Cooling canopy Google Street View reveals urban tree cover benefits

Google Street View images of more than 80% of Singapore's road network were analysed using an algorithm

(Keystone)

The mapping tool has been put to use by Swiss scientists to measure the impact of tree cover in cities. Researchers at Zurich’s Federal Institute of Technology (ETHZ) claim to have found the blueprint for determining how much green space urban areas need to improve quality of life. 

More than 100,000 Street View images were examined to map tree cover in Singapore and establish what benefits this brings. The team concluded that increasing the cover of the street tree canopy could reduce ground surface and air temperatures further on Singapore’s streets. “In addition, the relative quantity of the canopy may also serve as an indicator of evaporative cooling from leaves and rainfall interception,” said an ETHZ statement. 

In addition to bringing down temperatures, the foliage was found to have another quality. 

“In addition to cooling urban microclimates, these trees, which are integrated within dense urban street networks, also provide other benefits, such as reducing the risk of flash flooding and cleaning the air,” says Peter Edwards, Principal Investigator at the Future Cities Laboratory and Director of the Singapore-ETH Centre. 

Similar research has been carried out in temperate zones, but this was the first time such data could reveal the fruits of having tree cover in hotter climes. 

ETHZ researchers now want to use the relatively inexpensive method of utilising Street View to help urban planners identify areas of cities with low shade and prioritise the planting of new trees. 

“With urban populations exploding in megacities like Tokyo, Shanghai, and Delhi to well over 20 million people - it is important to understand how green spaces contribute to urban sustainability,” ETHZ stated. 

This technique could also be used in temperate climates where trees lose leaves in winter. 

swissinfo.ch

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