Effects Of Urban Green Spaces Research Articles

Fitting a Structural Equation Model to Community-Based Data to Explain the Mechanism Driving the Effects of Urban Green Spaces on Human Health

A theoretical meta-model was recently proposed to explain the mechanism driving the effects of Urban Green Space (UGS) on human health (Zhang et al. 2017: Journal of Urban Ecology, 1–13). On one hand, this meta-model suggests an indirect effect of UGS Provision (measured as quantity, quality or accessibility of UGS) through UGS Exposure (measured as visit frequency to UGS, duration of visit or intensity of activities taking place during the visit). On the other hand, UGS Provision may have an indirect effect on Exposure mediated by people’s perception of UGS, and UGS Exposure may influence also indirectly human Health but mediated by human motivation to use UGS. We tested these different expectations by fitting 12 structural equation models (SEMs) to data collected on these variables through semi-structured interviews. These 12 SEMs correspond to four different scenarios depending on how Provision was approximated. We found that any of the 12 SEMs can be used to explain the relationships between UGS and health condition (for all 12 SEMs, P>0.05). The SEMs analysis further show that only model 2 (where Provision is approximated as UGS quantity, and Exposure as duration), model 3 (where Provision is approximated as again quantity, and Exposure as intensity) and model 12 (where Provision is approximated as distance of the closest UGS from people’s house, and Exposure as intensity) are equally the best of all 12 models tested [Δ(models2,3,12) < 3]. However, apart from model 2 that has no significant path, models 3 and 12 have the same significant path (motivation ~ intensity; β=7.86±2.03, P=0.0002), suggesting that people who visit UGS may be motivated by opportunities of physical activities offered by UGS. When looking at scenario per scenario, this significant path still remains the same except for scenario 2 where the significant path is motivation ~ quality (β=-2.47±0.82, P=0.003), suggesting that the quality of UGS may also be an important motivation for a visit to UGS. In all scenarios, the best model is always the model where Exposure is measured as intensity irrespective of how provision is approximated. This suggests that it is not only UGS provision that matters most, but rather intensity, i.e. the type of activities people engage in when they visit UGSs. Overall, this study supports the theoretical meta-model tested, and we call for more questionnaire-based data collections at different scales to further clarify the mechanism driving UGS-health relationship in different contexts.

Multi-city comparison of the relationships between spatial pattern and cooling effect of urban green spaces in four major Asian cities

Studies on the role of urban green spaces (UGS) in mitigating the urban heat island (UHI) effect demonstrate the influence of two related, but distinct attributes of UGS: the composition (amount), and configuration (spatial attributes and distribution) of UGS patches. While the positive role of UGS amount in providing cooling effect seems unequivocal, it is still not possible to develop a consensus on the role of UGS configuration from the small number of studies that have been conducted to-date. The latter observation could be due to different methodologies, such as choice of landscape metrics and statistical methods used in different studies, as well as differences in urban form of cities. This study addresses the current knowledge gap by using a same set of methodologies applied to four cities of different urban forms: Singapore and Hong Kong as compact cities, and Jakarta, Kuala Lumpur as sprawling cities. Landsat imageries were used to derive land cover and land surface temperature (LST) maps. Different statistical and spatial analysis techniques were also used. We report several novel findings from this study: (1) only four metrics of percentage of landscape (PLAND), area-weighted mean shape index (SHAPE_AM), patch density (PD), and mean Euclidean nearest neighbor distance (ENN_MN) were adequate to explain UGS pattern-LST relationships in all four cities; (2) the relative importance of composition versus configuration of UGS in determining LST seems to be a function of the existing UGS pattern: what the average per unit area of the city is like in terms of patch size (area-weighted mean patch size (AREA_AM)), shape complexity (SHAPE_AM), and distribution (skewness and kurtosis) of patches; and (3) decision tree classifier is a novel and effective method to unravel hidden patterns in complex UGS pattern-LST relationships. Our results also provide insights on UGS management in cities for higher cooling effects. Greening priorities may differ among cities. In cities where configuration is not a determinant of LST (e.g. Kuala Lumpur and Hong Kong), greening may focus on providing conditions necessary for configuration to influence LST and adding greenery, and where configuration already affects LST (e.g. Jakarta and Singapore), the focus may be placed on optimization of UGS by providing larger, simpler in shape, more aggregated and connected, and less fragmented UGS patches.

