Kyoto impedes "heat island effect" research.

From:
http://www.asahi.com/english/nationa...070800288.html

GREEN IS GOOD: Tokyo leaves rooftop lawns to grow it alone

The Asahi Shimbun

For the Tokyo metropolitan government, the grass is greener if you don't
have to water it.

Summers in the big city aren't expected to cool down anytime soon. To combat
the so-called heat island effect, in which the city's high-rises and asphalt
make it several degrees hotter than outside areas, Tokyo officials are
experimenting with rooftop gardens that require no maintenance.

If all works out, the metropolitan government hopes to use the system to
cover apartment buildings it runs with grass and other greenery that can
absorb the throbbing heat of Tokyo summers.

The experiment started last November on the roof of a seven-story apartment
building in Kohoku 3-chome in Tokyo's Adachi Ward.

Short-grass turf and sedum, an all-weather plant that grows on rocks and
walls, were planted separately on a 100-square-meter plot built when the
building was renovated the same month. Sedum is considered suitably rugged
for rooftop gardens, as is short-grass sod, which is light and durable.

If they survive through the summer on only rainwater, the government plans
to use them as early as next spring on its other apartment complexes.

Since most public-run apartment buildings do not allow residents on the roof
and rarely employ janitors, rooftop greenery needs to be tough enough to
grow with almost no supervision.

One key is soil thick enough to retain water. But if the soil is too bulky,
roofs may have to be reinforced.

To avoid renovation costs, the Tokyo government has calculated the minimum
thickness needed by the two types of plants, according to an official at the
Bureau of Housing.

Meanwhile, government officials have been monitoring how well their garden
is growing without assistance. A Bureau of Housing staffer visits the
rooftop once a month to check out the plants' condition. They aren't dead
yet, and weeds have sprouted in the grass.

``We don't plan to water the plants in the summer. If they survive that, the
experiment will be a success,'' said the bureau official.

Private sector experts are also keeping a close eye on the results. An
official at a company specializing in rooftop gardens says no comprehensive
system for unsupervised gardens has been introduced, though suitable plants
such as sedum have been discovered.

(07/08)