Watershed Management

Maintaining a good forest watershed conditions lies in proper management of the forest floor. Even when disturbed, forest litter effectively reduces soil movement and excessive surface runoff. With time, more water will soak into the soil as organic matter blends into the surface soil. Of course, the forest floor must be protected from additional disturbances to accomplish these improvements.

Timber harvesting at periodic intervals, using systems compatible with site, soil, slope and stream characteristics, permits timber production and watershed protection to continue in harmony. Logging truck roads and skid trails are among the leading contributors to watershed deterioration. Skidding can cause deep ruts and seriously compact the soils. Skid trails should be designated and “logger choice” skidding should not be allowed.

Pre-Harvest Plan

Advance planning of the logging operation can prevent much of this erosion. Roads should be located on ridges, not in or near stream beds. Locate roads just to one side of the ridge line to improve drainage. When roads traverse the hillside, they should follow the contour and roll with the grade to avoid excessive cut and fill slopes. Road grades of 3 to 5 percent are desirable; however, sustained grades of 6 to 8 percent are acceptable when following Best Management Practices. An occasional short pitch of up to 15 percent can be tolerated if proper road drainage is built into the road, to avoid erosion.

Use dips frequently to break long grades. Construct cross-drains as needed and out slope road beds. Locate the roads far enough from water courses to provide an effective forested filter strip, 50 feet minimum. Keep trucks, tractors, skidders, and logs away from drainage channels. When logging is over, smooth out ruts and holes to prevent channeling runoff, install cross-drains and clean culverts (if used), and cultivate or rip and seed the abandoned roads with grass/legume seed mixture, including some preferred by wildlife species.

Skidding should be uphill on designated skid trails. Winching logs to this trail will minimize the number of skid trails, lower restoration costs and restrict land area that will be subject to reduced growth potential. Roadway and culvert drainage should be dispersed and slowed to retard runoff and encourage vegetation/forest floor filtering. Stabilize the streambank or channel by planting trees and fostering a vigorous, healthy timber stand.

Recommended Distance Between Water Bars on Skid Roads and Truck Roads

Grade Distance between Waterbars

Percent Feet
2 250
5 135
10 80
15 60
20 45
25 40
30 35
40 30

For many years timber harvesting was associated with the deterioration of forestland and streams. Research and experience have shown that the mere cutting of trees is not the cause of erosion damage in the forest.

Forest Roads and Trails
It is important to plan road systems that can provide permanent and efficient access throughout the woodland without damaging the watershed value of the forest.

The following checklist can control erosion on roads:

  1. Avoid logging during wet seasons or periods.
  2. Keep skid trails on grades of less than 15%.
  3. Keep roads on slopes less than 10%.
  4. Use approved stream crossings, bridges and/or culverts.
  5. Do not leave slash or tops in streams.
  6. Provide for proper drainage of skid trails and roads:
    • Outslope roads where feasible
    • Vary the grade
    • Use waterbars or dips, culverts, drainage dips, and diversions.
    • Divert water into protected areas.
    • Create sediment traps below water bars or dips outlets.
  7. Gravel roads where needed.
  8. Seed roads, skid trails and log decks.

Maintenance

To prevent four-wheel drive vehicle traffic during wet weather, access to roads and trails needs to be controlled by gates or other methods.

Areas used as logging decks make excellent wildlife patches. The problem with these areas are soil compaction and pH (the measure of the acidity or alkalinity of the soil). All forested areas which are cleared should be limed and fertilized. The necessary amount of lime and fertilizer can be determined by a soil test. You may want to consider developing some of these decks into small orchards for wildlife.

Logging and farm roads should be maintained for proper access and erosion control. Where these roads pass through recently harvested areas you may wish to widen the path to ten to twenty feet on each side.

These areas can be seeded with lespedeza or other wildlife food and periodically mowed or disced for maintenance. Every 400 to 500 feet you may wish to leave the natural vegetation. This will create strips which wildlife are more likely to utilize.

Fire lines which were constructed may be kept open by mowing every other year. If mowed, please follow the instructions in the wildlife section included with your management plan. If desired these areas may be disced and seeded with something which will be beneficial to wildlife, such as lespedeza, clover or small grain. These paths will also provide access, as walking paths, for yourself and other visitors to the property.

Do you want to harvest timber on your property, and have the logger follow "best practices?" For more information visit the Virginia Tech Sharp Logger Program.

Last modified: Thursday, 16-Apr-2015 16:33:21 EDT