Climate change is not only a burden for us humans, flora and fauna also suffer from more frequent weather extremes such as heat waves, heavy rain or storm. Trees are also not immune to these effects, but because of their great importance in the fight against urban heat islands, particularly worth protecting. We are only too happy to seek protection in the shadow of their big crowns. But who protects our protectors? For the well -being of more than 500,000 city trees, 70 specially trained tree nurses as well as certified tree controllers from the Viennese city gardens are mainly responsible all year round. Especially in summer you can enjoy a real health cure by 150 employees who are responsible for casting.
This is how the Viennese city gardens maintain young trees
Adult trees are very steadfast against external loads. This is not yet the case with newly planted or younger trees, which is why they need special care in the first four years. “We plant in between 4,000 and 4,500 trees in Vienna every year because they are still the best, most sustainable and long -lasting cooling devices,” says Climate City Councilor Jürgen Czernohorszky. However, they only start to develop their full climate effectiveness from the age of around 20 years. “Our goal is to keep the city trees vital with targeted maintenance measures – so that they can support us in the long term with all their valuable climate services. Trees are guarantors of our quality of life and we have to be the guarantors of their well -being,” says Czernohorszky.
1,000 automatic irrigation systems, 25,000 casting bags and Co.
The Viennese city gardens operate more than 1,000 automatic irrigation systems – and the trend is rising: In the underground of parks and green areas as well as in tree discs, further systems are to be installed in the future. Wherever no automatic irrigation systems are possible, young trees are poured manually for at least four years a week – while heat periods even twice a week. How intensely irrigated is at least depends on the weather and rainy amounts. Almost 25,000 irrigation bags, better known as “casting bags”, are also used in manual watering. They are placed around the trunk of the young tree and fixed with a zipper. Every sack holds 75 liters and is regularly filled by the Vienna city gardens. Another 100 liters are poured directly into the tree disc.
During the summer months, 150 employees of the Vienna city gardens are used every day with around 50 casting vehicles. They water young trees with around 400,000 liters of water a day!
The Viennese city gardens also react to the challenges of climate change with the sponge city principle. With this special construction technology, the root room of the trees is expanded under streets, parking spaces, sidewalks, etc. This means that rainwater can be saved better, and that in turn helps the trees to better survive the trees, stress factors such as heat or dryness. In addition, the sponge city principle promotes healthy city trees, improves the urban microclimate, binds CO₂, supports biodiversity and contributes to resource conservation. More information: https://www.wien.gv.at/umwelt/parks/schwammstadt.html
Only in very few cases do the best and most extensive care measures remain unsuccessful. This year the failure rate is just 0.5 percent thanks to the nursing routine of the Vienna city gardens. There are numerous causes for the failure of young trees – such as latent delivery damage, vandalism, traffic damage, extreme storm events etc. lack of irrigation only plays a role to minimal extent.
At a glance:
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More than 1,000 automatic irrigation systems
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Around 25,000 casting bags
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Werness of young trees: for at least 4 years, once a week (twice at heat waves)
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150 employees in action for watering
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About 50 casting vehicles
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400,000 liters of water per day in heat periods
Another climate, other trees
Not all tree species withstand multiple stress factors. The Viennese city gardens have therefore adapted their own tree range and are now increasingly planting those tree species that are particularly well with the city climate. The range consists of 25 types of tree, there is a list of everyone here: Climate male street trees for Vienna
Press photos: https://presse.wien.gv.at/bilder