How do riparian forests and woodlands purify water?
Forests and woodlands purify water in many ways. Trees, through their roots, absorb fertilizers and other pollutants and store them in their leaves, limbs and root systems. This keeps pollutants from being released into waterways. Forest floors contain leaf litter that filters out phosphorous from sediment particles. Forest floors also contain bacteria that convert harmful nitrates into nitrogen gas, which is harmlessly released back into the air in a process called denitrification. Trees have other aquatic value also. They preserve habitat for many species of fish and invertebrates by providing shade. In addition, leaves that fall into waterways provide food and habitat for small bottom-dwelling creatures including crustaceans, amphibians, insects and small fish.
