Progress 10/01/19 to 09/30/20
Outputs
Target Audience:The target audiences include industry members such as the growers of nursery crops, substrate suppliers, landscape architects, landscape contractors, architects, and engineers. Also, it is aimed to provide scientific data and educate government officials and public policy makers on the environmental, economic, and social benefits that green roofs can provide. In addition, it provides knowledge for fellow researchers as well as educates the general public. Results will be reported in peer-reviewed journals and in trade publications, presented at scientific and industry gatherings, taught in a specific MSU course on green roofs, and posted on our website. In addition, as a member of the Research Committee of Green Roofs for Healthy Cities, information gained will be included in future standards. It will ultimately contribute to educational products that promote the contributions of the green industry to environmental stewardship and sustainability. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Mentored one graduate student: Riley Rouse, MS Horticulture (committee member) (Defended July 2020) Guest lecture in FW 410 (Upland Ecosystem Management) on Green Roofs and Biodiversity (Spring 2020). Developed interdepartmental (HRT, FW, GEO, and PDC) course HRT 460 - Green Roofs and Walls, taught every fall semester at MSU. Presentation on green roofs for National Association Landscape Professionals via Zoom (April 2020). How have the results been disseminated to communities of interest?Research results will be reported in peer-reviewed journals and in trade publications such as the Living Architecture Monitor, presented at international and local scientific and industry gatherings, taught at MSU in an interdepartmental course on green roofs (HRT 460), and posted on our website (www.greenroof.hrt.msu.edu). Also, information gained from these studies as well as past studies is being used to develop a plant database where green roof practitioners, building owners, or anyone interested in green roofs can obtain information. In addition, as a member of the Research Committee of Green Roofs for Healthy Cities (GRHC), information gained will be included in future international standards and will be included in course literature for the Green Roof Professional Certification administered by GRHC. It will ultimately contribute to educational products that promote the contributions of the green industry to environmental stewardship and sustainability. What do you plan to do during the next reporting period to accomplish the goals?Publish paper on plant recommendations for the Midwestern United States (Currently in preparation, Journal of Living Architecture). Finish data collection, analyze data, and submit paper on stormwater management study comparing green roof systems. Analyze data and submit work for publication on long-term plant community study at HTRC where we are looking at how the initial levels of organic matter and plant species influences changes in OM over time and plant community. Analyze data and submit work for publication on long-term plant evaluations at HTRC where we are looking at the suitability of alternative recycled materials (crushed porcelain, foamed glass, and heat-expanded shale) for use in green roof substrates. Collaborate on substrate, plant selection, and carbon sequestration studies taking place in Turkey and Iran.
Impacts
What was accomplished under these goals?
Objective 1: Evaluate potential green roof plant species for initial establishment and for long-term plant community development. The objective of this study was to measure changes on organic matter over time and its effect on plant performance. We are quantifying plant establishment, long term plant performance, and substrate shrinkage dependent on the percentage of OM in the original substrate and plant community. During May 2013, eighteen roof platforms were filled with substrates consisting of heat expanded shale and either 0, 20 or 40% compost. Each platform was seeded with a mix of Sedum or native perennials and grasses. Substrate samples have been analyzed annually for percent OM, pH, P, K, Ca, and CEC by the MSU Soil and Plant Nutrient Laboratory. Data on absolute coverage of each species was also collected annually with a point frame transect to measure plant community composition and change. Data collection is complete and data analysis is currently being conducted. In general, sedum has dominated and OM has been increasing in the 0% plots and decreasing in the 40% plots. Another study was conducted in collaboration with scientists at Ferdowsi University of Mashhad in Iran regarding the carbon sequestration potential of green roofs. This study investigated the effect of green roofs on the carbon footprint and compared carbon dioxide emissions and sequestration of these roofs during their lifetime. Six cold and drought tolerant plant species including Sedum acre, Hylotelephium spectabile 'Boreau' (syn. Sedum spectabile 'Boreau'), Crassula capitella, Frankenia laevis, Vinca major, and Rosmarinus officinalis were