Up on the Roof

Among the many green features of Fieldston’s middle school is its green or vegetative roof. Actually there are two roofs, an upper and a lower green roof, both covered with vegetation that provides insulation in the winter and reduces heat in the summer.

ECF is fortunate to have two scientists leading exciting research projects on both roofs. Matthew Palmer, a plant ecologist and lecturer at Columbia, leads a project on the lower, or teaching, roof on the feasibility of using regionally appropriate native plants on green roofs. Typically, green roof vegetation is dominated by sedums, which are neither native nor attractive to native birds or insects. Palmer, who is interested in meshing restoration ecology with green roofs, has selected a variety of native plants that are specific to this area, some from the Hempstead Plain grasslands and others from the Rocky summit grasslands. They range from poverty oatgrass to butterfly milkweed. Use of regionally native plants increases the value of green roofs as habitat for insects and birds. 

Stuart Gaffin, a research scientist at the Center for Climate Systems Research at Columbia University, leads the project on the upper roof, which is equipped with a weather station and sophisticated real-time environmental sensors. The sensors and probes measure wind speed, rainfall, soil moisture, reflectivity and temperature on a green roof, compared to a nearby white (or light-colored) roof and a black roof. “This is a state-of-the-art system, university research quality,” says Gaffin. The data is accessible to students and teachers, and shared with Columbia. The instrumentation on the roof was supported by a grant from the E.E. Ford Foundation. Gaffin manages and directs green roof projects across the city.

The green roofs were installed in August 2008 as these photographs (PDF format, 3.6 Mb) demonstrate.  Then in the fall of that year, members of the Fieldston science faculty joined students in installing the new plant material. Eagle TV, a student-run news show,  filmed the event and interviewed experts and students about green roofs in general and Fieldston’s green roofs in particular.