Loggers threaten a third of rainforests in Congo Basin

The rainforests of central Africa are being systematically plundered for their hardwood timber trees, according to a 30-year survey of logging in the region.

Scientists believe the logging has accelerated in the Congo Basin over recent years as logging companies build more new roads through virgin forests. The roads also allow easier access to poachers, who kill wildlife for the local bush-meat trade.

Satellite images taken between 1976 and 2003 have documented the true scale of road construction and deforestation in six African countries - Cameroon, the Central African Republic, the Democratic Republic of Congo (DRC), Equatorial Guinea, Gabon and the Republic of Congo. The satellite study covered more than 1.5 million square miles, where almost a third of the land is subject to logging concessions and just 12 per cent of forests are protected.

Nadine Laporte, of the Woods Hole Research Centre in Falmouth, Massachusetts, said: "Central Africa's dense humid forests have long been regarded as among the most pristine on Earth, but in recent decades industrial logging has become the most extensive form of land use in the region."

The study used satellite images collected over three decades to build up a dynamic picture of how logging and road building in the rainforests of Central Africa have accelerated during the 30-year period. "Everyone thought that logging was expanding into the forests, but we did not know the extent of it," Dr Laporte said.

The 300 satellite images show that road building to allow access for logging companies has increased to a point where 30 per cent of the forests are now being actively logged for their most valuable trees, such as African mahoganies. Road building was found to be particularly dense in Cameroon and Equatorial Guinea, where most forest has been cut down at least once, according to the study, which is published in the journal Science.

The most rapidly changing area was the northern part of the Republic of Congo, where new road construction increased from 97 miles per year between 1976 and 1990, to more than 410 miles per year after 2000. Almost two thirds of the rainforests of central Africa are within the borders of the Democratic Republic of Congo, where the rate of road development, although relatively small, has also accelerated. Between 1986 and 1990, 208 miles of roads were built per year in the DRC. This increased to 283 miles per year between 2000 and 2002.

"We expect industrial logging concessions to expand, with commensurate increases in the rates of logging and road building associated with foreign investment," the study said.