chosen for the investigation. Carbon dioxide sequestration of these plants under certain light intensities in the range of 400-2600 μmol/m2.s was measured by an infrared gas analyzer. Then, carbon dioxide sequestration under all light intensities in the area of interest for a 40-year period from 1979 to 2019 was estimated with the help of Matlab. Carbon dioxide emitted during the construction of green roofs was estimated through the simulation of a four-story building with 180 m2 floor area in Design-Builder. Carbon dioxide emission due to roof maintenance activities was predicted based on cost estimates obtained from an economic analysis of maintenance activities. Results showed that carbon dioxide emissions due to the construction and maintenance of green roofs are much lower than the corresponding carbon dioxide sequestration values. For example, a roof with Frankenia laevis cover was estimated to sequester 68.7 kg/m2 of carbon dioxide over a 40-year period while emitting 22.65 kg/m2 of carbon dioxide during the same time. Under high light intensities (>1500 μmol/m2.s) Sedum acre, and under low light intensities (<1300 μmol/m2.s) Rosmarinus officinalis showed the best performance in terms of carbon dioxide sequestration. For light intensities in the range of 1300-2000 μmol/m2.s, Frankenia laevis had the highest increase in carbon dioxide sequestration rate. This work is currently under review in the journal Urban Forestry and Urban Greening. Objective 2: Develop sustainable green roof substrates from recycled materials. A long-term study comparing the suitability of recycled foamed glass and recycled crushed porcelain to a standard heat expanded shale substrate was initiated on roof platforms at MSU in 2013. These materials were produced from bulk waste intended for disposal in a landfill. Following seven growing seasons, plant coverage and substrate volumetric moisture content in both the foamed glass and porcelain has been equivalent or greater than that of the heat expanded shale. Data suggests both materials could be suitable for extensive green roofs. Objective 3: Quantify differences in water retention among green roof systems. A stormwater runoff study was initiated during March 2020 to compare the retention capabilities of various green roof systems. The study is being conducted on raised platforms located on a gravel container pad in Nunica, MI. Runoff is collected and measured after each rainfall event by nursery personnel. Rainfall is being measured and continuously recorded by a RainWise rain gauge and datalogger. Treatments include (1) 10.8 cm (4.25 in) of substrate standard green roof module (control), (2) 12.7 cm (5 in) of substrate green roof module, (3) 15.2 cm (6 in) of substrate green roof module, (4) 6.4 cm (2.5 in) of substrate over 5.1 cm (2 in) of rockwool, (5) 6.4 cm (2.5 in) of substrate over RoofBlue system, (6) 10.8 cm (4.25 in) of substrate on top of 10 cm (4 in) of rockwool, and (7) 10.8 cm (4.25 in) of substrate on top of a RoofBlue system. Data collection will continue until freezing temperatures interfere with data collection. Objective 4: Assess wildlife habitat contributions that green roofs provide in urban landscapes. The objective is to assess wildlife habitat contributions that green roofs provide in urban landscapes. We are evaluating characteristics associated with green roofs that make them successful for arthropods. Arthropods were collected by using sweep nets and pitfall traps on eight different green roofs in Michigan and Illinois. All arthropods were identified to family level and organized and counted to calculate species abundance, richness, and diversity using Simpson's diversity index, Shannon Weiner diversity index, and Evenness. Roof height, roof area, and percent vegetation cover of total roof area appear to have the most influence on arthropod communities and diversity, whereas substrate depth, vegetation type, and roof age may not be statistically significant factors. Rique Campa's expertise in wildlife habitat and wildlife research protocols will be invaluable in fulfilling this objective.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Tam, W.C.V., J.B. Burley, D.B. Rowe, and T. Machemer. 2020. Comparison of Five Green Roof Treatments in Flint Michigan with Freidmans Two-Way Analysis of Variance by Ranks. Journal of Architecture and Construction 3(1): 23-36.
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Eksi, M. and D.B. Rowe. 2019. Effect of substrate depth and type on plant growth in extensive green roofs in Mediterranean climate. Journal of Green Building 14(2):29-44.
- Type:
Other
Status:
Published
Year Published:
2020
Citation:
Rowe, B. 2020. Should there be policy specifying only native plants on green roofs? Living Architecture Monitor 22(2):8-9.
- Type:
Other
Status:
Published
Year Published:
2020
Citation:
Rowe, B. 2020. Can stormwater retention and energy savings both be maximized on one roof? Living Architecture Monitor 22(1):8-11.
- Type:
Other
Status:
Published
Year Published:
2019
Citation:
Rowe, B. 2019. The wonders of Dalea purpurea. Living Architecture Monitor 21(4):8-9.
