OUTDOOR COLUMN: STREAM CORRIDORS: A SOLUTION TO BANK ON

Imagine you are floating down your favorite stream. You are enjoying the beautiful scenery. There are trees along the stream; deer ahead of you on the gravel bar; fish striking your lure. . . Then you notice an eroding stream bank. You also notice that there are no trees or vegetation growing on the stream bank. Would this create problems for the streams? Do trees play an important role in the function of the stream? The answer would be "Yes!"

Trees do play an important role in the function of the stream. Trees growing along streams provide many benefits for humans, wildlife, fish and the stream itself. The strip of land bordering a stream channel is called a stream corridor or riparian corridor. In general, a good stream corridor is at least 100 feet wide and is composed of uneven-aged trees and shrubs. This wooded border benefits the stream by filtering sediment, absorbing runoff, controlling erosion, enhancing fish and wildlife habitat and producing wood products.

A healthy stream corridor filters sediment and controls erosion in several ways. During a flood, the stream-side trees and shrubs slow the water before it passes into adjacent fields. When the water is slowed, most of the sediment will be deposited within the riparian corridor, not in the bottomland field and pastures. The riparian corridor will also collect woody debris before it reaches the fields. The tree canopy and leaf layer on the ground protect the soil from the direct force of falling rain. The leaf layer also acts like a sponge by absorbing runoff from adjacent fields and trapping sediment.

Trees have widely spreading root systems that can grow two times or more the height of the tree. Over one-half of the root mass are composed of very fine, fibrous feeder roots that penetrate virtually every crack and pore in the soil. The root systems of trees growing near the water's edge hold the soil in place and help prevent stream bank erosion. A wide riparian corridor will ensure that banks are protected even when severe flooding removes some stream-side trees.

The large variety of trees, shrubs and other plants, plus the nearness of water, are the qualities that make riparian corridors important to wildlife. Riparian corridors provide food, travel lanes, escape and nesting cover to many species of wildlife. Thirty-nine percent of the state's terrestrial species use riparian vegetation for all or a portion of their life cycles. Of the 55 terrestrial state endangered, or rare species, 34 use riparian corridors.

Trees also shade the stream during the summer, moderating the water temperature. Leaves and insects from the riparian corridor become an important part of the food chain within a stream. Trees fall into the stream and provide hiding places for fish. These logs also provide habitat for insects, crayfish and other aquatic animals important in the diet of many fish.

Fertile soils along the stream provide a good site for growing high value trees. An occasional selective harvest of trees from the stream-side forest provides income for the landowner and helps maintain a healthy, productive forest.

Riparian corridors are unique, sensitive and provide for a wide variety of plant and wildlife species. Leaving a 100-foot corridor of trees along a stream will help prevent most stream bank erosion problems and help to improve water quality in Missouri. So, if you notice some trouble spots along your stream or would like to know how to avoid stream bank erosion problems, call the Missouri Department of Conservation office in Cape Girardeau at 290-5730.

Brad Pobst is a Missouri Conservation Biologist in Cape Girardeau County.