Planting trees connects children with nature and shows them that their hard work makes a difference in the world.

School children can take an active role in helping to green their schools by teaming with their teachers, administrators, and parents to plant trees on their school property. These projects pay multiple benefits by improving environmental conditions and providing multi-disciplinary learning for students of all ages. It teaches them about plants and shows them how their efforts make an impact that they and their communities can revisit for years.

Trees in a school yard improve air quality and can reduce temperatures in warm climates by 10°F. They provide shade in hot temperatures and and new signs of life. They are a small environmental investment that will pay dividends for decades to come. 

https://www.earthday.org/campaigns/reforestation/planting-trees-at-schools/