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Trail Construction and Maintenance Notebook

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Please see the updated 2007 Edition.

Introduction


Why write another trail construction and maintenance guide? Good question. Several good trail books and many local manuals already exist. These are being used to train trail crews throughout the country. Only a handful are published or widely available, however. Lots of great information is being circulated on photo-copied copies of photocopies.

The Missoula Technology and Development Center (MTDC) was asked to pull together basic trail construction and maintenance information, present it in an easy-to-understand fashion, and orient it just to activities done in the field. We do not intend to duplicate information already in the Forest Service handbooks or manuals for tasks better completed in the office, although we've tried to make sure this notebook is consistent with current policies and direction. We worked to keep it small and readable so it would end up in trail crew packs instead of propping up table legs.

Since this notebook covers just the basics, you'll want to read the more detailed Forest Service Trails Handbook (FSH 2309.18), Specifications for Construction and Maintenance of Trails (EM-7720-103), Standard Drawings for Construction and Maintenance of Trails (EM-7720-104), Standards for Forest Service Signs and Posters (EM-7100-15), Forest Service Health and Safety Code (FSH 6709.11), Transportation Structures Handbook (FSH 7709.56b), and selected references from the bibliography. Other sources cover winter trails, paved or surfaced trails, and other specialized trails.

We have also found there are many regional differences in techniques, tools, and terminology throughout the country. It is impossible to describe them all, and we hope you aren't offended if your favorite has been left out or called a funny name.

There is very little "new" about trail work. Our culture, though, has forgotten a lot about trails. Most of us know very little about water and dirt when we attempt our first trail job.

You might not do things the way they are described in this guide--that's cool! Understanding why things are done is at least as important as how. If you know why something is happening, you'll figure out a way to build a structure to match a need. Soak up the core concepts. Experiment and keep track of the results. Be curious. Add new techniques and tactics to your bag of tricks. Get dirty and HAVE FUN!

Metrication

Metrication lives! Standard International (SI) units of measurement (metric) are used throughout the text followed by roughly equivalent English measurements in parentheses. Bear with us as we join the rest of the world. There is a handy conversion chart on the inside back cover to help the metrically challenged make the transition.

One other word on measurements. Most crews don't haul measuring tapes around to measure things. A really handy way of keeping track of commonly used measures is to mark them on tool handles. For example, if your typical tread is supposed to be 600 mm (24 in), mark that distance on the shovel handle.

The Job of the Trail Crew

The most important thing in trail maintenance is your personal well-being and safety. Are you fit? Do you know your limitations? Do you have the skills you need?

Your personal gear, clothing, and safety equipment are important. Let's start with your feet. Most trail work is in pretty rough country. Leather boots, at least 200 mm (8 in) high, offer the best support and ankle protection and are a Forest Service requirement when using cutting or digging tools. Ankle-high hiking boots are okay for some trail work. Sneakers or tennis shoes do not give enough support and protection. Be aware of regional differences. In southeast Alaska, for example, rubber boots are the norm for most trail work.

Pants rather than shorts give greater protection from scrapes, insects, and sunburn. Long-sleeve shirts are best for the same reasons. Bring your foul-weather gear. You won't forget a good pair of gloves more than once. Drinking water, lip moisturizer, sunscreen, sunglasses, insect repellent, and personal medications round out the list.

Hardhats are an agency requirement for many types of trail work, especially when working in timber or when there is any chance of being hit on the head. Other safety gear you need includes eye protection for any type of cutting or rock work, ear protection near most motorized equipment, and dust masks for some types of rock work and in extremely dusty conditions. Don't start the job unless you are properly equipped. Take a look at the Forest Service Health and Safety Code (FSH 6709.11) for some good information that could save your life.

As a crew, you'll need a first aid kit, the training to know how to use it, and a realistic emergency and communication plan. The project leader should prepare a job hazard analysis that identifies the specific hazards of the work you will be doing, and should also hold safety briefings before you start and whenever you do something new.

Setting Priorities

High-quality and timely maintenance will greatly extend the useful life of a trail. The trail crew's task is to direct water and debris off the tread, and keep the users on it. The best trail maintainers are those with "trail eye," the ability to anticipate physical and social threats to trail integrity and to head off problems.

Even though you know the proper maintenance specifications, sometimes there is too much work for the time you have to spend. How do you decide what to do?

Since it's a given that there will always be more work to do than people to do it, it's important to:

  • Monitor your trail conditions closely.
  • Decide what can be accomplished as basic maintenance.
  • Determine what can be deferred.
  • Identify what area will need major work.

This 'trail triage' is critically important if your maintenance dollars are going to be spent keeping most of the tread in the best possible condition.