The influence of the spatial characteristics of urban green space on the urban heat island effect in Suzhou Industrial Park

Urban green spaces can mitigate urban warming problems to some extent. However, the cooling effect of plants differs spatially and temporally, and with plant features. To understand how plants affect urban surface and air temperature, 15 urban green spaces in Suzhou Industrial Park were selected to study the diurnal variation of summer air temperature. At the same time, the mitigation effect of different types of green spaces on the urban heat island (UHI) effect was investigated and further research was undertaken on the effect of green space area, perimeter area ratio, green space average canopy density, average leaf area index (LAI), and other factors influencing the cooling effect. Based on these studies, three representative parks were selected as samples to investigate the cooling effect of urban green space in terms of the water and wind environment. It was found that in the summer, large green spaces had a stable cooling and humidifying effect, while small green spaces had the opposite effect. The cooling and humidifying effect of large green spaces was more obvious and stable, and the cooling effect of small green spaces was more variable, with a heat preservation phenomenon occurring in some cases. The cooling effect of each green area was positively correlated with the green area, the average LAI of green space, and the average canopy density of green space. The cooling effect of each green area was significantly negatively correlated with the green area perimeter. Water bodies within green spaces did not contribute to cooling; however, the cooling effect was related to the wind environment. From the perspective of the planning and construction of city green spaces it is important to increase the green area and the reasonable planning green perimeter area ratio; however, suitable tree species should be selected in the greening process. The effect of urban greening in improving the urban ecological environment has been established. It was concluded that the cooling effects of such green areas are largely determined by plant type, canopy density, and park shapes. Therefore, it is suggested that a stronger emphasis is placed on the selection of plant species and the design of park shapes to achieve environmental cooling effects.

Effects of urban green spaces on residents’ well-being

Beijing is undergoing continuous urbanization, and considering the individual availability of urban green spaces is essential for alleviating the ecological problems created by this urbanization, especially in relation to improving residents’ well-being. To prove this effect, this article analyzed the social, mental, and physical well-being of current Beijing residents to determine their level of satisfaction, then applied the seemingly unrelated regression model to study how Beijing’s urban green spaces impact this well-being. The result showed that the higher the degree of resident participation with green spaces, the higher their well-being. Such participation includes actions like the frequency at which residents visit a park or green space. A significant inverted U-shaped effect was found between residents’ well-being and their distance from a park or public green space, indicating that residents with the highest well-being live between 1 and 5 km away, and residents with the lowest well-being live over 10 km away. Further, age, education, career status, marital status, years of residence in Beijing, residential area, and average income per month also have a significant impact on residents’ well-being. This study shows that green spaces can have a very positive effect on people’s welfare and provides support for their further promotion.

Study of the Cooling Effects of Urban Green Space in Harbin in Terms of Reducing the Heat Island Effect

The urban heat island (UHI) effect might cause extreme weather, which would seriously affect people’s health, increase energy consumption and cause other negative impacts. To construct urban green spaces is a feasible strategy to effectively weaken the UHI effect. In this study, the cooling effect of green spaces on the UHI effect was carefully investigated in summer and winter in Harbin city. Specifically, the vegetation index and surface temperature information were extracted by the grid method, and based on this data, the relationship between the urban green space and the UHI effect was analyzed quantitatively. In summer, the cooling effect is more significant. The average cooling extent reached 1.65 °C, the average maximum temperature change was 7.5 °C, and the cooling range was mainly 120 m. The cooling effect can be improved by adjusting the green space area, perimeter and shape. Increasing the green area (within 37 ha) or the green circumference (within 5300 m) can most economically improve its cooling effect. The shape factor would significantly affect the cooling effect within 0.03. The simpler the green space shape, the more obvious the cooling effect. In contrast, in winter the green spaces had a certain cooling effect when there was no snow cover or little snow cover, although this was still less significant compared with the situation in summer. The average cooling extent reached 0.48 °C, the average maximum temperature change was 4.25 °C, and the cooling range was mainly 90 m. However, there is no correlation between urban green space and the UHI effect in areas mainly covered by ice and snow. This work could provide protocols for urban green space design to effectively control the UHI effect of sub-frigid cities.

