‘Like Caring for a Pet’ – the App That Lets You Know if Your Neighborhood Tree Is Thirsty.
CityLAB Berlin's open-source Gieß den Kiez map lets residents see which street trees need water and log their own watering, and four other places have launched versions of it.
Gieß den Kiez, which translates to "water your neighborhood," is an interactive map run by CityLAB Berlin. It tracks more than 900,000 trees across the city and calculates the water needs of each one from its age, species and local rainfall. Users can see when a tree was last watered and log a watering of their own. Color-coding marks trees in critical need.
Amanda Gläser-Bligh adopted an eight-year-old linden outside her home in Charlottenburg through the project. During the hotter months she carries about 20 liters of water to the tree once a week. She reports that it no longer wilts in summer heat. "I named her Linda the linden," she said.
The project has run since 2020 and has 12,000 registered volunteers. Their work supplements that of district street and green space authorities, which water thousands of trees but cannot always keep up in increasingly hot summers. The biggest annual peak in watering, nearly half a million liters, came just after the 2020 launch at the start of the Covid pandemic. Project lead Anna Mehrländer believes watering gave people a reason to go outside and reconnect. Watering also rises during heatwaves: on 27 June, when Berlin hit an all-time high of 39.9C (103.8F), people poured 8,000 liters over trees across the city.
Urban forestry expert Cecil Konijnendijk supports citizen efforts of this kind. He said trees are increasingly seen as critical infrastructure rather than decoration, and that a new tree takes 30 to 40 years to deliver the ecosystem services of a mature one. He also pointed to soil volume and underground space as important for healthy roots, and noted that many trees are being pushed to their limits by drought.
Because the project is open source, any city can adopt it. Residents in Potsdam, Leipzig, Magdeburg and the 17th arrondissement of Paris have launched their own versions. "Anyone can copy the code and set up their own Gieß den Kiez," Mehrländer said. The main requirement, she added, is a data set of all the trees in a city.
At a Glance
- Gieß den Kiez maps more than 900,000 trees in Berlin and estimates each tree's water needs.
- The project began in 2020 and now has 12,000 registered volunteers.
- On 27 June, Berlin's record 39.9C day, volunteers poured 8,000 liters of water on trees.
- Potsdam, Leipzig, Magdeburg and Paris's 17th arrondissement have launched their own versions.
Sources
This brief was written by Brightside Report from the reporting linked above. Spot an error? Request a correction.