Urban and Regional Planning Review Vol. 4, 2017 | 111 Spatial Emerging Patterns of Vacant Land in a Japanese City Experiencing Urban Shrinkage A Case Study of Tottori City Keisuke SAKAMOTO, Akiko IIDA, Makoto YOKOHARI Abstract In response to the phenomenon of urban shrinkage that affects many Japanese cities, and its various associated social issues, the Japanese Government has implemented compact city policies as a part of urban planning. A compact city is characterized in Japan by dense and proximate urban areas that are linked by public transformation systems, but the feasibility of applying a single compact city model to different regional or local circumstances is susceptible. To understand the actual state of urban shrinkage, this study was aimed at examining spatial emerging patterns of vacant land in residential areas of mid-sized cities called “regional urban centers” in Japan where such patterns are still unknown. The study was conducted using a three-step procedure: a) identifying the overall trends of urban shrinkage in all Japanese regional urban centers and selecting a case study site b) constructing a detailed database of vacant land and five characteristics of the residential areas: age, orderliness, distance from the central area, convenience of public buses, and road width, and c) identifying the relations between the number of vacant lands and the characteristics of the residential areas by using a Poisson regression model. Tottori City, a regional urban center of Chugoku Region, was selected as the case study site. The results show that the convenience of public buses, one of the emphasized factors when the government made a compact city plan, had no relationship with the distribution of vacant land. It might be because Tottori residents highly depend on private cars and are little concerned with public transportations. Instead, a narrow road width appears to be one of the crucial hindrances of residential replacement. A high rate of vacant land then should be regarded not as problematic space but as a resource for reconstruction of residential areas, such as the widening of narrow roads. Keywords: urban shrinkage, vacant land, regional urban center, residential area, compact city Graduate School of Engineering, The University of Tokyo E-Mail: [email protected] (C) 2017 City Planning Institute of Japan http://dx.doi.org/10.14398/urpr.4.111 Urban and Regional Planning Review Vol. 4, 2017 | 112 1. Introduction Population decline in urban areas has been said to be a major factor associated with the process of urban shrinkage (Rybczynski and Linneman, 1999). A typical symptom of urban shrinkage is an increase in the number of vacant houses and the plots of vacant land. For example, in Philadelphia, U.S.A the population declined by approximately 200,000 residents while there was a parallel gain of more than 20,000 plots of vacant land between 1992 - 2010 (Wiechmann and Pallagst, 2012). Increases in vacant houses and vacant land can lead to social issues such as deterioration of the residential environment and inefficiency of public services (Wiechmann and Pallagst, 2012). In industrialized countries that have been facing population decline since the 1950’s many cities have suffered from urban shrinkage (Oswalt and Rieniets, 2007). In Japanese cities other than the metropolises: Tokyo, Osaka, and Nagoya, population loss has been a major concern too. Because these large cities offer better opportunities for education and employment, large numbers of people tend to migrate from smaller regional cities to the metropolises. In addition, population decline in the cities has been affected by a steady decrease in birthrates. The total fertility rate (1) in Japan was 1.41 in 2012, which is relatively low compared with other industrialized countries such as the U.S., U.K., and France (MHLW, 2014). Unless these two causes of depopulation are addressed, it is inevitable that regional cities in Japan will continue to suffer from urban shrinkage. This study is focused on urban shrinkage in mid-sized cities called “regional urban centers (2).” Of 578 cities in Japan (this total excludes the three metropolises), there are 42 regional-urban-center cities. These cities are a political and economic hub for their particular region and they have developed and expanded due to the inflow of population from neighboring villages, towns, and smaller cities. As neighboring municipalities have suffered depopulation and urban decay, the role of the regional urban centers have become increasingly important. However, these cities have also begun to experience population decline. In order to sustain the vitality of the regions, urban shrinkage in regional urban centers needs to be addressed. Responding to the challenge of urban shrinkage in the regions, the Japanese Government revised the Act on Special Measures concerning Urban Reconstruction in 2014 in order to promote a compact city policy. A compact city has three key characteristics in general: dense and proximate development, urban areas linked by public transport, and