The first priority for trail work is to correct truly unsafe situations. This could mean repairing impassable washouts along a cliff, or removing blowdown from a steep section of a packstock trail.

The second priority is to correct things causing significant trail damage--erosion, sedimentation, and off-site trampling, for instance.

The third priority is to restore the trail to the planned design standard. This means that the ease of finding and traveling the trail matches the design specifications for the recreational setting and target user. Actions range from simply adding "reassurance markers" to full-blown reconstruction of eroded tread or failed structures.

Whatever the priority, doing maintenance when the need is first noticed will help prevent more severe and costly damage later.

Trail Planning and Design

Recreation trails are for people. They allow us to go back to our roots. Trails help humans make sense of a world increasingly dominated by automobiles and pavement. They allow us to come more closely in touch with our natural surroundings, to soothe our psyches, to challenge our bodies, and to practice ancient skills.

Keep this in mind when designing, constructing, and maintaining trails. Although many trails have some purely utilitarian value, their esthetic and recreational qualities are important to most people. A well-crafted trail is unobtrusive, environmentally sensitive, and fun.

Human psychology also plays a role. A useful trail must be easy, obvious, and convenient. Trails exist simply because they are an easier way of getting someplace. Of course, many trails, such as wilderness trails, dirt bike routes, or climbing routes, are deliberately challenging with a relatively high degree of risk. Rest assured, however, that if your official trail isn't the "path of least resistance" for users trying to get from point A to point B, they will create their own trail. Your trail must be easier, more obvious, and more convenient than the alternatives (relative to the challenge level sought) or you're wasting your time and money.

A good trail may appear to have "just happened," but that appearance belies an incredible amount of work in scouting, design, layout, construction, and maintenance. Although this guide is focused on actual dirt work, we want you to clearly understand that solid planning is absolutely essential.

If you've ever encountered a trail "disaster," chances are that it resulted from short-circuited planning. Acts of God aside, some of the worst trail problems result from not doing the hard work of thinking before putting on the gloves and hardhat. Some glaring examples of "fixes":

  • Building out-of-rhythm short reroutes instead of rebuilding the old trail in place.
  • Feeble rock crib walls.
  • Stacked switchbacks with long, nearly level approaches.

Planning is not a hoop to be jumped through. Planning is stupidity avoidance. Do good planning for all levels of trail work.

Good planning also includes monitoring trail condition. It's hard to do good planning unless you have some idea of the current situation and trend.

Trail Specifications

The three best "friends" of a trail worker are a good baseline inventory of the trail, a current condition survey, and problem area reports. Hang out with these friends... get a clue.

All trails are not created equal. Each is ideally designed, constructed, and maintained to meet specific requirements. These specifications relate to the recreational activities the trail is intended to provide, the planned level of difficulty, the amount of use expected, and physical characteristics of the land. Ecological and esthetic considerations are also important.

For example, a narrow winding trail might be the right choice for foot traffic in wilderness, while one with broad, sweeping turns would be appropriate for an ATV (all-terrain vehicle) route. A smooth trail with a gentle grade is more appropriate for an interpretive trail or a trail designed for disabled persons (Figure 1 and Figure 2).

Photo of wilderness traffic
Figure 1--A narrow, winding trail might
be the right choice for wilderness

Photo of a smooth trail
Figure 2--A smooth trail with a gentle grade is
appropriate for an interpretive trail or a trail
designed for easy access.

Steepness or grade helps determine how difficult a trail is to use. The grade also has a direct bearing on how much design, construction, and maintenance work will be needed to establish solid tread and keep it that way. Grades range from 1 percent for wheelchair access to 50 percent or greater for scramble routes. Most high-use trails should probably be constructed in the 5- to 12-percent range. Trails of greater challenge or in more durable soils can be built at grades approaching 20 percent. Trails at grades over 20 percent become difficult to maintain in the original location without resorting to steps or hardened surfaces.

Specifications are important. You'll want to refer to the Forest Service Trails Management Handbook (FSH 2309.18) for guidelines for most any type of trail you'll have the opportunity to build.

Light on the Land

No discussion of trails is complete without talking straight to the topic of esthetics. We're talking scenic beauty here. Pleasing to the eye. The task is simple. An esthetically functional trail is one that fits the setting. It lays light on the land. It often looks like it just "happened."

This does not mean that land isn't disturbed during construction. Often terrain dictates that substantial construction is necessary. The final results can still be blended to fit the ground. Over time it will look like it lays gently.

Well-designed trails take advantage of natural drainage features, and are low-maintenance trails that meet the needs of the user. The trail might pitch around trees and rocks, follow natural benches, and otherwise take advantage of natural land features (Figure 3).

Photo of a trail.
Figure 3--Design and construct your trail to fit the land.

