Mount Udo, straddling the cities of Shimizu and Shizuoka in central Shizuoka Prefecture, is known for its beautiful views of Mount Fuji. But it is also being "polluted" by bamboo thickets.

According to an analysis of data provided by the geo-observation satellite Landsat, bamboo breeding areas in the prefecture increased from about 3,860 hectares in 1988 to 5,180 hectares in 2000.

Takao Nagano, 65, said Udo is "being polluted by bamboo." He is the leader of the citizens' group Enjoy Satoyama, which is active in the conservation of mountainous areas located near villages.

Kyoto Prefecture, where bamboo has long been used as a material for traditional crafts, including making utensils for tea ceremonies, landscape gardening and construction, faces a similar problem.

In recent years, the amount of mountain land where bamboo grows has expanded from about 5,300 hectares to 6,700 hectares in Kyoto Prefecture.

The prefectural government has been burying tin plates to prevent other plants growing wild in the mountains from being pushed out by the proliferation of bamboo.

Forestry Agency officials said an increase in the area occupied by bamboo would reduce the capacity of trees to absorb carbon dioxide in the air, contributing to global warming and disrupting the ecosystem.

The species of bamboo that is causing such a headache was reportedly brought to Japan from China in the 1970s. If it takes root in forests, the plants can grow taller than other trees and kill them off.

The Chinese bamboo was planted in mountainous regions close to villages in various parts of Japan except Hokkaido mainly to grow edible bamboo shoots.

Shoji Masuda, a senior environmental and forestry official at the Shizuoka Prefectural Government, said the size of bamboo-growing areas appears to be larger than officially reported.

The prefecture has distributed 3,000 pamphlets to participants in environmental conservation events to boost public awareness of the steady, and apparently unstoppable, encroachment of bamboo in the mountains.

"It costs (prefectural taxpayers) about 1 million yen per hectare if we ask cutters to chop down bamboo. But the stalks soon emerge again," Masuda said. "It would be more effective if we offer assistance to citizens' groups that aim to protect mountains."

Nagano believes the battle against bamboo will take a long time.

"It's very hard to pull out underground bamboo roots," Nagano said, adding that the only way to curb bamboo is to keep cutting it down as it grows.

If repeated cutting is carried out for five consecutive years, "the roots will spoil and die," he said.

Masaaki Nakagawa, 59, who founded the citizens' group Yushinmin four years ago, travels to mountains in Shizuoka Prefecture twice a month with 25 retired people to cut bamboo.

"We use handsaws and cut about 40 bamboo trees in two hours," he said. "All we can do at one time is chop bamboo in an area measuring 100 by 100 meters. We cannot keep up with growing bamboo."

Noting that one measure to combat the situation would be to encourage bamboo consumption, prefectural officials plan to hold an informal gathering with scholars and bamboo traders in an effort to come up with a workable solution.

Satoshi Fujiwara, a 55-year-old assistant professor at Tsuyama Technical College in Tsuyama, Okayama Prefecture, suggested making charcoal out of bamboo that could be used for purifying water. It could also be used as a fertilizer because bamboo charcoal contains potassium and can absorb nitrogen and phosphorous, according to Fujiwara.

The city of Kobe once asked him for ideas for disposing of bamboo stalks left after a panda at the city zoo had eaten the leaves.

His answer: Build a walkway in the mountain where bamboo was growing and make chips out of bamboo to lay on the walkway. Since there would be no grass, he said, a facility to make charcoal should be constructed on the mountaintop.

He also suggested that visitors be freely allowed to take home bamboo shoots.