The impact of tree clusters on air circulation and pollutant diffusion-urban micro scale environmental simulation based on ENVI-met

For urban planners, trees play a role in improving landscape quality, but their impact on urban ventilation is often ignored. By using the three-dimensional microclimate model ENVI-met, this article simulates 14 situations with different variables, aims to re-examine the impact of vegetation cover on aerodynamic effect. The results show that trees have a resistance effect on air flow, Especially the ratio of tree spacing/canopy width related to the continuous vortex area have a significance impact on wind speed, which is needed to be considered in urban planning of vegetation layout. Moreover, the distinguished theories under both conditions whether there is buildings or not are analysed, inspiring the planners and researchers to consider the relationship and discrepancy between different scales.