OSAKA (Kyodo) The elephants and other animals at Tennoji Zoo in Osaka may play a key role in the city's greenery project to cover some public areas with sweet potato plants as a way to help reduce the scorching summer heat.

The herbivores can solve a dilemma inherent in the project — "disposal" of the massive amount of leaves, stems and potatoes after the summer.

City officials said the animals' resulting output could be used as fertilizer, making for "the ultimate recycling project."

In the initial stage starting in April, for which the municipal government has allocated ¥90 million, sweet potatoes will be planted in open space in front of City Hall and on its roof, creating up to 150 sq. meters of green space.

The project will gradually be expanded to buildings and surrounding areas of all ward offices and about 430 elementary and junior high schools by the end of March 2012, the officials said.

Since the city has been promoting the reduction of waste disposal, how to dispose of the plant leaves and potatoes in the autumn had been emerging as a problem until the animals came to the rescue.

Mayor Kunio Hiramatsu suggested organizing a cooking contest on the roof of City Hall using the harvest, but the sweet potatoes — a type chosen for their leaves and not their taste — may find a more willing recipient in the elephants, officials said.