Because of the longer periods of heat caused by climate change, fewer trees survived in the cities, explains Franz Humberg.

"I would like to walk through every city and enjoy the many tall trees," adds the managing director of Humberg GmbH from Nottuln in the Münsterland region.

His company has the largest share of the market for protective devices for urban trees and their roots.

This is particularly noticeable with a view to the tenders that are sent to them.

Only 30 percent of third-party products are listed there, the rest come from them.

Humberg's competitors include Meier-Guss, Greenleaf and Joas.

Humberg has been developing site-specific planting systems for trees for more than 30 years.

One is now a technology leader, says Humberg.

An example of a product is the air supply that is placed under the tree root.

You do this because the tips of the roots always grow towards the air, so you don't want them to push up to the surface and cause damage, Humberg explains.

A frame provides stability

It has now been learned that a simple grid around the tree is no longer sufficient because the urban environment of the city offers suboptimal conditions for the trees to grow, says Humberg.

Due to a vertical integration of almost 100 percent, each product can be manufactured individually in a short time.

The root of the tree needs space to unfold and absorb air and water.

This is what Humberg's systems are designed for.

The company has several 1000 systems;

most are based on a similar principle, which is then adapted to local conditions, as Humberg reports.

In this way, trees could also grow old in the city.

A metal frame that is embedded in the floor and is therefore not visible ensures stability, explains the managing director.

This frame allows the tree to unfold its roots in loose soil and thus absorb air and water more effectively.

Munster residents water trees

Munich, Hamburg and Berlin are some examples where you can find Humberg systems of this type.

The system is constantly being improved;

for example, it is equipped with water reservoirs that either fill up when it rains or are filled manually.

This helps in longer dry periods.

Wolfram Goldbeck from the City of Münster's Office for Green Spaces, Environment and Sustainability noticed that these are becoming longer and harder as a result of climate change.

"Watering all the trees during dry periods is not logistically possible," he explains.

In Münster they even rely on the commitment of the citizens to give the trees water with their help.

The city has set up 37 water containers at 19 locations and handed out 250 water bags.

Humberg equips both the tree and the reservoir with sensors, which then provide communities with information about the level of the storage tank, temperature and humidity, Humberg explains.

Helmut Grüning, a specialist in water supply and drainage technology from Münster University of Applied Sciences, helped develop this system.