GIS-Based Analysis to Identify the Distribution and Accessibility of Urban Green Space in Dhaka Metropolitan City, Bangladesh

Urban Green Space (UGS) plays an important role in minimizing the negative effects of urbanization on city dwellers, which is predominantly factored into the accessibility to UGS. This study elucidated the distribution and accessibility of UGS in Dhaka, Bangladesh considering the paucity of such important scientific studies in the given area. The methodological structure of this study employed a multispectral Landsat satellite image from 2020 for identifying the logically defined UGSs, as well as a minimum proxy distance being the parameter to estimate accessibility to the UGS through a primary survey scheme and literature review. Considering UGS as a public area, we adopted a hybrid (combination of supervised and unsupervised classification) method followed by post-classification for UGS distribution assessment. The unsupervised classification identified the overall distribution of green spaces, whereas the anomalies of generated classes were rectified during the post-classification. Following the study findings, UGS in Dhaka metropolitan city accounts for only 602 ha or 1.9% of the total geographical space, with Ramna thana ranked as the highest contributor of 111 ha. However, in terms of accessibility to the UGS by city residents, 19.9% of the buildings in Dhaka metropolitan city were computed to be within the determined proxy distance of 500 m around the UGS. Also, parallel to UGS distribution, green space in Ramna thana (111 ha) exhibited the highest accessibility rate (64%) to the UGS compared with other thanas in Dhaka metropolitan city. The baseline findings will contribute to the long-term sustainable urban planning and development of more accessible green spaces in the study area.

Factors influencing the concentration of negative air ions during the year in forests and urban green spaces of the Dapeng Peninsula in Shenzhen, China

Negative air ions(NAIs)benefit the mental and physical health of humans,but rapid urbanization can decrease the abundance of NAIs.Quantifying the spatial and seasonal distribution of NAIs and determining the factors that infl uence the concentration during urbanization is thus essential.In the present study of a typical developing urban district in southern China,negative air ion concentrations(NAICs)in 60 forests sites and 30 urban green spaces were quantifi ed on seven consecutive days in each of the four seasons.Large seasonal variations in NAIC were revealed in forests and urban green spaces with trough values in summer.NAIC progressively decreased from forests to urban green spaces and was infl uenced by local land morphology,vegetation characteristics,and climatic factors.The vast,heavily vegetated northeastern region was the richest area for NAIs,whereas the narrow central region(urbanized area)was the poorest,implying dramatic impacts of urbanization on the spatial distribution of NAIs.The relationship between air temperature and NAIC was better fi tted with a quadratic equation than a linear equation.Moreover,the NAIC was more sensitive to local morphology in urban green spaces than in urban forests,indicating the vulnerability of NAIs in urbanized areas.Therefore,the appropriate design of local urban morphology is critical.

Construction of Ecological Network for Urban Green Space System from the Perspective of Landscape Ecology:A Case Study of Wanzhou District, Chongqing Municipality

Green spaces in Wanzhou District, Chongqing Municipality were not closely linked and failed to form an integrated ecological network, this paper analyzed and assessed current situation of green spaces in the local area from the perspective of landscape ecology, and then established the landscape ecology-oriented ecological network construction, restructured green paces in Wanzhou District using the landscape composition of "patch–corridor–matrix", and connected the scattered green patches using green corridors, so as to form a reasonable ecological network of green spaces.

Pattern Change of Urban Green Space in Beijing from 2000 to 2010

With the rapid urbanization in Beijing, the vegetated surfaces have been increasingly replaced by impervious built surfaces. A clear recognition on the changes in green spaces pattern is vital for urban administrators and planners to optimize the urban development areas and define the ecological protection red lines. Based on the SPOT images and field investigation data of urban green spaces within the sixth ring road of Beijing in 2000, 2005 and 2010, the study investigated the dynamic changes of urban green spaces in this area, by means of GIS techniques and landscape ecology methods. The results indicated that green spaces in Beijing have decreased by 207 km2 from 2000 to 2010 at the expense of agricultural lands and waters. Although there has been some increases in urban forests and grasslands, it cannot compensate the rapid decrease of urban green spaces. The land cover types conversion occurred mainly in the areas between the fifth and sixth ring roads while the zones encircled by the fourth ring road had a little change. In addition, landscape metrics such as number of patches(NP) and shape index(SHAPE) increased, but the mean nearest-neighbor distance(MNN), aggregation index(AI) and patch cohesion index(COHESION) decreased during the period of 2000-2010. Also green landscapes became considerably isolated and fragmented. The study disclosed the obvious changes of green space size, composition and layout in urban districts of Beijing City from 2000 to 2010, and highlighted that construction of urban green space should consider not only the geometric or aesthetic effect, but also the increase of vertical green volume and optimization of spatial layout to fully develop the ecological service functions of green spaces.

