Concentric Zone Theory

The Concentric zone (ring) model also known as the Burgess model is one of the earliest theoretical models to explain urban social structures. It was created by sociologist Ernest Burgess in 1925. He propounded the concentric zone theory in order to explain the structure and growth of city. The hypothesis of this theory is that cities grow and develop outwardly in concentric zones. In other words, the essence of the model is that as a city grows, it expands radically from its centre to different concentric circles or zones. 

Burgess offers a descriptive framework in which both aspects of human ecology - physical land use pattern and human relationships are implicit. Using Chicago as an example, Burgess viewed that as cities expand outwards, the interaction among people and their economic, social and political organizations also create radical expansion outward and form a series of concentric zones. The concentric model is based upon a process of invasion and succession. Invasion is a process which necessitates continual expansion of inner zones into outer zones, due to the natural 'aggression' of the migrant into the city. While succession occurs when an area becomes dominated by the activity invading that zone. 

There is competition in city among people for limited space. Only those can succeed who can afford best to pay and get the desirable location for their business and homes. Therefore, concentric zone theory reflects on going conflict between city dwellers and periphery villages. It also describes the process of concentration and segregation of social groups with the growth of city structure. According to this theoretical model there are five major concentric zones. These are as following: 

a) Commercial centre/Central Business District (CBD) 

b) Zone of transition 

c) Working class residence 

d) Middle1 higher class residence 

e) Commuter zone

                                                              Concentric Zone Model

a) Central Business District (CBD) 

The inner most ring zone or nucleus of the city is a commercial centre also called Central Business District (CBD). This zone is characterized by high intensity of commercial, social and civic amenities. It is the heart of the city which includes department stores, office buildings, shops, banks, clubs, hotels, theatres and many other civic buildings. Being the centre of commercial activities and location, it is accessible from all directions and attracts a large number of people. Therefore, it is a zone of the highest intensity land use and social interaction. High intensity of land use further indicates the high value of land and rents. 

As a result, the residential population in this zone is very small. People are always in search of cheaper, spacious and pollution free accommodation away from the core of the city. This is one of the reasons that the congested city area is deserted at weekends or on non-working days. 

Burgess further describes that the morphological structure of CBD is changing rapidly with our changing needs. Morphological structure of city includes buildings, roads and infrastructure. These rearrangements occur, in part, through demolition and new building construction. This is a continuous process of rebuilding since city began. Hence, it is obvious that older parts of the city are rebuilt and old land uses replaced.

 b) Zone of Transition 

Light Industries and slums mainly occupy this zone, may be seen in as many American cities. This zone was the home of numerous first generation immigrants. It has low income households, retrogressing neighbourhoods, one room houses and homeless men. It is a breeding place of crime, gambling, sexual vice and other social deviances. 

The physical deterioration and social disorganization leads to concentration of poor housing, poverty, juvenile delinquency, family disintegration, physical and mental diseases. Burgess studied Chicago city and he found the second concentric zone to be transitory in nature, comprising an area of residential deterioration due to congestion and encroachment. The zone surrounds the CBD area and fulfils their needs, like light industrial production and business extension houses. He also predicts that CBD will expand in this zone, as it will grow. 

c) Lower Working Class Residence 

Basically it is planned residential area, close to places of economic activity which often shift and moved to the outward rings. Being close to transition zone it is influenced by that zone, in terms of quality of life. It reflects the negative impact of industrial pollution and the cultural impact of slums. The working class residences subsequent outward rings are occupied by middle or higherclass residences. 

d) Middle Class Residence 

These may be separated in different rings in terms of class character and corresponding facilities. This is a residential area with all modern amenities of civic society. People who reside in these areas are native born Americans in single family houses or apartments. The houses are spacious in a pollution free zone. Sanitation, health facilities and all other requirements of a good quality life are found here. Proper transportation, communication and parking facilities are an added feature of this residential zone. The above features of this concentric zone clearly indicate a particular class character.

e) Commuter Zone 

It is located in the outermost concentric zone, beyond the area of higher class residence. This is a ring of encircling small cities, towns, and hamlets which taken together constitute the commuter zone. People from these areas commute on a daily basis towards the CBD or commercial centre for employment and business purposes but live in their small cities, towns and hamlets. Commuter zone is characterized by low density. It is relatively isolated and located in suburbs and satellite towns. Later on Burgess writes that there was no circle of towns or cities in the outer concentric zone of Chicago but a pattern of settlement existed along the railroads radiating out from CBD like spokes of a wheel. 

Limitations and Criticisms of Concentric zone model 

Concentric zone model is one of the simplest model available. This model accounts for the economic forces which drive development and the study of patterns present at the time of the study. But with the evolution and passage of time urban areas grew more complex and this model cannot define the development of existing cities. Some of the limitations and criticism include 

• Although widely appreciated in the United States, Burgess model is not applicable outside the US. This is so, as the pattern of growth is different because of various circumstances. 
• The relevance of this model decreased over time. With the advancement in the mode of transportation, mass transit vehicles, motor vehicles, cars changed the way people commute. Accordingly, their preference for living in a particular zone changed. 
• It does not take into account the effect of political forces and the restrictions imposed by the government for the improvement of living conditions. 
• In reality, no distinct zones and boundaries exist as overlapping of areas is possible in every town. The preference of people changes over time depending on the importance they associate for a particular benefit. 
• This model is not applicable to polycentric cities as many CDB exists in such towns. Moreover, every city is different, and the factors influencing the growth of a city are diverse.