The Role of Trees

Forests perform many important functions that affect humans.
Photosynthesis is the chemical process that takes place in the leaves. It uses sunlight and carbon dioxide (CO2) to produce sugars for the tree, and gives off pure oxygen (O2).
The forest canopy and root systems are natural water filters. The canopy re-distributes rainfall and shields the topsoil.
Forests store water. The forest floor can hold as much as five times its weight in water and a tree contains water in its roots, trunk, stems, and leaves. Forests help to regulate the flow of water in rivers and streams. Roots hold the soil in place and control erosion from wind and rain, preventing flooding and silting of streams and rivers.