It was one of the few places on the planet that remained unmapped and unexplored, but now Mount Mabu has started to yield its secrets to the world.
Until a few years ago this giant forest in the mountainous north of Mozambique was known only to local villagers; it did not feature on maps nor, it is believed, in scientific collections or literature. But after "finding" the forest on a Google Earth internet map, a British-led team of scientists has returned from what is thought to be the first full-scale expedition into the canopy. Below the trees, which rise 45m above the ground, they discovered land filled with astonishingly rich biodiversity.
The scientists found what they believe are three new species of butterfly, a previously undiscovered adder snake and new populations of rare birds. They also expect to find new plants among the hundreds of specimens they have brought back with them.
Photographs from the trip - published here for the first time - show just part of the forest, tropical creepers, giant snakes such as the gaboon viper, and other wildlife seen by the team, including small klipspringer and blue duiker antelope, noisy samango monkeys, elephant shrew, and the granite-like rocky peak of Mount Mabu. Back at Kew Gardens in west London, where he is based, expedition leader Jonathan Timberlake said the wonder of what they experienced was only sinking in now that they are home: "That's when the excitement comes out - when you come back home or start reading some of the background and realise you're breaking new ground."
Scientists "describe" about 2,000 new species a year but discovering new ones still captures the imagination, said Timberlake: "The phenomenal diversity is just mind-boggling - seeing how things are adapted to little niches, to me this is the phenomenal thing. If we don't have wonder as a human species, where are we? If we don't have excitement, what are we doing with our lives?"
Mount Mabu was "discovered" in 2005 when Timberlake's team were looking for a site for a conservation project. Soon afterwards, locally based conservationist Julian Bayliss visited the site and studied satellite photos which showed a forest of about 80 square kilometres.
"It's then we realised this looked [to be] potentially the biggest area of medium-altitude forest I'm aware of in southern Africa," said Timberlake, who has spent most of his working life in the region. "Nobody knew about it. The literature I'm aware of doesn't mention the word 'Mabu' anywhere; we have looked through the plant collections of Kew and elsewhere and we don't see the name come up. It might be there under another name, but we're not aware of any collection of plant or animals, or anything else taking place there."
After a few exploratory trips, in October and November this year 28 scientists and support staff from the UK, Mozambique, Malawi, Tanzania and Switzerland, with 70 porters, drove to an abandoned tea estate where the road ended and hiked the last few kilometres into the forest to set up camp for four weeks. One highlight was emerging from the canopy on the peak of Mount Mabu, 1,700m up, where "hundreds upon hundreds" of male butterflies had gathered in the sunlight to attract mates by flying as high as possible. "There were swifts flying in and peregrines in the air above: it was phenomenal," said Timberlake.
Outside the forest the land has been devastated by a civil war that lasted from 1975 to 1992, but inside scientists found the landscape was almost untouched. Ignorance of its existence, poor access and the forest's value as a refuge for villagers during the fighting had combined to protect it, Timberlake explained.
The scientists fear that with local people returning to the area, and Mozambique's economy booming, pressure to cut the forest for wood or burn it to make space for crops will threaten the ecology.
Visiting and describing what they found was the first step to conserving the new species, said Timberlake. "They are not propping up the earth in most cases, but if you know about them what right have you to destroy them? If you don't know about them, it was an accident; if you know about them, it's malicious."
How scientists found the unknown forest
Scientists based at the Royal Botanic Gardens in Kew stumbled across the existence of Mount Mabu after looking at Google Earth internet maps in 2005, in the hope of finding a site for a conservation project.
Conservationist Julian Bayliss visited the area soon afterwards and saw satellite photos of a large, unexplored forest. In late 2008, an expedition hiked into it and was confronted with a treasure trove of new species.