scholarly journals MEDIA COMPOSITION INFLUENCES GREEN ROOF PLANT VIABILITY IN THE OZARK HIGHLANDS

2012 ◽  
Vol 7 (4) ◽  
pp. 73-84
Author(s):  
D. C. Toland ◽  
C. P. West ◽  
M. E. Boyer
Keyword(s):  
Plant Species ◽  
Climatic Factors ◽  
Green Roof ◽  
Green Roofs ◽  
Roof System ◽  
Ozark Highlands ◽  
Rooting Medium ◽  
Growing Medium ◽  
Critical Components ◽  
The University

Plant selection and establishment are critical components for green roof health and success. Plant palettes (sets of plant species selected for specific conditions) for green roofs vary in their ability to confer benefits depending on the species make-up and their adaptation to particular environments and climates. The response of various species to climatic factors on rooftops is unknown for the Ozark Highlands region. The objective of this study was to compare plant survival and spread in three growing medium treatments (course and fine texture with compost and fine texture with no compost) installed as part of a green roof system. The study was performed on a green roof system at the University of Arkansas in Fayetteville over 3 years. Data were collected on 13 species installed in September of 2006 and surveyed on three dates thereafter: April 30, 2007; May 19, 2009; September 10, 2009. The treatments with added compost had statistically greater vegetated cover (from 73 to 87%) compared to the fine medium without compost (36 to 43%). In most cases the spread of individual plants was not significantly different between treatments. Results indicated that rooting medium containing compost increased survival and overall vegetated roof coverage, and identified various potential green roof plant species for the Ozark Highland environment. Two species, Sedum middendorffianum var. diffusum and Sedum spurium ‘Roseum’, did particularly well in all treatments. One species, Sedum kamtschaticum, did well only in the treatments with compost.

The effect of drainage height on plant-species composition on a semi-arid green roof system

2021 ◽  
Vol 67 (3-4) ◽  
pp. 149-155
Author(s):  
Har'el Agra ◽  
Hadar Shalom ◽  
Omar Bawab ◽  
Gyongyver J. Kadas ◽  
Leon Blaustein
Keyword(s):  
Species Composition ◽  
Plant Species ◽  
Plant Diversity ◽  
Urban Areas ◽  
Green Roof ◽  
Growing Season ◽  
Green Roofs ◽  
Plant Species Composition ◽  
Roof System ◽  
Semi Arid

Abstract Green roofs are expected to contribute to higher biodiversity in urban surroundings. Typically, green roofs have been designed with low plant diversity. However, plant diversity can be enhanced by controlling resource availability and creating distinct niches. Here we hypothesize that by using different drainage heights during the short plant-growing season in a semi-arid green roof system we can create distinct niches and plant communities. Our experiment took place at the University of Haifa, north Israel. We tested three different heights of drainage outlet: 10 cm under the surface of the substrate (Low), 1 cm under the surface of the substrate (Medium) and 3 cm above the surface of the substrate (High) on plant species-composition in green-roof gardens. Grasses cover was higher in High and Medium drainages while forbs cover was higher in Low drainage. Species richness was the highest in Low drainage while diversity indices showed the opposite trend. We conclude that by changing the height of the drainage we can create different niches and change species composition in a short time period of one growing season. This way we can create more diverse green roof communities and enhance biodiversity in urban areas, particularly in semi-arid regions.

scholarly journals Growth of Native Aromatic Xerophytes in an Extensive Mediterranean Green Roof as Affected by Substrate Type and Depth and Irrigation Frequency

HortScience ◽  
2013 ◽  
Vol 48 (10) ◽  
pp. 1327-1333 ◽  
Author(s):  
Maria Papafotiou ◽  
Niki Pergialioti ◽  
Lamprini Tassoula ◽  
Ioannis Massas ◽  
Georgios Kargas
Keyword(s):  
Plant Growth ◽  
Plant Species ◽  
Green Roof ◽  
Green Roofs ◽  
Native Plant ◽  
Substrate Type ◽  
Irrigation Frequency ◽  
Artemisia Absinthium ◽  
Grape Marc ◽  
Local Character

