Penrith, Australia

Photo by Penrith City Council

The power of plants and natural ecosystems to deliver benefits

How is the initiative shaped by scientific evidence of the potential for plants and natural ecosystems to deliver benefits?

Council has worked with leading urban heat experts at Western Sydney University to map heat across the region, to strategically identify priority hotspots for action. Over the summer of 2019/20, a network of 120 heat sensors were installed across the Penrith area, with air temperature results recorded at 10-minute intervals. Over 1.4 million temperature measurements were collected. There was a clear correlation in the results between greener areas and those with higher levels of canopy having cooler temperatures, and more urbanised spaces having higher temperatures. The resulting heat maps allow Council to identify priority suburbs/locations for practical actions such as tree planting to provide shade and cooling.

Prior to this research, official weather monitoring was only undertaken by the Federal Government’s Bureau of Meteorology (BoM). The weather station present is located away from urban spaces so is not unduly impacted by the urban heat island effect, and therefore does not reflect localised temperatures across the region.

This research recorded air temperatures of over 50oC at 6 locations in Penrith, and also showed significant outcomes such as the St Marys CBD remained up to 2.40C warmer at nighttime compared to surrounding residential areas, and 39 days were recorded over 350C compared to the BoM records of 24 days. The research provides a snapshot of the variabilities of heat across the region and an evidence -base for future action. It has also been applied in the development of the Green Grid Strategy and to develop a vulnerability assessment webtool for Penrith.

How has the city exploited the potential of plants and associated ecosystems to deliver more than one benefit?

Trees and green cover provide positive outcomes in terms of cooling urban spaces, boosting physical and mental health, and creating more desirable, soothing, and visually appealing suburbs and places. Council is promoting these benefits in a number of ways:

• The development of City Park in Penrith’s CBD, with construction commencing in late 2021. At around 7,000sqm, the City Park will convert open asphalt parking and low-density buildings into the cool green heart of the city, with an open lawn, shade trees, shade pergolas, water misting, and raingardens.
• Soper Place carpark, which will convert an open asphalt carpark into a multi-deck carpark covered in green walls. This will provide urban cooling, increased parking, and increase amenity and open space for the community.
• A green wall has also been installed in the foyer of Council’s Civic Centre providing a living ecosystem that benefits staff and visitors through enhanced visual amenity with greenery boosting mental health, also improving indoor air quality and providing better thermal comfort.
• Tree planting projects completed since 2018 include planting at sports fields for spectator shade, street trees for suburban areas, trees (and shade sails) being installed at children’s playgrounds, and planting in open parks and reserves. By critically choosing the right tree for the right application, these projects provide the priority benefit as well as associated benefits, for example, shading and cooling for a specific audience with flow on benefits for the community, beautification and urban renewal, and also delivering on biodiversity outcomes.