Upland vegetation and soils protect water quality, too. Vegetation intercepts rainfall and snow. Instead of running off directly into waterways, water either percolates into the ground to replenish groundwater; or the vegetation takes it up and, through evaporation and transpiration, releases it back to the atmosphere. Studies have shown that, for the most part, natural vegetated areas allow almost no excess runoff after rain storms. Vegetated areas next to waterways prevent soil erosion.

Vegetation also improves air quality by absorbing carbon dioxide and releasing oxygen. Trees act as natural air conditioners, too. In the summer, they provide shade, in the winter, they can provide insulation and wind control.

Last Updated: September 2006