Green roofs could be a way to increase vegetation in the center of old Mediterranean cities. The need for conservation of local character and biodiversity requires the use of native plant species, whereas the deficiency of water, particularly in semiarid regions, requires the use of species with reduced irrigation needs. Moreover, the aged buildings lead to the use of lightweight green roof constructions. Therefore, research was undertaken to investigate the possibility of using three Mediterranean aromatic xerophytes, Artemisia absinthium L., Helichrysum italicum Roth., and H. orientale L., at an extensive green roof in Athens, Greece. Simultaneously, the possibility of using locally produced grape marc compost was investigated. Substrate type and depth and irrigation frequency effects on growth of these species were studied. Rooted cuttings were planted mid-May in plastic containers with a green roof infrastructure fitted (moisture retention and protection of the insulation mat, drainage layer, and filter sheet) and placed on a fully exposed third floor flat roof at the Agricultural University of Athens. Two types of substrates were used, grape marc compost:soil:perlite (2:3:5, v/v) and peat:soil:perlite (2:3:5, v/v, as a control), as well as two substrate depths, 7.5 (shallow) and 15 cm (deep), and two irrigation frequencies, sparse (5 or 7 days in shallow and deep substrate, respectively) and normal (3 or 5 days in shallow and deep substrate, respectively). Increased contents of macroelements, total phosphorus (P) and potassium (K) in particular, were recorded in the compost-amended substrate, whereas both substrates had similar physical properties. Plant growth was recorded from May to October. The deep compost-amended substrate, independent of irrigation frequency, resulted in taller plants with bigger diameter and aboveground dry weight in all species. However, a remarkable result was that shallow compost-amended substrate with sparse irrigation resulted in similar or even bigger plant growth of all plant species compared with deep peat-amended substrate with normal irrigation. Thus, all three species were found suitable for use in Mediterranean extensive or semi-intensive green roofs, whereas the use of grape marc compost in the substrate allowed for less water consumption and the reduction of substrate depth without restriction of plant growth at the establishment phase and the first period of drought.

The Potential of Recycled Locally-Sourced Waste Materials for Green Roof Soil Mixtures

2017 ◽  
Vol 730 ◽  
pp. 445-451
Author(s):  
Hartini Kasmin ◽  
Siti Nur Ummiah Munir ◽  
Nur Syafira Razak ◽  
Nor Azizi Yusoff ◽  
Rosniza Kassim ◽  
...  
Keyword(s):  
Urban Areas ◽  
Climatic Factors ◽  
Green Roof ◽  
Water Storage ◽  
Green Roofs ◽  
Waste Materials ◽  
Peat Moss ◽  
Water Runoff ◽  
Maximum Water ◽  
Soil Mixtures

The increase in surface runoff has become a serious environmental problem and concern in Malaysia. Hence, promoting the use of green roofs in urban areas will potentially allow some storage area and time attenuation for any rainfall. Initial studies on a few substrate mixtures were done in order to find out the properties of green roof media. These included vermiculite (V), perlite (P) and peat moss (PM) together with locally-sourced waste materials such as empty fruit bunches (EFB) and wet diaper gel (D) which are expected to potentially retain more storm water runoff. A test on the substrate mixture properties and evaporation tests were conducted on seven types of soil mixtures. The results show that a basic substrate mixture of PVPM3,5,2 has a maximum water capacity of 50%. The modification and addition of diaper gel in DVPM1,3,2 and empty fruit bunch (EFB) in PEFBPM1,0.3,2 show an increment in both mixtures’ water holding capacity (54%). All the proposed mixtures have shown permeability values larger than 0.0005 cm/s. To investigate the maximum water storage availability, the evaporation tests show that both mixtures could provide 60 - 62 mm of water storage after 34 days without rainfall under ambient climatic condition (32 ̊ to 34 ̊) whereas under extreme heat temperatures (50 ̊), both mixtures took only 1 day to provide the same storage as the ambient condition. Therefore, this study has provided an initial understanding of the properties of the substrate mixture as well as the evaporation rate of the materials tested. This information can be used to demonstrate the relationship between soil characteristics and local climatic factors (temperature).

scholarly journals Modeling Green Roof Potential to Mitigate Urban Flooding in a Chinese City

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2082 ◽  
Author(s):  
Li Liu ◽  
Liwei Sun ◽  
Jie Niu ◽  
William J. Riley
Keyword(s):  
Green Roof ◽  
Water System ◽  
Green Roofs ◽  
Subtropical Climate ◽  
Urban Flooding ◽  
Climate Conditions ◽  
Roof System ◽  
Groundwater Levels ◽  
Rain Season ◽  
Peak Runoff

