Heatwave takes its toll on urban greenery – municipal works department calls on residents to help
The ongoing heat wave in the Rhine-Main region is not only affecting people, but also the approximately 10,000 urban trees in Groß-Gerau. The district town is therefore asking all residents to help water the trees in front of their houses.
The city reports that its building and maintenance department is working almost daily to water trees and other green spaces and protect them from prolonged heat damage. However, due to the ongoing drought, the staff are reaching their capacity limits.
Urban trees make an important contribution to the urban climate
Especially on hot summer days, trees provide shade, cool their surroundings, filter fine dust, and produce oxygen. They also offer habitat to numerous animal species.
"Urban green spaces are an indispensable part of our living environment. They provide cooler air, filter particulate matter, offer shade, supply oxygen, and provide habitat for animals. And all of this is free," emphasizes Mayor Jörg Rüddenklau. Wherever possible, surfaces are therefore being unsealed to improve the inner-city climate.
Young trees in the city center and along roadsides are particularly affected. They often only have small planting areas with heavily compacted soil available to them, so they suffer from water shortages very quickly. But even older trees now need additional support.
White trunk protects against heat damage
Many young trees are currently noticeable because of their white-painted trunks. This is a deliberate protective measure: the light paint reflects sunlight and significantly lowers the temperature inside the trunk. This can result in temperature differences of up to ten degrees Celsius on the sunny side.
Without this protection, extreme heat can lead to sunburn, frost cracks in the wood, or even permanent damage to the tissue inside the trunk.
Less rain than average
The precipitation figures also reflect the tense situation. According to the German Weather Service's measuring station in Wallerstädten, a total of 184 millimeters of precipitation fell between January and May 2026. The long-term average (1996 to 2020) for the same period is 190.8 millimeters.
While January and February were wetter than average, significantly less rain than usual has fallen since March. In June, only 26.5 millimeters of precipitation were measured up to the 24th of the month. The average for the entire month is 61.4 millimeters.
Here's how citizens can help
According to the city, a tree needs about 100 liters of water per week during a heat wave. It is recommended to water thoroughly once or twice a week – ideally early in the morning or late in the evening. This allows the water to penetrate deep into the soil and prevents it from evaporating too quickly.
The watering bags attached to many young trees can also be filled by citizens. Depending on the model, they hold between 50 and 100 liters of water and release it slowly into the soil over several hours. This allows the moisture to reach the root zone directly.
“Whether with a watering can, garden hose or a special watering bag – every bit of support helps,” is the appeal from the team at the construction and maintenance depot.
(GROSS-GERAU – RED/PSGG)
