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FOREST MANAGEMENT WORKSHOP MANUAL

LOGGING ROADS

If a stand of trees is going to be managed on a continual basis, there must be some type of road to allow access for cultural operations and harvest. Unfortunately, any type of road construction creates a variety of site disturbances that tend to accelerate erosion and increase downstream sedimentation. Low standard roads such as those used in logging or strip mining are particularly troublesome because of such factors as poor location and design and lack of erosion control measures. In fact, the major source of sediment from erosion in logging operations is from logging roads. As Federal and State laws come in effect, more and more attention will have to be given to this type of erosion. Public Law 92-500, the Federal Water Pollution Control Act of 1977, has a Section 208 which deals with non-point pollution. Non-point pollution, and sediment is pollution from large areas which contributes to poor water quality but the exact point at which it enters a stream cannot be determined, as opposed to point source pollution from a pipe which can be exactly pinpointed. Erosion from logging roads is non-point pollution, and as time goes by, this type of pollution will come more under government regulation. So as a management plan is developed for a woodland tract, consideration should be given to road locations designed to minimize erosion and to avoid problems in the future.

Most of the potential erosion problems are caused by one or more of these factors:

  1. Removal or reduction of vegetative cover.
  2. Destruction or impairment of natural soil structure and fertility.
  3. Decreased infiltration rates on parts of the road.
  4. Concentration of runoff or seepage water.
  5. Interception of subsurface flows by road cuts.
Planning
Skidding uphill causes less erosion than skidding downhill. Try to plan for hauling downhill on gentle slopes. On small ownerships, one well located haul road with a well planned skid road system, often provides access to the whole tract and requires a minimum amount of land. Well planned road systems are also aesthetically pleasing.
Location
Try to locate so that sustainded grades do not exceed 10% (10' rise per 100'), short grades may run as high as 20% (20' rise per 100'), but keep a maximum grade of at least 3% (3' rise per 100'), to facilitate drainage. Do not locate roads in streams and allow enough distance between the road and stream to filter sediment. Cross streams at right angles. Do not skid straight up and down slopes.
Drainage
This is the most important aspect of design. The most common drainage device used are culverts. They can be open or closed and are used more often on the main haul road. Open culverts can be made of logs or boards to intercept surface water and control rutting and gullying on the main haul road. Closed culverts are used most effectively where water runs continuously. Outsloping means sloping the road surface to allow runoff to flow evenly across the road without collecting.

For safety, in steep terrain logging roads could be insloped and water channelled to culverts and removed. An alternative to culverts is broad-based dips. These are installed after the basic roadbed is constructed. They are good for erosion control on both skid roads and haul roads and can be used where road grades do not exceed 10%. Here is a spacing formula for broadbased dips:

        Spacing=100 feet + (400/Road Grade %)
Maintenance
This is mainly a problem of water control. Make sure that culverts, dips, bridges, and outsloping are free to carry away water. After logging, usually it's best to remove open wooden culverts and install water bars. Seeding raw and denuded areas reduces gullying and prevents erosion. Opening the canopy to allow sunlight to reach the roadbed allows the road to dry out quicker and helps vegetation become established. Careful location and design can completely eliminate many road maintenance problems and minimize others.
Traffic regulation
Traffic must be regulated for proper maintenance.
Care after logging
Immediately following logging, main haul roads and skid roads should be smoothed and outsloped and drainage structures should be cleaned. Major skid trails and log landings should be seeded and have water bars or other drainage diversions installed. (Refer to bibliography for reference listing best management practices to control erosion on woodland).

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Last revised August 14, 1995.

Please send comments to: Duane Bristow (72711.1414@compuserve.com)