Urban Ecology
mahsa samadpour shahrak; Mehrdad Karimimoshaver
Abstract
Highlights- The research considered the effect of planting patterns on thermal comfort.- The research addressed population increase and its effect on the morphology of cities.- The results of comparison between the scenario without trees and the others demonstrate that the thermal comfort conditions ...
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Highlights- The research considered the effect of planting patterns on thermal comfort.- The research addressed population increase and its effect on the morphology of cities.- The results of comparison between the scenario without trees and the others demonstrate that the thermal comfort conditions exhibit great changes, and all the scenarios create better environmental conditions than the scenario without trees.- The findings show that simply moving vegetation and trees without changing their nature and dimensions and the environment can improve comfort to some extent. IntroductionThe increasing population has changed the morphology of cities and caused changes in the surrounding environmental conditions. Green space per capita is about 4.5 square meters in Iran, which is quite different from the global standard: 20 to 25 square meters per person (Haashemi et al., 2016). As a result, it seems necessary to increase the amount of greenery in cities. Lee et al. (2016) introduce shading and ventilation as the main factors in the improvement of thermal comfort conditions in the environment using trees. Vegetation reduces mean radiant temperature and improves environmental conditions through evaporation and daylight control and reflection (Salata et al., 2017). It plays a major role in the regulation of weather conditions by controlling and conducting wind flow and reducing wind speed and pressure (Perini et al., 2018).Theoretical FrameworkThermal comfort involves conditions of perception in which the surrounding environment is thermally satisfactory (Ashrae, 1997). In their review of the studies conducted in the field of thermal comfort in outdoor spaces, Johnson et al. have introduced the predicted survey average index as one of the most widely used indices among ones such as SET and UTCI. (Johansson et al., 2013). This index has been widely used in different regions with different climates (El-Bardisy et al., 2016; Salata et al., 2015; Abdi et al., 2020).This model was designed by Fanger in 1970, considering factors such as air temperature, average radiant temperature, and relative humidity and two personal variables including clothing resistance and activity level, used as a composite index. This index specifies the coefficients that are measured according to Asher’s thermal scale and indicates the average thermal sensation of a large group of people in a certain space (Fanger, 1970). Therefore, considering and measuring this index causes other microclimatic factors to be taken into account and obtained through the following formulae:PMV=(0.303e-0.036m+0.028)[(M-W)-H-Ec-crec-Erec]E=3.05×10-3(256tsk-3373-pa)+EswEc=3.05×10-3[6.99×5733(M-W)-pa]+0.42(M-W-58.15)Crec=0.0014M(34-Ta)Erec=1.72×10-5M(5867-Pa).The value of H can be measured directly and calculated using the following equation:H=Kcl=tsk-tcl/Icl.Moreover, previous research has pointed out the importance of planting patterns, trees, and vegetation and their impact on the environmental and microclimatic conditions of the region. The question that arises now is what kind of tree planting pattern, among the common ones, can have a better impact on the environment. In this study, therefore, the four common planting patterns of sextuple, quadruple, row, and scattered were selected to be applied in the same conditions and with the same number of trees.MethodologyIn this research, the ENVI-met software was used because the output provides most of the parameters required for thermal comfort, such as Ta, Tmrt, and wind speed (Taleghani et al., 2015), and the results have been validated and used by researchers (Taleghani et al., 2018). For data measurement, five receptors were selected at the central points of the site. These receptors were located so as to be scattered in the site and be capable of expressing the general state thereof. Therefore, three receptors at the central points of the site and two located around the site were selected. Moreover, because the average human height between the positions of sitting and standing is 1.50 meters, the simulation measurement was carried out at this height. The environmental data and information on the receptors were extracted during the study hours (10 am to 9 pm), and the average value was calculated for the predicted survey average index.Results and DiscussionThe analysis of the data and figures extracted from the software demonstrates that a more uniform shade is created in the environment in the scattered pattern than in the others, and because the trees are scattered in most parts of the site, solar access is more limited there than in the other scenarios. Moreover, ventilation conditions are easier in the row pattern than in the scattered pattern, and the warm wind passes through the trees more easily there due to the regular arrangement. Therefore, the best planting pattern is the one that creates the more uniform shade and better ventilation conditions. However, the results of the scattered pattern are the same in most parts of the site, and there is only a little difference between them in some cases. As a result, the scattered and row patterns of tree planting are better than mass planting and concentrated in certain parts of the site.ConclusionThe results of comparing the treeless scenario to the others demonstrate that the thermal comfort conditions change to a large extent, and all scenarios create better environmental conditions than the treeless state. Moreover, because the row pattern exhibits a lower average PMV for most receptors and most hours of the day, it is the best pattern. The sextuple pattern has high indices in most cases, and the quadruple pattern has a similar function to the sextuple one. Therefore, it can be concluded that the row and scattered patterns create better comfort conditions than the others. The results of this research can be used by architects, landscape designers, and urban designers. In this research, different patterns of trees have been compared, so future research can involve comparison of other plantings such as grass and shrubs and of the effects of different planting patterns.
