Nature is quite good at working out what needs to go where, and in what quantity. After all, it's had millions of years to become good at it; far longer than humans have been on the planet and building cities. Ecological systems are a balance, working in harmony to maintain order. When we tamper with that harmony, we cause problems.
There have been more forest fires within the Amazonian rainforest during the past twenty years than there have been in any previous twenty-year period on record. Climate change - which we contribute to - is partially responsible for this, but so is drought and deforestation. Densely packed forests stay damp and are difficult to burn. With less density, they dry out, and become prone to fire. A severe drought during 2007 led directly to the largest forest fire known so far, in which an area roughly equivalent to a million football fields burned to the ground, along with the animals that called it home.