Application of Drought-resistant Varieties in Urban Green Spaces

As the connotations of urban green spaces and urban eco-green spaces have been more realized,drought-resistant green spaces have become a unique development trend,and drought-resistant flowers have been more applied in green spaces.This paper summarized characteristics of drought-resistant flowers,foreign and domestic researches in this field,advantages and disadvantages of their application in urban green spaces,and proposed key directions of the future researches.

How Multi-Sensory Perception Plays a Landscape Restorative Role in Adelaide's Urban Green Space

Urban green space is an effective psychological restoration landscape site.However,Adelaide's urban green space tends to focus on visual design but neglect non-visual senses.Sensory influence is interactive and has profound and subtle effects on tourists.The purpose of this study was to investigate the relationship between auditory,tactile,and psychological restoration ofxirban green space from a multi-sensory perspective.This study used quantitative research methods to investigate auditory and tactile-related landscape factors that have a positive effect on restoration.It is expected that this study will contribute to the high-quality restoration of urban green space and promote human health.

Analysis of problems in urban green space system planning in China

这篇论文在在中国在一般、特殊的计划层次计划的城市的绿空间系统(UGSS ) 讨论主要问题。在一般计划水平， UGSS 的问题主要从在城市的性质空格的特征和城市的计划系统的限制因素的无知。大重要性在包围城市的区域在城市，而是绿空格的造的区域被纳入绿空格是不被注意的。而且，因为 UGSS 计划的区域被行政 zoning 严格地限制，绿空格系统在空间模式失去它的完整和合理性。城市的开发计划的时间表错配生态的恢复周期的步和进步。在特殊计划水平，在中国的 UGSS 的问题是空格数量是完了的绿色强调了，但是他们的布局的合理性被忽视……同时，空间结构的要求和到在城市的发展和自然生态的环境之间的平衡的绿空格布局经常被忽略。关于在计划惯例的 UGSS 的布局，存在问题是妥协到存在陆地使用，布局模式的计划绿空格的‘ f illing in' 途径和一个过分的强调。

Spatial dynamics of aboveground carbon stock in urban green space:a case study of Xi'an,China

Greenhouse gas emission of carbon dioxide(CO2) is one of the major factors causing global climate change.Urban green space plays a key role in regulating the global carbon cycle and reducing atmospheric CO2.Quantifying the carbon stock,distribution and change of urban green space is vital to understanding the role of urban green space in the urban environment.Remote sensing is a valuable and effective tool for monitoring and estimating aboveground carbon(AGC) stock in large areas.In the present study,different remotely-sensed vegetation indices(VIs) were used to develop a regression equation between VI and AGC stock of urban green space,and the best fit model was then used to estimate the AGC stock of urban green space within the beltways of Xi'an city for the years 2004 and 2010.A map of changes in the spatial distribution patterns of AGC stock was plotted and the possible causes of these changes were analyzed.Results showed that Normalized Difference Vegetation Index(NDVI) correlated moderately well with AGC stock in urban green space.The Difference Vegetation Index(DVI),Ratio Vegetation Index(RVI),Soil Adjusted Vegetation Index(SAVI),Modified Soil Adjusted Vegetation Index(MSAVI) and Renormalized Difference Vegetative Index(RDVI) were lower correlation coefficients than NDVI.The AGC stock in the urban green space of Xi'an in 2004 and 2010 was 73,843 and 126,621 t,respectively,with an average annual growth of 8,796 t and an average annual growth rate of 11.9%.The carbon densities in 2004 and 2010 were 1.62 and 2.77 t/hm2,respectively.Precipitation was not an important factor to influence the changes of AGC stock in the urban green space of Xi'an.Policy orientation,major ecological greening projects such as "transplanting big trees into the city" and the World Horticultural Exposition were found to have an important impact on changes in the spatiotemporal patterns of AGC stock.

