In the 7th century B.C., King Nebuchadnezzar II constructed the Hanging Gardens of Babylon, a series of simulated mountains with planted terraces.
According to the writings of an ancient historian, the site had “plants cultivated above ground level,” with “roots of the trees … embedded in an upper terrace rather than in the earth.” While the King was more likely concerned with pleasing his wife, who missed her verdant homeland, than with sequestering carbon or cooling the palace, the site became one of the earliest examples of a green roof.
Many forms of green roofs followed, including the sod roofs of northern Scandanavia, the roof garden atop the Hermitage in St. Petersburg, Russia, and the tiny garden on the Tower of Guinigis in Lucca, Italy. It wasn’t until the 1960s and 70s in Germany, however, that people began using green roofs as a means of improving the quality of the urban environment. It wasn’t long before the rooftop greenery expanded to cover walls.
Today, as the benefits and logic of green roofs and living walls become increasingly obvious, a new form of real estate is emerging. Once thought of merely as a protective covering and space to store unsightly air conditioning units and water tanks, rooftops are becoming new and powerful landscapes. In addition to adorning a property and adding space for living and recreation, green roofs and living walls have the potential to save energy, reduce maintenance costs, retain and use stormwater, create habitat, provide agricultural space, filter air, reduce noise and improve the quality of life.
But are all green roofs and walls reaching this potential? Who is leading the way? What techniques and materials are proving to be the most effective in green roof construction? Are green roofs and walls beginning to influence the fields of architecture and engineering? Join us as we take a look at what is, in North America at least, a new and very exciting industry.
We begin with a visit to Emory Knoll Farms, a nursery specializing in green roof plants. We not only had the chance to chat with the nursery’s owner, Ed Snodgrass, but also got to climb on top of his office and check out his own green roof.
We then head to Penn State University to speak with two gentlemen who are at the forefront of green roof and living wall research in the U.S. Dr. Robert Berghage, associate professor of horticulture and director of the Center for Green Roof Research, and Ph.D. Candidate Bob Cameron talk about the ups and downs of these relatively new technologies. They also take us on a tour of their greenhouse.
In this issue of Leaf Litter, we are pleased to launch a new section – our Non-Profit Spotlight. We are delighted to highlight Green Roofs for Healthy Cities.
For those interested in learning more about green roofs and living walls, we provide loads of resources. Be sure to check them out. Finally, catch up on the latest at Biohabitats.
As always, we want to know what you think. Share your thoughts on Leaf Litter by contacting our editor.