Small-scale gold mining has destroyed more than 170,000 acres of primary rainforest in the Peruvian Amazon in the past five years, according to a new analysis by scientists at Wake Forest University’s Center for Amazonian Scientific Innovation (CINCIA).

That’s an area larger than San Francisco and 30 percent more than previously reported.

“The scale of the deforestation is really shocking,” said Luis Fernandez, executive director of CINCIA and research associate professor in the department of biology. “In 2013, the first comprehensive look at Peruvian rainforest lost from mining showed 30,000 hectares. Five years later, we have found nearly 100,000 hectares of deforested landscape.”

The scientists at CINCIA, based in the Madre de Dios region of Peru, have developed a new data fusion method to identify areas destroyed by this small- or artisanal-scale mining. Combining existing CLASlite forest monitoring technology and Global Forest Change data sets on forest loss, this new deforestation detection tool is 20-25 percent more accurate than those used previously.

Both CLASlite and the Global Forest map use different kinds of information from light waves to show changes in the landscape. “Combining the two methods gives us really good information about the specific kind of deforestation we’re looking for,” said Miles Silman, associate director of science for CINCIA and director of Wake Forest’s Center for Energy, Environment, and Sustainability (CEES). Silman has researched biodiversity and ecology in the Western Amazon and Andes for more than 25 years.

Artisanal-scale gold mining has been hard to detect because its aftereffects can masquerade as natural wetlands from a satellite view. But the damage is extensive. Small crews of artisanal miners don’t expect to hit the mother lode. Rather, miners set out to collect the flakes of gold in rainforest.

Read more at Wake Forest University