SPATIAL GRADIENT ANALYSIS OF URBAN GREEN SPACES COMBINED WITH LANDSCAPE METRICS IN JINAN CITY OF CHINA

Urban green spaces have been arisen growing concern responded to the social and environmental costs of urban sprawl. A wide range of planning and policies has been and/or will be designed to protect urban green spaces and optimize their spatial pattern. A better design or planning of urban green space can make a major contribution to quality of environment and urban life, and furthermore can decide whether we can have a sustainable development in the urban area. Information about the status quo of urban green spaces can help planners design more effectively. However, how to quantify and capture such information will be the essential question we face. In this paper, to quantify the urban green space, a new method comprising gradient analysis, landscape metrics and GIS was developed through a case of Jinan City. The results demonstrate: 1) the gradient analysis is a valid and reliable instrument to quantify the urban green space spatial pattern precisely; 2) using moving window, explicit landscape metrics were spatially realized. Compared with quantifying metrics in the entire landscape, it would be better to link pattern with process and establish an important basis for analyzing the ecological and socioeconomic functions of green spaces.

An Assessment of Ecosystem Services of Urban Green Spaces Based on i-Tree

Ecosystem services of urban green spaces play an important role in the sustainable development of the urban ecosystem. How to quantify the ecological benefits of urban green spaces and evaluate their ecological services is a hot topic in related fields. Currently, with the advancement of science and technology, the assessment method has been developed from the traditional ones such as the Council of Tree and Landscape Appraisers(CTLA) method, afforestation cost method, and carbon tax method to CITYgreen and i-Tree. The latter two models have been widely used in countries of Europe and America, while the use of i-Tree has not been promoted in China. In this paper, i-Tree Eco(UFORE) was selected for research, and its application in the assessment of the ecosystem services of urban green spaces, including energy saving, air quality improvement, interception of rainwater, and aesthetic benefits, were analyzed. This study aims to provide a theoretical and scientific basis for the introduction and localization of i-Tree, as well as its generalization in the assessment of forest ecosystem services domestically.

Urban Green Spaces and an Integrative Approach to Sustainable Environment

This paper explains the benefits and challenges of urban green spaces based on the critical discussion of study results from different studies in different cities. The important roles played by green spaces are social, economic, cultural and environmental aspects of sustainable development. Urban green spaces can be a comprehensive tool for long term protection of environmental sustainability through improving the quality of life and air quality, increasing property value due to their amenity and aesthetic characteristics, and reducing the energy costs of cooling buildings. Urban green spaces also can provide ecosystem services in which the recreation and relaxation facilities are especially available to urban dwellers and tourists too. To confirm the multiple roles played by green spaces, certain level of qualitative improvements and distribution of green spaces within the urban area should be considered and incorporated effectively into the environmental sustainability agenda. To do this, an integrated approach regarding the planning, monitoring, designing and maintaining of urban green spaces is required for improving the environmental sustainability in cities in different countries.

Evaluation method of the ecological benefits of urban green spaces and application conditions

The importance of ecological benefit analyses about green space systems has been widely discussed on the basis of a per-ceived bias towards the landscaping effect of green spaces to be built in urban areas as opposed to the perception of comprehensive ecological benefits of designed plant communities. Given the basic principle of ecological benefit analyses and evaluation methods widely applied today, the methodology to calculate ecological benefits and to model the expansion of urban green spaces by CITY-green 5.0 and its conditions for application were explored. We propose that aerial images can be substituted by AutoCAD graphics of a green space containing detailed information of plant dispositions by digitizing the key features during the working process in order to evaluate the ecological benefits quickly and to offer proper guidance to the establishment of small scale green spaces in urban areas. The theoretical foundation, potential application range and prospects for extension of the method are introduced by using the analysis of ecological benefits of the green spaces on the campus of Southwest Forestry College, Kunming, as an example.

