Mitigating seasonal thermal paradox in urban pocket parks by phenology-driven synergy of mixed evergreen-deciduous planting: a case study of Chengdeli in Suzhou, China

Thermal paradox, simultaneous summer heat and winter cold stress, impairs pocket park functionality in high-density, hot summer-cold winter (HSCW) cities like Suzhou. This study quantifies how dynamic tree phenology resolves this dual-season challenge using ENVI-met simulations, validated by field measurements, across five planting scenarios in Chengdeli Park. The mixed evergreen-deciduous strategy (S4) achieved optimal mitigation: reducing summer UTCI by 3.34°C, via 40.21% shading, and increasing winter UTCI by 2.34°C through windbreak-solar synergy, Supported by the Thermal Performance Index (Total TP = +5), this nature-based dynamic solution transforms pocket parks into climate-adaptive infrastructure, providing evidence-based design guidelines for HSCW cities.