Hiking through a Colombian woodland on a sweltering afternoon, Víctor Morelos paused at a stream to splash water on his face. This would have been nothing out of the ordinary if it weren’t for the fact that Morelos has helped bring the stream to life. Two decades ago, the surrounding land had been exhausted by cattle ranching and devastated by gold mining. Now it is a forest in recovery. The area had been part of the family farm, but once Morelos’s parents were gone, it was too much for him to manage. So Morelos sold the degraded land to a group of buyers who had a vision of a once and future forest.

Luis Gonzalo Moscoso, a Medellín-based forestry engineer who led the buyers’ group, saw promise where others saw only the legacy of plunder. Moscoso was determined to bring back a diverse, flourishing forest in a place where farming, ranching and a gold rush had taken their toll. Twenty years later, it is a thriving secondary forest with some 120 tree species, providing habitat for birds and other wildlife, including at least one jaguar, which several years ago triggered a camera trap. The sale of carbon credits provides revenue that could be supplemented by selective logging of commercial timber species. The results show it is possible to resuscitate ecosystems seemingly destroyed by unregulated alluvial gold mining, says Moscoso, who hopes his experience will inspire others to tackle the problem in their own countries.

Moscoso, 59, worked as an agronomist with Colombia’s National Institute of Renewable Natural Resources and the Environment (Inderena) from 1982 to 1995, when few people were talking about climate change, and when reforestation mainly meant planting exotic species such as pine, teak and eucalyptus. “People said that native species wouldn’t grow on degraded soil,” he recalls.

But the skeptics didn’t convince him. He had grown up amid tropical forest and knew that some trees thrived on poor soil. Those species helped each other, he says. Some shed leaves that provided nutrients, others harbored helpful microorganisms in their root systems. “I saw that taken together, the forest consisted of countless plants, and that it was necessary to also consider the microorganisms and animals,” he says.

He went into business with several partners, creating a company called Asorpar and buying a few farms near the town of Cáceres, where backhoes still eat away the riverbanks and hillsides in search of gold. He later formed his own company, Forestpa, but he still manages the carbon credits for all of the original areas.

The work began with a government subsidy that allowed Moscoso to use bulldozers to rid the land of those scars, reshaping the terrain and filling the huge pits left by mining. To jump-start recovery, he planted non-native acacia trees (Acacia mangium), which fix nitrogen and shed leaves, improving the soil. Other species followed, including Cariniana pyriformis, Protium heptaphyllum, Dipteryx oleifera and Lecythis spp.

Experts debate “active” versus “passive” restoration—whether it is better for humans to play an active role in landscape restoration or let nature take its course—but Moscoso has little patience for that discussion. “I don’t think anything on this planet is passive,” he says, “especially not in an ecosystem.”

He helped nature along by selecting seeds, adding fertilizer, pruning young trees and cutting away vines. As time passed, however, and the wind, birds and other animals dispersed seeds, understory plants filled in the spaces between saplings, and the plantation began to look like secondary forest. From the outset, he tried to keep outside technical staff to a minimum, hiring local farmers to gather seeds, tend seedlings in nurseries, plant trees and provide ongoing maintenance. Morelos is among the Cáceres farmers who are now familiar with landscape-restoration techniques. Establishing a good relationship with the local community is more complicated than planting trees, but is crucial for success, Moscoso says.

The area of the Cauca Valley where Moscoso works is in many ways ideal, he says. The tropical climate is right, and river ports, highways and airports provide easy access as well as the means to ship timber or other forest products to market. The fact that the land has been seriously affected by gold mining is also attractive to investors who seek to support restoration projects.

But there are downsides, too. In Colombia, as in other Latin American countries, unregulated gold mining is closely tied to drug trafficking. In 2016, the Geneva-based Global Initiative against Transnational Organized Crime reported that 80% of the gold mined in Colombia is illegal. The group said the percentage is as high as 90% in neighboring Venezuela and stands at 77% in Ecuador, while it is lower in other countries—10% in Brazil, 28% in Peru and 30% in Bolivia. Farmers in the Cauca Valley grow coca along with food crops, and the combination of drug trafficking, gold mining and criminal gangs triggers turf wars. Moscoso says he and his workers must maneuver carefully among an ever-changing cast of illegal players.

A similar situation exists in Peru, where drug trafficking and unregulated gold mining contribute to a high homicide rate in the southeastern Madre de Dios region. Although Madre de Dios is home to major protected areas and nature tourism sites, including Manú National Park and Biosphere Reserve and the Tambopata National Reserve, the scars left by mining are so broad that they are visible from outer space. An estimated 95,750 hectares (236,603 acres) of land—an area nearly as large as New York City—was deforested for gold mining in Madre de Dios during 1985-2017, according to researchers at Wake Forest University’s Center for Amazonian Scientific Innovation (Cincia) in Puerto Maldonado, the region’s capital.

Deforestation is only one of the landscape changes caused by mining, says France Cabanillas, who coordinates Cincia’s reforestation and restoration program. Abandoned mines consist of barren expanses of dirt or mud punctuated by water-filled craters and mounds of discarded stones. Some mines are near scattered forest remnants, while others form large, muddy flats far from forest edges. The result, Cabanillas says, is terrain that is also part waterscape, which makes restoration more complex.

Miners in Madre de Dios also operate at different scales, he points out. In the case of smaller mines, they pump sediment-laden water from a pit and send it cascading over a sluice, where gold-bearing sand settles out. Larger operations use heavy equipment such as backhoes. Those miners are more likely to leave strips of forest or set aside more fertile topsoil. That can help jump-start restoration efforts once the mine is played out, Cabanillas says.

