A city planted trees where the heat maps were worst, and the effect showed within two summers
Targeting by surface temperature rather than by ward produced results the earlier programme never managed.
The previous programme distributed saplings evenly across wards. The new one distributed them by temperature.
How it was targeted
Thermal imaging identified the hottest hundred streets. Nearly all were in dense, low-income neighbourhoods with almost no existing canopy.
Two summers on, treated streets are measuring up to four degrees cooler at peak afternoon than untreated ones nearby.