It might seem counterintuitive, but tropical forest soils are, almost universally, terrible for farming. That’s due primarily to the insanely dense amount of life in these environments: In less alive forests, dead plant and animal matter has time to decompose and leach its nutrients into the soil. But in the tropical forest, huge numbers of insects, fungi, and bacteria devour any decomposing matter before it has a chance to enrich the soil. But people around the world live in tropical forests, and have had to figure out some way to make the soil actually productive. (The effects of the destruction...