosed “mouth-shaped” layout yielded the optimal performance, achieving a maximum daytime air temperature reduction and a corresponding humidity increase. Furthermore, layout orientation was identified as a critical modulating factor. Spatial configuration exerted a stronger influence on microclimate outcomes than structural complexity itself. This study provides a predictive, evidence-based framework for optimizing urban green space design. The framework and the derived design principles are directly transferable to other cities in humid subtropical climates, offering generalizable strategies to enhance microclimate regulation and climate resilience globally.