Conservation Matters April 2012

The Texas Land, Water and Wildlife Connection

Texas AgriLife Research and Texas A&M investigate green roofs

Green RoofsCould green roofs help solve urban energy issues? Texas AgriLife Research horticulturist Dr. Astrid Volder thinks so. With Texas AgriLife Extension Service agents and Master Gardeners, a team of researchers and a commercial building company in Houston, Volder is studying the viability of green roofs.

"These green roofs actually will help mitigate problems in the urban areas like what people call having an urban heat island," Vodler said. "Urban areas are usually a lot hotter than rural areas, so having plants on your roof will actually facilitate cooling."

In the United States, the green roof industry grew by 28.5 percent in 2010, up from  the 16-percent growth recorded in 2009, according to the annual survey by Green Roofs for Healthy Cities, a nonprofit network of public and private entities that promote research and implementation of such systems in North America.

"We're thinking that green roofs could be really, really good for Texas because of the insulating properties of the roof that could cool buildings," Volder said. "That could be wonderful in the summer for Texas buildings to provide additional cooling and reduce energy usage."

But there's a challenge.

"The problem with Texas is finding plant species that can survive in such a harsh environment," the horticulture researcher said. "A plant growing on a roof is going to receive a lot of solar radiation, very high light conditions and not a lot of rain. And the plant is growing in maybe 4 inches of soil on the extensive-type green roof.

"My part is to look at what plants may work on top of a green roof and also how some of these plants contribute to some of the properties of the green roof," she added.

Texas A&M students are also pitching in to research the possibilities of green roofs.

Next fall, students from a variety of academic programs will begin collaborating on an interdisciplinary, three-year project to install and monitor a green roof and a living wall atop a campus building. This is an initiative aimed at preparing students to become leaders in energy conservation and resource management, said Dr. Bruce Dvorak, an assistant professor of landscape architecture who is spearheading the effort.

The project is funded by a $100,000 Texas A&M reallocation grant for enhancing students' preparation for the workplace and society through high-impact learning experiences.

"A living wall, said Dvorak, "is a vegetated wall designed to achieve benefits similar to green roofs, but much less is known about its performance."

Though alternative campus sites for the rooftop project are currently under consideration, once under way, Dvorak said, the effort will engage up to 1,000 students in three colleges from at least seven undergraduate programs, including architecture, construction science, environmental geosciences, environmental studies, landscape architecture, horticulture and meteorology.

The project will add to the findings from green roof research Dvorak began in 2009 atop the Langford Architecture Center.

For more information, read the original TAMU press release on green roofs, read about Volder's green roof research, watch Volder discuss her research and read more about Texas A&M's green roof project.

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