accessibility to local services and jobs (OECD, 2012), which are followed in the Japanese compact city policy (MLIT, 2014). Several Japanese researchers have suggested that a compact city should also provide environmental and financial benefits to its residents. Some cities in Japan have already incorporated compact city policies in their urban planning. However, there has still been doubt in the U.S., an advanced country suffering urban shrinkage, as to whether a single compact city model is applicable and feasible for all cities, because conditions vary with city and locality (Neuman, 2005). Moreover, the use of a single, comprehensive compact city model lacks empirical support (Gordon and Richardson, 2007). For example, Hollander (2010) suggests that rather than apply a general model, policies should be tailored to the specific environment or neighborhood. Considering this and recent discussion about the compact city policy in Japan (Nozawa, 2014), the approach adopted by the Japanese Government seems somewhat problematic in that it is insensitive to the specific context and conditions of all cities. To address the urban form of Japanese shrinking cities in the future, it is necessary to understand the actual state of urban shrinkage in neighborhoods of such cities. Urban and Regional Planning Review Vol. 4, 2017 | 113 An increase in vacant land is a typical indicator of a neighborhood undergoing urban shrinkage. Previous research in Japan shows that the emerging patterns of vacant land are related to three particular residential area qualities: age, orderliness, and convenience of public train. Ohsawa, et al. (2009) examined the patterns of emergence and persistence of vacant land in residential areas of Kashiwa City, a suburban city of Tokyo, and found that both are related to the age of a residential area. Ujihara, et al. (2006) focused on Okayama City, a central city in the Chugoku Region, and found a relationship between the emergence of vacant land and disordered residential development. Sakai (2014) examined the causes of the increase/decrease in vacant land in suburban areas of Tokyo and Osaka, and suggested that good accessibility to urban centers by public train tend to decrease the plots of vacant land. However, previous research has been limited to metropolitan suburban cities and regional cities that still have population growth. Thus, it is unclear how the factors identified above impact on the increase in vacant lands in regional urban centers that continue to experience population decline. In particular, whereas public trains are a common means of transportation for intra-city traffic in metropolises or some large cities, they are mostly used for inter-city or urban–rural traffic in most regional urban centers, and public buses are instead the typical means of intra-city transportation there. On the contrary, unlike metropolises or other large cities where there is an adequate public transportation system and several central urban areas, daily transportation in most regional urban centers strongly depends on private cars and the centers have developed around a single central urban area. Thus, accessibility to the center is likely to be measured simply by the distance from the central area to neighborhoods. In relationships between the emergence of vacant land and neighborhood characteristics, road width has a possible influence, due to the difficulty in rebuilding. This is because the Japanese Building Standard Law stipulates that new housing developments must have a frontal road wider than 4.0 m, or there is difficulty in entrance and exit by cars. Hence, the purpose of this research is to identify the distribution of vacant land and the relationship between emerging patterns of vacant land and the five characteristics of residential areas: age, orderliness, distance from the central area, convenience of public buses, and road width of residential areas in a regional urban center that is undergoing urban shrinkage. 2. Method First, the case study site was selected by using official statistical data. Urban shrinkage is identified by three key indicators: population growth/decline rate, the increase/decrease rate of the number of vacant houses, and the increase/decrease rate of the area of vacant land. These indicators were used for assessing which regional urban centers have been experiencing urban shrinkage as compared with the metropolises and other large cities (2). The cities were classified into eight categories according to these indicators. Second, a database of vacant land was constructed by using ArcGIS 10.2. For the purpose of this research vacant land was defined as: (1) unused land that attracts rubbish and debris or grows weeds, or (2) unused land with a ‘For sale’ sign or roped off. The location of all vacant land in residential use districts in the urbanization promotion area (UPA) was recorded by a portable GPS in September 2014. Every plot of vacant land was then matched with satellite images from Google Earth, and their locations were illustrated by ArcGIS 10.2.