The Giving Tree by Shel Silverstein is a great read for both younger ages and older. Many people in this class have read this book I hope so you should know the plot. Basically a "boy" as he is referred to throughout the book finds himself as a young kid very attached to a tree, he loves the tree. This tree isn't just any tree though, it understands the boy and plays games with him like hide and seek. The tree lets the boy sleep in her shade and and eat her apples and they enjoy their time together. But as the boy gets older he finds a need for more serious things such as a house and a boat and money. The tree finds ways to give him all these things but it costs her everything except her stump.
I think the lesson learned from this book is that someone will always be there for you even when you feel all alone. The tree was there for the boy the whole book and supported him in times of need.