A Study on Daegu City Citizen’s Consciousness about Urban Green Space for Heat Wave Mitigation

Daegu City has the most number of heat waves every year in the last 10 years among 7 metropolitan cities in Korea. As the slang, such as ‘Daefrica(Daegu + Africa)’ shown, Daegu City is recognized as a high temperature region in the summer. The purpose of this study is to understand the perception of urban green space as a mediator for heat wave mitigation for Daegu citizens. First, about 93.3% of the respondents perceived what the heat was. The most frequent cause of the increase in the number of heat waves was the increase in energy use (34.9%), ‘indiscriminate development’ (24.9%), ‘automobile and traffic increase’ (17.9%), ‘greenery reduction’ (12.6% ) were the most common cause. Second, 87.1% of respondents had positive perception about the mitigation effect on the effect of urban green space as a medium to mitigate the heat. In addition, 26.7% of respondents answered that they are very effective in mitigating the effect of the heat of urban greenery, and 95.1% of them responded more than ‘normal’. Third, as a result of examining the priorities of short and long-term heat-related policies, the short term was the highest (37.5%) in responding to ‘electricity tariff realization’ because of the high dependence on air conditioners. In contrast to the short-term perspective, the long-term policy for mitigating the heat wave was overwhelmingly supported by ‘expansion of urban green areas’ (50.7%). This is a result of confirming Daegu citizens’ consciousness which is highly evaluating the effect of urban green space as a medium for mitigating the heat. Fourth, the importance and performance of ‘urban green space type’ for mitigation of the heat wave were examined. The type of urban green space belonging to the phenomena maintenance area (quadrant Ⅰ), which both had high importance and performance, was classified as ‘neighborhood park’. In addition, it was surveyed as ‘Ssamji(mini) Park’ as the type of urban greenery in the concentrated improvement area (quadrant Ⅱ) where the importance is high but the performance is low. We believe that the value of urban green areas for mitigating the heat waves has been fully recognized through the recognition of Daegu citizens. We hope that the results of this study will be used as basic data for future Daegu city heat and urban greening policy.

Subjective perception of noise exposure in relation to urban green space availability

Noise pollution has been recognized as one of major threats to the health of urban residents. Increasing green space availability can create a natural buffer to the adverse effects of living in an urban environment. These positive effects of urban green space can be directly related to an objective reduction of noise levels and – indirectly – to the subjective perception of noise exposure. In our study carried out in Lodz, Poland, we explored the relationship between objective noise levels and the subjective perception of noise exposure by urban residents in relation to urban green space availability. We refer to objective noise exposure expressed as GIS modelled Lden derived from noise maps (compliant with the Environmental Noise Directive, 2002/49/EC), and subjective (self-reported) perception of noise exposure as declared in a questionnaire-based survey. We compared the percentage of green space in a buffer, the objectively measured noise level, and the perceived exposure to noise to find the most appropriate radius of the green space buffer. We decided to choose the green space coverage which is not correlated with an objective noise level to avoid potential multicollinearity in regression models. This contrasts with most studies, in which the radius of the buffer is set a priori. We thus compared the selected buffer of green space coverage – 300 m (representing green space availability) – with perceived noise exposure. We used the spatial error probit model to differentiate the impacts of objective and subjective noise indicators, at the same time including also the factor of green space availability. We found out that the direct effect of objectively measured noise levels, education, the presence of noisy neighbours, and building characteristics were the most important variables influencing the self-reported perception of noise by urban residents. The indirect effect of green space availability on noise perception was not strong, yet statistically significant. Although our study does not provide clear-cut evidence, it indicates that the indirect, psychological effects of urban green spaces can positively affect the life satisfaction of urban residents.