The Middle and Lower Reaches of the Yangtze River (MLRYR) region, which has humid subtropical climate conditions and unique plum rain season, is characterized by a simultaneous high-frequency urban flooding and reduction in groundwater levels. Retrofitting the existing buildings into green roofs is a promising approach to combat urban flooding, especially for a densely developed city. Here, the application potential of the Green Roof System (GRS) and the Improved Green Roof System (IGRS) designed to divert overflowing water from green roofs to recharge groundwater were analyzed in a densely developed city, Nanchang, China. For the first time, the influence of GRS on the hydraulic condition of Combined Sewage System/Storm Water System (CSS/SWS) is analyzed, which is a direct reflection of the effect of GRS on alleviating urban flooding. The simulation results show that GRS can retain about 41–75% of precipitation in a 2-hour timescale and the flooding volumes in the GRS/IGRS region are 82% and 28% less than those of the Traditional Roof System (TRS) in 10- and 100-yr precipitation events, respectively. In the continuous simulations, GRS also enhances Evapotranspiration (ET), which accounts for 39% of annual precipitation, so that reduces the cumulative surface runoff. Considering the IGRS can provide more hydrological benefits than the GRS under the same climate conditions, we may conclude that the widespread implementation of both the GRS and the IGRS in Nanchang and other densely developed cities in the MLRYR region could significantly reduce surface and peak runoff rates.

scholarly journals Plants with Horticultural and Ecological Attributes for Green Roofs in a Cool, Dry Climate

HortScience ◽  
2019 ◽  
Vol 54 (10) ◽  
pp. 1703-1711
Author(s):  
John Erwin ◽  
Jonathan Hensley
Keyword(s):  
Plant Species ◽  
Panicum Virgatum ◽  
Green Roof ◽  
Weather Conditions ◽  
Green Roofs ◽  
Dragon’S Blood ◽  
Ecological Attributes ◽  
Koeleria Macrantha ◽  
Cold Hardy ◽  
Well Data

Green roofs are building surface treatments where plants are grown in medium on a rooftop to cool or insulate buildings and/or to ameliorate negative environmental impacts of buildings. We initiated a 2-year study to characterize medium and weather conditions on a rooftop in a cool-dry climate and to identify plant species with horticultural and ecological attributes that survive and thrive on an unirrigated semi-intensive green roof in a cool-dry climate. Eighty-eight cold-hardy, drought-tolerant species with horticultural or ecological attributes were identified and planted into 12.7-cm-deep medium in trays that were placed on a rooftop. Medium temperatures and moistures were recorded, and plant survival and vigor were quantified. Hourly medium temperatures varied from –22.3 to 43 °C. Monthly medium water moistures varied from –2.5 to –73.3 kPa from May to September, and from –7.6 to –195 kPa from October to April. Monthly air temperature, relative humidity and irradiance varied from –9.4 to 21.7 °C, 44% to 80%, and from 206 to 1222 μmol·m−2·s−1. Mean survival scores decreased (4 = 100% survival) from 2.6 with grasses, to 2.3 with succulents, to 1.8 with temperate perennials, to 0 for geophytes (all died). Among grasses, Festuca ovina VNS, Koeleria macrantha 07-901 ND, Panicum virgatum, and Sporobolus heterolepis performed well. Among succulents, Sedum acre, S. album ‘Coral Carpet’, S. cauticola ‘Sunset Cloud’, S. ‘Czar’s Gold’, S. ellecombianum, S. hybridum ‘Immergruchen’, S. requieni, S. sexangulare, S. spurium ‘Dragon’s Blood’, ‘John Creech’, ‘Pearly Pink’, ‘Ruby Mantle’, and ‘Tricolor’ performed well. Among temperature nonsucculent perennials, Allium ceranum and senescens ‘Glaucum’, Geum triflorum, Talinum calycinum, and Thymus praecox ‘Red Creeping’ performed well. Data on Sedum suggested that medium-low temperature was more limiting to survival than moisture level. The differences in species that performed well here, compared with other studies, underscores the importance of regionally specific green roof plant species studies.

scholarly journals Green Roof Plant Suitability Analysis for Northern Climates

2013 ◽  
Vol 23 (5) ◽  
pp. 563-574 ◽  
Author(s):  
Katherine L. Vinson ◽  
Youbin Zheng
Keyword(s):  
Plant Species ◽  
Green Roof ◽  
Green Roofs ◽  
Plant Production ◽  
Suitability Analysis ◽  
Production Growth ◽  
Diverse Plant Species ◽  
Extensive Green Roofs ◽  
Different Levels ◽  
Diverse Plant