The best trails show little evidence of the work that goes into them. A little extra effort spent widely scattering cut vegetation, blending backslopes, avoiding drill hole scars, raking leaves back over fillslopes, or restoring borrow sites pays off in a more natural-looking trail. Be a Master. Do artful trail work.

The ultimate compliment paid to a trail crew is to say, "It doesn't look like you had to do much work to get through here." Avoid the Bulldozer Bob look. Make your trail "just happen."

Trail Layout

There is a real art to trail layout. Some basics can be taught, but the locator must develop an "eye" for fitting the flagline to the ground. This skill can only be developed with experience. Hiking or walking cross-country does not qualify someone as a trail locator. Also there is a general assumption that a person who lays out logging roads can lay out trails. This is often not true. The road locator looks at the terrain through the eyes of a bulldozer. The trail locator must look through the eyes of a hand builder. There are many nuances to the trail flagline that don't exist with a road flagline.

Here are some steps to help you do a good job of trail layout. You will also want to look over the Forest Service Trails Management Handbook (FSH 2309.18) for lots more good information.

Planning the Route on the Map. Be certain you know the objectives of the trail--things like the intended user, desired difficulty level, and desired experience. Then go to the maps to determine a potential route.

Use topographic maps and aerial photos to map the potential route. On the map, identify potential Control Points, places where the trail has to go, where there is no choice because of:

  • Termini
  • Gaps or passes
  • Stream crossings
  • Rock outcrops
  • Known areas to avoid (threatened and endangered species, poor soils)
  • Known features to include (scenic overlook, waterfall).

Connect the control points and determine approximate grades along the route. Doing this helps to determine if the route is feasible, or if special structures like switchbacks or bridges are needed.

Scouting the Mapped Route. Tools to scout the route include clinometer, compass, altimeter, flagging of different colors, wire or wood stakes, roll-up pocket surveyor's pole, permanent marker to make notes on the flagging, field book, probe to check soil depth to bedrock, maps, and perhaps a GPS (global positioning system) unit. The objectives of scouting or reconnaissance are to:

  • Verify control points and identify additional control points not picked up on aerial photos.
  • Determine if the preliminary mapped route is feasible.
  • Find the best alignment that fits all objectives.
  • Identify natural features to enhance the user's experience.
  • Validate that the route is reasonable to construct and maintain.

Field scouting requires a sound knowledge of map and compass reading and of finding your way on the ground. Begin with the theoretical route, then try different routes until the best continuous route between the targets is found. Keep field notes of potential routes. It may be useful to hang reference flags at potential control points or features to help relocate them later. Reconnaissance is easiest with two people. One person can serve as a control point along the general route being scouted while the other searches ahead for obstacles or good locations.

Flagging the Final Route. Final flagging should wait until the best route has been determined by scouting.

Hang flags at about 3-m (10-ft) intervals. Don't scrimp. Flagging is cheap compared with the time spent locating the route.

Animals carry off flags, wind blows them down. You also obtain the best alignment with close flagging.

Flag the centerline. The steeper the sidehill, the more grade is affected by moving the line up or down the slope. Grade can be seriously compromised by leaving the construction crew too much latitude for deciding the final location.

Sometimes you have no choice but to go through a spot that ideally should have been avoided. Make sure the trail can be reasonably constructed through such spots.

One Person Flagging. Stand at a point that is to be the centerline and tie flagging at eye level. Then move about 3 to 6 m (10 to 20 ft) to the next centerline point and sight back to the last flag. When you have the desired location, tie another flag at eye level.

HINTS FOR LOCATORS

  • Large trees often have natural benches on their uphill side. It's better to locate your trail there than on the downhill side where you'll sever root systems and generally undermine the tree. Your specifications will tell you how close you can build to the tree.

  • Look for "natural platforms" for switchbacks. This saves on construction and better fits the land.

  • Cross ravines at an angle rather than going straight down and up the ravine banks.

  • Be sure to flag locations for grade dips or Coweeta dips.

  • Where vegetation is generally dense, patches of sparse vegetation are a good indication of shallow bedrock.

  • The more difficult the terrain, the more critical it is to flag the centerline location.

  • Don't trust your eyeball guess for grade; use your clinometer.

Two or More Persons Flagging. A person with a clinometer stands on the centerline point, directs a person ahead to the desired location, then takes an eye-level shot on that person if they are the same height. It is better to take a shot on a rod with bright flagging tied at the height of the clinometer reader's eye.

When the desired location is determined, the front person hangs a flag and moves ahead. The person with the clinometer moves up to the flag and directs the next shot. A third person can be scouting ahead for obstacles or good locations.


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Updated: 04/14/2014
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