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Progress 01/01/19 to 09/30/19
Outputs
Target Audience:The target audiences include industry members such as the growers of nursery crops, substrate suppliers, landscape architects, landscape contractors, architects, and engineers. Also, it is aimed to provide scientific data and educate government officials and public policy makers on the environmental, economic, and social benefits that green roofs can provide. In addition, it provides knowledge for fellow researchers as well as educates the general public. Results will be reported in peer-reviewed journals and in trade publications, presented at scientific and industry gatherings, taught in a specific MSU course on green roofs, and posted on our website (www.greenroof.hrt.msu.edu). In addition, as a member of the Research Committee of Green Roofs for Healthy Cities, information gained will be included in future standards. It will ultimately contribute to educational products that promote the contributions of the green industry to environmental stewardship and sustainability. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Mentoring two graduate students: Vincy Tam, Masters of Environmental Design in Landscape Architecture (committee member) Riley Rouse, MS Horticulture (committee member) Developed and teach interdepartmental (HRT, FW, GEO, and PDC) course HRT 460 - Green Roofs and Walls every fall semester at MSU. Guest lecture in FW 410 (Upland Ecosystem Management) on Green Roofs and Biodiversity (Spring 2019). Presentations on green roofs and walls at National Association Landscape Professionals, (March 2019) and American Society of Irrigation Consultants, Santa Fe, NM (May 2019). How have the results been disseminated to communities of interest?Research results are reported in peer-reviewed journals and in trade publications, presented at international and local scientific and industry gatherings, taught at MSU in an interdepartmental course on green roofs (HRT 460), and posted on our website (www.greenroof.hrt.msu.edu). Also, information gained from these studies as well as past studies is being used to develop a plant database where green roof practitioners, building owners, or anyone interested in green roofs can obtain information. In addition, as a member of the Research Committee of Green Roofs for Healthy Cities (GRHC), information gained will be included in future international standards and will be included in course literature for the Green Roof Professional Certification administered by GRHC. It will ultimately contribute to educational products that promote the contributions of the green industry to environmental stewardship and sustainability. What do you plan to do during the next reporting period to accomplish the goals?Continue with data collection of long-term plant community study at HTRC where we are looking at how the initial levels of organic matter and plant species influences changes in OM over time and plant community. Continue with data collection of plant evaluations at HTRC where we are looking at the suitability of alternative recycled materials (crushed porcelain, foamed glass, and heat-expanded shale) for use in green roof substrates. Continue collaboration on substrate and plant selection studies taking place in Turkey; continue collaboration on carbon sequestration studies taking place in Iran; analyze collected data to date from above long-term studies on campus; and develop and publish plant recommendations for the Midwestern United States.
Impacts
What was accomplished under these goals?
Objective 1: Evaluate potential green roof plant species for initial establishment and for long-term plant community development. A long-term study to evaluate establishment, survival, and changes in plant community over time was initiated on the Molecular Plant Sciences Building at MSU in October 2011. Twenty-two plant species including herbaceous perennials, grasses, and sedum were evaluated on a green roof at depths of 4.5, 10, or 20 cm over an eight-year period. Plants were watered immediately after planting and then periodically during the 2012 season to ensure establishment. No supplemental water was supplied thereafter so plants will have to rely on natural rainfall. A linear transect was used annually to measure community composition and change. All five species of sedum were still present at the end of the eight-year period, but only seven of the 17 herbaceous perennials and grasses survived. Of the herbaceous perennials and grasses, Allium cernuum was by far the dominant species in both the 10 and 20 cm deep zones. Sporobolus heterolepis and Koeleria macrantha also established themselves in the 20 cm zone, but all other species were either only present in trace amounts or had completely disappeared. Substrate moisture was probably the major factor in terms of species survival and a drought during 2016 was likely the cause for the large loss of species. Deeper substrates supported a larger variety of species, but plant species diversity decreased over time at all substrate depths. This study emphasizes the fact that if herbaceous perennials and grasses are to be successful on green roofs, then irrigation may be critical to mitigate drought and maintain species diversity. It also points out the importance of long-term studies to accurately evaluate green roof plant communities and provides the framework for a continuation of the same study in other areas of the world. Published in 2019 in Ecological Engineering (https://dx.doi.org/10.1016/j.ecoleng.2019.07.032). A second long-term study is being conducted to measure changes in organic matter over time and its effect on plant performance. The objective of this study is to quantify plant establishment, long-term performance, and substrate shrinkage dependent on the percentage of organic matter in the original substrate and plant community. During May 2013, eighteen roof platforms were filled with substrates consisting of heat expanded shale and either 0, 20 or 40% compost. Each platform was seeded with a mix of sedum or native perennials and grasses. Annual substrate samples have and will be analyzed by the MSU Soil and Plant Nutrient Laboratory for percent OM, pH, P, K, Ca, and