To select plant species and species combinations for northern climates, mats with different plant species and species combinations were constructed on a green roof plant production farm and later transported and installed on an urban rooftop. There were three treatments: two different planting combinations, which together consisted of 10 diverse plant species [both stonecrop (Sedum) species and nonstonecrop species], and a control, which consisted of 26 stonecrop species used for standard mat production. Growth measurements and observations were made at both sites and special attention was paid to the performance of species during the harvest, transportation, and installation stages, as well as during recovery postinstallation. All species but false rock cress (Aubrieta cultorum) were found to be suitable for extensive green roof applications in northern climates, although there were variations of suitability among the species. Good, mediocre, and poor interactions formed between numerous species, displaying different levels of compatibility. Finally, all species were considered appropriate for a mat production system; species that failed to germinate, species planted postinstallation, the frequently displaced rolling hens and chicks (Jovibarba sobolifera), and false rock cress were exceptions. Overall, many species in this study displayed successful, well-rounded growth. Based on results, species and species combinations were recommended for extensive green roofs in northern climates.

scholarly journals The native - exotic plant choice in green roof design: using a multicriteria decision framework to foster urban biodiversity

2022 ◽  
Author(s):  
Ana A. Calvino ◽  
Julia Tavella ◽  
Hernan M. Beccacece ◽  
Elizabet Estallo ◽  
Diego Fabian ◽  
...  
Keyword(s):  
Plant Species ◽  
Green Roof ◽  
Green Roofs ◽  
Exotic Plant ◽  
Beneficial Arthropods ◽  
Decision Framework ◽  
Exotic Plant Species ◽  
Multicriteria Decision ◽  
One Year ◽  
Roof Design

Green roofs are considered key elements of the urban green infrastructure since they offer several environmental benefits, including habitat provision for arthropods. To achieve these benefits and ensure green roof success, an appropriate plant selection is an important step in the design of these infrastructures, especially where green roof technology is emerging like in South American cities. So far, decisions of using native or exotic plant species in green roofs had never been evaluated taking into account the plant potential to foster beneficial arthropods. By applying an integrative multicriteria decision framework that combined the habitat template hypothesis with the potential of plants to attract floral visitors and natural enemies, we obtained a ranked set of candidate native and exotic plant species. Among the best-ranked candidate species, we further compared the performance of six native and six exotic species in 30 experimental green roofs installed in Cordoba city, Argentina. To evaluate plant success, the occurrence and cover of each species were recorded one year after establishment under two management conditions: regular watering and weeding of spontaneous plants, and no management (15 roofs each). All selected species increased their vegetative cover one year after establishment. More interestingly, native plants had an advantage over exotic plant species as they exhibited a significantly higher occurrence and a slightly higher cover with no management than exotics. Native annuals were able to reseed the following season even in the absence of management, thus highlighting the relative importance of lifespan as a useful plant trait for future studies in green roof design. Given that green roofs are one of the possible solutions to ameliorate the negative effects of urban habitat loss on arthropod diversity, the development of an integrative multicriteria decision framework that takes into account the potential of native and exotic plant species for promoting beneficial arthropods would give a new twist in plant selection processes for green roofs.

scholarly journals Increasing Evapotranspiration on Extensive Green Roofs by Changing Substrate Depths, Construction, and Additional Irrigation

Buildings ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 173 ◽  
Author(s):  
Daniel Kaiser ◽  
Manfred Köhler ◽  
Marco Schmidt ◽  
Fiona Wolff
Keyword(s):  
Green Roof ◽  
Green Roofs ◽  
Urban Environments ◽  
Normal Green ◽  
University Of Applied Sciences ◽  
Daily Evapotranspiration ◽  
Urban Heat ◽  
Cooling Effects ◽  
Cool Summer ◽  
The University

Urban environments are characterized by dense development and paved ground with reduced evapotranspiration rates. These areas store sensible and latent heat, providing the base for typical urban heat island effects. Green roof installations are one possible strategy to reintroduce evaporative surfaces into cities. If green roofs are irrigated, they can contribute to urban water management and evapotranspiration can be enhanced. As part of two research projects, lysimeter measurements were used to determine the real evapotranspiration rates on the research roof of the University of Applied Sciences in Neubrandenburg, Germany. In this paper, we address the results from 2017, a humid and cool summer, and 2018, a century summer with the highest temperatures and dryness over a long period of time, measured in Northeast Germany. The lysimeter measurements varied between the normal green roof layer (variation of extensive green roof constructions) and a special construction with an extra retention layer and damming. The results show that the average daily evapotranspiration rates can be enhanced from 3 to 5 L/m2/day under optimized conditions. A second test on a real green roof with irrigation was used to explain the cooling effects of the surface above a café building in Berlin.

