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Wetland Trail Design and Construction

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Glossary

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A

Aggregate-Crushed stone or gravel used as a base course for riprap, asphalt, or concrete pavement. Aggregate is also used in asphalt and concrete mixes.

Asphalt-A mixture of aggregate and asphalt cement, correctly called asphaltic concrete.



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B

Baluster-One of many vertical pieces between the top and bottom rails of a guardrail.

Image of baluster.

Batter, battering-Sloping the exposed face of a wall back either at a uniform angle, or stepping it back uniformly, the structurally sound way to build a timber wall.

Image of batter.

Bevel-Finishing the corner of a piece of lumber by removing a narrow portion of wood at a uniform angle to the edge and face. A bevel follows the grain of the wood (see chamfer).

Image of beveled edge.

Borrow pit-An excavation used to obtain fill for a construction site.

Braided trails-Parallel trails around a low, wet spot. These trails are not constructed, but are worn in the ground by trail users who do not want to get their feet wet or walk in mud. Each new trail funnels water to a low point. Users repeat the process, producing a series of trails.



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C

Camber-A slight bend in a timber.

Cantilever-The portion of a beam or plank extending beyond one or both of its supports.

Image of cantilever.

Chamfer-Similar to a bevel but done at the end of the piece of wood and across the grain.

Image of chamfer.

Concrete-A mixture of sand, coarse aggregate (crushed gravel or crushed stone), Portland cement and water correctly called Portland cement concrete. The wet mixture is placed in a form or trench and dries to a hard material.

Control points-Natural, recognizable features on the site or a series of survey stakes used to establish distances and elevations during trail construction.

Countersinking-Drilling a wide, shallow hole in a piece of wood for a washer and nut or for the head of a bolt or screw. Countersinking allows the hardware to be recessed below the surface of the wood. Countersinking reduces the amount of treated wood and will accelerate rot if the hole is exposed to moisture.

Image of countersinking.

Course-A single layer of building material of a uniform height. The material is placed one layer (or course) at a time on top of another layer (or course). Materials laid in courses include bricks, concrete blocks, timbers, and logs.

Crook-A defect in a log caused by a crooked tree.

Cross slope or cross pitch-The amount a surface slopes, measured perpendicular to the centerline of a road or trail.

Image of a cross slope.

Crown-The branches, twigs, and leaves of a tree. Also a paved surface that is higher in the center than at the edges.

Cupped, cupping-A board or plank whose edges are higher or lower than the center. Cupping is often found in decks, where the board edges are higher than the middle. Water, trapped in the cupped area, accelerates rot.

Image of cupping.

Curb-A wood, concrete, or stone trail component that rests on the ground or on the trail tread, rising 2 to 8 inches above the trail tread.



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D

Dap-A shallow hole or slot drilled or routed in a piece of wood. A dap is usually drilled to fit over a piece of hardware (a nut, the head of a bolt, or a portion of a steel plate or angle) that is connected to an adjacent piece of wood.

Image of a dap.

Deadman-A log or logs, heavy timber or timbers, a large block of concrete, a large boulder, or combination of the above that is partially or completely buried. Eyebolts placed in deadmen are used to anchor cables. Log or timber deadmen (without eyebolts) are used in log or timber retaining walls. They are placed perpendicular to the face of the wall, extending into the earth behind it to prevent the wall from falling over.

Image of deadmen.

Destination trail-A trail route that starts at a trailhead and ends at a point of interest, the destination. The trail user returns by the same route.

Driftpin-A 12- to 30-inch steel bar or pipe used to keep logs and timbers in place.



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F

Fisherman's knot-A knot used to tie a rope sling for moving logs and timbers. A single length of rope is tied into a loop using two overhand knots tied in each end of the rope and around the opposite end.

Footing-The part of a structural foundation that rests on the ground, spreading the weight of the structure and supporting the structure above. Footings are usually concrete. At remote sites the footings may also be mortared stone masonry.

Image of footing.

Froe-An old handtool used originally for splitting shingles and shakes. The froe consists of a heavy, 12-inch-long, straight steel blade with a wooden handle. The cutting edge of the blade is placed against the wood to be cut and a club or mallet is used to hit the face.

Image of a froe.

Frostline-The maximum depth that frost can be expected to penetrate into the ground.



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G

Glulaminated-A process used to fabricate long beams from short lengths of 2 by 4, or 2 by 6, or 2 by 10 lumber. The pieces are placed flat on top of each other with glue spread between them. Lengths are varied so that transverse joints in each layer are not opposite one another. Pressure binds the pieces together. The assembly may be two to four times longer than the longest individual piece of lumber within it.

Grade-The rate of climb or descent along the centerline of a trail. It is described as a percentage and expressed as the number of units of climb or descent per 100 units of horizontal distance. A +5-percent grade rises 5 feet in 100 feet, or 5 meters in 100 meters. A -2-percent grade descends 2 feet per 100 feet (or 2 meters per 100 meters). The plus symbol indicates climb. The minus symbol indicates descent.

Groundwater-Water contained in the soil a few inches to several feet below the surface of the ground. In wetlands, the depth to groundwater is often higher in winter and spring and lower in summer and fall.

Guardrail-A railing at the edge of a deck to prevent people from falling. A guardrail should be 36 to 42 inches above the deck.



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H

Handrail-A railing along a stairway to help people avoid falling down the stairs. A handrail should be 32 to 35 inches above the stairs.

Hardwood/softwood-Inaccurate logger's terms that have nothing to do with how hard or soft the wood is. By the logger's definition, hardwoods are deciduous trees with broad leaves and softwoods are conifers with needles. Aspen and red maple are "hardwoods," but their wood is soft; Douglas-fir and Atlantic white cedar are "softwoods," but their wood is hard. Some hardwoods, such as live oak and southern magnolia, keep their leaves through the winter. Some "softwoods," such as larch and bald cypress in the northern portion of its range, lose their needles in the fall.

Heartwood-The oldest wood of a tree, extending from the center of a log to the sapwood. The heartwood is the densest, strongest, and darkest wood in a log.

Image of heartwood.

Helical pile-A solid steel shaft 1½ to 2½ inches square with a series of steel helixes welded to the shaft. The helixes are similar to threads on a bolt or the threads on a powered earth auger. The smallest helical piles or screw piles are 6 inches in diameter and 30 inches long. A machine screws them into the ground.

Hewing-Using an ax or adz to cut a log so that its cross section is a square or rectangular.

Hummocky-Wetland terrain containing hummocks, ridges, and small mounds of earth 2 to 4 feet higher than the surrounding area.



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I

Invert-The bottom surface of a pipe, ditch, or culvert over which water flows.

Image of an invert.



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J

Joist-Usually a wooden 2 by 6, 2 by 8, 2 by 10, or 2 by 12, with the 2-inch dimension resting on a sill or ledger, toenailed into place, supporting a floor or deck.

Joist hanger-A steel angle or strap nailed to the side of a ledger and shaped to hold a joist. After the joist hanger is installed, the joist is placed within the joist hanger and the two are nailed together.

Image of truss hanger.


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Updated: 04/14/2014
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