From Hildburg Bruns
Shovels for more healthier trees! In Mitte, maples, linden trees and the like are given more space on the side of the road. So that rainwater can penetrate better to their roots.
The young maple, which the gardener Enrico and his colleague Monika are lifting into the planting pit on Thomasiusstraße (Moabit), has good starting conditions: fertilizer beads and white crystals (“TerraCottem”), which store water, have been added to 60 cm of tree substrate.
And on top come 15 cm of granite chips. Reminds at first glance of frowned upon gravel gardens (“gardens of horror”), but is good at retaining water. In addition, roses, lamp cleaners, sage and asters are planted.
For the first five years, new trees are watered with 200 liters every two weeks from April to the end of October. In this district alone, four tankers distribute 25,000 liters to 3,000 trees every day.
At the end, a galvanized steel grid comes around the new tree Photo: christian lohse
The enlarged tree disc measures around nine square meters and is three times larger than that of the neighboring trees. A parking space was lost for their expansion.
A total of ten trees have already been given more space for their roots. A start. Because this year, city councilor Almut Neumann (39, Greens) wants to free 5,000 square meters in the district of asphalt and concrete.
This tree is still alive on a small tree disk Photo: Christian Lohse
Not only under street trees, but also on the shoulders of sidewalks. Rain troughs with lawns are to be created there, wild flowers are to grow as insect food, or perennials are to be planted.
“We want to create small green oases and give the city back a piece of nature,” says Neumann. The locations have not yet been determined, but the budget is: 800,000 euros.
Mobile phone app shows the office where urgent watering is needed
A small gray box with a transmitter and battery delivers tree information to the mobile app of the Parks Department employees. The metal pin of the sensor is inserted into the ground next to the root ball and registers the moisture in the soil.
Tree expert Wolfgang Leder (63) controls the humidity with his mobile phone Photo: christian lohse
In the Mitte district alone, 500 trees are monitored with such sensors, for example on the newly planted median on Heidestrasse. “A signal is sent every six hours,” says Mitte’s tree expert Wolfgang Leder (63).
Another method: Laypeople can find out whether it is time to water from the traffic light diagram of the Plant Protection Office on the Internet. It is a symbiosis of actual weather data (including temperature, wind speed, radiation) plus expected precipitation.
The status is shown for the typical consumption of an unwatered small-leaved lime at a depth of 85 cm. If the curve falls into the red area, one thing is clear: please water!
So much felled, so little planted
A bitter balance: minus 4018 street trees in 2022. In the capital, 6557 trees were felled, but only 2539 were replanted! It was only the other way around in two districts – in Mitte and Tempelhof-Schöneberg the respective stocks grew.
Where does this mismatch come from? An expert from the environmental administration: “Due to increasing competition for space in the street space, increased construction activity and climatic changes, the location conditions have deteriorated.”
The second reason: many old trees – over 40 percent of the stock. The green space offices of the districts cannot maintain the stock as actually required with their budget and available staff.
The Senate will support them in 2023 with an additional 2.5 million euros. In addition, 1200 trees are planted as part of a fundraising campaign: