Biornis-Aesthetope

Lower Manhattan, NY, USA

An unprecedented achievement in green roof technology, the Biornis Aesthetope design supports a functioning biotope for birds migrating along the Atlantic Coast Flyway. Sited in Lower Manhattan, the structure sits atop a 12 story building overlooked by a new headquarters for a major investment bank. Visible resting areas, water pools, and organic vegetation create a desirable destination for birds to stop over in the lower Manhattan area.

The green roof system of the proposed Biornis Aesthetope provides benefits which far surpass those of typical extensive and intensive green roof systems. During the design process, the strategic management of a matrix of variables, ranging from the use of organic and inorganic soil substrates, gradients of water retention, insect hibernation patterns, and vegetative planting; to the resulting structural loading and construction cost, allows the Biornis-aesthetope green roof system to be flexible through its myriad iterations and still function as healthy biotope.

The typical benefits of a green roof are economic and environmental. The benefits of Biornis Aesthetope are sociopolitical at a global scale and cultural at the local scale. This green roof’s ability to produce a living habitat—a community of flora and fauna, waxing and waning, growing and dying, changing through the seasons, and maturing through the decades—provides a constant, sustainable, and renewable interest in the performance of the green roof.

Biornis Aesthetope is a high-performance green roof capable of producing the correct conditions for the creation of a biotope. The sculptural expressiveness of the green roof is necessary for the completion a sustainable biotope. Equally important to environmental considerations, Biornis-aesthetope creates an icon not only for the client, but also for New York City, in the very location that America’s heart and national psyche feels a void and yearning for expression, identity, and icon.

BAM believes the green roof will not only be an international sociopolitical icon, but also its performance as a green roof will be an icon and milestone for the “green” movement as well as the green roof industry. Among the traditional benefits of a green roof are the reduction of heat island effect, reduction of carbon dioxide effect, the reduction or airborne particulate matter, reduction of rainfall run off impacts, reduction of heating and cooling loads, and the lengthening of roof life.

However beneficial typical green roofs can be, in the majority of cases, they cannot support habitats. The reason for this is that they are almost entirely made from artificial materials. In considering the entire construction assembly, everything except the plants themselves are created from artificial materials. To keep the weight of the assembly as light as possible, the soils usually contain as little as 5% organic material. This means that 95% of the materials are inorganic and/or manufactured. Artificial materials are not necessarily bad, as they allow the weight of the roofs to be such that they are affordable and applicable in many situations; however, they are not sufficient for the production of a sustainable ecology.

The green roof of Biornis Aesthetope utilizes both organic and inorganic soil mixture types. One type is used in the extensive roof system, with inorganic soil mix, and the other type is an intensive green roof system, with a deeper technical section, ranging from 12 to 36 inches and containing soil mixtures with no less than 15% organic matter. 15% organic matter is crucial for insect habitation because without organic matter insects cannot be sustained. If the insects cannot be sustained, then the birds will not have a food source, and without a food source, birds will not use the roof as a refueling station, and if the birds do not use the roof, then the energy of the roof as a living organism cannot exist.

The depth of the intensive organic soil regions is important because it allows for vegetative plants to grow, which yields alternate and differentiated food sources. This is necessary for the creation of a community with complex ecological relationships. In the intensive regions of the green roof, the combination of soil depth and organic matter allows those regions to create biological identity and take on unforeseen characteristics as well a additional plant species that were not part of the original plantings. Eventually, tree saplings will take root. To prevent the growth of large trees (which the structure will not be able to support) the roof must be maintained twice a year to free it of saplings beginning to take root in the intensive regions. (Project completed by BAM in the office of Martha Schwartz, Inc.)

Project Facts Client: __ Structural Engineer: Buro Happold Ornithology Consultant: Scott Edwards, Harvard University Ornithology Consultant: Viviana Ruiz-Gutierrez, Cornell University Green Roof Technology Consultant: Christian Werthmann, Harvard University