Geo-Spatial Approach for Urban Green Space and Environmental Quality Assessment: A Case Study in Addis Ababa City

Depending on the rapid growth in infrastructural developments along with the increasing of human population, quality of cities is being deteriorated globally. Assurance of environmental quality is essential for urban planning and developments. This paper presents the potential application of urban green areas as an indicator of urban environmental quality in Addis Ababa, Ethiopia based on indicators of natural parameters extracted from remotely sensed images, and socio-economic variables derived from census data. Physical environmental variables such as land-use/land-cover data, surface temperature, normalized difference vegetation index, and transformed remote sensing variables derived from three landsat images of 1986, 2000 and 2015 were analyzed for the present study. Socio-economic variables including population density and greenhouse gas emission in 2012 were used. Regression analysis, factor analysis and overlay analysis were performed after the two groups of variables were integrated. Four factors such as greenness, crowd, heat island and greenhouse gas emission were used for interpretation. By assigning different weights to each of these factors and proportion of green areas, land-use/land-cover map, environmental risk map and environmental quality index map were generated. The results show deterioration of environmental quality in the study area. It is recommended that future studies should include more parameters to provide a holistic view of the changes in greenness of the city and to try to mitigate adverse effects of development activities leading to human density and depletion of green area in the city.

Application of Vertical Greening as a New Model of Expanding Urban Green Spaces

Vertical greening is a new pattern of expanding urban green spaces. Based on the concept of vertical greening, several approaches and available patterns were introduced for the vertical greening of urban spaces. Moreover, the mostly-applied vertical greening plants in China and their value were given to provide a new thought for urban greening.

Renovation of Urban Green Space Based on Regeneration of Historical Place——A Case Study of Jianqiao Historical Block in Hangzhou

The protected historical blocks always fail to undertake some necessary functions of modern cities because they inherit texture and skyline of historical spaces,and also traditional building density,so these blocks lack in popularity and fall into rigid display of folk customs.In view of the contradiction between protection and vitality,this study proposes the concept of"intergrowth between underground space and urban block"on the basis of theoretic researches and construction practices,aims at renovating urban public green spaces by following the principle of regeneration of place,so as to improve and make up modern urban functions of historical blocks,stimulate vitality of the community,provide an effective solution to the development of new cities and renovation of old cities.

Changing Roles of Traditional Small Urban Green Spaces (<i>Telajakan</i>) in Bali, Indonesia

Bali Island, Indonesia is undergoing rapid land use changes due to heavy development pressure and its fast growing urban population. One such urbanization phenomenon is the shrinkage, deterioration, and disappearance of traditional small urban green spaces in Denpasar, Bali. Focusing on telajakan, a strip of traditional green space between the wall of a housing compound and a ditch/pedestrian path in a roadside, the study aims 1) to investigate and document the changes that are occurring with regards to telajakan and 2) to assess the functions (roles) of telajakan in Denpasar. The research methods include vegetation assessment at a lot scale and in-depth homeowner and village leader interviews with the help of local experts. The results show that telajakan space is often paved over to give way to more front space for the property owner and to ease maintenance. It is also minimized or destroyed as the owner builds a more “western” style house. Traditionally telajakan has multiple functions such as provision of plant and flower materials for Balinese daily rituals, regu-lation of stormwater from the property, and offering semi-public space for street vendors and neighbours. However, the results show that: diversity of planted species is decreasing;only a couple of functions such as aesthetics and economics are strongly favored;and the semi-public nature of telajakan is being lost. Since telajakan is as much traditional green open space as part of the aesthetics of the Balinese architecture, its loss, minimization, and degradation lead to the loss of Balinese culture and identity. On the other hand, new meaning is given to telajakan’s functions such as neighborhood beautification and exhibition of the owner’s pride in the modern context. Therefore, policy recommendations to conserve telajakan in the changing urban fabric need to balance these changing needs of telajakan for its use and conservation of traditional rituals and culture of Bali.

