Ecological Design: Habitat restoration and living architecture in the Pacific Northwest
Notes by James Bornholdt
Speaker: Christine Thuring, MSc. Horticulture
Contact: christine.thuring@gmail.com
The Vision:
-By 2031 there will be 3 million metro Vancouver residents
-Vancouver is presently mostly impervious surfaces
-There is a lack of connection to nature in such impervious environments
-Pollinators needed for food production are in decline
Overview:
-Green Roof intro
-Green roofs for Biodiversity
-Policy Examples
-Green Roofs in Vancouver
Why Green Roofs?
-Stormwater mitigation
-The Daimler Chrysler headquarters in Stuttgart, Germany has green roofs to the extent that it can be taken off of the civic storm water grid
-Noise Attenuation and Air Quality
-Plants and green matter reduce noise and clean the air
-Lessening of the Heat Island Effect
-Urban areas are on average 5° F warmer than rural areas
-This difference can be reduced by green roofs
-Thermal Insulation
-Protection of Waterproof Roof Membrane
-UV rays from the sun are intercepted by the green roof before they can reach the membrane and cause damage to it
-Lower membrane temperature fluctuations
-Uncovered, roof temperatures can range from 5-65°
-This damaging effect is minimized when covered
-Ecological Compensation
-Green roofs create habitat for wildlife
-Human Biophilia
-Humans have an inherent fascination with nature
What is a Green Roof?
Basic Components (in order from top to bottom)
-Plants-Sedum is a drought resistant plant found in rocky mountain outcroppings which is very well suited for green roofs
-Substrate-Mostly volcanic minerals with low organic content
-Drainage layer
Waterproofing-Conventional designs are from Germany, which were adapted from Scandinavian sod roofs
Green Roof History:
-600 BCE: Hanging Garden of Babylon
-1000 CE: Norse settlement in L’Anse aux Meadows features sod buildings
-c. 1912: Green roofs are constructed in Berlin for fire protection
-1970’s: First extensive use of modern green roofs in Germany
-1999: Green Roofs for Healthy Cities founded in Toronto, Canada
Green Roofs for BioDiversity:
-Biodiversity issues not currently at the forefront of green roof motives
-Ecosystems Thinking and Ecological Design
-Designing like nature. All “waste” is recycled.
Living Roofs: The Ecological Approach:
-Humans don’t use roof space, so why not give it back to nature?
-Habitat Templates
-Naturally occurring plant combinations from natural roof-like settings
-Sedum from rocky outcroppings
-Plants normally found in beach/dune areas
-Local substrates
-Bear the genius loci (spirit of place)
-Weigh more than modern green roofs
-1914 green roof in Zurich used local topsoil
-This roof is currently a self sustaining habitat deemed a conservation area because of its untouched nature
-Topographic variety provides microhabitats
-Varying depths of green roof cover create varying moisture levels and thus diverse habitat areas
-Zurich train station roof creates ecological diversity by a mounded substrate design
-Roofs as habitat patches and corridors
-Greening Gotham: Rendering of New York City with green roofs
-Birds and butterflies can fly from rooftop to rooftop habitat
-The endangered Bay Checkerspot butterfly is supported by strategic green roofs in the Bay area
-Vancouver Convention Centre Expansion Project
-Almost 6 acres of native sedges, grasses, herbaceous perennials and bulbs
Green Roof Policies
Basel, Switzerland
-Better Flat Roof Project (1997)
-Intended to save energy costs through improved insulation qualities of green roofs.
-1 million SFr. spent to retrofit 85,000 of roof surfaces
-Mandated in 2002 that all new flat roofs must be green roofs with local substrates
-In 2005, 35,000 m2 were greened with 1.5 million SFr.
-Mostly mound and pond schemes to create biodiversity
London, England
-The rare Black Redstart is found to have adopted to brownfield sites along the Themes
-New development must replace or preserve this habitat
-Green roofs are made of rubble
Metro Vancouver Area
-Port Coquitlan mandated in Dec. 2006 that all new roofs greater than 5000 m2 must be vegetated
-Granville Island
-20 years of tar and gravel colonization has given rise to naturally occurring spontaneous green roofs
- Over 30 species have been documented living on roofs here
-Native plant trials at NATS nursery in Langley
-Ongoing research at BCIT
-New green skin research at UBC
Barriers to overcome
-Misconceptions, Myths, and Fears
-“Leaky condo” fiasco nothing to do with green roofs
-Lack of municipal support
-Material development
-Continuing research
Resources
www.greenroof.bcit.ca
www.greenroofs.com
www.NATSnursery.com
www.livingroofs.org
