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icon Trailbuilding Glossary - A-I

This list of 265 terms is extracted from 900-term list from the Trails and Greenways Clearinghouse website of the Rails to Trails Conservancy. The original list is from Trails Primer: A Glossary of Trail, Greenway, and Outdoor Recreation Terms and Acronyms, 2001, Jim Schmid, editor, South Carolina Department of Parks, Recreation and Tourism, Columbia, SC. Last updated January 2002.

A | B | C | D | E | F | G | H | I |   Glossary: J-Z

Abney Level: Hand-held instrument that is adjusted like a sextant and can be set to a fixed gradient. The user sights through the Abney to a fixed reference (usually a second person) until the crosshair bisects the bubble, this indicates the preset grade.
Abutment: Structure at either extreme end of a bridge that supports the superstructure (sill, stringers, trusses, or decks) composed of stone, concrete, brick, or timber.
Access Points: Designated areas and passageways that allow the public to reach a trail from adjacent streets or community facilities.
Access Trail: Any trail that connects the main trail to a town, road, or another trail system.
Adz (Adze): An ax-like tool for dressing wood.
Aggregate: Surface material made up of broken stone, gravel, and sand.
Alluvium: Sand, mud, and other sediments deposited on land by streams.
Altimeter: An instrument for measuring altitude.
Amenities: Any element used to enhance the user's experience and comfort along a trail.
Angle: Angle is measured with a straight vertical as 90 and a straight horizontal as 0. A grade of 100% would have an angle of 45.
Apron: One of the three main elements of a waterbar. It catches water running down the trail and directs it off. Apron is also the transition area on a switchback (also called the "landing").
Armoring: Reinforcement of a surface with rock, brick, stone, concrete, or other "paving" material.
Aspect: The particular compass direction a trail or site faces. Aspect affects the amount of solar radiation and year-round moisture to which a site is subjected.
Attractive Nuisance: Something on a trail or greenway that attracts users and that is potentially dangerous to them, such as a mineshaft without a fence around it.
Axe (Ax): A tool with a long handle and bladed head (single bit - one sharp side or double bit - two sharp sides) for chopping deadfall from trails, shaping stakes for turnpikes and waterbars, and cutting notches for structures made of timber.
Backcountry: An area where there are no maintained roads or permanent buildings-just primitive roads and trails.
Backcut: The vertical part of a bench cut that is blended into the backslope.
Backfill: Material used to refill a ditch or other excavation, or the process of doing this action.
Backslope: The cut bank along the uphill side of the trail extending upward from the tread. Usually sloped back by varying degrees, depending on bank composition and slope stability.
Bank (Embankment): The part of the soil next to a stream, lake, or body of water where the soil elevation adjacent to the water is higher than the water level.
Bar: A sand or gravel deposit in a streambed that is often exposed only during low water periods.
Bark Spud: A tool with a 1- to 4-foot long wood handle and a dished blade used to remove bark from logs by sliding between the bark and the wood.
Barrier: A structure installed to protect an environmentally sensitive area. A barrier can be hard (fence); live (planted); a combination of hard and live; or a terrain feature (berm). A barrier can be physical (obstructing passage) or psychological (deterring access).
Base: The primary excavated bed of a trail upon which the tread, or finished surface lies.
Base Camp: A semi-permanent camp set up after traveling into an area from which day trips for trail work or enjoyment can be made. This allows you to leave heavy gear in one place for several days.
Baseline: A line of reference crossing your path of travel used to make following a compass bearing closer to foolproof. Baselines include roads, powerlines, railroad tracks, and rivers. If you are heading to a bridge over a river, set the compass bearing for the bridge. If you are off by several degrees, you will arrive at your baseline of the river, knowing that you need to look for the bridge.
Bed: The excavated surface on which a trail tread lies.
Bed: The bottom of a channel, creek, river, stream, or other body of water.
Bedrock: Solid rock material underlying soils and other earthy surface formations.
Bench: A long seat (with or without a back) for two or more people.
Bench, Full: Where the total width of the trail tread is excavated out of the slope and the trail tread contains no compacted fill material.
Bench, Half: Where half the width of the trail tread is excavated out of the slope and the outside of the trail tread contains the excavated and compacted material.
