In their design for Oerliker Park, the planning group Zulauf, Seippel, Schweingruber, Hubacher & Haerle uses the ability of spaces to adapt to changing needs as their central idea. The park is intended to be realized in phases in order to accommodate the growth of "Central Zurich North", a new part of the city.
Because future parameters are uncertain, the planners designed an allpurpose framework – a kind of green building – that can be filled over time.
The designers took up the theme of change, and young ashes were planted in a dense grid, interspersed with fields of cherry, sweetgum and pawlonia trees. These will gradually grow into a bright “hall of trees”. The development process will be guided by maintenance measures that function as designed interventions and that bring a unique quality to each phase of the development (Figs. 1-4).
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Fig. 1. Planting the ashes in Oerliker Park in 2001, simple saplings/ forest nursery products |
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Fig. 2. One year later, sizeable trees have grown from the meagre saplings (photo: Volkmar Seyfang) |
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Fig. 3. Design for Oerliker Park. Initial stage: a grid of young trees defines the space |
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Fig. 4. Design for Oerliker Park. End stage: The structure of the space is determined by changing the spacing of the tree grid (reproduced with permission by Zulauf, Seippel, Schweingruber). |
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Fig. 5. Sections through the park show the development of the dense "field of trees" to the spacious "hall of trees" (reproduced with permission by Zulauf, Seip – pel, Schweingruber) |
A detailed development plan lays out the rules for guiding the intervention. Over decades, the dense tree grid of 4×4 m2 will gradually be widened to 8×8 m2 in places. The landscape architects have appropriated the thinning process from forestry; it is comparable to thinning a forest stand. Trees that die will not be replaced. In this way, the grid will slowly dis
solve. From an initial, stark regularity, a certain irregularity will develop as time passes (Fig. 5).
Fig. 6. Guiding the development process at Oerliker Park: With the planting of young ashes, the landscape architects direct the transformation and growth process. The process is guided through maintenance inter
ventions based on feedback, i. e. after assessing the existing situation (after Grosse – Bachle 2003).
The vegetation concept for Oerliker Park is principally determined by strategic considerations. The landscape architects have grasped the theme of ever-present change and playfully influenced the growth process of the young ashes. They make creative use of the survival strategies of wild plant populations, such as the process of self-thinning, to suit the changing needs of the space.
Planting trees in an open space at regular intervals is comparable to the initial set-up of a game (Schmid 2001). As in a board game (e. g. Go), new configurations arise over time through planned interventions. The rules of the game are familiar, the final positions only approximately predictable. A differentiated structure of the space, marked by dense and open spaces will develop step by step through the thinning of the homogeneous field of trees. A shady passage, a bright clearing, an open space will have replaced
the regular grid in 25 years. By highlighting and giving value to intermediate stages, these stages take on a new quality (Fig. 3-4).