Assessing Rainwater Quality Treated via a Green Roof System

2021 ◽  
Author(s):  
Thomas Schatzmayr Welp Sá ◽  
Mohammad K Najjar ◽  
Ahmed W A Hammad ◽  
Elaine Garrido Vazquez ◽  
Assed Naked Haddad
Keyword(s):  
Water Quality ◽  
Experimental Study ◽  
Green Roof ◽  
Green Roofs ◽  
Ammonia Nitrogen ◽  
Rain Event ◽  
Water Crisis ◽  
Roof System ◽  
Rainwater Quality

Abstract The shortage of water worldwide is increasingly worrying. Studies in the field suggest that sustainable water resource management via water recycling is fundamental to alleviate the issue. The use of rainwater is an important alternative source that must be considered, mainly, in the water crisis facing the planet. When integrated with the concept of green roofs, the capturing and treatment of rainwater in these structures becomes an even more ecological and sustainable practice. The water drained by the roof can be used for non-potable uses, such as flushing toilet bowls. One of the main concerns when using rainwater, even for non-potable uses, is the quality of the water available, so as not to put users' health at risk. In this way, the present work proposes to experimentally analyze the quality of rainwater drained in a green roof prototype for reuse purposes. The green roof prototype was installed on an experimental bench. After each rain event (four in total), two water samples were collected in the following situations: rainwater captured directly by a container next to the bench, and rainwater drained by the green roof prototype, captured by a container through existing drains at the base of the prototype. The analyzes of the collected samples were carried out at the Environmental Engineering Laboratory (LEMA / UFRJ) and performed according to the Standard Methods for the Examination of Water and Wastewater. Specifically, the experiments examine physicochemical and biological parameters following a rain event on a green roof prototype for sanitary use. Experimental results that were observed and analyzed include color, turbidity, pH, ammonia nitrogen, nitrite, nitrate, orthophosphate, total coliforms, and thermotolerant coliforms to indicate the rainwater quality from green roofs. The majority of parameters assessed were within the value thresholds indicated by the Brazilian standards, while the results of orthophosphate, fecal coliforms, color, and turbidity were not. The greatest divergence is in the concentration of orthophosphate, where a concentration of 10.88mg/L was obtained in this experimental study while other authors present values ​​of 0.1 and 0.01mg/L. Total coliforms also presented high values, but within the expected range. Comparisons with technical documents and international references related to water quality to identify possibilities of the use of rainwater were also conducted. Results indicate that the water quality has the same order of quantity for turbidity, nitrite, and ammonia nitrogen parameters across the standards. Based on such observations, filtration and disinfection processes are therefore required in the green roof system for the use of rainwater for sanitary. Finally, the experimental study of rainwater quality on the green roof presented similar results comparing with international references. The use of green roofs combined with the use of rainwater demonstrates the potential and benefits as an alternative to face the water crisis.

Innovative green roof with high water retention and durability

2019 ◽  
Author(s):  
Thomas Cornelius Buch-Hanser ◽  
Guangli Du ◽  
David John Duffus
Keyword(s):  
Water Retention ◽  
Green Roof ◽  
Water Reservoir ◽  
Green Roofs ◽  
High Water ◽  
Water Retention Capacity ◽  
Storm Events ◽  
Concrete Element ◽  
Retention Capacity ◽  
Roof System

<p>Given the rapid increase in urban populations, combined with the effects of climate change, cities are struggling to provide green spaces to address liveability as well as adaptability to new challenges. Water retention and bio-diversity are the main advantages of green roofs. There are, however, limitations to green roofs that impede their acceptance and proliferation. There is for example uncertainty on how much water they retain during major storm events. In terms of building technology, green roofs today aren’t robust, and the risk for leakage through the roof membrane is disproportionally high when compared to the cost. A newly developed innovative green roof system with high water retention capacity and high durability will be presented. The patented prefabricated technology incorporate insulation and membrane into a single concrete element, ensuring improved robustness, quickened building times and a long term durable product. Initial indications for pricing indicate that the system is price-neutral when compared with green roofs as they are built today. The optimized structural performance obtain same loadbearing capacity, as existing systems, in spite of the relatively increased space created for water reservoir, without compromising the insulation capacity, hence the new green roof system further contribute to increased sustainability.</p>

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