Arbor is a data spatialization of the urban forest of Palo Alto. The sculptural installation consists of 120 ribs arranged radially within King Plaza at Palo Alto City Hall. It uses the database of over 45,000 public trees in the city’s Open Data Portal as the basis for a collective, three-dimensional map of one aspect of the city’s ecology: all trees in the public realm. The installation performs like a compass, with each rib corresponding to a different “pie slice” of territory radiating outwards from City Hall. The trees are represented by bumps on the outer edge of each rib, so the zones with more trees result in ribs with more relief. The custom laser-cut ribs are arranged in a circle, gradually changing in height, profile, and color to create a dynamic form that is different from each side.

Arbor looks to historical examples of optical devices that operate radially, such as the zoetrope and the cyclorama, both of which use radial geometry to create dynamic spatial conditions. Individually, each rib represents the density of trees in its corresponding zone of the city. Collectively, the ribs coalesce into a singular yet dynamic form that becomes a spatial relief map of the city’s shared network of trees.

The installation is designed to produce maximum spatial effect with a minimum amount of material that nonetheless maintains structural integrity as a long-term public artwork. 120 primary ribs fabricated from laser-cut, powder-coated 16 ga. steel with integral stiffening flanges are supported by ¼” steel base plates, and connected by a series of staggered horizontal 16 ga. ribs. All connection points consist of a tab bent from the vertical rib that is mechanically fastened to the horizontal rib. A custom algorithm negotiates the joint locations with both the global variation in height across the vertical ribs and the variation of the data-driven relief pattern cut into each rib. The script calculates the joint location, generates the tab and slot geometry, ensures that the joints conform to structural constraints, accounts for fabrication and assembly tolerances that were determined by full-scale prototypes, and automatically produces the two-dimensional fabrication files. This algorithmic negotiation produces a tectonics of contingency between the ecological data and the material assembly, whereby the form, texture, and effect of the installation are resultant from both but irreducible to neither.

Arbor is on view in Palo Alto’s King Plaza through January, 2022. 

https://www.variableprojects.com/arbor/