25/06/2009 (NZ Herald), Tripa - Perched halfway up a tree on the Seumayan River, a young orang-utan lounges on a branch, eating fruit.

In the distance, smoke rises from an illegal fire, one of dozens lit to wipe out the virgin rainforest and replace it with oil palm plantations.

It's burning season on Indonesia's Sumatra island, where vast tracts of vegetation are being torched to meet the soaring global demand for palm oil.

The pace is especially frenzied in the peat swamp forests of the Tripa region, one of the final refuges of the critically endangered orang-utan - and a company owned by one of Britain's most venerable trading groups is among those leading the destructive charge.

Prized for its productiveness and versatility, palm oil is used in everything from lipstick and detergent to chocolate, crisps and biofuels.

Indonesia and Malaysia are the world's biggest palm oil producers - but they also shelter the last remaining orang-utans, found only on Sumatra and Borneo islands in the same lowland forests that are being razed to make way for massive plantations.

In Indonesia, one of the largest palm oil companies is Astra Agro Lestari, a subsidiary of Astra International, a Jakarta-based conglomerate which is itself part of Jardine Matheson, a 177-year-old group that made a fortune from the Chinese opium trade and is still controlled by a Scottish family, the Keswicks, descendants of the original founders.

Conservation groups are targeting British supermarkets to alert consumers to the effects of the palm oil explosion.

But the Independent can reveal that Jardines, registered in Bermuda and listed on the London Stock Exchange, is implicated in ripping out the final vestiges of orang-utan habitat.

Environmentalists are dismayed by the activities of Astra Agro, one of the main companies operating in Tripa.

They point out that Tripa belongs to the nominally protected Leuser Eco-System, renowned for its exceptional biodiversity, and claim that the plantation businesses are contravening a logging moratorium as well as engaging in illegal practices including burning land.

Orang-utans are vanishing at an alarming rate in Borneo but in Sumatra their situation is even more precarious.

The Sumatran orang-utan - more intelligent and sociable than its Borneo cousin and with a unique culture of tool use - is likely to be the first great ape species to go extinct.

There are believed to be just 6600 left, mostly living in unprotected areas of Aceh province.

Their lowland forests remained relatively undisturbed during the long-running separatist war in Aceh, but since a peace agreement was signed in 2005, it has been open season.