Green space relations with residential values in downtown Tokyo – implications for urban biodiversity conservation

Abstract

This study examines the relationship between biodiversity and the housing value of residential areas in downtown Tokyo, and reviews the history of green space planning and surveys of present residential attitudes towards green space in the metropolitan area. Throughout the research, biodiversity is operationally represented by a “green coverage ratio”, while standardised data on land and rent prices are used to assess the value of residential areas. The results confirm that the green coverage ratio and housing value are correlated. The study concludes that there is a need for development of a more accurate and integrated policy database that will provide explicit definitions of management targets, locations and clients for promotion of green space in Tokyo.

Notes

1. MLIT plans to prepare a land database for open access including information about address, price, function, floor area ratio and building-to-land ratio, in cooperation with the National Tax Agency beginning in March 2006. The database is planned to hold data at block level, and this will allow further analytical research.

2. Addresses in TM are divided into municipalities and SWA. Each municipality and SWA ward is divided into a district (chou), block (ban) and building (gou). Technically, it is possible to track data at gou level. But block is detailed enough because within the unit block price-determining factors do not significantly vary.

3. The Recruit Residential Price Index (RRPI) provided monthly by Recruit Co., Ltd. is one of the most significant housing price indexes in Japan. The RRPI also adopts the three factors as well as floor space as variables, applying the Hedonic price method. It covers prefectures and the 23 SWA wards.

4. Daytime population (DTP)=residents + inbound population – outbound population.

5. The description of green field land in Article 3 of the City Green Zone Act is “forests, grass fields, shores, rock fields and other similar or adjacent fields that form fine natural environment”.

6. Suburban SWA in TM = TM – (SWA + islands + Nishitama Area). Islands and Nishitama Area are removed because the forests in these areas have not been significantly affected by urbanisation. Most of these are beyond 50 km radius of Tokyo Station, and beyond the commutershed of the SWA.

7. Major 7 is a portal site on the Internet for potential purchasers of new condominiums run by eight major real-estate companies. These companies provide 22% of private condominiums in Japan.