Human beings need lungs to breathe in oxygen and breathe out carbon dioxide. Without our lungs, we couldn't survive. Trees on the other hand, act like the lungs of the earth. Trees help the planet breathe by turning carbon dioxide into clean, pure, oxygen.
Trees and forests around the world also act like the planet's air conditioning system and keep the planet cool. They help stop global warming. Global warming happens when we burn too much oil or gasoline and when we cut down too many forests. Global warming makes the weather change in serious ways, which is why it's important to stop it from happening. Protecting forests keeps our planet cool.