Building Forest Trails
by Chris Schnepf

Authors Note: Many landowners are interested in improving recreational access to their property. This information from North Carolina State may provide some helpful information to you. This article is excerpted from: Recreational Forest Trails: Plan for Success, North Carolina State University Cooperative Extension Service Web site. Authored by Leon Harkins, Mark Megalos, Roger Moore, and Scott Payne. This web site also includes a variety of photos and video clips to help illustrate the concepts discussed here .-- Chris Schnepf

Reconnaissance and Pre-construction. Begin planning a trail by obtaining a legal survey description or plat of the property. Good choices are either a survey map of the property or a tax map (aerial photo) from your county tax office. Begin to identify major landmarks, including access roads, buildings, and power lines, on a photocopy of the map.

Transfer the boundary lines to a contour or topographic map. Topographic maps illustrate the physical features of the property and are useful in locating cliffs, watercourses, swamps, and other unique or problem areas. A topographic map of the property allows you to identify steep and difficult areas to be avoided when constructing the trail. You also can map major vegetation types, water bodies, clearings, existing roads, and rough topography.

Topographic maps are available from your Natural Resources Conservation Service office, outdoor outfitting stores, survey or engineering supply houses, or directly from the U.S. Geological Survey. The preferred map scale is 1 inch equals 24,000 feet.

If the proposed trail location will not follow a major watercourse or other land feature, you will need to survey the property systematically. By walking over the property you can record the location of key features and unique areas. The only true way to locate all the important and unique interpretive items and objects is to use the grid method of surveying.

The grid method, used frequently by foresters, requires sampling of the whole tract, ensuring that no key features are overlooked. The grid method allows for the systematic sampling of a property. Transect lines are established on a compass bearing that runs into the longest path across a property. Parallel lines are then followed so that a total "survey" of the property is made at a chosen distance--for example, 100 or 200 feet.

As you traverse the property, record roads, water bodies, timber changes, or other major interest points on your map. Flag important areas that are likely to be included in the final trail. Record all pertinent information in your field notes, as it will become the basis of your final layout.

Once all of your property's features have been identified and flagged, begin a rough layout of possible routes on the field map. In laying out the trail, avoid straight lines by winding the trail to conform to the land's contour. Maneuver from one interpretive point to the next, flagging as you go, until all points have been connected.

With practice and thorough knowledge of the property, most people can design a successful trail. Remember that no amount of office preparation can substitute for actually inspecting the property. The following tips will help you create successful forest trails on your property.

Favor trail placement in areas with:

• well-drained soils

• natural openings

• scenic vistas

• open timber

• light brush and vegetation conducive to easy travel

• special historical, ecological, and natural features

• access to and view of water bodies or streams

• natural drainage, such as side slopes and gently rolling terrain

• natural contours, such as those along terraces

• seasonal differences and experiences

• safe crossings of roads, railroads, and power lines

• good access from parking areas

• minimal conflict with existing land-use or management activities.

For safety, environmental, and economic reasons try to avoid locating trails in:

• wet and flat areas with poor drainage constraints

• frequently flooded bottomlands

• areas of unstable, fragile, or erosive soils prone to mud or rock slides

• areas where there are steep slopes and abrupt elevation changes

• areas that include bluffs, cliffs, and ledges, except where included for their scenic beauty

• locations requiring bridges or culverts

• areas of heavy vegetation requiring excessive clearing and periodic pruning and maintenance

• areas with fragile vegetation or rare and sensitive habitats

• cultural and archeological sites, except where featured as a part of the trail

• places where visitors could have adverse effects on wildlife or other resources

• timbered areas subject to blowdown, falling limbs, or lightning strikes

• road and rail crossings where sight distances are limited

• old mine areas and other natural or man-made hazards

• areas requiring multiple switchbacks or retaining structures.

Trail Layout. The final layout of a trail can be flagged or painted so that subsequent clearing and construction can proceed with minimal supervision. The key to success in trail design is to define and follow clear objectives. Most important, keep it interesting!

Keep these points in mind when laying out the trail:

• Vary trail alignment and direction.

• Avoid sameness by varying vegetative cover.

• Take advantage of natural features and diversity.

• Feature beautiful overlooks and vistas, seasonal landscapes, and clearings.

• Change the grade periodically but strive to maintain the trail on mid-slope positions to promote good drainage and minimize erosion.

• Keep trails inconspicuous, natural, and suitable to the land. The purpose is to heighten the "natural experience," not to construct another four-lane highway.

• Design a trail that tantalizes the senses: sight, smell, touch, and hearing.

• Avoid monotony by adding curves and zig-zags that add to the natural experience. Often the shortest distance between two points is the least interesting.

• Trail length can vary, but 1/2 to 1 mile is usually best.

• Create a loop or rough figure-eight trail that will return the user to the starting point. A connecting trail at the midpoint will allow visitors to choose a shorter or longer walk.

Trail Construction. After the trail route has been marked, construction can begin. Construction activities include tree removal, brushing or clearing, pruning, minor excavation, and occasional foot-bridge construction. Careful pre-construction planning can minimize the need for these activities.

Construction activities should be prioritized to accomplish the greatest amount of work within the available time and other resources. Brush clearing often yields the greatest return in defining the trail and opening it up to early use. Later, intensive projects such as removing trees, installing interpretive signs, or constructing bridges can be completed to refine the trail.

Trail clearing and brush removal can be accomplished with chain saws, mechanical brush cutters, hand saws, brush axes, regular axes, hatchets, loppers, and pruning saws. Hand clearing can be expensive and time consuming. However, labor availability may be the greatest obstacle to completing trail work. Greatest results are usually achieved when landowners can complete the work themselves.

