Offenbach City's green space expansion: Portable tree trunks proposed as a temporary solution
In the heart of Offenbach, a city known for its vibrant culture and bustling city centre, a new initiative is taking root - the Green Belt. This project aims to enhance the city's ecological performance and quality of life by incorporating green urban rings and outdoor spaces with vegetation.
However, implementing extensive tree planting in Offenbach's city centre presents several challenges. The dense construction with multi-storey buildings and limited open spaces, coupled with technical limitations such as underground car parks shared across buildings, restrict tree root growth and underground planting systems. The need for hybrid timber construction combined with reinforced concrete structures further complicates matters, posing design constraints on how and where trees can be integrated without compromising structural integrity.
To tackle these challenges, the city and planners are exploring innovative solutions. One such approach is vertical urban greening and green façades, which bring vegetation into limited spaces. Special structural engineering solutions are also being considered to support green features without interfering with buildings’ foundations. Another strategy is to combine greenery with multipurpose spaces in mixed-use developments, maximising ecological benefits in urban density.
Despite these challenges, Offenbach is making progress. The market square, for instance, presents a new opportunity for significant greenery. However, conflicting uses such as pedestrian paths, bus stops, parking spaces, outdoor dining, lighting, seating areas, and underground car parks make greening difficult here. As an interim solution, mobile tree tubs continue to serve on the market square, with some initial planting shock due to delayed delivery and early summer start. Despite this, the young trees have since recovered and thrived.
Meanwhile, the S-Bahn station forecourt redesign with more greenery is still planned for the coming years. Until then, mobile tree tubs will serve as an interim solution. The city estimates costs of up to 17,000 euros per tree location for future ground-based plantings due to the complex installation of root spaces and irrigation systems. Particularly climate-effective tree types, like those with skeletal soil and plant charcoal, are even more expensive.
Citizens will be involved in the process of developing the Green Belt concept, with a planning office commissioned to develop a concept for the project. The city council has provided the necessary funds, and the city is committed to the goal of creating a Green Belt from the German Unity monument, through the Stadthof, to the Hugenottenplatz.
Offenbach's Green Belt initiative is part of a broader urban renewal effort using integrated green design despite the dense urban fabric and technical construction limits. The strategy relies on combining innovative green technologies, structural engineering adaptations, and multi-use building design to overcome tree planting and greening restrictions.
[1] Source: City of Offenbach press release, dated 2nd January 2023.
What about incorporating more greenery into our home-and-garden lifestyle, considering the challenges faced with tree planting in Offenbach's city centre? For instance, could gardening techniques that cater to limited spaces and vertical urban greening be applied to our homes or balconies to contribute to the Green Belt initiative, thus helping Offenbach realize its goal of creating a thriving and ecological city?
