Contribution of urban trees in reducing land surface temperature: Evidence from china's major cities

Abstract

Urban trees mitigate urban heat by altering evapotranspiration processes and providing shade to their surrounding environment. Nevertheless, the impact through which three-dimensional tree characteristics alleviate Land Surface Temperature (LST) remain uncertain, especially for climatic zone differences. In this study, we investigated the potential of trees to mitigate LST in 35 Chinese major cities and quantified the importance of diverse factors influencing the magnitude of cooling effects. Results showed that LST in tree-covered areas was about 2.23 °C lower than their surrounding built-up areas during summer, but an opposite temperature pattern was observed in winter and these cities are mostly distributed in Bs (arid-steppe) and Dw (cold-dry winter) climate zones. Moreover, we found that for every 1 m increase in tree height, LST decreased by ∼ 0.19 °C and ∼ 0.10 °C during summer and winter, respectively. Notably, we also found seasonal and climatic zone differences in the drivers of tree cooling intensity, with the digital elevation model (DEM = ∼13.21 %) as the key factor. These findings can help planners and architects better understand the effects of tree cooling, which can be a significant guide to reducing urban heat.