Green Roof Research at. Michigan State University

Transcription

1 Green Roof Research at Michigan State University Bradley Rowe Michigan State University Department of Horticulture

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3 Design Intent Intensive greening Extensive greening

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7 Cantonel University Hospital, Basel

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11 Rigi Kaltbad Edelweiss

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17 Why Green Roofs?

18 Benefits Aesthetics Recovery of green space Biodiversity Water and air purification Longevity of roof Noise reduction Stormwater management Quantity and Quality Moderation of urban heat island Building insulation Carbon sequestration

19 Research at MSU Plant selection Stormwater Thermal properties Carbon sequestration

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21 Stormwater Quality Retention Slope Substrate Depth Vegetation Type Instrumentation Curve Numbers

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24 3 Hydrograph 10 mm rainfall Oct 4, 2002 Vegetation Reduced peak Rainfall or Runoff (mm) 2 1 Rainfall Gravel Media Vegetated Delayed total Time After Initial Rainfall (h)

25 MSU Campus = 14.2 million sq ft of roof surface

26 If all MSU campus roofs were green 64,821,351 gallons = 8,665,354 cubic feet = 245,375 cubic meters...would have been retained (2003)

27 Niagara Falls - Canada 1 minute, 48 seconds

28 Curve Numbers Slope Curve Number (CN) 2% 84 7% 87 15% 89 25% 90 Traditional Roof CN=98

29 Photo Walbridge Aldinger

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31 PSSB Roof 60 Top of Insulation 50 Temperature (C) Ambient Air Vegetation Gravel 10 08/01/06 08/02/06 08/03/06 08/04/06 Date

32 Energy Efficiency Source: National Research Council, Institute for Research in Construction

33 Plant Evaluations Substrate depth and composition Nutrient requirements Rate of establishment Growth Survival and persistence Competition/Succession Environmental tolerances Plant stress Evapotranspiration Carbon sequestration

34 Growth and Coverage Survival Growth index Visual rating Biomass Image analysis Point frame Relative abundance Absolute cover

35 August 2001

36 August 2001

37 September 2002

38 May 2004

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40 Sedum Crassulacean acid metabolism

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42 Propagation 2 months

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44 Competition #2

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46 Quantifying drought tolerance Watering regimen Measurements Growth, survival, evapotranspiration, and chlorophyll fluorescence

47 Carbon sequestration Sampled Above ground biomass Below ground (roots) Soil carbon content Sample preparation Dried Weighed Ground to a fine powder

48 Carbon sequestration Total carbon concentration determined Carlo Erba NA1500 Series 2 N/C/S analyzer Carbon accumulation Multiply dry matter weight by total C concentration

49 Carbon sequestration Preliminary study (2006) 12 roofs in Michigan and Maryland 1 to 6 years in age 1.27 to 10.2 cm depth Sedum based Above-ground only

50 Results - Preliminary study Average: 162 g C/m 2 Range: g C/m y = (2.72 x Age in months) r 2 = Carbon (g.m -2 ) Age of Green Roof (months)

51 Results - Preliminary study Mean above-ground carbon content of select extensive green roofs Location MSU Communication Arts Building East Lansing, MI Mean Substrate Depth (cm) Age (months) Carbon (g m - 2 ) MSU HTRC East Lansing, MI Ford Motor Company Rouge Plant Dearborn, MI

52 Results - Preliminary study Mean above-ground carbon content of select extensive green roofs Location Mean Substrate Depth (cm) Age (months) Carbon (g m - 2 ) MSU HTRC East Lansing, MI MSU HTRC East Lansing, MI Renaissance Center South River Colony Edgewater, MD

53 Carbon sequestration MSU PSSB Depth = 6 cm Species Sedum acre Sedum album Sedum kamtshaticum Sedum spurium Substrate only Time to equilibrium Harvested three times during the growing season

54 Results - PSSB Mean carbon content at end of first growing season (October 2007) Species g C m -2 Above Ground Roots Soil Total S. acre A 11.9 A A A S. album A 15.9 A A A S. kamtschaticum A C A A S. spurium A 83.5 B A A Mean Mean separation in columns by LSD (P 0.05). Uppercase letters in columns denote differences among species (n=20).

55 Results - PSSB Mean carbon content at end of first growing season (October 2007) Biome Type Temperate Species forest g C m -2 Above Ground Roots Soil Total S. acre A 11.9 A A A Cultivated Land Temperate Grassland S. album A 15.9 A A A S. kamtschaticum A B A A Desert Scrub Plant biomass (g C/m 2 ) 8,000 1,400 3, Mean Soil Organic Matter (g C/m 2 ) 11,800 12,700 19,200 5,600 S. spurium A 83.5 C A A Mean Mean separation in columns by LSD (P 0.05). Uppercase letters in columns denote differences among species (n=20).

56 Carbon sequestration Detroit Metropolitan area Land area of rooftops 6,335 hectares - commercial 8,399 hectares - industrial 20% green roofs ~19,000 metric tons of carbon sequestered ~ 0.2% of the carbon emitted by Detroit s major electric utility in 2005

57 Results - PSSB Above Ground biomass Root Biomass Substrate Grams C per m Jun Jul Aug Sep Oct Nov Month (2007)

58 Influence of design on function Aesthetics Native species/plant diversity Stormwater Energy Irrigation Transpiration rates Soil fertility Maintenance DEPTH

59 Stuttgart Office of Gardens, Cemeteries, and Forestry

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61 Current status Germany 10-15% growth for past 10 years 12% of all new flat roofed buildings Govt. incentives Europe United States

62 Barriers to acceptance Lack of awareness Cost Data regarding benefits Technical information Standards FLL, ASTM, FM Global Incentives

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64 Swiss Convention Center, Basel

65 MSU Green Roof Research ( GreenRoofs.com ( Green Roofs for Healthy Cities (