Greening of a car park in Mainz with TreeParker

During a renovation project in Mainz, an existing car park was greened using the TreeParker system. By combining 532 modules with water and air provision (LUWA) and underground anchoring, 21 climate-resilient trees were given optimal growing conditions without damage to infrastructure. The project demonstrates how smart collaboration and innovative tree pits lead to a sustainable, future-proof design.

Mainz is the historic capital of the federal state of Rhineland-Palatinate in Germany. The city is known for its rich culture, university, wine tradition and as the birthplace of Johannes Gutenberg, the inventor of the printing press. On Dr Martin Luther King Way, a local connecting road, a renovation was carried out on the adjacent car park at a shopping centre. The goal was to replace the existing planting in the car park with a climate-adaptive and high-quality green design.

During the planning phase, the replacement of planting in the parking area developed into a broader renovation project for all planting areas around the shopping centre. It soon became clear that standard tree pits were insufficient and that a soil cell system was required to increase the rootable volume. An additional soil investigation confirmed this necessity.

For the 21 climate-resilient serviceberries and field maples, the conditions had to be optimised to provide them with a healthy future. The choice for the tree pit design fell on the innovative TreeParker system. A total of 532 TreeParker modules of 120 cm high were applied. The soil cell system makes it possible for roots to grow freely both vertically and horizontally, without damaging the surrounding infrastructure. In addition, the LUWA system was used for optimal irrigation and aeration of the trees. Underground root ball anchoring provides the necessary stability for the trees during the growth phase and creates an immediate final appearance, as tree ties are not required.

The first contact regarding TreeParker took place in 2021 and completion followed in spring 2023. This enabled the wishes of all stakeholders to be realised quickly. ‘That only works if everyone pulls in the same direction,’ says Dipl.-Ing. Alexander Magerl of GEFA, who, together with his colleagues Andre Carstens and Manfred Widmann, was responsible for project supervision and coordination. ‘Throughout the project, there was continuous contact with the supplying company, allowing obstacles to be addressed in advance and enabling a flexible response to changing schedules, for example during construction inspections.’

The contractor Hüfner & Kuchenbuch Garten- und Landschaftsbau GmbH was also satisfied with the quick and straightforward implementation of the system. ‘The installation of the TreeParker modules was surprisingly simple and uncomplicated. It was possible to respond well and flexibly to the utilities to be installed,’ says site manager Markus Ludwig. During meetings on site and throughout the various project phases, designer Dr Ulrike Sacher (independent landscape architect bdla) and Kathrin Nitschke and Hannah Gruber from Wohnbau Mainz GmbH were very satisfied with the collaboration: ‘We received excellent guidance and expert support during the planning and installation.’

The project in Mainz shows what a successful renovation of planting areas can look like. Through cooperation between the client, designer, contractor and supplier, a sustainable and climate-adaptive concept was realised. The selection of the right tree species and the use of modern, innovative solutions are crucial in this regard. Climate-resilient species, such as serviceberries and field maples, are optimally suited to the conditions in Mainz. The trees not only provide space for biodiversity, but also improve the urban climate by providing shade and enhancing air quality.