Open Space Heat Stress In Social Housing Districts. The role of trees depending on urban form

As global warming worsens, understanding the vulnerability of urban areas to extreme heat becomes crucial. Social housing districts, due to their urban form and demographic composition, are identified as high-risk areas for heat stress. This study investigates the impact of trees on mitigating outdoor heat stress in social housing districts, focusing on the Mediterranean region, particularly the metropolitan area of Barcelona. Using mean radiant temperature (MRT) as a key parameter, we use simulations to assess the influence of trees on heat stress in two districts differing in building types: linear blocks vs towers. Our results point out that, in the absence of trees, the latter is more vulnerable to heat stress, since it lacks long-term shaded spaces, such as the corridors generated by the linear blocks. In contrast, when trees are considered, tree-induced shading significantly decreases MRT and shifts its distribution pattern so that both fabrics exhibit similar performances, achieving the same percentage of open space with moderate heat stress (22%). Our findings underscore the importance of a performance-based design approach, emphasizing the need to consider both urban form and tree cover for effective heat stress mitigation in social housing districts.