Project Learning Tree is an award-winning environmental education program designed for teachers and other educators, parents, and community leaders working with youth from preschool through grade 12. Project Learning Tree uses trees and forests as windows on the world to increase students’ understanding of the environment and actions they can take to conserve it. Since 1976, PLT has reached 145 million students and trained 765,000 educators to help students learn how to think, not what to think about complex environmental issues.