Green Roofs Save the Planet and Money in the Bronx

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Installing plants on roofs as a way to save energy and cut down on pollution is gaining momentum across the city. Green roofs have begun to sprout in several New York City neighborhoods. In the South Bronx community activists, researchers and landscape architects are joining forces to try to convince property owners that green roofs will help their bottom line. WNYC's Cindy Rodriguez recently attended the opening of a green roof on Garrison Avenue.

REPORTER: The American Bank Note Building looks like an expansive semi- abandoned, brick warehouse. On the inside i a maze of hallways lead to small non-profit office spaces, artists with performance studios and commercial businesses. . And from the roof of the building on a warm Fall evening the view of the South Bronx is clear:

CARTER: If you look to your right you'll see the Bruckner Expressway, if you look to your left you'll see sewage sludge palletizing plants, smoke stacks, waste facilities a couple of power plants and all those impacts come right here and we are the ones that are dealing with it.

REPORTER: Majora Carter is a fast talking community activist who recently won a Macarthur Genius award for her work - fighting poverty and pollution in the South Bronx. Her non-profit group, Sustainable South Bronx is housed on the fourth floor and installing a green roof on the building owned by private landlord was her idea:

CARTER: A green roof cleans the air, it deals with storm water management so that we don't have to expand our sewage treatment plants in the neighborhood and it also attracts beautiful things like butterflies and songbirds while also keeping standing water at bay so it doesn't attract things like west nile producing mosquitoes.

REPORTER: The architect who designed the green roof says the plants should be able to absorb up to 80 percent of the storm water that gathers on the roof. Run off from a storm can force untreated sewage into rivers and the hope is the less run off, the less we have to rely on water treatment plants. Plants add a layer of protection to the roof and therefore can extend its life. A green roof is also supposed to reduce heating and cooling costs by acting as an insulator. And if green roofs were clustered together, some scientists believe the temperature of a hot city could go down. Researcher Joyce Rosenthal says this is called lowering the Urban Heat Island effect:

ROSENTHAL: The Urban heat Island effect is the tendency of urbanized land cover, concrete, asphalt, man made surfaces when it replaces natural vegetative cover, soil and trees to literally change the weather and climate of an urban area relative to rural and suburban areas.

REPORTER: Rosenthal says an experiment in the 1990's showed that New York was four degrees hotter than its surrounding suburbs and rural areas. She says that's because asphalt and black tar absorb the suns rays, retain it and then re-radiate it back into the atmosphere. A green roof would help reduce that effect.

This South Bronx Green Roof covers about a thousand square feet and is planted in the shape of a U. Black rectangular plastic planters of varying depths hold a variety of small plants picked not for their beauty but for their durability and function. Landscape architect Kathleen Bakewell says this young garden will be a carpet of green by next year:

BAKEWELL: It's starting to slow down because its getting cold. Some things will die down some things will stay and have a really nice presence and then in the spring there will be a burst of green:

REPORTER: The garden is supposed to be self sustaining and live off the rain water. It's planted with plants of the common nursery variety like purple coneflower and garden juniper on one side and "native Bronx plant life" on the other. The idea is to let them compete and see which fares better.

The landscape architects also want to see what types of new plant life might sprout up so Bakewell and her designer Susanne Boyle have purposely left several large planters with nothing in them but dirt:

ARCHITECTS: It might be seeds flying in from somewhere else outside of this roof, birds dropping something we're just going to watch and learn. That's the thing about communities the competition can change over time. Somethings may do very well somethings may not do very well and we will be studying all that so that we can continue with more roofs throughout the Bronx and New York and really learn from each one and apply that knowledge

REPORTER: Green roofs do not come cheap. Bakewell says 16 to 24 dollars a square foot is common but prices can certainly be higher. With the help of Joyce Rosenthal who is currently studying green roof projects around the world, the architects and Majora Carter hope to prove the cost is worth it when you consider the public health and environmental benefits. It is difficult to tell how many green roofs exist in New York City, Bakewell has worked on four others, the largest one in the city just opened up over the silver cup studios in Long Island City and Bronx Borough President Adolfo Carrion says he knows of 9 other green roofs in the Bronx alone. Carrion says any new development that comes to his borough must have a green roof:

CARRION: We can't force anybody but we are certainly creating incentives by saying we will be very supportive of your project and very friendly to your project if you consider using green roof technology just like we say if you work with us and hire local contractors and local residents we will look very favorably upon your project.

REPORTER: Majora Carter wants more public officials to stand behind green roof technology:

CARTER: The bottom line is that this is one small project and we recognize that but if the city decides to put into place a mechanism that makes it easier to do sustainable development than yes we are going to feel it first in low income and low income communities of color.

REPORTER : She hopes that one day an aerial view of her South Bronx will look more like parkland than black tar and smoke stacks.

For WNYC, I'm Cindy Rodriguez