Streamside Forest Buffers are Important for Water and Wildlife
Over one third of the land in the Chesapeake Bay watershed is either covered by development or agriculture. This poses obstacles to water quality in the form of nutrients, sediments, and other pollutants, but also to terrestrial wildlife that have little or no habitat in these settings. Trees planted along city streets and in suburban backyards may feel like a sort of coexistence with nature, but in reality these manicured settings provide habitat for very few native species. Farmland can also be deceptively “natural”; despite expansive hayfields and lush row crops, there are few places for wildlife to nest, raise young, or eat. Waist-high hay and six-foot-tall corn are eventually cut, leaving no cover for all but the smallest animals. Luckily, both water quality and wildlife habitat issues can be addressed with one management practice: buffering streams and water bodies with forest cover.
Healthy streams and watersheds rely on functional riparian forest corridors. A streamside forest will trap and filter nutrients and sediment from the uplands that would otherwise flow into the stream, and the overhanging tree canopy will cool down the water to make it suitable for trout and other native aquatic fauna. They can also be important for terrestrial wildlife, especially in landscapes dominated by agriculture or development. Stream corridors that hold trees, dense shrubs/saplings, and native herbaceous vegetation provide breeding, foraging, and escape cover for an array of upland and lowland wildlife species that would other have little to eat and no shelter from predators or the elements.
If you have existing forest cover around a stream, protecting and restoring it will be best for the water and wildlife. The width of buffer needed to improve water quality depends on the quality of the buffer and the adjacent land use, but 35 to 50 feet should be sufficient in most cases. A 50 foot buffer on either side of a stream will also be beneficial to many wildlife species such as deer, rabbits, woodcock, and pheasants, but many area-sensitive songbirds and other species require at least 150 feet of forest cover on each side.
In areas currently devoid of canopy cover, planting trees and shrubs may be necessary. Natural regeneration can successfully restore riparian corridors in some situations, but in predominately non-forested landscapes there are often either not enough seed sources or too much pressure from invasive vegetation that chokes out beneficial native species. Improvements in water quality require canopy cover to reduce water temperature and perennial vegetative cover to filter nutrients and sediment. Buffers can be improved for wildlife by planting diverse overstory species that provide food (oaks, blackgum, tulip-poplar, black cherry) and shrubs that provide dense cover and food to improve winter survival (alders, silky dogwood, red-osier dogwood, viburnums, ilexes). Additionally, consider pollinators when planting riparian buffers; in heavily developed and farmed landscapes these forests are often their only habitat as well. Pollinators require undisturbed soil and brush for nesting and nectar sources over the duration of the growing season. Consider the blooming period of trees and shrubs and try to ensure that there will be something flowering over as much of the year as possible, and avoid disturbing the herbaceous layer to encourage growth of native wildflowers such as ironweed, Joe-pye weed, and goldenrod.
Establishing a buffer by planting can be challenging, but there are many online resources and technical guidance to assist interested landowners. Visit forestsforthebay.org to see what assistance is available in your state or email me at firstname.lastname@example.org if you are interested in restoring streamside forests on your property.