The vegetation in watersheds effects the quality of the water. Grasses,
shrubs, and trees make up the majority of plant cover. As they fall and
decompose, they add the organic components to the soil. Trees are the
protectors of the watershed. The tree litter protects the soilís
surface as the roots of the tree protect the soil from erosion. Trees
also provide a canopy that keeps the water cool so organisms donít die
of thermal pollution. The canopy can also reduce the force of the
rain and the velocity of wind in a watershed.
Plant cover is important to a watershed to prevent the erosion of
valuable soil as water rushes downstream. Plant cover also provides food
and protection for many small organisms.