Analysis situation of urban green space framework in Tehran

Introduction. In recent years, the development of cities and the increase in urban population has upset the balance of urban ecology in Iran. The destruction of agricultural fields and natural areas, as well as changes in the function of urban green spaces have caused environmental problems. Therefore, the main purpose of this study is to investigate the distribution of green space in Tehran with an environmental sustainability approach. Materials and methods. The research method is applied in terms of purpose and descriptive-analytical in terms of method. Basic information has been obtained through library studies and Tehran Municipality and using GIS, mathematical and statistical methods such as entropy coefficient, Concentration level method, Lorenz curve, Location quotient (L.Q) method, Distribution quotient (D.Q) method distribution of Tehran green space function were analyzed. Results. The results show the unbalanced and inappropriate spatial distribution of green space and the critical environmental situation in the 22 districts of Tehran. According to the entropy coefficient model, district 18 is the most unbalanced distribution and in contrast, district 2 has the most balanced distribution. The results of the concentration level method based on the value of C obtained for each of the districts showed that districts 4 and 1 with the level of 2.141 and 2.103 have the highest concentration level and other districts have much less concentration level than these districts. The Lorenz curve also indicates that the distribution of urban green spaces in 22 districts of Tehran is different from the uniform distribution, and in some districts, it is higher than the uniform distribution and, in some districts, it is lower, which indicates an unbalanced distribution between the districts. Location quotient (L.Q) method and distribution quotient (D.Q) method also showed that the concentration and density of green space use in different districts of Tehran was inappropriate and unbalanced. Conclusions. This research show that according to the 8 million population in Tehran, its per capita green space is 16.27 square meters and its distribution is unbalanced in 22 districts. Also districts 1 and 22 with a per capita of 33.85 and 58.67 square meters and having 204 and 77 green spaces in the suitable situation and districts 10 and 11 districts with a per capita of 2.58 and 4.96 and having 51 and 30 green spaces are in the unsuitable situation. And according to the statistical methods used, the green space of the districts has an unbalanced spatial distribution. In the 1990s and 2000s, there was a greater tendency for construction in the northern districts and about 45 % of the city’s gardens were destroyed during these years, and most of the destruction occurred in the northern districts.