Residential Land Use

Most urban land is devoted to residential use. However, within an urban place there is a great deal of heterogeneity and differentiation among areas and neighborhoods. One of the most powerful trends in urban form which began as early as the 1920s but excelerated raipdly in the 1950s and 1960s has been the growth of suburbs. As the interstate highway system and intraurban expressways were completed, the frictions of distance which tied many activities to the urban core were reduced. Widespread automobile ownership enabled many households to move greater distances from their jobs and suburban retail and service functions developed to accomodate the needs of suburbanizing populations. At the same time, manufacturing and warehousing that required large parcels of land with convenient access to transportation routes also moved outward. These centifugal forces continue to impact the form and structure of urban land.

Do these trends imply that the three models of urban land use are no longer useful? Many researchers have suggested that the traditional models are obsolete. However, many of the concepts used in devloping the traditional models contunue to be useful when analyzing patterns of urban land. For example, one result from the analysis of rent gradients is that the intensity of land use should generally increase as we move closer to the CBD. When we apply this notion to residential patterns, we would expect population densities to be higher as one moves closer to the CBD and population densities to lower in suburban locations. In most cases, this continues to be true. Population density for Charlotte, North Carolina is illustrated in Map 1and clearly shows a pattern of decreasing density with distance from the CBD.

Map 1 Population Density in Charlotte, NC, 1989. Population density in the Charlotte, NC region illustrates how the intensity of residential land use declines with distance from the CBD. In this map, population density is mapped by census tract and is color coded with lowest density in yellow and the highest density in brown. Note that the single census tract in the middle of the map is Charlotte's CBD. Can you explain why population density is low there? Source: U.S. Census Summary Tape File and DDViewer.

The data mapped in Map 1 show the distribution of population at a single moment in time. However, as discussed above patterns of urban land use evolve over time and are subject to change. As cities have grown, much of the population has moved outward. Since households obviously require shelter, one way to examine the changing spatial patterns of population is examine the patterns of housing construction as in Map 2. This figure shows the pattern of homes that were built prior to 1940 as well where new homes were built beteen 1960 and 1990. Note how the pattern of new home construction has gradually proceeded in a set of rings at greater distances from the CBD. Prior to 1940, the housing stock was largely concentrated around the CBD and along a corridor stretching westward from the central city. As time progressed, new housing was increasingly constructed away from the central city. With each passing decade, the proportion of housing built away from the central city increased.

Map 2 New Home Construction in Charlotte, NC New home construction provides one reflection of changes in the distribution of population. This map is actually four maps in one showing the distribution of homes built prior to 1940, and new homes that were built between 1960 and 1990. Notice that most homes built before 1940 were located in close proximity to the CBD and along one of the major east-west transport routes. As the city grew, most additions to the housing stock took place at increasing distances from the CBD. If you analyzed this map from the perspective of Burgess's Concentric Zone Model, what would the map imply about the processes of "invasion" and "succession"? Source: U.S. Census Summary Tape File and DDViewer.

One of the more important features of both the concentric zone and sector models of land use was that residential areas are likely to be differentiated according to a number characteristics. In Burgess' study of Chicago, he found that neighborhoods and "social areas" could frequently be defined by their socio-economic statuts or racial/ethnic composition. The processes of "invasion" and "succession", the tendency for people to live near others who are like them, and the practice exclusionary zoning are among the factors that lead to neighborhood differentiation according race, ethinicity, income, and occupational status. In the case of Charlotte, North Carolina race is a differentiating charcateristic of residentail areas as shown in Map 3.

Map 3 Distribution of African American Population in Charlotte, NC, 1989 Specific areas of cities are frequently identified according to their racial or ethnic composition. San Francisco's Chinatown and Boston's North End are two famous examples of racial/ethnic concentration. This map shows the distribution of African American population in Charlotte, NC. Areas shaded in yellow have the lowest proportion of African Americans and areas shaded in brown have the highest proportion. Differentiation is common in American cities and Charlotte is no different in that respect. Social areas are also evident along other socio-economic dimensions. Think about your neighborhood; what characteristics do most people share in common? Source: U.S. Census Summary Tape File and DDViewer.

Household income is another feature that distinguishes neighborhoods. Continuing with the Charlotte example, Map 4 illustrates the distribution of households by income level. There are several features of this map that are noteworthy. First, as indicated by the brown portions of the map, higher income households generally tend to live further from the central city. Census tracts in yellow are the areas of lowest median income and are generally found closer to the central business district. Areas in orange and red are middle groups that are located in between. Thus, one pattern that seems to emmerge is a neighborhood distribution, defined according to median household income, that loosely conforms to the concentric ring model. Note, however, that there is also a clearly identifiable wedge of high income households that streches to the southeast, which is more suggestive of Hoyt's sector model. Finally, it should also be noted that there are a small number of middle- and high- income areas in the CBD. The fact that urban residential areas are also distinguished by the occupations of people who live there (Map 5) has led many think of residential patterns as social divisions of labor.

Map 4 Median Household Income in Charlotte, NC, 1989 Another way in which areas are differentiated is according to income. Like the maps above, high income areas are shaded in brown and low income areas are in yellow. Try to relate the patterns of income to the three theoretical models of land use. Can you identify elements of more than one model? Can you explain how low income households can dominate residential land uses near the central city if land values are higher near the CBD. Source: U.S. Census Summary Tape File and DDViewer.

Map 5 Location of Persons Holding Managerial and Professional Occupations Occupation is one component of socio-economic status. Compare this map to Map 4. What similarities do you see? What model of urban land does this map remind you of? How would explain the high proportion of managers and professionals living near the central business district and how would you reconcile this with the map of Median Household Income? Source: U.S. Census Summary Tape File and DDViewer.