https://www.wired.com/story/the-horrifying-science-of-the-deforestation-fueling-amazon-fires/

Being a rainforest, the Amazon isn’t supposed to burn out of control, unlike California’s drier landscape, which is built to burn and burn explosively. Yet here we are, watching swaths of the Amazon go up in flames. And we can easily nail down the cause: humans. Deforestation is what’s driving these blazes, and there is some horrifying science behind that.

Since the 1970s, 20 percent of the Amazon has been deforested, totaling about twice the area of California. But deforestation isn’t an organized shrinking of the rainforest, paring it down from the edges in. Humans carve out farmlands, sometimes leaving a neat edge where the forest meets the fields, or even creating islands of forest surrounded by crops or grazing fields for cattle. Indeed, agriculture is far and away the primary driver of deforestation in Brazil.