One of the key challenges in urban heat island mitigation is the efficient allocation of resources to the most effective measures and to locations where they are most needed. While our knowledge on the potential of certain heat mitigation measures to reduce urban heat is generally broad and scientifically sound, in many times we still lack effective tools that would promote their large-scale adoption according to evidence-based prioritization policies. To drastically change the way our cities are planned and managed vis-a-vis the current climatic crisis, we should therefore also advance action prioritization methods that could support efficient and effective implementation of the measures we consider to be the most effective.
Planting of shade trees is regarded as one of the most promising heat mitigation measures because it can be widely and easily promoted and controlled by municipal planners and decision-makers for mitigating the effects of climatic vulnerabilities caused by exposure to solar radiation. Taking in mind this exceptional significance of street trees, we developed a novel and comprehensive approach to a city-scale analysis of street-level outdoor shade conditions that enables a municipality to effectively direct its shade intensification efforts, mainly through tree planting, to shade-deficient locations and to quantify the planting potentials of street trees according to the physical properties of the cityscape. The method is based on the production of shade maps that reflect the spatial hierarchy of street-level shading conditions in the city and on the high-resolution and comprehensive mapping of street trees. The article exemplifies how the method could be implemented in urban planning, taking Tel Aviv-Yafo, a city of hot summer Mediterranean climate, as a case study.