Natural Outdoors Environments and Obesity: The Multicase-Control Study in Spain (MCC-Spain)

Background/Aim: Overweight and obesity are associated with increased risk of coronary heart disease, stroke, respiratory disease, cancer and all cause mortality. The association between green spaces and reduced risk of overweight/obesity has been previously studied, but results are not consistent. We studied the association between surrounding greenness and residential proximity to green areas and overweight/obesity in Spain. Methods: 8112 study participants between 20-85 years old were recruited between 2008-13 from 23 hospitals in 12 provinces of Spain, as part of the multi-case control Spain study (MCC-Spain). We geocoded the current residence of each participant, and assigned different indicators of exposure to natural outdoor environments: access to urban green areas according to Urban Atlas; access to agricultural areas according to CORINE Land Cover 2006 and surrounding greenness according to the average of the Normalized Difference Vegetation Index. We used multinomial logistic mixed-effects models with a random effect for hospital and adjusted for potential confounders. We also explored the potential modifier effect of individual socio-economic status, degree of urbanization and sex. Results : Access to urban green areas seemed to slightly reduce the risk of overweight/obesity after adjusting for age, sex, case-control status, education, socioeconomic status at individual and area level and degree of urbanization of place of residence [overweight: RRR (95%CI)=0.93 (0.79 – 1.09), obesity: IRR(95%CI)=0.89 (0.73-1.08)]. The protective effect of urban green spaces was more pronounced in densely populated areas. On the contrary, access to agricultural areas seemed to increase the risk [overweight: adjusted RRR (95%CI)=1.13 (0.97-1.32), obesity: adjusted IRR(95%CI)= 1.08 (0.9-1.3)]. No effect was observed for surrounding greenness [overweight: adjusted RRR (95%CI)= 0.97 (0.91-1.04), obesity: adjusted IRR(95%CI)= 0.97 (0.89-1.05)]. Conclusions: No clear association was observed between access to green spaces and overweight/obesity. The suggested effects however, were depended on land-use.

Experimental studies on the effects of green space and evapotranspiration on urban heat island in a subtropical megacity in China

Urbanization is one of the most important driving forces of global change. With the quick expansion of the urban environment's size and population, its urban heat island intensity (UHII, expressed as the temperature difference between urban and rural areas) has rapidly increased. The situation is even worse in megacities, whose populations are greater than 10 million. However, very few studies quantitatively reveal the effects of green space and land use/land cover (LULC) on the urban thermal environment because they lack detailed measurements. This study focuses on quantifying the effects of green space on the urban heat island (UHI) in Shenzhen, a subtropical megacity in China. Extensive measurements (air temperature and humidity) were taken using a mobile traverse method in an 8 km long transect, where a variety of LULC types were included. Measurements were conducted at 2-h intervals for 2 years (repeated a total of 7011 times). The relationship between evapotranspiration (ET) and UHII was also studied based on measured data, to understand the mechanism of the cooling effect of vegetation. The main conclusions obtained are as follows: (1) There are obvious differences in the air temperature and UHII among different urban landscapes. The ranking of temperatures from highest to lowest is commercial area > urban village > urban water body > urban green space > suburb. The difference in the UHII is also obvious, especially from 20:00 PM to 06:00 AM, when the UHII is usually greater than 2 °C. (2) Green space and water bodies in the urban environment have obvious effects on reducing the air temperature through evapotranspiration. The cooling effect of urban green spaces is better than that of urban water bodies. Compared to commercial areas, urban water bodies can relieve the UHII up to 0.9 °C, whereas urban green spaces can relieve the UHII up to 1.57 °C. (3) There are obvious linear relationships between air temperature, UHII, and green space in nighttime. Air temperature and the UHII decrease linearly with an increase in urban green space. The correlation is relatively weak in daytime, when the cooling effect of vegetation might be offset by other factors in urban thermal environment. (4) Obvious correlation between ET and UHII was observed and a good positive linear relationship between ET and the decreasing rate of UHII (UHII′) was obtained, revealing that the faster ET is, the better UHII mitigating efficiency could be gained. An ET rate of 6.12 mm d−1 could cause a 0.12 °C per hour decrease in UHII under our experimental condition. These results indicate that an increase in urban green space's ET could be a useful way to improve the urban thermal environment and mitigate the UHI.

