"Follow the trail of charcoal," de Merode had said at the WildlifeDirect office. "Charcoal is the biggest threat to the park."

Charcoal, as we discover over the next few days, is the main source of energy, and evil, in North Kivu. Charcoal is used by 98 percent of the households for cooking, boiling water to make it potable, and also for heat. In the city of Goma, a constant pall of charcoal smoke smudges out the sun and makes the rough streets, rumpled with hardened lava from the 2002 eruption of Nyiragongo, appear to be pathways to hell.

Bound by Lake Kivu to the south, Goma is a tin-roofed shantytown that in the past decade has swelled with people fleeing conflict. Its population now stands at roughly 700,000, with several hundred thousand more in nearby refugee camps. The UN has a force of 5,700 mostly Indian soldiers garrisoned in and around the city. Their headquarters, like most of the office buildings and homes of NGOs, is a miniature fortress—armed guards, metal gates, 12-foot-high concrete walls strung with razor wire.

Because of the fertile, volcanic soil, the area around the park is one of the most densely populated regions in Africa, with more than a thousand people per square mile. Neatly hand-hoed fields of potatoes, cassavas, bananas, and beans run right up to the park boundaries. There is no buffer zone between human activity and the verdant hysteria of the forest, just a rock wall buried beneath foliage. Charcoal, made from trees cut and reduced to carbon in makeshift mud ovens, comes from inside the park.

The most valuable, old-growth trees are the source of hardwood charcoal, which burns hotter and longer than softwood charcoal. To try to save the forests, NGOs like the World Wildlife Fund have planted millions of trees, especially fast-growing eucalyptus, around the park as a sustainable source of wood.

One 150-pound sack of hardwood charcoal lasts the average family about a month. With more than 100,000 families living within 20 miles of the southern end of Virunga National Park, the demand amounts to 3,500 to 4,000 sacks of charcoal a day, and this does not include the needs of Rwanda, which has outlawed the production of charcoal to protect its forests.

This much charcoal cannot be transported without a fleet of trucks. The Congolese army has the trucks, and it has suppliers in the forest: the Hutu militias. A sack of charcoal sells for $25 on average. Do the math: De Merode estimates that in 2006, when gorilla tourism brought in less than $300,000, the Virunga charcoal trade was worth more than $30 million.

Robert Muir, project manager for the Frankfurt Zoological Society's Virunga National Park conservation effort, says that charcoal production has already devastated approximately 25 percent of the old-growth, hardwood forest in the southern half of Virunga National Park, and at the current rate of destruction, the entire southern sector could go up in smoke in ten years.

"But it can be stopped, it must be stopped, and it will be stopped," he says.