بررسی و ارزیابی تغییرات شاخص های تمرکزگرائی جمعیت شهری طی برنامه های اول تا پنجم توسعه ایران (1394- 1368) (مقاله علمی وزارت علوم)
درجه علمی: نشریه علمی (وزارت علوم)
آرشیو
چکیده
هدف این مقاله مطالعه سطح و روند تحولات شاخص های تمرکزگرائی جمعیت با توجه به اهداف سیاست های تعادل منطقه ای و شهری طی برنامه های اول تا پنجم توسعه ایران (1394-1368) است. روش تحقیق روندپژوهی جمعیتی و منبع داده ها سرشماری های کشور است. نتایج نشان می دهد که علی رغم تصریح اهداف توازن و تعادل توسعه منطقه ای و شهری در تمامی برنامه های توسعه اول تا پنجم جمعیت در تمامی سطوح ملی، کالبدی، استانی و شهری همواره به سوی مراکز گرایش داشته است. دو نوع تمرکزگرائی جمعیت تشخیص داده شد، یکی تمرکزگرائی سطح ملی با محوریت البرز جنوبی که همواره مستمر، عام و فراگیر بوده است و به عنوان نقطه ثقل اسکان جمعیت در سطح ملی عمل کرده است، دوم تمرکزگرائی منطقه ای که جریانی ضعیف تر، موقعیتی و غیر فراگیر بوده است که به عنوان مراکز ثقل منطقه ای سکناگزینی جمعیت عمل کرده است. طی دوره زمانی برنامه اول و پنجم توسعه میزان نخست شهری در کشور روبه کاهش نهاده، اما در مقابل شهرهای طبقه دوم جمعیتی (250 -100 هزار)، دارای بالاترین رشدهای جمعیتی و تمامی شهرهای طبقات متوسط جمعیتی (99999-10000) دارای رشد منفی جمعیتی بوده اند. به طورکلی، نتایج نشان می دهد عدم تعادل منطقه ای و شهری در کشور تا حدود کمی تعدیل شده و مراکز ثقل تمرکزگرائی جمعیت شهری ازنخست شهرها به شهرهای مرتبه دوم تغییر نموده است، ولی همچنان رشد جمعیت شهرهای متوسط زیر 100 هزار نفر منفی است؛ لذا می توان گفت توزیع فضائی جمعیت منطقه ای و شهری از وضعیت ساختار پیرامون به مرکز شدید به ساختار پیرامون به نیمه پیرامون در حال تغییر است.Examining Shifts in Spatial Population Concentration Indices across Iran's First to Fifth Development Plans (1989-2015)
The objective of this research paper is to analyze the trends observed in spatial population concentration indices within the context of regional and urban balance policies during Iran's first to fifth development plans spanning the period of 1989 to 2015. The study employs a trend analysis methodology, utilizing data derived from Iran's censuses. The findings of the research reveal a consistent inclination of population movement towards urban centers, despite the articulation of regional and urban balance objectives in all development plans. This phenomenon manifests in two distinct forms of population centralization. Firstly, a persistent, overarching pattern of national-level centralization emerges as the gravitational center of population settlements in the country. Secondly, a more localized and variable form of centralization is observed in the regional context, wherein certain areas function as regional centers of population agglomeration. Over the duration of the first to fifth development plans, there is evidence of a decline in urban primacy. Interestingly, cities classified as second-tier (with populations ranging between 100,000 and 250,000) exhibit the highest rates of population growth, while cities belonging to middle-tier categories (with populations ranging between 10,000 and 99,999) experience a negative population growth. In conclusion, the overall outcomes indicate a slight amelioration in regional and urban imbalances. Consequently, a shift is observed in the spatial distribution of regional and urban populations, transitioning from an extreme periphery-center structure towards a periphery-semi-periphery arrangement.
Keywords: Decentralization, Urban primacy, Migration, Urban hierarchy, Regions.
Introduction
The process of urbanization in Iran has experienced a consistent upward trajectory over the past five decades. In 1956, the level of urbanization stood at 31.6%, a figure that rose to 74% by 2016. However, this growth has been characterized by a significant imbalance, with a persistent center-periphery pattern dominating the urbanization structure of Iran. Consequently, an essential objective of Iran's development plans has been the attainment of balanced regional and urban development, alongside initiatives aimed at urban decentralization and population control in metropolises and major cities over the past 50 years.
The primary objective of this paper is to investigate the level and trends observed in spatial population concentration indices concerning the objectives of regional and urban balance policies during Iran's first to fifth development plans spanning the period of 1989 to 2015. The geographical categorization employed by the Iran Atlas of Urban and Regional Planning Studies divides the country into three regional levels: large (physical) regions, middle regions (provinces), and micro regions (cities). These development plans have consistently aimed to establish a sense of equilibrium in both population and development across these distinct levels (Latifi, 2011). As a result, the study will examine changes in distribution and concentration indices of the urban population at three levels: A) population concentration trends within macro-physical regions of the country, B) population concentration and displacement trends within middle regions (provinces), and C) an analysis of indicators pertaining to urban population concentration within first cities, metropolises, and urban hierarchies.
