New research reveals why forests in the Peruvian Amazon struggle to regenerate after gold mining. The study highlights severe soil and water depletion caused by suction mining, making reforestation nearly impossible.
New research has shed light on why the Peruvian Amazon is struggling to recover from gold mining activities. The study, published in the journal Communications Earth & Environment, attributes this environmental challenge not only to soil degradation but also to a significant reduction in water availability.
The research emphasizes that the common gold mining method called suction mining reshapes the terrain by draining moisture and trapping heat, creating inhospitable conditions for tree seedlings.
“We’ve known that soil degradation slows forest recovery,” co-author Josh West, a professor of Earth sciences and environmental studies at the USC Dornsife College of Letters, Arts and Sciences, said in a news release. “But this is different. The mining process dries out the land, making it inhospitable for new trees.”
Impact of Gold Mining
Led by Abra Atwood, a postdoctoral research fellow at the Woodwell Climate Research Center and a former student of West who earned her doctorate at USC Dornsife in 2023, the research team examined abandoned gold mining sites in the Madre de Dios region of Peru.
The team, comprising also of researchers from Columbia University, Arizona State University and Peru’s Universidad Nacional de San Antonio Abad del Cusco, used advanced tools such as drones, soil sensors and underground imaging to study the impact.
The method of suction mining involves blasting soil with high-pressure water cannons. This process filters out gold particles but washes away nutrient-rich topsoil, leaving behind stagnant ponds and towering sand piles.
Electrical resistivity imaging, a technique used by the researchers, showed that sand piles drain rainwater up to 100 times faster than undisturbed soil and dry out nearly five times quicker, leaving insufficient moisture for new roots.
“It’s like trying to grow a tree in an oven,” added West, emphasizing the challenging conditions on sand piles where surface temperatures can reach up to 145 degrees Fahrenheit (60 degrees Celsius).
Reforestation Challenges and Solutions
Despite some regrowth near pond edges and low-lying areas, large patches of land remain bare, particularly where sand piles dominate.
“When roots can’t find water and surface temperatures are scorching, even replanted seedlings just die,” Atwood said in the news release.
The difficulties faced in reforesting these mining-damaged areas pose a significant threat to the Amazon’s biodiversity.
From 1980 to 2017, small-scale gold mining obliterated over 95,000 hectares of rainforest in Madre de Dios — a region more than seven times the size of San Francisco.
Gold mining continues to drive nearly 10% of deforestation across the Amazon.
There is hope in rethinking recovery efforts. The researchers suggest that active reshaping of mine-altered terrain — flattening sand piles and filling in ponds — could improve moisture retention and aid tree regrowth. This is critical as natural erosion is too slow to address the urgency of reforestation.
“There’s only one Amazon rainforest,” added West. “It’s a living system unlike anything else on Earth. If we lose it, we lose something irreplaceable.”