The area was the "largest ever tract of contiguous certified tropical forest in the world", partners said in a statement after the forest won certification meant to avoid deforestation. It more than doubled an existing CIB concession.

"Timber production does not have to be synonymous with the destruction of tropical forests," said Scott Poynton, executive director of the Tropical Forest Trust, a Geneva-based non-profit charity that works with industry to conserve forests.

Pygmies in Congo used GPS satellite handsets to pinpoint sacred sites on maps in the Pokola rainforest to ensure that they would be untouched by loggers.

"For instance, at a large Sapelli tree prized for its edible caterpillars, or an important collecting point for medicinal plants, they simply selected the appropriate icon and the GPS records the location," the statement said.

The handheld mapping device "made it possible for the pygmy communities to communicate to us the specific forest resources that they hold sacred", said Robert Hunink, executive vice president of DLH Group.

The area of forest received certification from the Forest Stewardship Council, an independent non-profit group which tries to set standards for logging companies to avoid deforestation.

Forests in the Congo Basin cover about 1.81 million sq km (700,000 square miles), making them second largest in the world after the Amazon.