Corridor clearing

1. Definition & Purpose

The purpose of corridor clearing is to clear the space through which the trail will pass.

  • Consider:
    • vegetation trimming or removing
      • tree cutting and stump removing
      • branch trimming
      • grass and bushes trimming
    • clearing the first organic layer of material on the ground
    • removing stones and boulders (if not used as natural feature)
  • When building a new trail, clearing the corridor helps to:
    • define the route of the trail,
    • enable the trail builder to safely transport tools and equipment as they build the trail,
    • create fall zones,
    • ensure an acceptable sightline
  • When maintaining an existing trail, consider:
    • maintaining a visible trail surface
    • maintaining sightlines
    • maintaining fall zones
  • It is mandatory to follow the legal or the landowner’s guidelines on what you are allowed to cut – and what not.
  • Plants tend to keep growing even stronger after a corridor was cleared because the sun penetrates the ground. Therefore, it is important to consider corridor clearing as a regular maintenance task.

Trail clearing parameters are (Figure 1):

  • trail tread (the surface of the trail without organic material)
  • trail ceiling (distance from trail tread to the canopy)
  • the trail corridor, which is the trail tread plus fall zones and/or cut areas to reassure better visibility

Figure 1 : Trail corridor parameters, source: Felton, 2004; Trail Solutions: IMBA’s Guide to Building Sweet Singletrack


2. Key Considerations

2.1 Typical Characteristics

2.2 Key Aspects

3. Specific building techniques and tools

Cutting trees

  • Cutting trees is a profession and requires specific techniques, tools and safety gears. Refer to national country regulation and available courses.
  • See the tools and gears inventory list for a detailed list of cutting tools and associated material to create a checklist according to the situation.

Removing stumps

  • Stumps need to be completely removed from the ground.
  • If not done properly, after some time, leftovers will appear on the trail surface and might become dangerous for wheels or riders.
  • When cutting the tree, leave a good leverage handle about 1-1,5m from the ground.
  • Machines will maybe have the power to shake and bend the remaining stump enough to break the root system
  • If hand building or in many cases when machines won’t be strong enough to break the roots, trail builders will have to dig around the stump and cut the roots until it is possible to break the remaining ones using the lever.
  • Winch and straps or chains are very useful and powerful tool when you have somewhere to hold on
  • Cutting roots means using sharp tools in gravely or sandy ground which will rapidly deteriorate the sharpness of the tool, consider bringing old saw, spare chain for chainsaw or axes you can easily resharpen
  • Check the Nordic saw on the tool list for roots cutting

Trimming trees

  • When trimming living trees consider the optimal season considering vegetation growth (usually autumn, winter or early spring)
  • Consider the right tools to cut the intended diameter in a clean manner
  • Cut living trees at the right spot (see figure xx)
  • See the tools and gears inventory list for a detailed list of trimming tools and associated material to create a checklist according to the situation.

Removing boulders

  • Heavy weight lifting or transportation is always easier with machines
  • But it is very impressive the load that a crew of people using appropriate tools can move
  • If not done right, moving boulders can be very dangerous in 2 ways: Accidents and long terme back-injuries
  • To avoid both, the working crew needs to be taught the safety measures and be very well coordinated
  • Using rock-bars as lever make the work a lot easier and helps keeping a safe distance
  • Using ropes, straps, jack lift, winch and rock sling will help transport the boulder for few meters
  • Rock bars can serve as sliding rails as well
  • In steep terrain always install a retaining wall with wooden plank below the working zone and hold rocks with straps to assure they can’t roll down the hill.
  • Rocks are great building material, always consider using them as support or features

4. Illustrations & Media

Photo 1: Stump removal using a chain winch

Figure 3: Pruning off branches correctly

5. References

  • Felton, V. (2004). Trail Solutions: IMBA’s Guide to Building Sweet Singletrack (IMBA (International Mountain Bicycling Association), Ed.). International Mountain Bicycling Association.
  • International Mountain Bicycling Association. (2001). Building Better Trails: Designing, Constructing and Maintaining Outstanding Trails.

6. Further information