Glyphosate and 2,4-D, among others, cause the trees to defoliate, and end up weakened or dead in a process that takes months. Next criminals remove the remaining trees more easily and drop grass seeds by aircraft, consolidating deforestation.
Brazil’s environmental agency, IBAMA, discovered that in addition to land grabbers, cattle ranchers use the method in order to circumvent forest monitoring efforts.
Pesticides have been dropped from planes and even helicopters with the aim of evading IBAMA, the Brazilian environmental agency, for years as a method to clear remote and hard-to-reach areas of the Amazon rainforest. That practice — used more frequently since 2018 — takes longer than clear-cut deforestation (the removal of all existing vegetation using heavy machinery). On the other hand, pesticide use cannot be detected via real-time satellite imagery.
According to IBAMA, some pesticides work as defoliants. The dispersion of those chemicals over native forest is the initial stage of deforestation, causing the death of leaves — and a good part of the trees. The material is burned and surviving trees are removed with chainsaws and tractors.
“Although human-induced forest degradation takes a few years to happen, the process is advantageous to criminals because chances of being caught are very low. We can only see the damage when the clearing is already formed,” notes an IBAMA official who spoke with Mongabay on the condition of anonymity. “A dead forest is easier to remove than a living one. Certain (not all of them) pesticides practically leave only big trees standing.”