Quantifying the cool island effects of urban green spaces using remote sensing Data

Urban Heat Island (UHI) leads to increased energy consumption, aggravated pollution and threatened health of citizens. Urban green spaces mitigate UHI effects, however, it is still unclear how the green space characteristics and its surrounding environment affects the green space cool island (GCI). In this study, land surface temperature (LST) and land cover types within the outmost ring road of Shanghai, China were obtained from Landsat 8 data and high-resolution Google Earth data. The GCI effects were defined in three aspects: GCI range (GR), amplitude of temperature drop (TA) and temperature gradient (TG). Pearson correlation analysis was processed to get the relationship between the aspects and impact factors. The results indicated that the GCI principle could be explained by the thermal conduct theory. The efficient methods to decrease LST of green spaces include increasing green space area while staying below the threshold, adding complexity of green space shape, decreasing impervious surfaces and enlarging the area of water bodies. For the surrounding environment of the green spaces, increasing vegetation and water body fractions or decreasing impervious surfaces will help to strengthen GCI effects. The findings can help urban planners to understand GCI formation and design cool green spaces to mitigate UHI effects.

The Effect of Urban Green Spaces on the Urban Thermal Environment and Its Seasonal Variations

Urban green spaces have been shown to decrease land surface temperature (LST) significantly. However, few studies have explored the relationships between urban green spaces and LST across different seasons at different spatial scales. In this study, using Changchun, China as a case study, landscape ecology and comparative approaches were employed quantitatively to investigate the effects of the composition and configuration of urban green spaces on the urban thermal environments. LST maps were retrieved from Landsat 8 Thermal Infrared Sensor (TIRS) data acquired on four dates that represented four different seasons, and detailed information of urban green spaces was extracted from high resolution imagery GF-1. Normalized differential vegetation index (NDVI) and six landscape metrics at patch, class, and landscape level were used to characterize the spatial patterns of urban green spaces. The results showed that urban green spaces did have significant cooling effects in all seasons, except for winter, but the effects varied considerably across the different seasons and green types, and seemed to depend on the NDVI and size of urban green spaces. Compared to shape metrics, the negative relationships between the LST and the area and the NDVI of urban green spaces were more significant. Both the composition and configuration of urban green spaces can affect the distribution of LST. Based on findings with one city, given a fixed area of urban green spaces, the number of green patches can positively or negatively affect the LST, depending on if the number is larger than a threshold or not, and the threshold varies according to the given area. These findings provide new perspectives, and further research is also suggested, to generate a better understanding of how urban green spaces affect the urban thermal environment.

A review on the urban green space cooling effect based on field measurement of air temperature

With the development of urbanization, the effect of urban heat island has become increasingly evident. As an essential component of the urban natural landscapes, urban green space plays an important role in mitigating the effect of urban heat island. However, facing the rapid urbanization and changing environment, how to rationally plan and design the green space and realize its best cooling effect which can improve the urban environment and microclimate is still an urgent problem to be solved. So there is a strong need for mulitiscale researches on the cooling effect of urban green space. This paper systematically gave a review on the cooling effect of urban green space based on field measurement of air temperature, the main factors that influenced the cooling effect of green space were explored from three aspects including the area and shape characteristics of urban green space, the structure characteristics of vegetation and the external factors which affected the cooling effect, and the characteristics of the cooling effect of the green space were summarized from the aspect of time variation and distance decay. Then, the main problems and future research prospects of urban green space cooling effect were put forward.

