October 24, 2014

Green Roof Study Published in CATE

The intensive green roof under discussion in Cities and the Environment grows atop House 5 (the Flora Rose House) at Cornell University in Ithaca, New York.

For the last three summers, members of our research group have been conducting ecological research and monitoring of plant communities on seven KieranTimberlake buildings at Cornell University, Middlebury College, University of California San Diego, and Yale University. The research has allowed us to revisit projects up to a decade old, meet with numerous building and landscape managers, consult with green roof experts from across the country, and learn a great deal about how the design and detailing of green roofs on our projects have fared over time.  
Additionally, the study has yielded some interest in the research community for its use of novel field methods and its graphic representation, which has allowed for spatially explicit data collection and mapping. The study of community dynamics is rooted in the ability to discern, test, and communicate the relationship between landscape patterns and ecology function or performance. As designers, our ability to diagram and draw relationships analytically has allowed us to explore green roof systems in new and revealing ways. 

Sequential species maps of the House 5 roof allow for visualization of plant communities over time. Each color represents a uniquely identified species. Color groupings represent family types while white space represents bare ground.

Recently, Stephanie Carlisle and Max Piana published a methods paper in Cities and the Environment (CATE), a peer-reviewed journal of urban ecology with an audience of both academics and practitioners. The paper, "Green Roofs Over Time: A Spatially Explicit Method for Studying Green Roof Vegetative Dynamics and Performance," uses the green roof on House 5 at Cornell University to discuss plant dynamics, the role of maintenance and disturbance regimes, emergent and ruderal vegetation, and ecological performance metrics. It suggests further innovation with sensor deployment and other means of directly measuring roof performance.  
A case study paper that compares House 1 (an intensive roof) and House 2 (an extensive roof) at Cornell is forthcoming for the Journal of Living Architecture. A book chapter that delves more deeply into the theoretical basis for studying green roof plant assemblages will be published in Green Roof Ecosystems, due out next year.