Forests are the best form of land use for sustaining water quality and quantity. Studies clearly show that the amount of forestland within a watershed is an indicator of water quality and healthy aquatic ecosystems. In urban areas, trees and forests are part of what is referred to as the community’s “green infrastructure” and help reduce stormwater runoff. In rural areas, forests protect municipal water supplies, mitigate the impacts of flooding, replenish groundwater aquifers, and provide recreation and critical fish and wildlife habitat, as well as a variety of wood products.
Timber harvesting can directly impact water quality by affecting how water flows through an area. In particular, constructing roads, trails, and log landings can reduce soil permeability, increase soil erosion, and divert and concentrate water flow, leading to a channeling effect. Concentrated water flow can also erode banks and put undue pressure on bridges and culverts.
The Acceptable Management Practices (AMPs) for Maintaining Water Quality on Logging Jobs in Vermont, adopted in the fall of 2016, contains preventative measures to help control soil erosion and protect water quality. The AMPs are designed to minimize the effects of logging on the natural hydrologic functions of forests. The guidelines discuss how to absorb or disperse runoff, retain soil nutrients, filter sediment, prevent fluctuations in water temperature, and contribute organic material to surface waters.