Green roofs are implemented to reduce the urban heat island effect; however, studies are limited to comparing the reduction in urban heat island effect before and after implementation, and the focus is on the structural stability of the building rather than urban heat island reduction. In this study, using the sky view factor (SVF) in ENVI-met, a 3D microclimate modeling program, urban spaces were classified as closed, semi-open, and open areas. Meanwhile, the green roof types were subdivided according to the vegetation coverage rates, which included grass, shrubs, and trees. The vegetation ratio was evaluated using ENVI-met to determine which of the 10 scenarios was most effective for each urban space. The thermal environment was most comfortable in semi-open areas. Therefore, the green roof scenario with 70% grass and 30% trees was effective in closed areas, 50% shrubs and 50% trees were best in semi-open areas, and 70% grass with 30% trees, or 30% grass and 70% trees, was best in open areas. This study provides a basis for creating green roof guidelines aimed at improving the urban thermal environment, as well as creating other green infrastructure elements in cities.

Recent health threats from fine particles of PM_2.5 have been warned by various health organisations including the World Health Organisation (WHO) and other international governmental agencies. Due to the recognised threats of such particulate materials within urban areas, counter measures against PM_2.5 have been largely explored; however, the methods in the context of planting types and structures have been neglected. Therefore, this study investigated and analysed the concentration levels of PM_2.5 in roads, planting areas, and residential zones within urban areas. Moreover, the study attempted to identify any meaningful factors influencing the reduction of PM_2.5 and their efficiencies. After surveying PM_2.5 in winter and spring season, there were serious reductions of PM_2.5 concentrations within the areas of pedestrian paths, planting, and residential areas compared to other urban areas. In particular, a significant low level of PM_2.5 concentrations was shown in the residential areas located behind planting bands as green buffer. This research also found that three-dimensional volumes and quantity of planting rows play a critical role in reducing PM_2.5. A negative correlation was shown between the fluctuated concentration rate of PM_2.5 and quantity of planting rows—single row of trees showed fluctuated concentration rate of PM_2.5, 84.77%, followed by double rows of trees 79.49%, and triple rows of trees 75.02%. Especially, trees need to be planted at certain distance to allow wind to diffuse fine particles rather than dense planting. Finally, planting shrubs also significantly reduces the concentration level of PM_2.5—the fluctuated concentration rate of the single layer showed 88.79%, while the double layer and the multi-layer showed 81.16% and 68.93%, respectively—since it increases three-dimensional volume of urban plantings.

Over the last decades, a number of bio-retention facilities have been installed in urban areas for flood control and green amenity purposes. As urban amenity facilities for citizens, bio-retentions have a lot potential; however, the literature on bio-retentions focused mostly on physiochemical aspects like water quality and runoffs. Hence, this paper aims to explore psychological aspects of bio-retentions such as perceptions and landscape aesthetic value for visitors. In order to achieve this purpose, the study employed on-site interviews and questionnaires in the chosen three case studies as research methodology. For the 3 different locations of bio-retention facilities, interviews and questionnaires were carried out. The surveys of 100 bio-retention users were conducted, investigating their general perceptions and landscape aesthetics of the bio-retention facilities. The paper found that only 34% of the interviewees recognised bio-detention facilities, illustrating that most visitors were not aware of such facilities and were unable to distinguish the differences between bio-retention and conventional gardens. On the other hand, the majority of interviewees strongly supported the concept and function of bio-retentions, especially those who recognised the differences in planting species with conventional urban open spaces. Such main findings also encourage further studies of seeking quantitative values by conducting a correlation analysis between the functions and aesthetics of bio-retention facilities.

The relationships between land cover characteristics in riparian areas and the biological integrity of rivers and streams are critical in riparian area management decision-making. This study aims to evaluate such relationships using the Trophic Diatom Index (TDI), Benthic Macroinvertebrate Index (BMI), Fish Assessment Index (FAI), and random forest regression, which can capture nonlinear and complex relationships with limited training datasets. Our results indicate that the proportions of land cover types in riparian areas, including urban, agricultural, and forested areas, have greater impacts on the biological communities in streams than those offered by land cover spatial patterns. The proportion of forests in riparian areas has the greatest influence on the biological integrity of streams. Partial dependence plots indicate that the biological integrity of streams gradually improves until the proportion of riparian forest areas reach about 60%; it rapidly decreases until riparian urban areas reach 25%, and declines significantly when the riparian agricultural area ranges from 20% to 40%. Overall, this study highlights the importance of riparian forests in the planning, restoration, and management of streams, and suggests that partial dependence plots may serve to provide insightful quantitative criteria for defining specific objectives that managers and decision-makers can use to improve stream conditions.

Advances in 3D printing technology are giving rise to attempts to utilize the technology in various fields, including landscape design. However, exploring the potential of 3D printing technology has been largely neglected in the context of landscape design and education. Therefore, this study aimed to examine the implication of 3D printing technology for both education and practice in landscape design. We analyzed the literature and examined the current state of 3D printing technology. We also conducted case studies with secondary school students and landscape practitioners to assess the implementation of the technology. Secondary school students demonstrated positive responses, such as increased interest and participation and improvement of understanding, through workshops using 3D-printed models. The semi-structured interviews with landscape practitioners on the implication of the technology confirmed the limitations of 3D printing in terms of cost, delivery time, scale, and level of detail.

It is imperative to develop a methodology to identify river impairment sources, particularly the relative impact of socioeconomic sources, to enhance the efficiency of various river restoration schemes and policies and to have an internal diagnosis system in place. This study, therefore, aims to identify and analyze the relative importance of the socioeconomic factors affecting river ecosystem impairment in South Korea. To achieve this goal, we applied the Analytical Hierarchy Process (AHP) to evaluate expert judgement of the relative importance of different socioeconomic factors influencing river ecosystem impairment. Based on a list of socioeconomic factors influencing stream health, an AHP questionnaire was prepared and administered to experts in aquatic ecology. Our analysis reveals that secondary industries form the most significant source of stream ecosystem impairment. Moreover, the most critical socioeconomic factors affecting stream impairment are direct inflow pollution, policy implementation, and industrial wastewater. The results also suggest that the AHP is a rapid and robust approach to assessing the relative importance of different socioeconomic factors that affect river ecosystem health. The results can be used to assist decision makers in focusing on actions to improve river ecosystem health.