The City of Vienna received the European City of the Trees (ECOT) Award today. The prize was awarded by the European Arboricultural Council (EAC) at the EAC annual general meeting in Vienna with international guests.
That EAC pays tribute to that with this award outstanding commitment the city for her urban Ökosystem through intensive research and innovative measures for improved adaptability to changing climatic conditions. Jan Goevert, chairman of the ECOT working group in the EAC, was most impressed by Vienna’s outstanding Rainwater management. “Here, Vienna unreservedly joins the ranks of the youngest ECOT prizewinners from 2018 (Apeldoorn) and 2019 (Moscow),” said Goevert. “There, too, climate trees and water play a decisive role. Vienna’s all-encompassing commitment to its trees can also serve as an example for other European cities to emulate. “
“I would like to congratulate the Vienna City Gardens on this well-deserved award,” says Climate City Councilor Jürgen Czernohorszky. “The city gardeners do one thing every day important contribution for making Vienna the most livable city in the world. To ensure that this remains the case in view of the effects of the climate crisis, our experts have taken innovative measures to improve our City trees suitable for the climate close. This is of particular importance Sponge City Principle to, with which the city gardens create the best conditions for healthy and vital trees. “
“The Vienna City Gardens pay special attention to the green lungs of their city! They not only look after 500,000 trees, but are also responsible for the planning, construction and maintenance of currently 1,000 municipal parks, ”adds City Garden Director Rainer Weisgram.
This was the basis for this year’s decision “Exemplary tree management” for the over 500,000 Viennese trees named by the expert committee. As part of the selection process, the focus was primarily on the package of measures taken by the Vienna City Gardens to support the city trees:
- Run an urban nursery
- Development of a range of city trees
- Patented Viennese tree substrate
- Centralized tree care and tree control groups
- Watering and young tree care management (e.g. standardized larger tree grates)
- Strict tree protection law
- Traffic safety through the Vienna tree cadastre
Innovation Sponge City Principle
Trees need one suitable underground root space with pores for soil air and soil water. In the city, soils are often highly compacted, so that they can hardly be penetrated by roots and / or have far too few air and water-carrying pores. With the sponge city principle, this vital root space is created for the city trees. In the long term, the best possible care can be guaranteed with rainwater – without draining water into the sewer system.
The sponge city principle for city trees implements important environmental goals:
- Rainwater retention, evaporation and infiltration as a contribution to convergence with natural and local water cycles,
- Evaporation and shading to positively influence the urban microclimate,
- The development of healthy and efficient urban trees,
- CO2 fixation in large trees,
- Promotion of biodiversity – trees as habitats for plants and animals,
- Improved well-being of city users through visible and effective urban greenery,
- Resource conservation through site-specific construction methods and the use of regional materials.
The Viennese tree substrate
In contrast to the “Forest as a natural location” or in a park, street trees are surrounded by structural engineering structures (streets, sidewalks, cycle paths, parking lots, town squares, pedestrian zones, bridges, cable routes or noise barriers). In addition, the root areas are exposed to increased stress factors from traffic, soil compaction and sealing, underground installations, construction work and pollutants.
Around the Viennese city trees if possible optimal conditions Vienna City Gardens – together with scientists – developed a special tree substrate. the Project series “Development of tree substrates for Vienna’s city gardens” was tested in tests lasting several years, including under realistic conditions in the Sonnwendviertel urban development area. Since then, each time a young tree is planted, the respective tree slice has been filled with this substrate. The substrate consists of organic and mineral substances that form a improved water storage capacity and good ventilation to guarantee. The materials used come from Vienna or the surrounding area – the substrate mixture is produced by the Vienna City Gardens themselves. Two patents have been granted for the Vienna tree substrate.
The Viennese range of street trees
With the help of international experts, the Vienna City Gardens have in recent years compiled a list of those tree species that can cope well with the special conditions in the city. That Viennese street tree range will be ongoing evaluated and customized. Overall, the range consists of around 30 tree species, types and sorts that are characterized by their special heat tolerance. The most common tree types in the street area in Vienna are maple, linden, chestnut, ash, plane tree and hackberry. Up to 150 trees of various genera, species and varieties can be found in Vienna’s parks and in the street area.
Around 4,500 young trees will yearly planted by the Viennese city gardens. The tree anchoring takes place via a three-pole anchoring. A white trunk coating serves as sun and frost protection for the planted young tree, and it is also given a mowing protection sleeve. So that the young tree can develop splendidly, it receives regular planting and training cuttings from the Viennese city gardens.
The Viennese city gardens operate over 1,000 irrigation systems. Young trees that are not supplied by automatic irrigation systems are watered once a week for three years – twice a week during hot spells. 150 employees with 50 watering vehicles water daily with around 300,000 liters of water. The manual watering is supported by watering bags that are placed around the trunk of a young tree.
The Vienna tree cadastre
It is essential to keep a tree register in cities with large tree populations.
Of the Tree cadastre is primarily a working tool for the Viennese city gardens to fulfill the traffic safety obligation (according to ÖNORM L 1122). All trees and trees are documented, clearly assigned in terms of their location and can thus be easily managed. The tree register will continuously adapted. Around 386,000 trees are recorded in the Vienna tree register, around 96,500 of which are street trees (avenue trees).
In this way, essential data on the tree you are looking for, such as genus and species, trunk circumference and crown diameter, the height of the tree and – if data is available – the year of planting can be found out. (City vienna)