Benchmarking Tree Canopy in Sydney's Hot Schools

This project identified the 100 most vulnerable schools to heat in Greater Western Sydney using a newly developed Heat Score. The Heat Score combines socio-economic information that captures exposure, sensitivity and adaptivity of local communities to heat with environmental data related to surface and air temperatures of urban space. Following the identification of the 100 schools, high-resolution aerial imagery was used to remotely measure a range of attributes at each school. These attributes included the area covered by buildings and open space, as well as the area of tree canopy cover and manmade shade structures. We determined the size of close to 5,000 individual objects to establish a benchmark of shade in Sydney’s hot schools. Key findings: » Mean area covered by the 100 schools is 23,000 m ². » On average 18% of that area is shaded » Tree canopy cover makes up the majority (15%) of the shaded area. » Tree canopy cover increases with the area covered by a school. » Public schools tend to cover larger areas and thus have more tree canopy cover compared to Catholic and independent schools. » Urban Heat Island effects were reduced when the area of shade was increased. Additional tree plantings will provide microclimatic benefits. However, the present study reveals that a dual approach is necessary to increase canopy cover among the target schools that differentiates between needs and opportunities. Catholic and independent schools have the highest need for additional tree canopy cover as their current cover is low. These schools tend to have less open space available for plantings. Successful strategies will require establishing low numbers of carefully selected trees at strategic planting locations to deliver the greatest local shading and cooling benefits. Public schools offer the greatest opportunities for mass planting of additional trees as they have large areas of open space available. Planting sizeable clusters of trees will provide the greatest cooling benefits not only for the school but generate microclimate and environmental benefits for the surrounding communities. Analyses provided in this report will assist the development of the most effective tree planting strategies for each of Sydney’s 100 hot schools.