Bench, Partial: Where part of the width of the trail tread is excavated out of the slope and the rest of the trail tread is made up of fill material.
Bench Cut: A relatively flat, stable surface (tread) on a hillside occurring naturally or by excavation. When excavated often referred to as full, half, or partial bench.
Bench Mark: A metal disk set into the ground for use as an exact reference point by surveyors. Bench marks are indicated on a topographic map with an X and the letter BM with an elevation next to it.
Berm: The ridge of material formed on the outer edge of the trail that projects higher than the center of the trail tread.
Blaze: A trail marker. Blazes can be made on a tree by scraping away some of the bark and painting a 2-inch by 6-inch vertical rectangle. Plastic or metal triangles or diamonds (known as blazes) with the name of the trail or a directional arrow imprinted can be purchased and nailed to trees to mark a trail route.
Bleeder (Kick Out, Diversion Dip): Graded depression angled to drain water sideways off the treadway.
Blowdown (Windfall): Anything (trees, limbs, brush, etc.) blown down on the trail by the wind.
Blowout: An area from which soil material has been removed by wind. Such an area appears as a nearly barren, shallow depression with a flat or irregular floor consisting of a resistant layer, an accumulation of pebbles, or wet soil lying just above a water table.
Bluff: A steep headland, riverbank, or cliff.
Boardwalk: A fixed planked structure, usually built on pilings in areas of wet soil or water to provide dry crossings.
Bog(s): A mucky or peaty surface soil underlain by peat where little direct sunlight reaches the trail, or where there are flat areas that are difficult to drain.
Bow Saw: A 16-, 21-, or 36-inch thin bladed saw with a curved handle used to cut brush or trim small branches.
Bridge: A structure, including supports, erected over a depression (stream, river, chasm, canyon, or road) and having a deck for carrying trail traffic. If the bridge is over two feet above the surface, it should have railings.
Brush: Vegetation or small flora.
Brushing: To clear the trail corridor of plants, trees, and branches, which could impede the progress of trail users.
Brushing-In (Obliteration): To pile logs, branches, rocks, or duff along the sides of the tread to keep users from widening the trail; or to fill in a closed trail with debris so that it will not be used.
Buffer (Buffer Zone): Any type of natural or constructed barrier (trees, shrubs, or wooden fences) used between the trail and adjacent lands to minimize impacts (physical or visual). Buffers also provide a transition between adjacent land uses.
Bush Hook (Bank Blade): These tools are used for clearing brush, briar, or undergrowth too heavy for a scythe and not suited for an ax. The Bush Hook with a 36-inch handle and 12-inch hooked blade (sharpened on one side) cuts easily on the "pull" stroke. The Bank Blade is similar to a Bush Hook, but its wide blade is straight and sharpened on both sides. Bushwhack: Off-trail hiking (originally where the going was difficult, where many bushes had to be whacked). Now it is often used to mean off-trail travel regardless of whether the going is difficult or not.
Cable, Wire: A thick, heavy rope, made of wire strands.
Cable Fly Zone: The hazardous area a cable can potentially move to when it comes under tension, or is suddenly released from tension.
Cable Gripper: A device that clamps onto a cable when tension is applied to the attachment point.
Cable Strap: A pre-cut length of wire rope (that may have eyes on both ends), which is used in rigging applications.
Cache: A supply of food, water, or tools, usually buried or hidden.
Cairn: A constructed pile of rocks located adjacent to a trail used to mark the route. Often used in open or treeless areas where the tread is indistinct.
Canopy: The leaf cover in a forest stand, consisting of its upper layers.
Cap Rock: Rock placed in the top or uppermost layer in a constructed rock structure, such as a rock retaining wall.
Chain Saw: A portable, gas-operated saw with a loop chain carrying cutting teeth.
Check Dam: Log, rock, or wood barrier placed across deeply eroded trails or erosion channels to slow the flow of water enough to allow accumulation of fine fill material behind the structure to fill in the trail tread.
Choker: Loop of rope or cable cinched around a load so it gets tighter, or "chokes" the load under pressure.