Urban Architecture
mehrdad shahbazi; mansour yeganeh; M Bamanian
Abstract
Open spaces play a vital role in enhancement of the quality of any environment or space. Human biological conditions can be improved through an increase in the quality of space, which can be achieved when individuals’ everyday psychological needs as well as the functional, environmental, and aesthetic ...
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Open spaces play a vital role in enhancement of the quality of any environment or space. Human biological conditions can be improved through an increase in the quality of space, which can be achieved when individuals’ everyday psychological needs as well as the functional, environmental, and aesthetic aspects are considered. Therefore, environmental vitality can be regarded as an integral part of a desirable architecture that seeks to convey a sense of vitality to the audience. The present paper sought to explore the theoretical domain of the research conducted in the area of vitality through meta-analysis of environmental vitality factors. The research population consisted of forty articles (twenty domestic and twenty foreign papers) published during the 2008-2018 period. The data were collected from the articles based on the Prisma protocol, which had been adapted by experts. A systematic review method was used for data collection, meta-analysis was employed for data analysis, along with the funnel, linear regression, distribution error, and heterogeneity Q test methods, and the data extracted from the review were evaluated using CMA2. Linear regression and multivariate regression were then used to investigate the relationship between every two independent variables and their relationship with the dependent variable, environmental vitality. The findings of the study were addressed from two aspects. From the structural analysis aspect, the general characteristics of the articles were studied in terms of vitality. From the content analysis aspect, the most important assumptions of meta-analysis (the homogeneity of the studies and consistency among them) were examined. The findings of the research demonstrated that there were positive, direct relationships between the effects of the independent variables on vitality and between vitality and the independent variables. This means that vitality increases as the independent variables rise. The theoretical foundations of the field have not yet reached the depth and breadth required for research, which needs greater organization. The research topics, theoretical frameworks, and theoretical achievements should be subjected to methodological revision to gain scientific accuracy, which is also dependent on research, including studies that involve meta-analysis. The best efforts to conduct such research should reduce the drawbacks. Some of the weaknesses in previous studies can be noted on that basis. More than half of the research performed in the field (60%) was evaluated as based on moderate and weak theoretical foundations. This could be accounted for in terms of the failure to utilize up-to-date, firsthand resources, to provide high levels of consistency, and to adapt the structures of the materials presented in the theoretical foundations to meet the main purposes of the papers. This could be attributed to the weakness of the theoretical foundations of the research. A total of 49 variables were extracted after the theoretical foundations were examined and analyzed. Furthermore, the variables of safety and security exhibited the greatest impacts on environmental vitality, and social participation and social interaction were found to be the most effective. Conversely, building shape exhibited the least effect on environmental vitality, and the effects of the other variables were found to be almost constant. Thus, the above design recommendations and planning criteria can lead to high quality in an urban open space in terms of communication, vitality, diversity, and appearance.
Urban Design
Farhang Mozaffar; Ali Asadpour
Volume 1, Issue 3 , August 2012, , Pages 3-12
Abstract
Social patterns in open space organizations have a key role in shaping most of 20th urban theories. This paper identifies the formal and social patterns in planning the residential open spaces in famous theories and projects of urbanization during 20th century and compares them with experiences of Iranian ...
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Social patterns in open space organizations have a key role in shaping most of 20th urban theories. This paper identifies the formal and social patterns in planning the residential open spaces in famous theories and projects of urbanization during 20th century and compares them with experiences of Iranian urban organizations in an analytic manner from the past to present. Historical – interpretative method established in this research was combined with case studies. From the formal viewpoint in the early 20th century theories, 4 categories of open space organizations could be identified: "grid organization", "linear", "central" and "complex" patterns, which have been tended towards complex patterns during the second half of the century. Moreover, try to remove social hierarchy, providing class equality and common ownership of open spaces seen in the first half of the century has been replaced by social stability, social equality and simultaneous attention to both public and private open spaces. However, the modern construction in country is almost the continuation of the early century proven strategies that mainly use the central and grid patterns and lack of certain social patterns in their designs. Hence, considering current world conditions and national experiences and achievements and belief principles, it is suggested to pay attention to the social concepts like social capital social interaction along with suitable patterns of open space organization (for example, complex) while particular separating and dividing public-private fields and measuring public priorities.