Literature Review
Studies examining urban population decentralization policies can be categorized into two distinct subjects. The first category consists of research that has conducted positive assessments of the effects brought about by the implementation of such policies. Kondo (2018) and Anh (2003) have provided favorable evaluations of urban population decentralization policies in Asia. Chen, Liu, et al. (2013) demonstrated that China experienced a faster increase in urban population compared to economic growth until 2004; however, since then, Chinese cities have undergone a more balanced distribution. Lee (1997) also noted that urban primacy in South Korea reached its peak during the 1970s but has remained relatively stable since the 1980s due to decentralization policies. Furthermore, several studies have indicated that Iran's urban system exhibited a trend towards centralization by the end of the 1980s, but since the early 1980s, the concentration of urban population has gradually decreased, leading to a more balanced distribution (Zebardast, 2006; Farhoudi et al., 2009; Seifodini et al., 2014). These studies attributed such changes to the implementation of urban decentralization policies in Iran. The second category encompasses studies that have shown the continued centralization of the urban population in various forms, with the distribution of population within the urban hierarchy becoming increasingly imbalanced. Rakhshani Nasab and Zarrabi (2010) and Taghvaei and Saberi (2010) have demonstrated this trend. Rakhshani Nasab and Zarrabi (2010) revealed that between the years 2006 to 2016, Tehran, Mashhad, Isfahan, Tabriz, and Qom maintained a stable position within the country's urban system, while Karaj ascended from 13th place in 1986 to 5th place in 2006 due to the influx of population overflow from Tehran.
Methodology
The research methodology employed in this study involved documentary research and trend analysis. The primary sources of data were the databases of the Central Bank, Statistics Center, and the Program and Budget Organization of Iran. To examine the trend relationships of the indicators, trend line regression was utilized. In order to align the data with the time periods of the development plans, interpolation and extrapolation techniques were employed. To measure urban concentration, several indices were utilized, namely the index of equilibrium, urban primacy index, two-city index, Ginsberg or four-city index, Mehta's four-city index, Herfindahl concentration index, entropy index, and Henderson de-concentration index. These indices provided a comprehensive assessment of the level of concentration within urban areas.
Results
The findings indicate that despite the objectives outlined in the first to fifth development plans, aimed at achieving regional and urban equilibrium, the population has consistently gravitated towards central areas at the national, regional, provincial, and urban levels. Two distinct forms of spatial population centralization have been identified. The first involves national-level centralization, primarily centered on Southern Alborz, which has exhibited enduring, widespread influence. This region has functioned as the main hub for population settlement on a national scale. The second form pertains to regional population centralization, which is comparatively weaker, situational, and limited in scope. These regional centers have served as focal points for population settlement. Provinces in the Zagros and Azerbaijan regions have continually experienced a decline in population, with southern and central Alborz regions being favored. During the initial implementation phase of the first plan, the developmental disparity between Tehran Province and the average score of the nine lower-ranking provinces was 28 times. By the time the fifth development plan was enacted, this discrepancy had decreased to 21 times. Over the course of the first to fifth development plans, urban primacy has diminished. Conversely, cities classified in the second population class (100,000-250,000) have exhibited the highest population growth rates, while cities in the middle population classes (10,000-99,999) have experienced negative population growth. Overall, the results demonstrate a slight alleviation in regional and urban imbalances within the country. The centers of concentration for the urban populace have shifted from primary cities to secondary cities. However, medium-sized cities with populations below 100,000 still face negative population growth.
Discussion and Conclusion
The urban spatial growth pattern in Iran reveals an increasing concentration of the urban population in the first and second urban classes, while lower-class cities experience a decline in population in favor of these urban centers. The results demonstrate that despite the objectives set forth in the urban development plans, focusing on strengthening medium-sized cities, the urban population has gravitated towards megapolises and larger cities with populations exceeding 100,000. By comparing the changes in Mehta's index with the levels proposed by Richardson, it is evident that Iran's urban primacy has transitioned from a state of "super-primacy" to a "primacy" level during the first to fifth development plan period. This shift indicates that the urban structure is still far from an ideal situation; however, there is a general trend towards achieving better balance within Iran. Consequently, we propose that the spatial distribution of the regional and urban population is evolving from an extreme periphery-center structure to a periphery-semi-periphery structure.
Acknowledgments
I would like to express my sincere gratitude to the esteemed Professor, Dr. Gholamreza Latifi, for his invaluable guidance and advice throughout the process of writing this paper. His expertise has greatly contributed to the quality and depth of my work.
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