Degradation of Urban Green Spaces in Lagos, Nigeria: Evidence from Satellite and Demographic Data

The study aimed to assess the potential of using Remote Sensing (RS) da-ta to evaluate the changes of urban green spaces in Lagos, Nigeria. Land-sat Thematic Mapper and Landsat 8 (Operational Land Imager) data pair of May 4, 1986, December 12, 2002 and January 1, 2019 covering Lagos Government Authority (LGA) were used for this study. Supervised image classification technique using Maximum Likelihood Classifier (MLC) was used to create base map which was then used for ground truthing. Ran-dom Forest (RF) classification technique using RF classifier was utilized in this study to generate the final land use land cover map. RF is an en-semble learning method for classification that operates by constructing a multitude of decision trees at training time and outputting the class that is the mode of the classes (classification). Lagos census population data was also used in this study to model population projection. Extrapolation of the model was used to predict data for the years, 2020 and 2040. Re-sults of the study revealed a reduction of urban green spaces due to agri-culture and settlement. While the remote mapping revealed the gradual dispersion of ecosystem degradation indicators spread across the state, there exists clusters of areas vulnerable to environmental hazards across Lagos. To mitigate these risks, the paper offered recommendations rang-ing from the need for effective policy to green planning education for city managers, developers and risk assessment. These measures will go a long way in helping sustainability and management of land resources in Lagos.

On Approach of Quantifying Economic Benefits of Urban Green Space:A Case Study of Wuxi City

Urban green space has its important social, economic and ecological benefits. Quantifying of those benefits helps healthy development of urban green space. The essay discusses approach of quantifying direct economic benefits of land utilizing and construction derivated from urban green space system itself through the optimization of space structure and ecological function. It is the affirmation and promotion of the achievements of urban greening industry.

Ecological Planning and Design of Urban Green Space System of Sanya City

The construction of International Tourism Island has accelerated the development of Sanya City. The population aggregation and the external extension of urban area have brought a lot of negative effects, such as discontinuities of green space matrix, dysfunction of green wedge permeation, deficiency of eco-corridor, structural imbalance of green space system and so on. The overall layout of Green space system known as "One Belt & Three Bays, One Core & Six Towns, Two Axes & Three Wedges, Two Net Synchronous-construction" strengthens the eco-connection among different groups and green space in central area of the city, and realizes the collaborative construction of both resource corridor and landscape corridor. The eco-layout of green core, green corridor and green patch helps keep the integrity of large vegetation patches, enhances the eco-connection of different types of green space and improves finger-shaped network of urban green space. The most efficient way to promote the circulation of urban ecosystem and the positive development of Sanya City is to plan multilevel and three-dimensional eco-space structure and maximize ecological benefits of green space system.

Spatial patterns of urban green space and its actual utilization status in China based on big data analysis

Urban green space(UGS)is essential for sustainable urbanization and human well-being.The utilization status of UGS is closely related to the provision of ecosystem services for urban residents.Limitations on data availability,however,have led to the absence of a comprehensive approach for evaluating the actual utilization status of UGS at a large scale.Furthermore,differences in actual UGS utilization between intra-urban and peri-urban areas have not received enough attention.This study used big data analysis by combining point of interest(POI)and land use and cover change(LUCC)to quantify the spatial patterns of UGS utilization,and to evaluate the actual utilization status of UGS in 366 cities on the Chinese mainland.We also explored the differences in the actual utilization of UGS in intra-urban and peri-urban areas.The results showed that 94.01%of UGS resources in China had not been utilized.There was a clear pattern of spatial mismatch between the stock and the actual utilization of UGS,especially in the north-western region indicated by the Hu Huanyong Line.The actual utilization rate of UGS was closely related to the regional develop-ment level.There was a certain mismatch between the actual utilization and stock of intraurban green space(IUGS).The hot spots of the actual utilization rate of IUGS were in Yunnan,Guizhou,and Sichuan Provinces in southwestern China.The differ-ences in UGS actual utilization rates between IUGS and peri-urban green space(PUGS)were small in eastern China,but large in south-western and northwestern China.The actual utilization rate of IUGS in most Chinese cities was significantly larger than that of PUGS,indicating that PUGS were not well utilized.Our results provide scientific support for urban and regional planners in targeting specific areas for UGS design and development,and in optimizing future UGS planning in China.