"All the armed groups, including the FDLR [Forces démocratiques pour la liberation du Rwanda], and some individuals in the army are implicated in the traffic of makala [charcoal]," said Emmanuel de Merode, director of Virunga National Park.
"Illegal trade in makala generates sale of up to US$30 million per year. A large proportion of this money goes to the armed groups," said De Merode.
Charcoal trade is common in the east. On the roads leading to Goma, North Kivu Province's main town, lorries and bicycles are often seen stacked with sacks of charcoal sourced from militia strongholds.
In Rutshuru territory, the FDLR controls loggers, charcoal burners and sellers, according to trader Solomon Mubake.
Traders in North Kivu obtain their charcoal from Rugari in Rutshuru, 35km north of Goma, or Burungu and Kitchanga, 80km and 90km west of Goma, respectively.
"The FDLR consider the forest as belonging to them... they have sub-divided it into tracts of about 5km, which three or four FDLR combatants monitor [day and night] when [the FDLR] are not fighting," said Mubake.
When they do not requisition the loggers, the FDLR imposes monthly taxes of between $5 and $25 per logger.
"It's better to stay in the house without exploiting the charcoal when one is not able to pay the $5... The people are afraid to die as the FDLR have no prisons," said Mubake. "These days, there is a lot of settling of scores. The FDLR kill those who betray them."
In Masisi territory, charcoal trade is mainly under Congrès national pour la defense du peuple (CNDP) control. Theoretically, the CNDP ceased to be a rebel movement with the integration of its elements into the army in January. But on the ground the reality is different.
"There are still checkpoints and barriers [manned] by armed elements who claim to belong to the CNDP and who are also taking $5 per month in tax and demand money to allow the passage of each sack of charcoal to the market," said Bimwa Shebatende, a distributor.
Villagers who do not obey CNDP rules are chased from their homes.
The situation is similar in South Kivu Province where the same armed groups control the charcoal trade.
Mathilde Muhindo Mwamini, president of a women's group, denounced the exploitation of civilians, especially women and children in the charcoal trade, as well as the engagement of army officers.
"It [charcoal trade] is one of the activities carried out by the FARDC [Congolese army]. They... sometimes use the civilian population to cut the wood [and] to make the charcoal... but they sell it themselves," Muhindo said.
She said in the past it was the FDLR who exploited the charcoal, having started these activities as refugees.
The Congolese army and the UN Mission in the DRC (MONUC) have since January conducted military operations against the FDLR and other militia in the east aimed at improving civilian security and cutting the militias' sources of financing.
The FDLR is a 6,000-strong armed group that has been a key factor in the instability in the Kivu provinces ever since its founders fled Rwanda in the wake of the 1994 genocide. Some 30 percent of the FDLR's forces are now Congolese.
At least 80,000 people were displaced in June in North Kivu and another 17,000 in neighbouring Orientale Province, according to the UN Office for the Coordination of Humanitarian Affairs (OCHA).
MONUC says the army's operation Kimia II has helped oust the FDLR and other armed groups from the mining sites but not from their forest hide-outs.
"Kimia II is aimed at recovering the main mining sites. [This] has been done and is being done but there are other sources of income [still available] for the FDLR and the armed groups," said MONUC military spokesperson, Lt. Col Jean-Paul Dietrich.
Counting the cost
According to De Merode, almost 92 percent of the makala produced in North Kivu comes from trees harvested in the park. Virunga is a world heritage site notable for its active volcanoes and diverse habitats housing endangered species.
So far, 20 percent of the park, about 790,000ha, has been destroyed by illegal wood-cutting and charcoal-burning and at least 120 park rangers have been killed by various armed groups, he said.
"For us, it is the ICCN [l'Institut Congolais pour la conservation de la nature] that has paid the price of the armed groups' presence with [their] blood," he said. The ICCN manages DRC's national parks.
The ICCN is supporting alternative energy sources such as biomass briquettes, which can be made from leaves, tree bark and fruit peelings or other farm waste. The production is low cost due to the abundance of raw materials and the briquettes also provide 70 percent more energy than makala.
It is distributing briquette production kits in Rutshuru and to IDP camps with the aim of reducing financing for militias, because the earnings will be collected in the villages and not in the forests where the FDLR are, said De Merode.
However, some NGOs are worried: "There are negative consequences to offsetting the charcoal trade," said Laura Miller of the NGO Mercy Corps. "Briquette presses may be destroyed by the rebels that control the charcoal trade, or community members may be forced to produce or transport charcoal for them."