German cities launch tree‑watering and cooling measures amid heatwave

The city of Karlsruhe is asking residents to help protect its street trees during the prolonged heat and drought. The municipal horticulture office advises watering each tree with about 100 litres once a week, ideally in the early morning or evening, and is handing out 50 free watering cans to volunteers. The cost of this extra watering is estimated at roughly €10 per tree per year, and officials say the effort can reduce leaf loss and dead branches across the city’s tens of thousands of trees.

In Berlin’s Karl‑Marx‑Straße, landscape architect Marco Schmidt used an infrared camera to record surface temperatures of up to 54 °C, far above the 30 °C air temperature. He points to the lack of vegetation and the difficulty of planting trees in the heavily paved area. Schmidt proposes temporary cooling methods such as nightly misting of the pavement or installing fine‑mist spray systems, as well as adding shade structures like canopies. Both cities are experimenting with low‑cost, water‑based interventions to mitigate the extreme heat’s impact on urban infrastructure and public comfort.