Climate Action Merribek: people in Brunswick, Coburg, Fawkner and Glenroy wanting action on climate change

Tackling Urban heat at CB Smith Reserve with more trees

February 17, 2023 at 2:38 pm John Englart Leave a comment

Merri-bek Council have started work in tackling the urban heat of the CB Smith Reserve car park in Fawkner by providing more spaces for canopy trees to be planted.

Asphalt surfaces commonly heat up to 60 degrees Celsius during warm summer days. That acts as a heat bank which then radiates during the night keeping the local area at elevated temperatures during the night. This can affect nearby residences. A spot temperature reading was taken on 17 February of the asphalt road in front of the community hall with a spot temperature reading of 58.2C A concrete section of the road at the same location was 51.2C Ambient air temperature in the shade was 38C.

The car park as a hard surface also contributes to excess water for stormwater systems during torrential rain events and can contribute to flash flooding.

Trees planted around the car park can provide canopy shade to some of the asphalt bitumen. Tree evapotranspiration will also contribute to a local cooling effect. Trees will also soak up some of the water during rain events reducing water runoff and issues associated with stormater sysrems being overwhelmed. Trees also can add to urban biodiversity. Nest boxes in trees for microbats can provide a natural predator for mosquitos and other insects.

Cars parked in the shade will also require less air conditioning to cool down, thus producing less vehicle emissions.

Climate Action Merri-bek reported in March 2022 that tackling the urban heat of at grade car parks was an easy win for urban cooling and climate adaptation. This is based on urban research from the University of Western Sydney.

“At-grade car parks are an ideal starting point. They represent the ‘low-hanging fruit’ for urban cooling efforts. While unavoidable today and in the near future, at-grade car parks are predominately unshaded; made from black, heat-retaining asphalt; widespread and fairly uniform; and often large in size. Changes to current designs of at-grade car parks can therefore have a big impact. A number of strategies to effectively reduce surface heat of car parks are commercially available. Cooling car parks not only addresses their status as local heat islands, but it also leads to lower ambient air temperatures in downwind environments. “

Dr Sebastian Pfautsch et al in Despicable Urban Spaces: Urban Car parks (Feb 2022)

The report goes beyond highlighting the problem of urban heat. It also proposes solutions. The most effective cooling techniques for car parks will:

• Reduce the area covered by impermeable black asphalt
• Coat remaining asphalt with reflective surface sealants
• Increase open space (permeable pavements)
• Use solar reflective (light-coloured), porous surface materials
• Use existing tree canopy for shade cover
• Introduce infrastructure for strategic shading
• Use climate-adapted trees species with wide, dense crowns
• Irrigate green infrastructure (active or passive)

Planting trees is perhaps the easiest, most environmentally friendly solution for the cost involved, returning multiple benefits.

The concrete Skatepark in CB Smith Reserve has already had a light coloured sun sail erected over part of the skatepark. This will reduce warming of the concrete and make it useable on hot days.

The initial work by Merri-bek Council at CB Smith Reserve in Fawkner will help establish a baseline for further transformation of urban car parks in Merri-bek to address urban heat.

Reference:

• Pfautsch S., Wujeska-Klause A., Paolini R., van den Nouwelant R., Morrison N. (2022) Despicable urban places: hot car parks. Western Sydney University, 68p. DOI: 10.26183/7q7a-f148 URL: https://doi.org/10.26183/7q7a-f148

Entry filed under: climate change info, Merri-bek Council, news, urban forest. Tags: car park, CB Smith Reserve, Fawkner, urban forest, urban heat island effect.