Climate change is affecting trees in Dessau-Roßlau – hazel trees are dying!

Climate change is affecting trees in Dessau-Roßlau – hazel trees are dying!

Recently, the drought in Dessau-Roßlau has left devastating marks, especially on the hazel trees in Mendelssohnstrasse. Michael Krell, a recognized expert in urban greenery, reports that five of the trees planted there, which were considered robust and heat and frost resistant decades ago, have already died. Others show clear signs of crown thinning. This robust tree species, actually widespread from the Balkans to the Himalayas, was intended as a beacon of hope for urban green space planners. But the reality is different, and Krell highlights the difficulties of planting in urban environments - this is often problematic for trees. Dead trees and unsightly tree slices are now a common sight in the city. A photo that Kirsten Lott, the head of the urban green department, took on Elisabethstrasse illustrates the situation.

The positive effects that trees have on the urban climate are well known, but their impact is limited. Particularly in urban heat islands, which are increasingly being created by climate change, attention is focused on the importance of urban and street trees. These not only provide shade, but also play a central role in climate protection by cooling the environment through evapotranspiration. However, old trees in densely populated areas suffer significantly from heat and drought stress.

Challenges and opportunities

The city's goal is to create suitable conditions for its trees to thrive. This also includes selecting heat- and drought-tolerant tree species for new plantings. A brochure published by the German Garden Office Managers' Conference and the Association of German Nurseries lists 65 tree species that are recommended for urban areas. Among other things, there are early-flowering species such as tree hazel and cornelian cherry, which are an important source of food for pollinators such as bees. But the diversity of tree species is crucial for biodiversity, which in turn ensures the stability and performance of urban ecosystems.

The challenges should not be underestimated: the years of construction of new residential areas and the resulting soil compaction have significantly worsened the conditions for tree growth. Climate change is making site conditions even more difficult, and the immigration of new harmful organisms poses a further threat Federal Environment Agency explained.

The future of urban trees

A qualified analysis of the location factors and the targeted selection of tree species that can withstand future climatic conditions could help to increase the lifespan of trees and improve their functions in the cityscape. In Dessau-Roßlau there are around 200 tree fellings every year, while the city struggles with 3,500 tree defects at the same time. The plan for ambitious new plantings seems to be in place, but the city budget only has around 50 new plantings available each year. And in difficult locations, the costs for replacement planting can be between 4,000 and 5,000 euros.

Another point of discussion remains the mix of species in the streets, as many tree species, such as poplars and plane trees, bring their own challenges. While the tree of heaven, which is considered an invasive species, had to be put on the brakes, locust trees, as noted in the cable route, are surprisingly popular. They are achieving magnificent growth in urban areas, and they show that a lot can be achieved with the right selection. Kirsten Lott would also like to see an application that enables city residents to book tree locations through sponsorships.

The discussion about the city and street trees in Dessau-Roßlau shows that there is a lot to be done to keep the cityscape green and lively. It is important to have the right strategy in order to continue to meet the challenges of climate change and urban life. But with a good plan and the commitment of citizens, it could be possible to make the city an even better place for all of us.