Jakarta (AsiaNews/Agencies) – While the jungles of Sumatra were being stripped by land-hungry settlers over the past 30 years, the island's remote southern mountains remained a stronghold for some of Asia's last wild tigers and the critically endangered hairy rhinoceros.

But having survived the incursions of poachers, loggers and farmers, one of the last great tracts of protected virgin rainforest in Southeast Asia is being destroyed at an alarming rate thanks to the booming coffee export trade, according to conservationists.

They have estimated that about 20 per cent of the breathtakingly beautiful 340,000-hectare Bukit Barisan Selatan National Park has already been hacked down for illicit plantations.

They fear that unless action is taken quickly, the park's tigers, elephants and rhinos could vanish within 10 years because of the world's craving for caffeine.

A report published today by WWF called "Gone in an Instant" blames international coffee companies for buying illicit beans, often unknowingly, from middlemen who abuse a lack of regulations to mix those from the 20,000 tonnes grown illegally inside the park with legitimate crops from elsewhere in Lampung province.

The global conservation body said the low-grade robusta beans grown in the area were used inadvertently by some of the biggest names in the business - including Kraft Foods, Nestle, and ED&F Man - to make instant and packet coffee and energy drinks.

Nestle was one of the companies praised by researchers for trying to find ways of keeping illegal beans out of its products. Others have pledged to take action after researchers contacted them. Some of those singled out by the study, including London-based ED&F Man, denied buying any illicit beans.

Researchers used satellite imaging, interviews with farmers and traders, and monitoring of trade routes to track the progress of illicit coffee from cleared jungle land inside the park to the morning brew in Britain, Germany or America.

Nazir Foead, WWF's director of policy and corporate engagement, said: "WWF doesn't want to shut down the coffee industry in Lampung province, but we're asking multinational coffee companies to implement rigorous chain-of-custody controls to ensure that they are no longer buying illegally grown coffee."

Jonathan Atwood from Kraft, makers of Maxwell House and Kenco Coffee, said: "Traceability is very difficult. We are making the assumption that some of this illicit coffee might be in our supply."

At stake is the survival of some of Asia's rarest and most spectacular mammals, including three subspecies found nowhere else in the world. The park is home to 40 Sumatran tigers—about 10 per cent of the animals left in the wild—and about 80 Sumatran rhinos, which are only found in three other parks on the island.

A quarter of the 2,000 Sumatran elephants are also thought to be within the park.

Indonesia is now the fourth-biggest coffee producer in the world after Brazil, Colombia and Vietnam, and half of its production is in Lampung.

The "coffee rush" has brought 15,000 squatter families to the park. WWF said about 40,000 hectares had been cut down for coffee plantations inside the park's protected area. Government officials and overstretched park staff have done little to stop them.

One coffee farmer, Suratno, admits to growing one and half hectares of coffee inside the forest. "I don't feel guilty. There is still plenty of forest in there."