Large forests are important to us in many ways. They give us wood for building and heating . They are a home for many kinds of plants and animals. And for many city people forests are a place to go for a vacation. People can learn about nature there. They can breathe fresh air and sleep in quiet place.But there is one more reason why forests are important for everyone.The leaves on the trees in a forest help clean the air. Dirty air is a problem in many parts of the world. Without our forests this problem might be much worse.