What was it all about?

This project explored the importance of the nursery industry in mitigating heat stress in cities. It examined the potential benefits of urban green infrastructure including easing extreme summer temperatures, reducing heat-related health impacts by providing tree shade to streets and buildings, and by ambient cooling through evapotranspiration.

Population growth and rapid development in Australia’s major cities has led to the transformation of many urban landscapes and resulted in engineered infrastructure dominated by heat-absorbing surfaces and less vegetation.

The heat accumulation that results, known as the urban heat island effect, can cause the ambient temperature to be several degrees higher than that of nearby rural areas.

The heat mitigating potential of different vegetation schemes was investigated using three scales of analysis – suburb, neighbourhood and household. Western Sydney was chosen as the geographic focus for the project due to its heat vulnerability with computer modelling performed for three suburb centres – Parramatta, Penrith and Campbelltown.

The research resulted in several key findings and recommendations that support a strategy for increasing vegetation in urban areas. For example, it found vegetation coverage in the Western Sydney area can reduce the average summer air temperature by up to two degrees Celsius and should be considered as a heat wave mitigation strategy.

It also found that the benefit of increased vegetation coverage in reducing summer heat stress and heat-related hospital admission rates is greatest in the parts of the city that are the most heavily urbanised.

The research findings are valuable to local council and urban developers to promote more resilient urban designs, to householders for planting more trees and use the strategic positioning of vegetation to mitigate the impact of heat waves. The methodologies may also be used to demonstrate the benefits of urban greenery in other areas of Australia.