The rebel leader hero who has 'betrayed' Aceh's orang-utans

When the former rebel leader, Irwandi Yusuf, became governor of Indonesia's Aceh province, he proclaimed a "green vision" for the war-torn region. Lush forests would not be sacrificed for short-term profit, he promised. True to his word, he chased illegal loggers in his jeep.

But, five years on, Mr Irwandi has dismayed supporters by authorising the destruction of a peat swamp forest which is one of the last refuges of the critically endangered Sumatran orang-utan. The move breaches a presidential moratorium – part of an international deal to save Indonesia's forests – as well as legislation protecting a conservation area where the Tripa swamp is located.

Aceh lies at the north-western tip of Sumatra, where three-quarters of the Tripa forest has already been replaced by palm oil plantations. Conservationists warn the remainder – home to the densest population of orang-utans – is crucial to the ape's survival. There are believed to be 6,600 Sumatran orang-utans left in the wild, with up to 1,000 in Tripa.

Global demand for palm oil – used in soap, biscuits and biofuels – is blamed for widespread forest destruction by Indonesia and Malaysia. The granting of a new permit to one of Indonesia's biggest palm oil companies, PT Kallista Alam, threatens another 4,000 acres. Although the area is comparatively small, the move could set a dangerous precedent, according to Ian Singleton, who runs the Sumatran Orang-utan Conservation Programme. "If this goes ahead, no forest is safe," he said.

Mr Irwandi, 51, used to be idolised by many Acehnese. He was a leader of the rebel movement, which fought for independence from Indonesia for 30 years, and was in prison in the capital, Banda Aceh, when the province was devastated by an earthquake and tsunami in 2004. The walls of his jail came crashing down. "I didn't escape from prison – it escaped from me," he said later. He helped negotiate a deal that granted Aceh limited autonomy and became governor in 2006.

In Aceh, some locals call oil palm the "golden plant", the cash crop they hope will lift them out of poverty. In Tripa, though, the conversion of an ancient forest to a monoculture is causing hardship to communities, which depend on the peatland system. Villagers, who accuse the palm oil companies of taking their land, have filed a criminal complaint against the governor.

Mr Irwandi – whose actions have been linked to his campaign to be re-elected next month – is also being sued by environmental group, WALHI Aceh.

"We're really disappointed with our governor," said Muhammad Nizar, the group's campaigns director. "It seems like he tries to get a good image in Indonesia and abroad, but he doesn't really care about the forest."

Mr Irwandi's spokesman said correct procedures were followed in granting the permit to Kallista Alam.