Amazon's rain forest

They pretty much all result in desertification. The rainforest has very poor soil that is only maintained with lots of plant cover. When we get rid of the rainforest for our multitude or reasons, the topsoil washes away. Then there are not enough nutrients for more plants to grow. Without plants to hold moisture, there is no extra moisture to evaporate back into the clouds to make rain. So the deforested areas literally turn into deserts and experience lower precipitation.
We mainly deforest the rain forest, which is just chopping down trees for lots of reasons. After the trees are cleared away, the land is only fertile for a brief period of time, so farmers are constantly moving and chopping down more trees. We cut trees down for land also, for houses, and farms etc. We use the trees for lumber, houses, furniture, and paper too. By cutting down all the trees, humans have driven many animals out of their homes into open area, with no protection. This causes extinction of some animals. We also drive natives out too. Like I said previously, the land stops being fertile. Basically lots of negative things. I'm sure that is because there are no trees there anymore it causes floods when it rains, and washes away lots of soil, because there is nothing to hold the soil down anymore. And its just not pretty anymore.