15/03/2012 15:03 GMT | Updated 15/03/2012 20:47 GMT

Sascha Von Bismarck Finds Unlawful Connections Between Forests, Sifaka Lemurs and Guitars

"I could say it's important to understand the real nature of the problem, on the ground, to help create political will to make solutions, but it's also true to say I like getting out of the office."

Sascha Von Bismarck is speaking to me from the Washington office of the Environmental Information Agency (EIA), but it's very clear his thoughts are further afield, in the forests of Madagascar, where the rate of logging for export has cut huge chunks out of the woodscape, endangered the surrounding eco-system around and even put the cuddly silky sifaka lemur at risk of extinction.

It was the EIA's previous decade-long research into logging that helped the Lacey Act be passed, limiting logging in all parts of the world to sustainable levels.

Although this was gratifying in itself in terms of EIA recognition and credibility for the expedition to the logging hotspot of Madagascar, it also meant that, when Bismarck and a colleague travelled to the Indian Ocean island masquerading as wood traders, they were uncovering crimes, not just amassing data. This made them commensurately more vulnerable to native perpetrators, once they had reached the epicentre of the business in Antalaha, northern Madagascar, something of which they were only too aware:

"There were a few risky moments to choose from," remembers Von Bismarck, who joined the EIA 15 years ago, doing pure research into the impact of climate change before turning undercover detective in some of the world's most notorious trading regions.

Deep in the jungle of Madagascar, logging continues despite being outlawed since 2006 - Picture: EIA, this use only

"My colleague recognised someone on our plane as the most influential wood trader, and our key moment came a day later when we were introduced to him. He put us through our paces before accepting our back story, and we were subsequently given the green light to be shown around, and ask relatively open questions."

This subterfuge, including a five-day excursion deep into the jungle, made clear the scale of devastation wreaked by traders hungry for foreign coin.

"You only needed a day there to see for yourself," reports Von Bismarck. "The commerce all around you is dependent on illegal logging. There is hope for other economies to take over, like growing vanilla crops, and even logging itself, if done correctly. But the resource is being exploited by criminal networks, who are not interested in preparing for the next generation."

Joining the dots between such networks in developing countries and rich western distributors has been the EIA's speciality. It previously shone on a light on the wood used in Wal-Mart's baby cribs, and influenced the supermarket behemoth to alter its purchasing policies. The wood from Madagascar turned up in Gibson Guitars, something the company denied all knowledge of, and a lawsuit is now ongoing.

Much of the wood logged in Madagascar ends up in western products - Picture: EIA, this use only

"It gives wood a bad name," says the campaigner, hitting his stride. "Why would you want to own a beautiful instrument created in such exploitative conditions?

"This kind of law is all about having forests working for everyone. Instead, I'm sitting in a little canoe, trying not to tip over, with the wood flowing past you in the other direction to China and the US."

Von Bismarck has evidently worked tirelessly for the EIA's mantra "protecting the environment with intelligence", since what he calls a "founding moment" when he was studying fish in Africa's Lake Victoria. "I suddenly realised that the fish in this lake which 30 million people depended on for protein would be extinct for the sake of export product. The consequences were enormous."

For a Harvard graduate who speaks a one-man dinner-party of languages, there must be easier ways to earn a living?

"There may be easier ways, but nothing so gratifying. It's an immense privilege."

Madagascar, Lemurs and Spies is on BBC2 Thursday 15 March at 8pm (and on iPlayer) as part of the Natural World series

Discover more about the Environmental Investigation Agency at www.eia-international.org

Sascha Von Bismarck has taken the EIA's findings back to Washington