Asbury Woods Nature Center (AWNC)has turned green! Not only green in color, but also in building techniques. During our recent expansion project, a green, vegetative roof was installed. AWNC and Millcreek Township School District were awarded an Energy Harvest grant from the PA Department of Environmental Protection (DEP) to add this green technique to the expansion project. The designers, Roofscapes Inc. of Philadelphia, designed the roof to not only look pretty, but also for functionality. A green roof is ideal in situations where a building is being built (or renovated in Asbury’s case) and a bigger footprint is made, causing a stormwater retention basin to be needed.

Advantages

• Green roofs absorb about 75% of rainwater runoff that would have ended up running off into retention basin
• Smaller retention basins can be used.
• Green roofs moderate daily fluctuations in a building’s temperature - acting as a cooling agent during the summer months (a typical asphalt roof can reach 120° versus the vegetative roof
  reaching only about 80°) - helping to insulate a building during the winter months.

The roof and plants were installed by Lichtenfels Nursery of Johnstown, PA. Special drainage mats were laid as the base to the roof holding 4”of special mineral/soil mix that the plant are planted in. The plants are mainly alpine plants able to adapt to the harsh temperature extremes seen on roofs (from wet rain and snow to dry scorching sun). The majority are sedum, talinum, and allium.

The annual maintenance of the green roof is very simple. No mowing or watering is needed once the plants are established. All that is needed is to pull weeds or any tree seedlings that have taken up root on the roof about twice a year.

Now that the snow has fallen, not much can be seen up on the rooftop. Once the snow has melted, and the sun is shining again, come on out to Asbury Woods Nature Center and take a peek at the green roof.

Written by Julie Blackman, Watershed Educator, AWNC