Deforestation probably started with fire and experts think 40%–50% of the Earth's original forests have been lost. Some of these forest losses happened around 10,000 years before agriculture began, but accurate information about deforestation has only been available in the past few decades. 

Deforestation can be traced back to 10,000 BC when humans started to cut down trees.  They did this because they wanted to make room for farming and taking care of animals.

Back then, a lot of the land where farmers wanted to grow their crops or raise their animals was covered in forests. So they had to cut down those trees to make space. Can you imagine that? All those trees being cut down!

Even today, farming is still one of the main reasons why deforestation happens. In fact, it's responsible for at least 80% of deforestation in places where it's really warm, like in the tropics. Farmers need more land to grow food for all of us, and sometimes that means cutting down trees.

But it's important to remember that trees are really important for our planet. They give us clean air to breathe and provide homes for many animals. So we need to find ways to protect our forests and make sure we don't cut down too many trees. That way, we can take care of our planet and the animals that live here.

500 years ago Sao Paulo in Brazil was covered by the Mata Atlantica rainforest and indigenous people farmed using agroforestry. 

Today Mata Atlantica is almost fully cleared. In the 20th century the Brazilian government encouraged people to cut down trees to make way for mono culture (single crop) farming in the area. Now people are turning back to agroforestry (trees and crops together) and are replanting native trees and plants in an effort to stop deforestation.

Half of deforestation happened between 8,000BC and 1900 so in the past century the amount of deforestation became 99 times the amount it was.