Predicted models for potential canopy rainfall interception capacity of landscape trees in Shanghai, China

This study aimed to build urban green space with environmental functions (e.g., canopy interception of rainfall) and adjust hydrographic balance to some extent for forecasting the potential canopy rainfall interception capacity of landscape trees and the effects on rainfall distribution. The effects of urban green space on interception and runoff reduction have been conceptualized, but not quantified. Therefore, the leaf area index and the water storage abilities of 17 kinds of landscape trees in common use were measured, at Shanghai, and canopy rainfall interception capacity was calculated using the interception formula. The predicted rainfall interception capacity models were established choosing tree morphological characteristics (diameter at the breast height, height, and crown width) as variables. The model test showed that the errors of 12 models were less than 5% between the predicted and the measured data and the errors of four models were within 5 and 10%, with the error for only one model being between 10 and 11%. Also, the study indicated that conifer trees were able to hold more rainfall compared with broad-leaved trees per unit area (k). The results showed that these models could effectively predict the potential capacity of canopy rainfall interception for landscape trees in Shanghai area and were beneficial for species selection in constructing plant communities, aiming to improve the rainfall interception capacity of urban green space.

Heat mitigation by greening the cities, a review study

In the past decades, many studies have proposed urban greening as a method to mitigate the rising temperatures in cities and urban heat islands. The cooling effect of urban green spaces can be divided into two components; cooling intensity and cooling extension. These two components are affected by different factors. This paper provides a review of research on the impact of urban greening on temperature and on the parameters that have an effect on that. Based on this review, two categories that have an effect on cooling intensity and cooling extension were identified: internal factors and external factors. These play an important role in the effectiveness of urban green spaces. As internal factors or indexes, the following were extracted; Size index, Shape index, Vegetation species and Tree canopy coverage are the most common indexes in most of the studies. The external factors can be divided into climate and surrounding properties. A discussion of the reviewed studies reflects the impact of each index on the cooling intensity and cooling extension. The existing methods and techniques for determining these indexes have also been considered in this paper. As such, this study is helpful for designers and planners for decision-making during the design phase.

The urban forest and ecosystem services

The urban forest and ecosystem services

Effect of Urban Green Spaces and Flooded Area Type on Flooding Probability

Countermeasures to urban flooding should consider long-term perspectives, because climate change impacts are unpredictable and complex. Urban green spaces have emerged as a potential option to reduce urban flood risks, and their effectiveness has been highlighted in notable urban water management studies. In this study, flooded areas in Seoul, Korea, were divided into four flooded area types by cluster analysis based on topographic and physical characteristics and verified using discriminant analysis. After division by flooded area type, logistic regression analysis was performed to determine how the flooding probability changes with variations in green space area. Type 1 included regions where flooding occurred in a drainage basin that had a flood risk management infrastructure (FRMI). In Type 2, the slope was steep; the TWI (Topographic Wetness Index) was relatively low; and soil drainage was favorable. Type 3 represented the gentlest sloping areas, and these were associated with the highest TWI values. In addition, these areas had the worst soil drainage. Type 4 had moderate slopes, imperfect soil drainage and lower than average TWI values. We found that green spaces exerted a considerable influence on urban flooding probabilities in Seoul, and flooding probabilities could be reduced by over 50% depending on the green space area and the locations where green spaces were introduced. Increasing the area of green spaces was the most effective method of decreasing flooding probability in Type 3 areas. In Type 2 areas, the maximum hourly precipitation affected the flooding probability significantly, and the flooding probability in these areas was high despite the extensive green space area. These findings can contribute towards establishing guidelines for urban spatial planning to respond to urban flooding.

