Evaluating tree replacement for thermal comfort in urban green squares: Munich case study and climate projections to 2050

As climate change impacts intensify, urban green infrastructure (UGI) becomes essential for city adaptation. Urban green squares, among UGI types, are easy to implement and integrate into neighborhoods, making them vital for urban resilience. Although their cooling benefits are well established for current conditions, future microclimatic assessments are scarce, creating a critical research gap. This gap is significant because ongoing greening practices coupled with rising tree mortality rates are expected to degrade the microclimate and reduce human thermal comfort in these spaces. This study evaluates the impact of urban green squares on human thermal comfort, measured by Physiological Equivalent Temperature (PET), under future climate change scenarios considering projected tree mortality. We focus on two urban squares in Munich, Germany, using micrometeorological simulations with the ENVI-met model to assess the effects of urban design and tree-planting strategies. Our simulations suggest that by 2050, intense and extreme heat stress will cover up to 96% of the squares’ area due to climate change and tree loss, compared to about 75% today. Analysis of different tree replacement scenarios highlights potential heat mitigation strategies that urban planners could implement progressively. Recommendations emphasize customized approaches for each square, diversification of tree species, and planting of climate-adapted trees to improve survival rates. However, devising effective tree replacement plans that prioritize vital trees remains contentious and calls for further investigation. This study advances understanding of future urban microclimates and provides actionable insights for sustainable urban green space design amid climate change.