Forested Urban Roofs

magazine highlighted a new form of green roof: the forested roof. In Manhattan, on top of a building designed by Skidmore, Owings & Merrill, NY-based landscape architect, Thomas Balsley, FASLA, designed a “a monoculture of evergreens that emulates northern forests.” Metropolis writes that Balsley’s designs are “undu­lating stands of Austrian pines [that] deliberately avoid the usual sedum carpets and overly manicured containers of roof greenery.”

Balsley said to Metropolis that a forest roof wasn’t what the client initially had in mind: “The developer asked me to design a roof garden, but when I heard about his love of art and the architect’s commitment to Modern design, I decided to look past doing a busy roof garden.” The forest has added value to the property, and apartments with views of the trees are viewed as more valuable. “All residents have access to the tree-covered roof, but the views it creates became a major selling point for the high-end condos, which helped to justify the installation costs.” 

The roof landscape includes more than a hundred 25-to-35-tall trees set in mounds of earth hidden by shrubs. Each tree sits in a four-and-a-half-foot-deep soil bed, which are designed to hold the deep root systems. (The soil beds for these trees are much deeper than those for more conventional green roofs). “In addition to the standard benefits of storm-water retention and insulation for the building, the trees improve air quality.” The trees may eventually reach 60-feet high.

Read the article and see more photos

Image credit:  Shigeo Kawasaki / Thomas Balsley Associates

5 thoughts on “Forested Urban Roofs

  1. Karen Twisler 06/18/2009 / 8:29 am

    Folks, don’t be proud of this! Planting 100+ Austrian Pines is a monoculture that’s very susceptible to disease (and Austrian Pine is not known for its disease resistance; see diplodia). “Emulates the Northern forests”? You mean the way Speed Racer emulates NASCAR? What’s that client going to do when he has to lug all that firewood down a skyscraper? As Landscape Architects, we should know better!

  2. Pierce 06/18/2009 / 2:07 pm

    I’ve been in northern forests that are essentially monocultures.

  3. Jeffrey Ling RCA 06/22/2009 / 6:05 am

    Nice idea, but are the trees ‘anchored’ for now and in anticipation of 2025, or 2050?

    As engineered systems, all trees must have a building platform to support both the botonical physiology and the structural engineering. This means cubic feet of root zone for the sub-soil root mass to form and support the above ground tissues. There is no static state for these trees!

    As in many other urban sites, if the objective is to have trees and replace them every 10-15 years, then the pre-planting investments are less important, but, “50′ pines” on top of a tall building, face weather events and micro-climate affects, never produced in a “northern woodlands”. This could be a nightmare where “moving firewood down the elevator” is the least of the manangement’s concens.

  4. Zakery Steele 06/25/2009 / 10:12 am

    “…a new form of green roof” ???

    LDS Conference Center roof, Salt Lake City, UT …a semi-forested roof that was completed nearly TEN YEARS AGO (2000) with bristlecone pines and other native plantings. This was completed even before ASLA’s green roof.

    Zimmer Gunsul Frasca Partnership, Architects

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