Why should you be a friend to trees Trees are a valuable natural resource. People depend on trees for food, and animals depend on trees for food and shelter. But most important, we depend on trees because they add oxygen, a gas we all need, to the air. While trees give us many wonderful products, we must also protect them because we can't live without them. This nonfiction picture book is an excellent choice to share during homeschooling, in particular for children ages 4 to 6. It’s a fun way to learn to read and as a supplement for activity books for children.This is a Level 2 Let’s-Read-and-Find-Out Science title, which means the book explores more challenging concepts for children in the primary grades and supports the Common Core Learning Standards, Next Generation Science Standards, and the Science, Technology, Engineering, and Math (STEM) standards. Let’s-Read-and-Find-Out is the winner of the American Association for the Advancement of Science/Subaru Science Books & Films Prize for Outstanding Science Series.