Effect of urban green space changes on the role of rainwater runoff reduction in Beijing, China

The effects of urban green spaces on stormwater runoff have increasingly attracted attention because of climate change and rapid urbanization conditions. This study investigates the spatial–temporal changes of urban green spaces in Beijing and estimates their effects on rainwater runoff reduction based on an empirical model. Results indicate that green spaces in Beijing decreased by 199km2 from 2000 to 2010 and that landscape patches became increasingly isolated and fragmented. The volume of rainwater runoff controlled by urban green spaces first increased and then decreased with the increase in summer rainfall. The runoff reduction rate continuously decreased from 23% in 2000 to 17% in 2010, which is mainly attributed to the composition changes in urban green spaces. In addition, an immense regional difference that is closely related to the changes in the largest patch and aggregation indices of urban green spaces are observed in different regions. This study recommends an optimal landscape pattern of urban green spaces for the planning and management of green spaces in highly urbanized areas.

Associations between green space and health in English cities: an ecological, cross-sectional study.

Green space has been identified as a modifiable feature of the urban environment and associations with physiological and psychological health have been reported at the local level. This study aims to assess whether these associations between health and green space are transferable to a larger scale, with English cities as the unit of analysis. We used an ecological, cross-sectional study design. We classified satellite-based land cover data to quantify green space coverage for the 50 largest cities in England. We assessed associations between city green space coverage with risk of death from all causes, cardiovascular disease, lung cancer and suicide between 2002 and 2009 using Poisson regression with random effect. After adjustment for age, income deprivation and air pollution, we found that at the city level the risk of death from all causes and a priori selected causes, for men and women, did not significantly differ between the greenest and least green cities. These findings suggest that the local health effects of urban green space observed at the neighbourhood level in some studies do not transfer to the city level. Further work is needed to establish how urban residents interact with local green space, in order to ascertain the most relevant measures of green space.

The effect of green spaces on cities with health and efficiency approach

Abstract. Being in modern space and increasing population and urbanization growth have turned the cities into the center of living gatherings and various activities and they are encountered with the shortage of public green spaces. By transition from modernity space and being in postmodern world and nostalgic sense in these spaces, the need of citizens to spend leisure time is increased and returning to green spaces in modern cities has caused that it has great social, mental and cultural effects on urban dwellers in these spaces. This study is based on descriptive-analytical method and besides explaining the importance of green space in current modern cities and the analysis of social, cultural and mental effects of development of these spaces; some recommendations and solutions are presented to improve urban management performance regarding the improvement of social, cultural and mental effects of urban green spaces in metropolises. The suitability of design of open space in various dimensions and its consistency with cultural, social, natural features and living conditions as the result of coordinated performance of various layers of city by affecting the behaviors of residents can make the neighbors comfortable and create intimate and good townships. The findings of the study are: Green spaces in cities above ecologic return have good effects in most of social and psychological fields but these spaces in case of weak urban management performance can provide some unsuitable functions. Urban green spaces and urban management affect each other as urban green space has no suitable function without active and sustainable urban management.

The cooling effect of urban green spaces as a contribution to energy-saving and emission-reduction: A case study in Beijing, China

Urban green spaces have been proven to significantly decrease ambient air temperature and mitigate heat islands created by urbanization. However, the environmental benefits of cooling provided by urban green spaces have rarely been measured. In this paper, we estimated the energy-savings and emission-reduction contribution of urban green spaces in Beijing, applying a empirical model. Our calculations suggest urban green spaces play a major role in reducing energy demand and increasing CO2 sequestration. Urbanized Beijing has 16,577 ha of green space which could absorb 3.33 × 1012 kJ of heat via evapotranspiration during the entire summer. The cooling effect reduced the air conditioning demand by 3.09 × 108 kWh which amounts to a 60% reduction in net cooling energy usage in Beijing. The annual reduction in CO2 emissions from power plants associated with electricity saving would reach 243 thousand tons with an average of 61 kg/(ha day). Also, the cooling effect and the environmental benefits of urban green space in Beijing largely depend on the green space's structure and size. Urban managers and landscape planners should take advantage of this research to plan, design and manage green spaces in heat island areas.