Abstract

The Urban Heat Island (UHI) effect increases surface and air temperatures, affecting urban health and well-being. A well-known UHI mitigation measure is the increased roadside tree vegetation facilitating evapotranspiration and shade. In its implementation, the identification of thermally optimal street tree configurations and a quantitative assessment of how various street tree configurations impact the roadside thermal environment were deemed essential and were chosen as the main aims of the study. Twelve tropical urban canyons were categorized into three clusters representative of different street tree placement and configuration scenarios. A control cluster devoid of any roadside trees was also selected. The CFD-based 3-D microclimate model ‘ENVI-met’ was used to identify suitable roadside urban tree planting scenarios for better microclimate regulation. From a tree planting scenario analysis done as part of the study, the greening scenario of using a ‘Continuous tree row (Densely foliated – high Leaf Area Density - LAD)’ tree configuration was recognized with the highest ambient temperature reduction of 1.41 °C. The study outcomes reveal that tree configuration of high LAD street trees placed in closer spacing contributes towards the better cooling effect of roadside environments and thus improves thermal comfort for warmer tropical climates of higher humidity levels. The study’s findings offer valuable insights for urban planning professionals and policymakers involved in designing future cities and urban developments. They emphasize the importance of strategic tree-planting designs and configurations to enhance thermal comfort and livability in urban areas. This highlights the need to avoid ad-hoc procedures and instead prioritize well-planned roadside tree configurations within urban canyons.

中文翻译：

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热带城市峡谷行道树配置和布局对路边热环境的影响

摘要

城市热岛（UHI）效应会增加地表和空气温度，影响城市健康和福祉。一项众所周知的城市热岛缓解措施是增加路边树木植被，促进蒸散和遮荫。在实施过程中，确定热最佳行道树配置以及定量评估各种行道树配置如何影响路边热环境被认为至关重要，并被选为研究的主要目标。十二个热带城市峡谷被分为三个集群，代表不同的行道树放置和配置场景。还选择了没有任何路边树木的控制簇。基于 CFD 的 3D 微气候模型“ENVI-met”用于确定合适的路边城市树木种植方案，以实现更好的微气候调节。根据作为研究一部分进行的植树情景分析，使用“连续树行（密集叶状 - 高叶面积密度 - LAD）”树木配置的绿化情景被认为最高环境温度降低了 1.41 °C。研究结果表明，高 LAD 行道树间距更近的树木配置有助于改善路边环境的冷却效果，从而提高湿度较高的温暖热带气候的热舒适度。该研究的结果为参与设计未来城市和城市发展的城市规划专业人士和政策制定者提供了宝贵的见解。他们强调战略性植树设计和配置对于提高城市地区的热舒适性和宜居性的重要性。这凸显了避免临时程序的必要性，而是优先考虑城市峡谷内精心规划的路边树木配置。