Lawn Garden Research Articles

Archaea rather than bacteria govern green roofs greenhouse gas production

Urban air quality can be improved through a variety of strategies, one of which is to increase the amount of urban vegetation. In cities where there is insufficient ground space for increased vegetation, roof space can be utilised to establish green roofs that help to mitigate harmful gas content in air. This study uses the closed static chamber method to determine the scale of greenhouse gas (GHG) fluxes from three green roof types: Sedum mat roofs (three sites), lightweight clay aggregate (LECA)-based roofs (four sites), and Gramineae sod roofs (six sites). GHG fluxes from these sites were also compared with those from a flat roof lawn garden and a natural control area. Our results highlight the importance of soil-based archaea in affecting all GHGs from green roofs. Mat and LECA roofs had similar carbon dioxide (CO2) fluxes, but CO2 flux from sod roofs was strongly affected by substrate composition. Furthermore, CO2 flux had a similar seasonal variation across all study sites, with the lowest fluxes in May and September, and the highest fluxes in June, July and August. The main process involving methane (CH4) on green roofs was oxidation, with sod roofs having stronger oxidation levels than either mat or LECA roofs. This was further confirmed by microbial data on methanogens and methanotrophs. There was no significant nitrous oxide (N2O) flux from any of the study sites. According to the results, we conclude that non-fertilised green roofs are not significant sources of GHGs and will rather help to mitigate GHG levels in urban areas, like Gramineae-based roofs may be used effectively for CH4 consumption.

岩崎小彌太邸から国際文化会館への変遷を通した建築と庭園の関係性に関する研究

The International House of Japan was established in 1952 for the purpose of promoting international exchange and mutual understanding. The present location of the house used to be the residence and garden of Koyata Iwasaki, the fourth president of the Mitsubishi Zaibatsu, which resided from 1930 to 1945. The residence was destroyed in the war destruction in 1945 and was replaced by the International House of Japan ten years after. The purpose of this study is to achieve clarity of the spacial structures of Iwasaki residence and the current International House of Japan. The study was taken place by, first of all, searching for scattered records, and analyzing the documents in the periodical order. Secondly, the present state of the garden was cleared up by surveying the placements of plants and rocks. Finally, the spacial characters of the Iwasaki residence and the International House of Japan were compared to clarify the changes that took place in the transformation phase. As a result of this analysis, the spacial features the Iwasaki residence became clear ; it carried a courtyard, a tea room, a fall and a running water, with the architecture and garden intricately entwining. Meanwhile the International House of Japan which inherited the garden from the Iwasaki residence took a different approach in dealing with the garden ; the architecture kept some distance away and placed a vast lawn garden in between. Rooftop garden were also installed to be correlated with the garden while meeting the modern architecture style.

明治期東京の近代邸宅空間における洋風庭園の様式と空間

In the last several years, an explosion of papers argue about Japanese modern landscape, there are design of residential gardens, policies of park and landscape of resort and so on. This paper clarifies the formation period of semi-western gardens in Tokyo during the Meiji period and its spatial characteristics, particularly Shiba-niwa (lawn garden), by analyzing the trends in western house construction and relationship between building layout and garden design within premises. The result leads to the following hypothesis. The formation period of Shiba-niwa style overlaps with the period of western building construction boom around the mid-Meiji period (1882 - 1902). The concept of Shiba-niwa was to integrate the juxtaposed arrangement of Japanese and western buildings, typical building layout in modern residential spaces, into coherent landscapes with simple combination of spacious lawns and gently meandering paths, that is a remarkable characteristic reflecting the modernization of traditional garden design.

旧岩崎邸庭園（１９００年頃〜１９４５年）の構成と意匠

Tokyo Metropolitan garden of Kyu-Iwasaki-tei garden (former Iwasaki’s residence in Taito Ward, Tokyo), constructed by Hisaya Iwasaki the third president of Mitsubishi Group, is today known as one of finest examples of gardens of Meiji period. This paper examines the initial spatial composition of the garden during Hisaya’s ownership (1885-1945) and the original design of Shiba-niwa (lawn garden), which has been a decisive characteristic of the garden, under a restorative approach based on interview to Hisaya’s bereaved family, examination of existing drawings and old photographs, and comparative study with the other Meiji gardens. The examination clarifies that the garden was chiefly comprised of four areas; the lawn garden, the Shoin (Japanese style house) garden, the approach and rotary, and the flower garden. Particularly, this study notices significant characteristics of the lawn garden that deserve to title this garden a standard model of Meiji gardens in Tokyo. The result also indicates that the site itself formerly formed Japanese and Western landscape axes, corresponding to the coupling of Japanese and European style houses.

Study on evaporative cooling effect of roof lawn gardens

In a very hot climate equivalent to a Japanese summer, the reduction of heat coming into rooms is very important with respect to thermal comfort and energy efficiency. The objective of this study is to investigate the evaporative cooling effect from roof lawn gardens planted in non-woven fabric as one mode of passive cooling. It was confirmed by field measurements during the summer that the amount of heat coming into the rooms was reduced by a roof lawn garden. That is, the surface temperature of the roof slab decreased from about 60 to 30°C during day time, which was estimated to be followed by a 50% reduction in heat flux into the room by simple calculation. The evaporative cooling effect from roof lawn gardens is considered to play an important role in reducing heat flux. In order to evaluate the evaporative cooling effect of a roof lawn garden, analysis of the heat and moisture transport in the lawn garden is required. Thus, along with those field measurement, a wind tunnel experiment in a room was carried out in order to obtain the basic information for understanding and predicting the heat and moisture transport in the lawn. Furthermore, a numerical calculation by a simultaneous transport model of heat and moisture was carried out using the results of the wind tunnel experiment. The calculated results were in fairly good agreement with the measured values, and the evaporative cooling effect by the roof lawn garden was shown. For more accurate and quantitative evaluation and prediction, sensitivity analysis of the transport parameters and the examination of the proposed model including measurements are required.