Under the shredded canopy of the Peruvian Amazon, lunar landscapes replaced the old forests. Since the 1980s, gold mines in the Amazon have been gaining ground, snacking on the floors, sucking water and leaving behind sterile areas where nothing grows. Far from a simple deforestation episode, this extraction transforms the environment irreversibly, compromising the very capacity of the nature to regenerate.
The extraction is not limited to a white cut. It transforms lush forests into dead areas, riddled with artificial basins and sand mountains. The most common process, called “mining suction”, consists in spraying the soil with high pressure water cannons, then sucking sediments to extract the gold particles. This method, practiced by small often family structures, is particularly destructive for the local environment.
According to Eurekalert, these practices lead to an irremediable loss of the arable layer, rich in nutrients. This surface soil, essential to vegetable life, is literally raised, replaced by a sterile substrate where heat and drought settle permanently. Once these areas are abandoned, natural regeneration is almost zero, despite the ambient humidity of the region.
The gold mines in the Amazon transform the ground into a arid trap
The effect of this transformation goes far beyond the simple deforestation. The soil of the old mining areas behaves like a giant sieve. Rainwater infiltrates so quickly that it does not stay long enough to hydrate the roots. The study relayed by Live Science indicates that in primary forest zones, water penetrates the soil barely a few centimeters per day. In the exploited areas, this infiltration reaches fifteen meters a day.
The consequences are visible to the naked eye. The ground temperatures regularly exceed 60 degrees Celsius, and the surface can dry five times faster than in the intact forest. Even the young shoots replanted do not survive. Josh West, co-author of the study, sums up the situation by comparing these attempts to “grow a tree in an oven”.
In the rare areas where vegetation returns, we always find the same determining factor: the proximity of water. The edges of ponds or natural hollows keep a little humidity, which promotes partial vegetable recovery. But on the mounds left by extraction, the vegetation remains absent, the roots finding neither freshness nor organic matter to settle.
The data collected thanks to sensors, thermal drones and electrical resistivity analyzes show that this lack of water is the main obstacle to regeneration. The addition of fertilizers or biochar has little improves the results, because the problem does not only come from the ground, but from the way in which it interacts with water and heat.
Concrete solutions to restore a damaged landscape
Faced with such a observation, scientists are not content to alert. They offer concrete rehabilitation tracks, provided they act quickly and on a large scale. It would first be a question of filling the mining basins and of flatten the pile of sand, to bring the surface closer to the level of the water table. By reconfiguring the terrain, the roots of future trees could more easily access underground water.
But this operation requires significant logistical and financial means. Even the simplest techniques, such as the spreading of sowing or assisted planting, remain ineffective if the land is not corrected beforehand. On the other hand, in certain legal concessions, experiments succeed in relaunching a plant regeneration by preserving the arable land from the extraction.
Some researchers even plan to exploit sandy residues as a resource. The sand being highly sought after for construction, its extraction could then be revalued economically while preparing the land for a faster repair. This idea is still theoretical in areas with a strong illegal presence.
The urgency is clear. According to the authors of the study, the restoration of the Amazon will only be able to lead by completely rethinking mining practices, by awareness of local actors and by giving priority to areas close to water. Because a humidity without humidity does not grow back, and each hectare lost represents a slow but deep injury for the world climate.
