"When I first came here three years ago, the people were very hospitable and generous. But now they are cold," said Yang. "It's hard for them to get along with the bird people."

The locals, however, are eager to make a profit. "I'm afraid I won't live to be 100 years old. I work 12 hours a day now. Worse, along with their money, the bird people bring viruses and waste," said Huang Cheng, who sells barbequed pork.

Three years ago, Huang Wenzhuan, 30, worked in Dongguan, Guangdong province, but he returned home and now also sells barbecued meats from his house. "I don't till the land like my parents. I sell 5 kilograms of barbecued pork every day during the busy season. Bama is changing; we didn't lock our doors at night before."

Folk tunes as therapy

"If food is the material wealth of the Bama people, the folk songs they sing every day are their intellectual assets," said Chen Jinchao, chairman of the village's Longevity Research Institute. He believes that singing folk songs encourages the elderly to maintain an open nature and helps them shed anger and anxiety.

But the elderly seldom come together to sing folk songs nowadays, except as entertainment for tourists. Instead, many sit at the doors of their family inns as living advertisements of the healthy local lifestyle.

"I'm sorry you cannot understand my language. I wish you a pleasant stay in Bama," said 110-year-old Huang Masongmou, speaking in the language of the Zhuang ethnic group.

Huang has two daughters and one son, all in their late 80s, and more than 200 offspring through five successive generations in the village. Her grandson-in-law, Ya Hanzhong, said: "She lives a regular life and eats two bowls of corn porridge every meal. She's happy that we've moved to a new house and have visitors everyday."

Huang Makang also lives in the neighborhood. At 107, she may be the world's oldest pumpkin and wine saleswoman. Dressed in clean, tidy clothes, she is talkative and happy to have her photo taken with visitors. Her sister died in her sleep last year aged 103.

Huang Lilin sells local specialties in Longevity village. "Harmonious family relations make the local people happy during their long lives," said the woman in her 30s who hopes that she will live until she is 100, "But I'm not sure about that, because life has changed here."

Companies have also arrived in Bama, hoping to tap into the "bird people market" and develop longevity products, and pyramid sales outfits have also come to sell healthcare items.

Two water companies have monopolized the spring water resources. Their slogans are "Some people drink me for more than 100 years" and "The water with a life of its own."

Ding Ling, who owns a hemp-processing business in Bama, said: "Hemp is the key to Bama's longevity because of its power to promote cell regeneration." The locals drink soup made from hemp every day and Ding's hemp oil and cosmetics are popular overseas.

Despite her success, Ding is concerned about the changes, "It's disturbing to see so many sick people elbowing their way into Bama before the county has the ability to deal with their influence on the local environment."

Although many medical experts believe environmental therapy can help medical treatment, they stress that it can't replace formal hospital treatment and say it's dangerous for so many patients to live in a place that lacks basic medical care facilities.

"The bird people, mostly poor urban residents, are afraid of death. But local people take death lightly. The sharp contrast between the natural beauty and the artificial lethargy created by the bird people has instilled a weird feeling in me", said Ding.

Development plans

Wei Ruifen, deputy head of the county, said the provincial government plans to make Bama into a world-class tourist resort in the next five to 10 years.

"We are trying our best to accelerate infrastructure construction to accommodate more high-end visitors", she said. "We have monitoring points across Bama to detect changes in environmental quality and will act to protect the environment in the event of problems."

When a highway is built in a few years, the county government will enforce restrictions on the number of visitors and vehicles entering Bama.

"No vehicles will be allowed to enter the core zone. The natural resources are the village's most valuable assets," said Wei.

Huang Bifeng, deputy director of the Bama tourism bureau said: "Despite government help, we still lack funds, talent and expertise. All we can do now is reduce the environmental damage as much as possible."