Trail Building Indoctrination
Frequently when we talk to civic groups, hiking clubs and government agencies the question of chain saws come up. For some reason when the novice hears “trail building” they think chain saws. The short answer is, NO, we don’t go into the woods and cut down trees to build a trail. Chain saws are used mostly to clear downed trees that block the alignment of the trail.
Most trail building tools are adapted from wilderness fire fighting tools. The four principal tools are:
The Mattock- The basic trail building tool has its origins in the Bronze Age and Ancient Greece. The word mattock begins to appear in the early 17th century. Mattocks come in two styles, the cutter and the pick. Pick Mattocks are useful in rocky soils where the pointed end can penetrate between rocks and loosen the ground. Cutter mattocks are the tool of choice for initial removal of duff and the root zone above usable mineral soil. These terms covered below.
McLeod- A wilderness fire fighting tool developed by Malcolm McLeod in the early part of the 20th century. McLeod was a Forest Service employee and created the tool by welding a long tine rake with a wide hoe blade. The blade is usually sharpened. As a fire fighting tool it is used to pull up roots and quickly dig fire lanes. The head is removable so fire fighters can carry the tool in a backpack and keep their hands free. As a trail building tool it is invaluable for removing roots, moving soil along the trail and for final grooming of the trail tread.
Fire Rake – the volunteer student in the foreground is using a fire rake. Behind her is a student using a McLeod. Both tools are used for removing leaf litter, organic matter (known as Duff) and the root layer from the ground.
Later in the process both tools are used for final grading and grooming of the trail tread.
Pulaski- The Pulaski is a versatile double headed cutting tool. It is used to cut roots and cut out small bushes and saplings. Pulaski’s are kept very sharp and generally are the only tool with a leather head covering for safety.
Here volunteer students remove a sapling from the trail alignment with a Pulaski in a process known as “Grubbing.” Saplings and small trees in the trail corridor are first cut off about 40 inches from the ground. The resulting stub provides leverage needed to pull out the tree with the roots intact. Leaving the roots behind invites the tree to grow again in the trail and leaves a tripping hazard.
The tool is named for its inventor, Edward Pulaski, a Forest Service Supervisor in Idaho at the beginning of the 20th century. He took an axe and welded a narrow cutting blade at right angles on the opposite side. The tool can be used for cutting trees or quickly removing burning roots of small trees and bushes. Pulaski is well known for protecting his fire crew during the disastrous Wallace fire in 1910 by taking them into an abandoned mine. Of 45 men, only five did not make it. The site is now a museum.
Loppers- The same long handled pruners used to cut small branches are also used to cut roots up to two inches out of the trail tread.
Hand Clippers- Common garden clippers used to cut small roots and branches. Many volunteers bring their own clippers and carry them in a belt sheath for safety and convenience.
Folding Saws- Small trimming saws generally with a nine inch blade. Used to trim branches that overhang the trail or cut larger roots out of the trail.
Rogue Hoe and Grubbing Hoe- In CTC parlance the photo here is of a Rogue Hoe. Except Rogue refers to a manufacturing company that makes a variety of tools. In 2015 CTC added a similar tool with four wide prongs, or teeth, on one side, also made by Rouge Manufacturing.
We call it a “Grubbing Hoe” because it is an efficient tool for removing or “grubbing” out tree roots in the trail corridor. The version we use is only 5.5 inches wide, so it is excellent for clearing duff around rocks as well.
The Behavior of Water
” No factor in trail construction is more important than proper drainage, and many sections of good trail are damaged and destroyed by erosion which could have been prevented.” —CIVILIAN CONSERVATION CORPS, Construction of Trails Handbook, 1937
The above quote from 80 years ago speaks to modern trail building techniques. A sustainable trail means it is resistant to the impact of water, hikers and to a lesser extent, wind.
Unfortunately it took more than 60 years before the study of water run off was converted into sound guidelines for trail construction. A full discussion of dealing with water in trail design is not the intent of this section. But a little insight to how water behaves relative to a trail helps builders understand why trail is designed a certain way.
