The survival of a number of endangered species in Indonesia, including orang-utans, is threatened by illegal logging in their forest homes.

The BBC's Jonathan Head: "The destruction is increasing"

The London-based Environmental Investigation Agency (EIA), a campaign group, has worked with an Indonesian environmental organisation, Telapak, to produce a report on the threat.

The report, "The Final Cut: Illegal Logging in Indonesia's Orang-utan Parks", is based on work at five places in two of Indonesia's national parks.

They are Tanjung Puting in central Kalimantan, and Gunung Leuser in northern Sumatra.

The report says both parks are home to "a stunning array of biodiversity and are world-renowned centres for orang-utan research".

It says the number of orang-utans in the wild has halved in the last decade, with no more than 15,000 to 25,000 animals left.

Law flouted

The report says both parks are being destroyed by massive commercial-scale logging, which is taking place in defiance of Indonesian law.

The report speaks of "virtual anarchy" in the parks, and says corrupt officials have allowed the logging to intensify.

It names the individuals it says are profiting from the theft of the timber.

Dave Currey, the EIA director, said: "I have witnessed scenes of appalling devastation in both of these so-called protected parks".

"The logging is totally out of control. The government of Indonesia must act against the timber barons directing this destruction."

The forests are going, and so are their inhabitants

In Tanjung Puting, the investigators found numerous logging camps, and "an extensive network of wooden rails used for dragging the timber out".

They say trucks and barges are used to remove the wood, which ends up in local sawmills and factories.

In Gunung Leuser, they saw loggers with chainsaws at work in an area which provides prime orang-utan habitat, and is the only place where the apes have been seen using tools.

EIA and Telapak say illegal logging is now greater than legal timber production in Indonesia.

They want the government not only to act against the timber profiteers, but to replace local authorities in the area of the parks.

They say about 80% of the orang-utans' forest habitat has been destroyed in the last 20 years.