CEC. Plant coverage is recorded using a point-frame transect once each season during August to measure community composition and change. So far, sedum has dominated and OM has been increasing in the 0% compost plots and decreasing in the 40% compost plots. Another study is being conducted in collaboration with scientists at Ferdowsi University of Mashhad in Iran regarding the carbon sequestration potential of green roofs. This study is investigating the effect of green roofs on the carbon footprint and is comparing carbon dioxide emissions and sequestration of these roofs during their lifetime. Six cold and drought tolerant plant species including Sedum acre, Hylotelephium spectabile 'Boreau' (syn. Sedum spectabile 'Boreau'), Crassula capitella, Frankenia laevis, Vinca major, and Rosmarinus officinalis were chosen for the investigation. Carbon dioxide sequestration of these plants under certain light intensities in the range of 400-2600 micromol/m2.s is being measured by an infrared gas analyzer. Carbon dioxide sequestration under all light intensities in the area of interest for a 40-year period from 1979 to 2019 was estimated with the help of Matlab. Carbon dioxide emitted during the construction of green roofs was estimated through the simulation of a four-story building with 180 m2 floor area in Design-Builder. Carbon dioxide emissions due to roof maintenance activities will be predicted based on cost estimates obtained from an economic analysis of maintenance activities. Preliminary results show that carbon dioxide emissions due to construction and maintenance of green roofs are much lower than the corresponding carbon dioxide sequestration values. Objective 2: Develop sustainable green roof substrates from recycled materials. A long-term study comparing the suitability of recycled foamed glass and recycled crushed porcelain to a standard heat expanded shale based substrate was initiated on roof platforms at MSU in 2013. Both of these materials were produced from bulk waste intended for disposal in a landfill. After seven growing seasons of data collection, plant coverage and substrate volumetric moisture content in both the porcelain and foamed glass has been equivalent or greater than that of the expanded shale. Data suggests that both candidate materials could be suitable for use in extensive green roof applications. Another study investigating the potential use of recycled materials was conducted at Istanbul University as limited research has been conducted on plant material and substrate types in this climate zone. Two types of growing substrates: a commercial substrate consisting of crushed brick and clay (45%), pumice (45%), and organic matter (10%), and a recycled substrate including 90% coarse pumice (10-20 mm) and municipal compost (10%), were tested in three depths of 4, 7 and 10 cm. Tested plant species included Achillea millefolium, Armeria maritima, Sedum acre and Sedum album. Overall, the commercial substrate performed better than the recycled pumice. In addition, deeper substrates promoted greater survival and growth for nearly all species tested. Neither A. maritima or A. millefolium survived in the recycled pumice at any depth, whereas they did survive when grown in the commercial substrate when grown in depths greater than 7 cm and 10 cm, respectively. Both would likely require supplemental irrigation to be acceptable for green roofs in Istanbul or locations with a similar climate. Both Sedum species survived in all substrate types and depths. Information gained can be utilized by green roof professionals in the Istanbul region and in other parts of the world with a similar climate. Published during 2019 in Journal of Green Building 14(2):29-44. Objective 3: Quantify differences in water retention among roof systems. No activity on this topic during the reporting period. Objective 4: Assess wildlife habitat contributions that green roofs provide in urban landscapes. The objective of this study is to assess wildlife habitat contributions that green roofs provide in urban landscapes. We are evaluating characteristics associated with green roofs that make them successful for arthropod establishment. Arthropod samples were collected over a seven-month period by using sweep nets and pitfall traps on eight different green roofs located in Michigan and Illinois. All arthropods collected were identified to family level, then organized and are being counted to calculate species abundance, richness and diversity using Simpson's diversity index, Shannon-Wiener Diversity Index, and Evenness. Roof height, roof area, and percent vegetation cover of total roof area appear to have the most influence on arthropod communities and diversity, whereas substrate depth, vegetation type, and roof age may not be statistically significant factors.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Vandegrift, D.A., D.B. Rowe, B.M. Cregg, and D. Liang. 2019. Effect of substrate depth on green roof plant community development on a Michigan green roof. Ecological Engineering 138:264-273. (https://dx.doi.org/10.1016/j.ecoleng.2019.07.032).
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Eksi, M. and D.B. Rowe. 2019. Effect of substrate depth and type on plant growth in extensive green roofs in Mediterranean climate. Journal of Green Building 14(2):29-44.
- Type:
Other
Status:
Published
Year Published:
2019
Citation:
Rowe, B. 2019. Enhancing biodiversity on green roofs through plant selection. Living Architecture Monitor 21(3):6-7.
- Type:
Other
Status:
Published
Year Published:
2019
Citation:
Rowe, B. 2019. Funding green roof plant research in North America. Living Architecture Monitor 21(2):10-11.
- Type:
Other
Status:
Published
Year Published:
2019
Citation:
Rowe, B. 2019. A critical review of twenty years of green roof plant research in North America. Living Architecture Monitor 21(1):9-10.
- Type:
Other
Status:
Published
Year Published:
2019
Citation:
Rowe, B. 2018. Asters provide exceptional fall aesthetic appeal. Living Architecture Monitor 20(4):7-8.
- Type:
Websites
Status:
Published
Year Published:
2019
Citation:
Green roof research at Michigan State University, 2019, www.greenroof.hrt.msu.edu
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