 How do trees clean the air? They soak up the dirty air on their leaves, branches, and trunks, which means clean air for us. Hmm, cool. I didn't know that. Yep, but the forest does more than give us clean air and water. It gives us shade for hot days, birds to listen to, and trees to climb. Wow, that's awesome. I didn't know how cool the forest could be. Hey, let's go explore some more.