Circle of Danger: The area surrounding a trail worker that is unsafe due to tool use. The inner (or primary) circle of danger is the area the tool can reach while being used. The outer circle of danger is the area the tool could reach if the trail worker lost control or let go of the tool.
Clearing: Removal of windfall trees, uproots, leaning trees, loose limbs, wood chunks, etc. from both the vertical and horizontal trail corridor.
Clearing Height (Vertical Clearance): The vertical dimension, which must be cleared of all tree branches and other obstructions that would otherwise obstruct movement along the trail.
Clevis (Shackle): A U-shaped metal piece with holes in each end through which a pin or bolt is run. Used to attach two objects together.
Clinometer: A hand-held instrument used for measuring percent of trail grade. The user sights through the Clinometer to a reference (usually a second person) and reads the measurement directly from the internal scale.
Col: A pass between two mountain peaks; or a low spot in a mountain ridge.
Collector Ditch: A drainage structure that intercepts water flowing toward a trail and channels it underneath the trail through a culvert.
Come-along: A strong cable fitted with a ratchet to gain mechanical advantage for moving heavy objects over the ground with comparative ease. It is often used in trail work to move large rocks or bridge timbers.
Compacted: The degree of soil consolidation that is obtained by tamping with hand tools or, or heavy equipment.
Conservation: Controlled use and protection of natural resources.
Construct (Construction): Building a trail where no trail previously existed.
Contour Line(s): A line on a topographic map connecting points of the land surface that have the same elevation.
Contour Trail: Trail constructed such that it follows a contour, with its elevation remaining constant.
Control Points (Targets): Features that trail users will want to naturally head towards, or try to avoid (views, obstacles, etc.). These features should be flagged and used to help layout a trail.
Corduroy: A rustic form of puncheon using native logs (3 to 5 feet in length) laid parallel on wet saturated ground and covered with a tread of soil. Corduroy typically rots out quickly.
Course: An even layer of stones, similar to a course of bricks, that forms a foundation, intermediate layer, or cap stone layer in a stonewall.
Critical Point: The outside edge of the trail. It's called the critical point because this is where trail maintenance problems (usually related to drainage) begin. Rounding the outside edge helps water to leave the edge of the trail.
Crosscut Saw: A long saw that was favored a century ago by loggers felling trees. Used today in federally designated Wilderness Areas, or by those who prefer not to use chainsaws.
Crown (Crowning): A method of trail construction where the center portion of the tread is raised to allow water to disperse to either side of the trail.
Crowned Trail: A trail bed built up from the surrounding area and sloped for drainage (usually by excavating trenches parallel to the trail).
Culvert, Cross Drainage: Pipe- or box-like construction of wood, metal, plastic, or concrete that passes under a trail to catch surface water from side ditches and direct it away from a trail.
Culvert, Stream Bed: Pipe- or box-like construction of wood, metal, plastic, or concrete that conveys a stream under a trail without constricting waterflow.
Cut and Fill: The process of removing soil from one area and placing it elsewhere to form a base for any given activity.
Cut Slope: An earthen slope that is cut. For example, a trail built lower than the existing terrain would result in a cut slope.
Day Pack: A soft pack (smaller than a backpack), favored by day hikers and trail workers for carrying food, water, and other supplies.
Daylight Edge: The outer edge of a trail. The point where the trailway and the cross slope meet.
Deadfall: A tangled mass of fallen trees or branches.
De-berming: Removing the high ridge of material that has formed along the outer edge of a trail, allowing water to once again flow off the trail and not down the trail.
Debris: Any undesirable material that encroaches on a trail and hinders the intended use.
Decking (Flooring): That part of a bridge, puncheon, or boardwalk structure that provides direct support for trail traffic.
Doubletrack Trail: A trail that allows for two users to travel side by side, or make passes without one user having to yield the trail. Double-track trails are often old forest roads.
Downed Tree: Fallen tree that blocks the trail.
Downslope: The downhill side of a trail.
Drain, Cobble: A cobbled improvement to the trail surface that allows drainage (usually from an intermittent wet seep) across the trail for continued passage along the trail without damage to the soil.
Drainage: Getting water off the trail.
Drawknife: A tool with a sharp blade and handles at both ends used to strip bark from small-diameter logs.
Drop-off: Slope that falls away steeply.