Two principal concepts prevail: The Fifty Percent Rule, and the Ten Percent Rule.
Fifty Percent Rule- This rule applies mostly to trail designers but helps explain to builders why a trail was routed to one place and not another. Simply it says; the grade of the trail must not exceed fifty percent of the natural slope it is cut into. For example, if the natural hill side is a 30 percent slope (17 degrees), the grade of the trail must not exceed 15 percent (8.5 degrees). This allows rain water to sheet across the trail rather then turn and run down the trail tread creating an erosion problem. If the trail grade is steeper than half the angle of the natural slope, water will not have the speed to cross the trail. The trail tread itself has an outward angle of about 3 to 5 percent. More on that in the next section.
The Ten Percent Rule is a reminder that the average grade for the trail should not exceed ten percent for reasons of maintenance and ease of hiking. Grade reversals and variations in the trail grade allow for water to run off and give the hiker a break fro long up hill sections. Sometimes the trail will be slightly more that ten percent. Sometimes less. But we shoot for and average of ten percent over a giver section.
Climbing Turn- When space and terrain allow, climbing turns are the preferred way of gaining elevation. Numerous guide books prescribe the proper way to build a climbing turn. The diameter of the turn varies according to the purpose of the trail. Multi-use trails may have a radius of around fifty (50) feet. On foot traffic only trails, like the CT, the diameter can be fifteen or twenty feet depending on the slope of the land.
Fortunately, trail alignments on new sections of trail (or realignments) are surveyed and laid out by trained and experienced designers. Volunteer trail builders need only follow the flag line left by the designer. But having a general understanding of climbing turn theory helps the new trail digger understand why the trail is being built in a specific way.
Switchback- Switchbacks are used to change elevation when the side slope is to steep to create a climbing turn. Proper switchbacks require attention to the ruling percentage of the side slope and percentage of grade for the trail. Like crib wall, building them requires some study, instruction and practice. Poorly built switchbacks can easily wash out leading to maintenance headaches for years to come.
SMALL WATER CROSSINGS
Step Over- Sometimes called a Rock Hop crossing. Typically used on a dry brook or seasonal drainage. Like all rock crossings the key is to use rocks big enough that they won’t be dislodged by water flow from a heavy rain. The rule of thumb is, if one person can move it, it isn’t big enough.
Rocks on both sides need to be at the same level. This allows water to rise evenly on both sides lifting leaves and sticks out of the gap. Uneven placement allows sticks to hang up, holding back debris and clogging the crossing. With a fourteen inch minimum gap, the volume of water should keep the crossing clear and not interfere with the stride of a hiker.
BIG WATER CROSSINGS
Wider streams require different solutions. Shallow streams can be crossed using large flat rocks if they are available. Like the Step Over crossing, rocks have to be big enough not to be dislodged during heavy stream flow. The rocks also have to be placed so the tops are all even. As the water rises over the tops of the rocks, it will lift debris out of the gaps and there will be no uneven places for floating sticks to snag. Spacing between rocks in a stream crossing varies with local conditions but a gap of 20 to 24 inches is reasonable. Less than that invites constant visits to clear debris.
Bridges are the next solution. They can be simple spans made out of locally obtained materials, or complex engineering projects. Above is the Possum Creek bridge under construction in 2012.
Bridge construction projects are fun to volunteer on, but the design and engineering is left to professionals.
US Forrest Service / USDOT Trail Handbook – latest edition. CTC tries to give a copy of this to everyone who takes the WagonMaster (Crew Leader) training class:
Virginia Greenways Trail Building handbook:
National Park Service. Chapter 5 on trail structures and drainage design issues. Detailed, well written and a wealth of information:
NPA North Country Trail Scenic Park Construction Manual. Runs from Michigan to Pennsylvania. Part of the Great Eastern Trail. Another excellent reference for trail building challenges.
“How Wilderness Trails are Built in the 21st Century” written by Mark Richie, CMTB, CTC Life Member, Head CTC Trail Trainer. Photos by the author unless noted.