12,000 neighbors signed up to water Berlin's street trees

Berlin has roughly a million street trees, and 12,000 people have now signed up to help water them. A free app called Gie\u00df den Kiez, German for "water your neighborhood," maps more than 900,000 trees and calculates each one's needs based on age, species and recent rainfall. Volunteers log their waterings, see when a tree last got a drink, and locate the nearest public pump. On June 27, when Berlin hit an all-time high of 39.9 degrees Celsius, people poured 8,000 liters over the city's trees in a single day. Anna Mehrl\u00e4nder, who has led the project for over a year, expected people to care. She did not expect this. "I was really surprised at just how deeply people care about trees," she says, "for many people it's almost like caring for a pet." Amanda Gl\u00e4ser-Bligh carries 20 liters up and down her stairs each week for a linden she named Linda. Passersby stop and stare. Then they ask, and then they look up at the tree a little differently.