Bank Research Suggests Tokyo Needs More Rooftop Greening

The Development Bank of Japan (DBJ), a government-affiliated financial institution, released a report titled "Outlook of the Greening of Buildings for Improvement of Urban Environment: Focusing on Cost and Techniques for Rooftop Greenery" on April 8, 2004. The report shows that the actual green area in Tokyo did not expand as much as expected, although the awareness about the greening building rooftops is growing.

The report estimates Tokyo's "green area rate" (percentage of the total area covered in vegetation and water surfaces such as lakes and rivers) at 60 percent in 1932, however it dropped to 35 percent in 1962, 30 percent in 1974 and 29 percent in 2000.

Meanwhile, the Tokyo Metropolitan Government (TMG) is trying to increase the green area rate in its 23 wards to 32 percent over 15 years from fiscal 2001. Facing difficulties in creating parks space and other types of public green areas due to the lack of available land, the TMG is trying to increase rooftop greenery, and has set a target of 1,200 hectares of rooftop greening over 15 years. But only about 13 hectares of rooftops were greened in fiscal 2002 under an ordinance that makes rooftop greening mandatory in the Tokyo area.

The DBJ report points out barriers to spreading rooftop greening, including high initial costs and the lack of awareness about the benefits of planting trees and shrubs, such as mitigating the "heat island effect" and reducing air conditioning costs. The report also suggests that government measures, such as giving subsidies for rooftop greenery to reduce its initial cost and expand the market, and introducing an integrated, easy-to-understand performance index, could contribute to expanding green areas in Tokyo.




Posted: 2004/08/23 02:52:27 PM
Japanese version