A short boat trip along the Madre de Dios River from the mining town of Laberinto takes Cabanillas past dredges and riverside sluices to a mining concession where he is experimenting with different trees and nutrient combinations to see which will be most effective in the region’s climate and soil.

While Moscoso opted to recontour areas affected by mining before he began planting trees, Cabanillas is leaving the landscape as it is and is monitoring the recovery. Closing down a mine, he says, does not necessarily mean returning the terrain to its pre-mining state.

During the high-water season, when rivers overflow their banks, nearby mine craters become habitat for fish that swim from the river into the seasonally flooded forest and back. The abandoned, water-filled pits attract birds and other animals that feed on fish, including caimans and even some giant river otters.

The impact of these water sources is not altogether positive, however. Sediment in the pits tends to contain mercury, which can enter the food chain, on account of the miners’ prior use of that substance to help separate out gold. A Cincia study conducted last year during the May-through-September dry season found that fish caught in abandoned mining pits showed mercury levels 43% higher than fish caught in natural lakes in Manú National Park, where there is no mining.

At each of his test areas, Cabanillas begins by talking with miners. The researchers study the plants and animals in the ecosystem and use a drone to map the area. The detailed images enable them to determine how much of an area is soil, forest remnants, water and piles of stone discarded during mining.

Beside a water-filled pit at the concession near Laberinto, vegetation is already sprouting on the stone piles, dropping leaves that will help other plants take root.

Nearby, scores of trees—a mix of native, timber and fruit varieties—are divided into plots and carefully labeled. Cabanillas is testing different growing methods, building on research by Francisco Román, Cincia’s chief scientist. The study of four native species—Apeiba membranacea, Ochroma pyramidale, Ceiba pentandra and Erythrina ulei—found that seedlings planted with root balls and nutrients gained a better foothold in the degraded soil. (See "Mercury from mining prompts emergency in Peru" —EcoAméricas, May 2016.)

There are now 60 species in test plots totaling 42 hectares (104 acres) in mining concessions, indigenous communities and protected areas where miners once worked illegally. The researchers are testing the use of biochar made from sawdust from sawmills or from the shells of Brazil nuts, one of the region’s flagship forest products.

In some of the test areas, biochar is added around the seedling. In others, it is combined with a nutrient mix. Seedlings in control plots are planted without nutrients or biochar. The researchers suspect that the biochar will absorb water and some nutrients, possibly to the detriment of the trees, but that it will eventually release the nutrients back into the soil, sustaining the plant, Cabanillas says. It may also absorb mercury and other metals, keeping them away from the plant.

Building body of knowledge

One goal of the research is to produce data that Peru’s National Forest Service can use to develop restoration plans for degraded landscapes, especially areas affected by gold mining. “There’s a lack of available scientific information, probably because of the difficulty of working in mining areas,” Román says, adding that most scientific literature focuses on forest restoration in pasture or farmland. “There’s a lack of technical knowledge about how to restore, with what species and with what remediation techniques.”

There is no single formula, however. While restoration of protected areas damaged by mining will involve native tree species, for instance, reforesting denuded private or community lands may include commercial timber species, fruit trees, palms and other trees useful to local residents. Indeed, maintaining the forest and making it profitable enough to persuade people to leave it standing is a challenge.

In Colombia, Moscoso calculates that a combination of future timber revenue and carbon-credit sales on the voluntary market can finance restoration. Carbon credits are already supporting the work done on nearly 1,300 hectares (3,200 acres) of land near Cáceres. The initial restoration cost of US$2,000 to $3,000 per hectare was partly offset by a $1,200 per-hectare government subsidy. To fully recoup the investment and cover maintenance costs, he turned to the voluntary carbon market, selling 434,000 credits through the South Pole Group. Buyers include Avianca and Copa airlines and the Brazilian cosmetics company Natura.

Currently there are 192 monitoring plots, where workers measure the trees and calculate carbon storage, and there is an official inspection every five years by South Pole, a green-finance firm with offices in Medellín, and the nonprofit Colombian Institute of Technical Standards and Certification (Icontec).

Navigating income streams

The price of carbon credits for reforestation with native species has fluctuated between US$4 and $11 per ton of carbon since the project began in 2000—higher than that for single-species pine or eucalyptus restoration, Moscoso says. He expects to recoup his investment by 2025 and use a combination of carbon credits, selective logging and environmental services to cover future maintenance costs and produce an eventual 14% annual profit. He also plans to seek certification for over 5,000 hectares (12,355 acres) of additional land where he is managing restoration. Besides testing restoration techniques, Moscoso hopes his efforts convince others that restoration can make good economic sense. “We’ve turned a liability into an asset,” he says.

Miners could reap the benefits he has, he says, by restoring the landscapes where they have worked and taking advantage of fast-growing timber species as well as slower-growing trees. Meanwhile, a local landscape-restoration industry could develop, providing jobs for local farmers who have learned restoration techniques. Some who have worked with Moscoso have moved on to undertake other restoration projects.

Walking through one of the forests that he helped plant 20 years ago, he says that when they started, “This place was zero trees and zero carbon stocks.” He hopes for a day when the forest may be more valuable than the gold and cattle that led to the deforestation in the first place.

For his part, Morelos has overcome his own skepticism. When he first heard the reforestation plan, he says, “I thought they were crazy. “ He waves a hand at the forest around him and adds, “Look what it’s like now. It’s enviable.”