Forestry Best Management Practices
By Brian MacGowan and Duane McCoy
Did you know it can take up to 500 years or even longer to form one inch of topsoil? Rich, fertile soils form the basis for our forests. Their loss can affect forest growth, but also lower water quality from surface runoff. Forest Best Management Practices, or BMPs, are a set of practices designed to control soil erosion caused by human disturbance.
There are many forestry BMPs that are utilized in Indiana. Describing the technical details of them all is beyond the scope of this article. The Indiana DNR Division of Forestry has a more comprehensive guide online at http://www.in.gov/dnr/forestry/2871.htm. However, we describe below some of the more commonly used practices. To the surprise of most people, the cutting of trees in a logging operation has little impact on soil erosion. In fact, logging pales in comparison to other forms of soil disturbance, such as high-tillage agriculture or urbanization. The majority of BMPs for logging operations deal with forest roads and skid trails. Their design, construction, use and maintenance have by far the most impact on what soil erosion could potentially occur due to logging.
Road Design – Roads and trails provide access for logging but also facilitate regular access for many other land uses. For example, access is important for monitoring and controlling invasive species and wildlife viewing. However, landowners should minimize the amount of roads and their width as much as possible. Where you do have roads, keep grades between 2 and 10 percent if possible and avoid environmentally sensitive areas including seeps and waterways. Federal, state and local regulations may limit use and crossings in and around wetlands and some streams.
Steep Slopes – Depending on equipment available and future road use, landowners should install dips, culverts, turnouts, or water bars on sloped roads. The spacing of drainage structures depends on the steepness of the slope. For example, water bars should be placed every 250 feet for a 2 percent grade but every 60 feet for a 15 percent grade.
Stream Crossings – If a road must cross a stream, cross at right angles at a point where the streambed is straight and uniform and limit activities to periods of low to normal flows. A temporary bridge, culvert or ford may be necessary for crossing some streams depending on site characteristics and planned road use. Temporary structures should be removed as soon as their use is completed.
Use of Roads – Avoid using roads during wet periods. This may cause excessive rutting or erosion and/or may damage other features.
Fuels and Lubricants – Improper handling of fuels, lubricants and other chemicals can contaminate soil and water. Restrict fueling and maintenance activities to a designated area, such as part of a log landing which are typically located away from water and not prone to runoff.
BMPs are recommended
Even Though they were developed in accordance with the US Clean Water Act and in cooperation with the Indiana Flood Control Act, Forestry Best Management Practices are not required by law in Indiana for logging done on private lands. It is up to each landowner to specify their use in the timber sale contract. Clearly, their use helps protect our soil and water resources that we all depend upon. Requiring the use of BMPs on a timber sale could reduce your timber sale income. But in many cases, timber companies are set up and trained to install BMPs and the benefits to soil health and water quality are worth having the BMPs done by the logger at the time of harvest. Some timber companies may not want to bid on your timber if you require them to install BMPs, but if the logging company does not do the BMPs then you may need to do them at your own expense or risk degradation of your roads and trails due to soil erosion.
Installing BMPs on a timber sale is the right thing to do to be a good steward of the land. Many states require the use of BMPs, and the Indiana Classified Forest and Wildlands program and the Forest Stewardship Council requires landowners to control soil erosion. As always, the advice of a professional forester can be invaluable to landowners. See How to Choose a Forester in the previous issue for more information.
Brian MacGowan is an Extension Wildlife Specialist with Purdue University’s Department of Natural Resources. He also has served as secretary and editor for the Woodland Steward since 2008. Duane McCoy is a Timber Buyer Licensing Forester with the IDNR Division of Forestry and Dan Shaver is a Certified Forester and the Operations Manager for the Forest Bank, a working woodlands program offered by The Nature Conservancy.