Mechanized construction and clearing is often less expensive than hand labor; however, its use should be tempered by concerns for aesthetic and site disturbance. For instance a tractor-mounted rotary mower may make short work of brush control yet leave unsightly stumps behind. Clearly, some combination of mechanical and hand work is needed to complete trail construction in a timely and cost-effective manner. Let the your interest and ability as well as local conditions be your guide.

Trail Width, Clearing Heights, and Grade Specifications. Trail width varies with intensity and type of use. Short recreational or interpretive trails to be used for small groups should be wider than lightly used, longer trails. Trails should be at least 2 to 4 feet wide. Widths of 6 to 8 feet are needed for pleasure walking and in areas with steep drop-offs. Educational or interpretive trails must be wide enough to accommodate small groups, especially at points of interest.

Clearing width should be at least 4 feet along the trail or 2 feet wider than the trail on either side of the actual walkway. Wind the trail around large, existing trees within the trail's path rather than opting for total removal, and prune those trees' lower branches back to the trunk.

Clearing should be kept to a minimum. In cleared areas, cut all brushy vegetation flush with the ground. Clear all hazards adjacent to and above the trail. Strategically located fallen logs and large rocks can be left in place to discourage vehicular use and add to the natural variety of the trail. On trails that will be used by school groups, make small clearings (turnouts) adjacent to points of interest that will allow group instruction.

Clearing heights should be at least 7 feet for foot trails, 8 feet for biking trails, and 10 feet for equestrian trails. Periodic maintenance and monitoring at different seasons of the year will be needed to prune drooping and ice- or fruit-laden branches.

The grade, or slope, of the trail is the single most important factor in design and layout. The trail grade influences the length of the trail, level of difficulty, and drainage and maintenance requirements. Avoid creating long, sustained grades that can be tiring and monotonous to users. Try to maintain gentle slopes of 10 percent or less (less than 1 foot of drop over a 10-foot stretch). Gently undulate the grade to provide natural drainage and variation. Where steep grades are unavoidable, construct waterbars to slow runoff flow and to avoid erosion

A line of rocks can be used instead of the log to slow water flow. Bury two-thirds of each rock in the soil.

Periodic Maintenance. Natural processes are constantly shaping and altering the forests, and trails are no exception. Periodic upkeep and repair of trails must be scheduled at least annually. Some degree of mechanical or chemical control of resprouting brush will be required. Likewise, wooden and rock structures may need repair or replacement. Always build with weather- and rot-resistant materials to extend the life of structures.

To reduce the need to maintain and replace signs, consider using numbered signs keyed to an accompanying interpretive brochure that can be updated inexpensively as forest conditions change

Periodic maintenance helps you avoid major construction. Schedule your maintenance in relation to the amount and extent of use. You also should consider the safety or liability constraints of your users. Maintenance on disability-accessible trails should include controlling weeds, preventing excessive cracking, and protecting the surface against erosion.

Surfacing Materials. Materials used to cover high-traffic and sensitive areas may need to be replaced or replenished periodically. When choosing these materials, seek out local supplies of natural bark, mulch, wood chips, sand, and gravel, preferably those that can be found on the tract.

In wet areas with seasonal or standing water, surfacing is generally not feasible. In these areas use boardwalks, catwalks, decks, or log bridges to provide access and minimize disturbance. Always provide handrails in deep-water areas and where boardwalk height is greater than 2 to 3 feet.

Top Ten Trail Construction Tips.

• Decide the purpose of the trail before beginning the planning process. Educational, recreational, and scenic trails differ in layout, design, and interpretation.

• Know users' needs and provide ample resting areas, benches, and pamphlets or brochures for their enjoyment. Plan carefully to save resources and avoid problems.

• Hit points of interest. Maximize users' exposure to natural features, water bodies, and vegetation changes.

• Keep the trail natural in appearance by blending it with its surroundings and by using natural and native materials in construction.

• Follow the contour whenever possible to maintain a gentle trail slope with a grade of less than 10 percent.

• Vary the direction of the trail to add variety.

• Keep trail length between 1/2 and 2 miles; whenever possible, create a loop so that users can return to the starting point.

• Trail width should be a minimum of 2 to 4 feet with a trailside vegetation clearing of an additional 12 inches on each side. Trails that will receive heavy use and trails on steep terrain should be 6 to 8 feet wide. Maintain an overhead clearing height of 7 feet for foot trails, 8 feet for bike trails, and 10 feet for horse trails.

• In concentrated or heavy-use areas, trail surfacing may be required. Use low-cost native or natural materials such as wood chips, bark, or mulch.

• Consider trail markers, informational signs, and brochures, especially on self-guided nature and interpretive trails.

Sources of Additional Information.

• Ashbaugh, B. L., and R. F. Holmes. 1967. Trail Planning and Layout. National Audubon Society. New York, NY. 104p.

• Fogg, G. E. 1986. A Site Design Process. National Recreation and Park Assoc., Alexandria, VA. 185p.

• Fogg, G. E. 1981. Park Planning Guidelines Revised. National Recreation and Park Assoc., Alexandria, VA. 202p.

• Larsen, D. M., and W. R. Miles. Nature Trails. Agricultural Extension Service, University of Minnesota. Extension Bulletin Number 368. 15p.

• PLAE, Inc. 1993. A Design Guide for Universal Access to Outdoor Recreation. Berkeley, CA. 240p.

• USDA Forest Service 1985. Trails Management Handbook. (FSH 2309.18) 84p.