Conservationists in Indonesia have warned that fires set to clear land have killed and injured hundreds of endangered orangutans. Environmentalists are also concerned the burning of rainforest and peat bogs is contributing to global warming.
Widespread fires in Indonesia have claimed millions of hectares of land this year on Sumatra and Kalimantan - the Indonesian part of Borneo - destroying sensitive wildlife habitat and spewing out a thick haze that has choked neighboring countries.
Palm oil companies, loggers and farmers set fires during the dry season each year to prepare land for crops, but the blazes often rage out of control.
The area destroyed this year was some of the only remaining habitat left for orangutans, a protected species with a rapidly declining population.
The only great apes living outside Africa, orangutans can only be found on the islands of Sumatra and Borneo, which is divided between Indonesia and Malaysia.
Willie Smits, coordinator of the Borneo Orangutan Survival Foundation, says time is running out for the endangered primates.
He said, "The populations are all extremely threatened because of the fragmentation of the forest. You need a minimum of three thousand orangutans to have a thousand year chance of survival and that forest has to stay intact in one big piece. There's only two or three years left in which we can prevent that these remaining populations are going to become extinct."
Smits says that only one in three orangutan young are estimated to live, and mothers only give birth on average once every eight or nine years.
Smits adds that the forest habitat, in particular the sensitive peat moss bogs known as "domes", should not only be protected for the benefit of wildlife, but also to stop the rise in greenhouse gas emissions.
"If we look at the amount of carbon in the peat that is being released because of the collapsing domes and the fires, that amount is huge," he said.
"If we would lose the tropical peat swamps, of which Indonesia has more than 50 percent in the world, we would be looking at a doubling of global emissions for the next thirty years."
Fires in peat bogs are particularly hard to stop, because they can smolder underground for weeks without being detected.
Smits says orangutans that survive the fires often flee toward water, where they are more likely to encounter humans.
The Borneo Orangutan Survival Foundation rescued 137 injured orangutans in central Kalimantan from fires or from assault by humans during the land-clearing season, but discovered the remains of many more.