Branching Urbanism: From Line to Field
New York, NY, 2003

We propose that the Highline be developed as a catalyst for a new form of urbanism. More than the adapted reuse of the narrow band of track and the space immediately below, this proposal projects a broader band of variegated frequencies into the city through which it flows.

Branching Urbanism: From Line to Field
Our proposal for the reuse of the Highline imagines a form of urbanism uniquely suited to complement the existing structure of the elevated track. Branching urbanism involves material organizations that grow laterally over time through simple, ramiform mechanics. Branching systems are distinct from more general networks because they possess a single, hierarchically dominant spine and clear directionality. Secondary and tertiary branches move out of the primary line, loosening its braids into a field. Smaller tendrils are increasingly sensitive to surrounding local conditions as they move outward, and their redundancy produces flexibility in numbers. Their excess also allows them to act as larger groups rather than single elements producing the emergence of larger zones. These qualities bring with them a higher degree of organizational control, allowing designers, policymakers, and citizens to predict and steer the system toward a desirable configuration.

We propose that the Highline be understood as the pre-existing spine of a potential ramiform urbanism poised to propagate new conditions now and in the future through limited expansion into the surrounding neighborhoods. This new form of urban design avoids the pitfalls of both masterplanning and ad hoc, piecemeal development while capitalizing on their strengths. From the former it borrows the coherence of an identifiable organization, from the latter the flexibility of implementation over time as space and funding becomes available. Like all healthy organisms, branching urbanism grows in fits and starts and adapts to a changing environment. This is not theoretical speculation. We believe this form of urban design possesses a pragmatism and manageability that makes it both real and possible morphologically, fiscally, and politically.

"Highline" is an apt description of the existing condition of this infrastructure: a line high in the air. Were it to be opened for public access in its current state this description would remain the same, making the track an underwhelming addition to an environment as dynamic, variable, and saturated with speed and activity as Manhattan. Pedestrian flow through the city is neither linear nor of uniform speed. The Highline could become a major pedestrian infrastructure that would shape and be shaped by the multivalent flows of people through plant material. Our proposal operates at various speeds and, through carefully located and redundant access devices turns the line into a field. Further, branching urbanism gently redirects urban pressure outward, exerting influence on its surroundings.

Physical Description: Pure Circulation
Branching systems are not unique to plants. While many naturally occurring biological and physical systems such as corals, fissures, lightening, and rivers exhibit dendritic tendencies, so too do many artificially engineered conditions. Interestingly, the tracks of the adjacent railyard and of the Highline itself branch out into their surroundings, illustrating the contextual relevance of this kind of organization in this part of Manhattan.


Our proposal consists of four basic elements installed upon the Highline as space and funding permit. These simple components and their straightforward installation will lead to complex results:

Long, narrow, lightweight greenhouses placed end to end with alternating ends subtly rotated out beyond the edge of the Highline to assert spatial and material presence on adjacent public space. Along 10th Avenue this pressure would be directed eastward to capture the space between the track and the street. Along 30th Street the projection would be northward in anticipation of the eventual public platform covering the railyard. Each unit is a near-primitive rectangle constructed of common greenhouse materials and techniques.

Elongated Ramps (all ADA compliant)
Highly visible ramps extend away from the highline to amplify its physical and programmatic presence, drawing people off of the sidewalks into the Highline. These ramps are intentionally redundant, occurring every two blocks. This produces a high level of permeability and exchange between city and project which works to draw more users of greater variety into the Highline. Diversity of user groups and the associated mixture of speeds of movement, levels of concentration and distraction, intentions, and desires is essential to the creation of rich public space.


Staggered between ramps on the opposite side of the track are stairs occurring every two blocks. These provide an even higher level of circulatory saturation and encourage faster, more direct access than the ramps. Some of these stairs have attached elevators. Taken together, the ramps, stairs, and elevators provide access at roughly every block. The admixture of different speeds and densities of pedestrian flow produces a riparian model for circulation, complete with eddies, turbulence, rapids, and meanders.


Recreation Path
Approximately half of the width of the line is left open to provide a walking and running surface extending the entire length. While one edge hugs the outer curb of the Highline the other passes in and out of each greenhouse. Elongated islands of existing native grasses remain in place between the path and the greenhouses. This could be developed immediately along with a number of stairs and ramps for access, using existing grasses to fill areas for future greenhouse placement (see phasing diagram.)

Other Elements
A number of pedestrian amenities are also included to support the primary elements, including benches, two cafes, tables and chess tables, built-in chaise lounges (south-facing for sunbathing), and undulating topography at street level.