Why do we need trees?
Boy do we all need trees! Why? Let me explain. Humans, and virtually all other critters, live on a gas called oxygen. Oxygen is one of the gases found in air and every single cell inside you needs the oxygen you inhale for energy! Sure, you also need food, but your body couldn't even make use OF the food you eat if you didn't have that oxygen. When you exhale, you get rid of gases from the air that your body can't use, as well as gases that your body's cells have produced while at work. This includes a modest amount of carbon dioxide gas that was in the air you breathed in as well as the carbon dioxide that was made by your body.
Now the remarkable thing is that humans can't breathe pure carbon dioxide. Heavy-duty amounts of carbon dioxide are poisonous to them. In fact, that's why so many of you have alarms in your homes, similar to smoke alarms, that are made to go off if they detect the presence of serious amounts of carbon dioxide being belched out of something such as a furnace. So how come all you humans exhaling hasn't made a world filled with nothing but carbon dioxide? Because of trees. Through their leaves, trees take in carbon dioxide from the air, use it to make the sugar that is their food, and release gases they don't use back through their leaves. What don't they use?
Oxygen. Amazing, huh. And amazingly lucky!
So the answer is yes, yes, yes. We like trees, but even more importantly, we NEED trees. We couldn't afford to lose them!