Niniek Karmini, Mantangai – With smoke from nearby forest fires stinging his eyes, the conservationist aims his tranquilizer dart at the orangutan high in the Borneo jungle. After several misses he manages to knock her out.

Rescuers lower the giant, red-haired beast with ropes and take her to a reserve – temporarily safe from slash-and-burn land-clearing, poachers and machete-wielding farmers who are killing around 1,000 apes a year, said Hardi Baktiantoro of the Borneo Orangutan Survival Foundation.

Southeast Asia's Sumatra and Borneo islands are the orangutans' last homes, and environmentalists say the estimated 60,000 animals remaining could disappear from the wild within the next decade.

Hundreds of fires set annually by Indonesian farmers, plantation owners and palm oil companies are speeding things along, said Baktiantoro and other enviromentalists.

This year's blazes are some of the worst in 10 years and have sent a thick, choking haze over much of the region, especially Indonesia's Sumatra island and Borneo – which is shared by Indonesia, Malaysia and Brunei.

"The fires are out of control," said Baktiantoro, after teams of rescuers trudged for hours through the jungle in search of primates needing help, a task made harder by visibility of less than yards.

The sun burns orange in a gray sky, smoke fills the nose, irritates the throat and stings the eyes.

"We believe we have lost more orangutans than before," said Baktiantoro, who like many Indonesians uses one name. An estimated 2 million acres has been torched on Borneo this year, according to Walhi, an environmental group.

This drives apes into plantations in search of food, and farmers fight them off with machetes, clubs and guns.

"Sometimes they destroy acres of land and eat hundreds of buds," said Muji Harto, a palm oil worker in Lamandau district in Central Kalimantan province. "We know they're endangered and protected. But what else can we do?"

The small-time farmers say the real culprits are the big palm oil plantation companies, which they say burn forest on a large scale and are responsible for most of the haze.

Encounters between humans and orangutans – which comes from the Indonesian and Malay words "man of the jungle" – are often horrific.

Most of the 45 orangutans rescued and taken for medical treatment in Borneo in recent weeks have wounds to testify to that, said Anand Ramanathan, an emergency relief worker with the Washington-based International Fund for Animal Welfare.

Though some had respiratory problems and burns, most were injured by man, he said, some arriving with chopped-off paws, wide facial gashes or bullet-riddled bodies. Baktiantoro said babies are often kept as pets or sold abroad.

"Many of these orphans will end up being traded internationally," he said from a wildlife center in Nyaru Menteng district, where some 400 orangutans, a quarter of them orphans, were being prepared for reintroduction into the jungle.

But even though the apes are lucky simply to have survived another year, farmers say they have practiced slash-and-burn techniques for generations and will continue to do so next year.