Duff: A matted layer of decaying organic plant matter (leaves, needles, etc.) of forested soils. It is highly absorbent and quickly erodes under traffic.
Elevation: The height of a place (mountain or other landmark) given in the number of feet or meters above sea level.
Embankment: Structure made from soil used to raise the trail, railbed, or roadway above the existing grade.
Equestrian: Of horses, horseback riding, riders, and horsemanship.
Erosion: Natural process by which soil particles are detached from the ground surface and moved downslope, principally by the actions of running water (gully, rill, or sheet erosion). The combination of water falling on the trail, running down the trail, and freezing and thawing, and the wear and tear from traffic create significant erosion problems on trails.
Erosion Control: Techniques intended to reduce and mitigate soil movement from water, wind, and trail user traffic.
Facer: Structural member in retaining walls and abutments that is placed at right angle to the structure or trail tread.
Fall Line: Direction water flows down a hill (path of least resistance). Constructing a trail on the fall line encourages water to run down the trail.
Fill (Material): Gravel or soil used to fill voids in trail tread and to pack behind retaining walls and other structures.
Fill Slope: Area of excavated material cast on the downslope side of trail cut (also called embankment).
Fire Rake: A tool with triangular tines used to cut duff and debris from fire breaks or trail corridors.
Firebreak: A strip of forest or prairie land cleared or plowed to stop or prevent the spread of fire.
Fire Road: Unimproved dirt road that allows fire fighting and ranger vehicles access to the backcountry.
Flagging: Thin ribbon used for marking during the location, design, construction, or maintenance of a trail project.
Flagline: Flagging, tied to trees, indicating the intended course of a trail prior to construction.
Flags, Wire: Wire wands with square plastic flags at one end for field layout and marking of new trail or relocations of trail sections.
Ford: A natural water level stream crossing; which can be improved (aggregate mix or concrete) to provide a level, low velocity surface for trail traffic.
Friction Pile: Post hammered into muck until friction prevents further penetration; foundation for puncheon or boardwalk.
Gabion Baskets: Rectangular containers (usually made of heavy galvanized wire) that can be wired together, and then filled with stones to make quick retaining walls for erosion control.
Gaiters (Leggins, Puttees): Coverings that zip or snap around the ankles and lower legs to keep debris and water out of your boots.
Glade: An open space in a forest.
Global Positioning System (GPS): A system used to map trail locations using satellites and portable receivers. Data gathered can be downloaded directly into GIS database systems.
Grade: The amount of elevation change between two points over a given distance expressed as a percentage (feet change in elevation for every 100 horizontal feet, commonly known as "rise over run"). A trail that rises 8 vertical feet in 100 horizontal feet has an 8% grade. Grade is different than angle; angle is measured with a straight vertical as 90 and a straight horizontal as 0. A grade of 100% would have an angle of 45.
Griphoist: A brand name for a manually operated hoist that pulls in a cable at one end and expels it from the other end; used to move rock or timber needed for trail structures.
Grub (Grubbing): To dig or clear roots and tree stumps near or on the ground surface of the trail tread.
Grub Hoe: A tool with a blade (various weights) set across the end of a long handle used in building and repairing trail tread and digging trenches.
Hazard Tree (Danger Tree, Widow Maker): Tree or limb that is either dead, or has some structural fault, that is hanging over, or leaning towards the trail or sites where people congregate.
Header, Stone or Rock: A long, uniform stone laid with its narrow end toward the face of a retaining wall or crib used intermittently to structurally tie in the other rocks laid in the wall.
Hogback: A rounded ridge.
Infill: The stone or soil material used to fill gaps in trail or wall construction/revetment work.
Inslope (Insloping): Where the trail bed is sloped downward toward the backslope of the trail; causes water to run along the inside of the trail.
Interpretive Trail (Nature Trail): Short to moderate length trail (1/2 to 1 mile) with primary function of providing an opportunity to walk or paddle and study interesting or unusual plants or natural features at user's pleasure. The ideal nature trail has a story to tell. It unifies the various features or elements along the trail into a related theme.
Intersection (Junction): Area where two or more trails or roads join together.

Glossary: J-Z

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This page was last updated September 3, 2003.