Comparison of building development in urban areas and outdoor laboratories and in different substrate compositions

Description

As part of a construction project on Bertastrasse in 2022, sewers, utility lines, road construction, bicycle measures and tree planting were carried out and new seating was created. A tree appraisal revealed that the existing trees had extensive bark damage or rot and only had a short life expectancy. Other trees were severely affected by the snowfall in January 2021. Around a third of the 295 street trees therefore had to be removed and are now to be replaced with 16/18 young trees. In addition, the tree population in the neighbourhood is to be increased with 60 more trees.

In Heinrichstrasse, the street space will be redesigned to suit the neighbourhood and climate by June 2023. To this end, parking spaces are to be reorganised, an additional 48 trees replanted and the road surface renewed. In addition, more rainwater will be retained according to the sponge city principle, which is to be evaporated via the urban greenery. The living conditions of all trees are also to be improved with a special tree substrate and larger root volume.

On behalf of Grün Stadt Zürich, the ZHAW is to scientifically monitor the development of 15 trees in three tree pit systems (equipped with plant-care sensors). The scientific monitoring will be carried out by assessing the trees over three years (2023-2025). The results will be compared with the results from the ‘Substrate 2.0’ trial project. The aim of the project is the scientific comparison between tree development in urban areas and outdoor laboratories, as well as in different substrate compositions. Furthermore, statements can be made about the effect of the water potential sensors in irrigation management. This can not only improve tree maintenance, but would also provide insights into the improvement of the tree substrate.