Interdisciplinary Green Roof Research Group

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Interdisciplinary Green Roof Research Group at Texas A&M
The interdisciplinary green roof research taking place on the Langford building at Texas A&M University was initiated spring of 2009. CRIC Grant funds were used to purchase monitoring equipment for twelve 2 by 2 square green roof modules donated by Tecta America. Plants were donated by Emory Knoll Farms and growth media by Rooflite. The focus of the center is to explore possibilities for low-input green roofs for central Texas through quantitative research.

The 12 modular green roof trays were randomly assigned in order and placed across a structural shelf to expose the units to a rooftop environment typical to the Texas A&M campus. The modular trays represent the Tecta Green (Tecta America) product, with a 10 cm deep substrate. A water conservation approach was used to better understand minimal watering requirements for extensive green roofs in this climate. The modular trays were assembled and planted on April 3, 2009. Three species of plants were investigated including Talinum calycinum, Delosperma cooperi and Sedum kamtschaticum. Nine individual plants were installed of each species in three modules. A total of 27 plants were installed across 9 trays, with 3 tray left unplanted. All species of plants became established in the modular trays during the year marked by extreme drought, however, not all plants performed equally. During the drought, Talinum calycinum performed best though the first growing season, and Delosperma cooperi performed well with only a few signs of stress. Sedum kamtschaticum did not establish well, as about one-half of the plants perished.

College Station, Texas had been in a drought the previous year and forecasts for the 2009 growing season predicted the drought to lessen over the summer, but this was not the case. Some rain fell after the plants were installed, but beginning May 25 to July 19th, no rain fell. This included 55 days without precipitation and 28 days with temperatures over 100 (37.8c). Since plants were still in their establishment period, a water conserving approach was used. Irrigation was applied by hand at a rate .25 depth of water per module, if less than that same rate fell over the previous 7 days. The plots were irrigated only 14 times during their establishment period beginning April 3rd through fall of 2009. Typical irrigation for landscaping in Texas consists of about 1-2 per week making use of municipal potable water.

During the summer and fall of 2009, temperature probes were installed on the surface and below the surface of the modules to measure the cooling effect of the plants. Rain buckets were also installed during late fall of 2009 and early 2010, to measure stormwater runoff. We expect to publish results describing temperature, stormwater quantity and quality, and plant performance in the near future.

The 2010 growing season began with a dry and warm May but returned to normal temperatures and above normal precipitation for June and July. August set several records for maximum temperatures. Less than 1" of precipitation fell from July 28th through September 9th. The toll of heat and drought at the end of the growing season stresses all plants, but several species pulled through without irrigation. More information and updates will be added with future publications in 2011. All of the 2009 plantings have been removed and new plantings were installed in 2010 and again 2011.

A new research site has been set up on the Langford Buidling with over 800 s.f. of green roofs and two living walls. The blog site for the langford Green Roofs on Campus is http://tamugreenroof.wordpress.com/

Grant Funding
2009 The College Research and Interdisciplinary Council (CRIC), College of Architecture, Texas A&M University Grant

2012 Green Roofs on Campus Mutidisciplainary Experiential Learning with Green Roof and Living Wall Technologies project funded through a Tier One Program grant, Dean of Faculties, Texas A&M Univeristy.
Direct Support/Contributions
(Chronological Order)

Tecta America (April, 2009)
http://www.greenroof.com/

Emory Knoll Farms (April, 2009)
http://www.greenroofplants.com/

Skyland/Rooflite (April, 2009)
http://www.skylandusa.us/

Dr. Don T. Conlee, Department of Atmospheric Sciences (rain bucket, rain gauge) (August, 2009)
http://atmo.tamu.edu/

LiveRoof: http://liveroof.com/

Joss Growers http://jossgrowers.com/


Note: If you or your organization would like to contribute or make donations to advance our green roof research, please contact Bruce Dvorak at: 979-458-0628 or bdvorak@tamu.edu