Date: 16-7-2024
Last month, a report from the Green City Challenge revealed that greening in many Dutch cities and towns is decreasing. This concerns the greening of urban living environments, such as public green spaces and gardens. The report ‘Care for Green’ by the Rotterdam Audit Office shows that while there is a great desire to green cities, there are insufficient financial resources available. Additionally, municipal departments are often thinking too much within their own frameworks instead of collaborating. These are worrying developments in light of increasing climate change.
More Tiles, Less Green
The Green City Challenge report shows that the proportion of tiles and asphalt in Dutch public spaces has increased by 0.5%. At the same time, the proportion of private and public green spaces has shrunk by 2.6%. There is a slight increase in shrubs by 0.3%, but tree canopy coverage has decreased by 0.6%. Only 15% of cities are covered with trees. This is far below the 30% prescribed by the 3-30-300 rule*. Due to population growth, the amount of green space per inhabitant has drastically decreased. This applies to both public green space per inhabitant, which has decreased by 8%, and total green space per inhabitant, which has decreased by 19%. According to the Utrecht Audit Office, the number of households in Utrecht has increased by about 7% over the past 7 years. At the same time, the green space has only increased by 2.5%, meaning there is net less green space in the area. In short, many thousands of square meters of valuable green space have been lost.
*3-30-300 Rule
3-Rule: there are at least 3 mature trees close to every home, school, or workplace. 30-Rule: each neighborhood has at least 30% tree canopy for shade and cooling. 300-Rule: from every home, school, or workplace, there is a park within 300 meters where people can spend time and recreate.
The Green City Challenge report shows that the share of tiles and asphalt in public spaces is increasing by 0.5%, while the share of public and private green spaces is shrinking by 2.6%.
Building vs. Greening
Figures from ABF Research show that in 2023 there is a shortage of 390,000 homes in the Netherlands. Researchers looked at population growth and expected housing construction. The housing shortage has risen sharply because the number of households in the Netherlands is increasing faster than expected. This is largely due to the arrival of Ukrainian refugees. There are also fewer places in nursing homes, causing the elderly to stay in their homes longer. To solve the housing shortage, more homes will need to be built. In practice, this means that green will give way to grey. Even though green spaces in public areas and gardens are already under pressure.
Green gives way to grey to solve housing shortage
Common Interest in Green and Grey
We often talk about ‘green or grey’ as if they are opposites. At first glance, the green and infrastructure sectors are indeed two totally different worlds. The green sector mainly focuses on creating and maintaining green spaces to promote a green living environment and improve biodiversity. The infrastructure sector, on the other hand, focuses on developing and maintaining physical structures to support safety, well-being in society, and economic growth. Despite the differences between these sectors, they meet in one important common value: improving the quality of our living environment. Both sectors are indispensable for achieving this common goal.
Cost-Effective Green
Investing in the right tools for trees in built environments yields significant long-term savings in time, labor, and maintenance costs. When trees receive proper support from the time of planting, the chances of growing into large, strong, and healthy trees are significantly higher. This reduces the risk of diseases and premature failure, meaning the trees do not need to be replaced frequently or require intensive maintenance. Additionally, these measures prevent damage to surrounding infrastructure, such as root heave and broken cables and pipes due to root growth. This prevents dangerous traffic situations and exorbitant repair costs. By carefully planning and investing in the viability of green spaces in urban environments from the outset, cities can operate more efficiently and cost-effectively in the long run.
Root heave in the public space
Integrating Green into Grey
From now on, let us not think in terms of ‘green or grey,’ but ‘green and grey.’ This does not have to be a choice. With the right tools and techniques, green can be seamlessly integrated into grey infrastructures. In recent years, innovative projects have been built where green and infrastructure go hand in hand.
The Trudo Tower, the vertical forest in Eindhoven (The Netherlands)
Trudo Tower in Eindhoven
The Trudo Tower, located in the creative urban area Strijp-S in Eindhoven, is an impressive example of a project where green is integrated into grey. This vertical forest is 70 meters high and provides space for 125 mature trees (up to 6.5 meters high) and 5,200 shrubs, plants, climbers, and creepers. The tower was designed by architect Stefano Boeri, also known for Bosco Verticale in Milan. Bosco Verticale consists of two skyscrapers with heights of 111 and 76 meters. Together, the towers accommodate 730 trees, 5,000 shrubs, and more than 12,000 other plants. Planting trees on high-rise buildings poses a challenge as they are exposed to strong winds at such heights. The stability of the trees is a crucial factor to ensure the safety of residents and city visitors. For this, GreenMax’s root ball anchoring was applied in the Trudo Tower. Root ball anchoring provides underground stability for trees while maintaining their natural freedom of movement. So far, various wind speeds have swept past the Trudo Tower, and the trees still stand upright.
Trees at spectacular heights at Wonderwoods in Utrecht (The Netherlands). Image source: Wonderwoods
Wonderwoods in Utrecht
Wonderwoods is a unique and innovative tower in the heart of Utrecht that combines urban living with nature. With a vertical forest of 360 trees and nearly 10,000 plants, this will be Utrecht’s green eye-catcher. Not only is the vertical urban forest beautiful to see; the trees and plants together absorb 5,400 kg of CO2 annually and provide more than 41,400 kg of oxygen. Here too, GreenMax’s root ball anchoring has been used to provide the trees with the necessary stability.
Trees on a roof structure at Beursplein in Amsterdam (The Netherlands)
Planting Trees on Concrete Roofs
Not only vertical forests are a solution to integrate green into grey buildings; planting trees on concrete roof structures is also an option. For example, trees have been planted on Beursplein in Amsterdam above a large underground bicycle cellar. Because there is a bicycle cellar under the square, a roof structure is automatically created on the square. This resulted in a very low construction height available for the trees. Additionally, the square needed to be suitable for heavy loads during events, where settlement differences and root heave were not acceptable. The TreeParker system offered a solution here. In this underground tree bunker system, trees receive extra growing space without damaging the surrounding infrastructure. The same applies to Mediaplein in Antwerp and Place de la Comédie in Montpellier, where trees were planted in the TreeParker system above an underground parking garage. At first glance, it seems as if the trees are standing in the concrete, but underground they have all the space, nutrients, water, and oxygen needed to grow old healthily.
Trees on a roof structure at Mediaplein in Antwerp (Belgium)
Collaboration Between Sectors
The necessity of good planning and preparation emphasizes the importance of an integrated approach between the green and infrastructure sectors. By strengthening the collaboration between these sectors, innovative solutions can be developed that benefit both urban green spaces and infrastructure. This results in a future-proof and livable environment where people enjoy living, working, and recreating. A valuable and indeed necessary investment for future generations.