Twenty-five attacks on logging facilities by saboteurs claiming to represent Chile's indigenous Mapuche people were registered in the first five months of 2016 by forestry subcontractors' union Acoforag.
That resulted in an estimated 9 billion pesos ($13.5 million) in damage, up from 3 billion pesos in all of 2015 and 638 million in 2014, according to the union.
Latin America's two largest forestry firms Empresas CMPC and Empresas Copec subsidiary Arauco have been among the worst affected.
Behind the attacks -- according to politicians and law enforcement authorities -- are two small, mysterious groups who say they want an autonomous Mapuche state. They are becoming increasingly well organized and sophisticated in their tactics, law enforcement, loggers, and politicians say.
The groups complain that the logging industry's introduction of water-hungry radiata pine and eucalyptus trees since the 1980s has damaged the ecosystem.
"Before, we had many water resources and natural spaces that were the center of our cultural lifeblood, our food, our spirituality and our strength," said Jose Osvaldo Millanao, a Mapuche leader, ...