BUENAVENTURA, Colombia -- In a muddy creek on the outskirts of town, hundreds of thick logs were piled up waiting to be turned into planks and plywood. Luis Mercedes, a veteran logger, admits he felled the trees and floated them downriver without a permit, but he says poverty forces him to cut corners.

Authorities see it differently. They fear that unregulated logging, mining and other gray-market activities along the coast are turning into sources of income for rebels and criminal gangs that haunt the area.

Colombia and the nation’s largest guerrilla group resumed peace talks in Havana this week in hopes of ending a bloody, 50-year civil conflict. The talks come as the country is braces for a possible new spate of violence starting Sunday when the Revolutionary Armed Forces of Colombia, or FARC, lift a unilateral ceasefire imposed over the holidays.

Both sides have said they’re optimistic that the sweeping five-point peace plan will bring an end to the violence by year’s end. But hurdles remain. Among them, the FARC will be required to give up the drug trade.

But on this marshy western Pacific coast, long-known for its cocaine smuggling routes, authorities say the guerrillas are diversifying into industries that are harder to detect because they’re easily camouflaged amidst the poverty, and the final products — wood and gold — are legal.

“The narco-terrorists have realized how lucrative these businesses are, and there are areas along Colombia’s Pacific that are abandoning coca cultivation and turning to illegal mining and other activities,” said Vice Admiral Rodolfo Amaya, commander of the Pacific Navy fleet. “These bandits want to control any industry that is producing cash.”

Along with their regular cocaine seizures in 2012, Amaya’s troops impounded 181,000 cubic-feet of wood — enough to fill two Olympic-size swimming pools — 19.4 tons of illegally caught fish and shutdown three mining operations run by the rebels.

Not all of the illegal trade is funding the FARC, Amaya said, but there are clear guerilla links among most of the mining and some of the logging.

Since its formation in 1964 as a largely rural guerrilla with Marxist underpinnings, authorities say the FARC has evolved into a powerful crime syndicate financed by drug-running, extortion and a wide-array of economic activities. In November, government troops found a clandestine oil refinery run by the guerrillas. Some analysts fear these profitable enterprises could keep factions within the FARC from embracing a peace deal.

These new industries “have to be on the negotiating table” in Havana, said León Valencia, director of Corporación Nuevo Arco Iris, a think-tank that studies the conflict.

“Cocaine and kidnapping used to be the primary sources of FARC financing in the 1990s and part of the last decade,” he said. “But that has changed. Now they’re into mining, smuggling gasoline out of Venezuela and all sorts of other illegal activities.”

Often the lines between illegal and informal operations are blurry.

Mercedes, the 54-year-old logger, admits that he sometimes has to pay guerrillas and other armed groups to move wood out of or through their territory. But he said his line of work is not an exception. Street vendors, cattle ranchers and truckers in Buenaventura also pay the vacuna, but authorities aren’t cracking down on those industries, he complained.