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  • Right tree, right place (ur...
    Morakinyo, Tobi Eniolu; Ouyang, Wanlu; Lau, Kevin Ka-Lun; Ren, Chao; Ng, Edward

    The Science of the total environment, 06/2020, Volume: 719
    Journal Article

    The re-integration of trees into the urban landscape is a veritable strategy for urban climate mitigation and adaptation. However, dysfunctional trees in terms of urban heat mitigation are dominant in many sub-tropical cities' landscapes due to the lack of scientific basis of tree selection. Therefore, this study proposes and evaluates a methodological framework as an approach for “right tree, right place” for urban heat mitigation through parametric ENVI-met simulations that involve the combination of 54 generic tree forms and 10 characteristic urban morphology – Sky-View Factor (SVF). Results show variable temperature regulation by tree forms (species) with varying magnitude in different urban morphology. Daytime and nighttime temperature regulation effects were between 0.3 °C – 1.0 °C and 0.0 °C – 2.0 °C, respectively depending on tree forms and SVF value. Furthermore, the Heat Reduction Potential (HRP) of trees forms were determined in terms of their human thermal comfort improvement. In general, we found a range of +5% and − 20% depending on SVF, negative and positive values imply heat reduction and increment, respectively. With the competing shading effect of buildings, the HRP of trees reduces from high to low SVF area with variable magnitude among tree forms (species). Hence, the proposed morphology-based tree selection approach was evaluated by comparison with two uninformed selection approaches in a realistic urban neighborhood in Hong Kong. Results clearly indicate the proposed approach's capability in improving human thermal comfort by up two times more than either of the other approaches. Finally, evidence-based recommendations were given for the reference of policy-makers when they make urban green development plan. Display omitted •A “Right tree, right place” approach for optimum urban heat mitigation was proposed.•The approach was developed and evaluated through a parametric case study under hot-humid prevailing climate.•Proposed approach was found significantly more efficient compared to two others in a realistic urban neighborhood.•Heat reduction potential of trees was location-dependent and species-specific.