Climate change threatens trees in Braunschweig: stress and lack of nutrients!

Climate change threatens trees in Braunschweig: stress and lack of nutrients!

Climate change has a direct impact on the trees in Braunschweig and the surrounding area, according to a study by Technical University of Braunschweig revealed. Extreme heat, persistent drought and a lack of nutrients take a toll on the trees. In the last three months, the region has received just 40mm of rainfall, just 25% of the usual 160mm.

City trees show clear symptoms of stress. Plane trees in particular are in poor condition, such as in front of the Katharinen cafeteria. These trees suffer from premature leaf fall and reduced vigor. The water shortage is particularly problematic, as it dries out the soil not only in summer but also in spring.

Existential threats to tree species

The situation is so serious that native tree species such as beech and oak are experiencing existential stress. This is particularly the case in urban and shallow locations. This water shortage weakens the trees' immune systems and makes them more vulnerable to pests and pathogens. Insects such as the bark beetle and the oak processionary moth are spreading in northern Germany.

Current reports show that only one in five trees in Germany is considered healthy. The pressure exerted by climate change on the forests in Central Europe requires adapted forest management. Another problem is the lack of sulfur, which has been exacerbated by stricter air quality laws.

Research approaches to improving resilience

To combat these challenges, scientists at TU Braunschweig conducted research into targeted sulfur application to increase the trees' stress resistance. Both pot and field trials are on the agenda to analyze the effects of sulfur deficiency on plant health. The findings could provide important impulses for future forest management.

Another approach to promoting drought resilience of urban trees is through the Federal Environment Agency supports. The research work aims to select suitable regional soil substrates and climate-adapted tree species and varieties. Comparative studies at tree nurseries and real city locations are planned.

A central aspect of resilience is the appropriate equipment of tree locations. Young trees are particularly susceptible to drought stress, while older specimens are better able to deal with these challenges. In Hamburg, for example, almost half of the street trees are over 40 years old, making them more resilient to the effects of climate change.

Protection and maintenance of the established tree population is therefore crucial for sustainable urban development. In order to better manage water needs, it was recommended that more frequent and consistent watering be included in the contractual obligations. Sensors that measure soil moisture at different depths show that existing substrates may no longer be sufficient to ensure water absorption.

In summary, the condition of the city trees in Braunschweig is a striking example of the challenges of urban vegetation in the face of climate change. The ongoing research projects will be crucial for how communities will deal with changing climatic conditions in the future.