The Treemakers by Christina L. Rozelle is the first book of The Treemakers Trilogy. It's about a 16 year old girl, Joy, who has to work making "trees" so everyone will have air to breath. Joy becomes restless and wants to flee the prison and the torment the Superiors have thrust upon all those who make the "trees."
This is a very interesting concept. I have never read a book quite like this. The world building was fabulous and the characters were well fleshed out. The author spins a wonderful tale of a world so far gone that it is frightening. I can't wait to read the second installment.