i

The Forest Service, United States Department of Agriculture (USDA), has developed this 

information for the guidance of its employees, its contractors, and its cooperating Federal and 

State agencies, and is not responsible for the interpretation or use of this information by anyone 

except its own employees. The use of trade, fi rm, or corporation names in this document is for 

the information and convenience of the reader, and does not constitute an endorsement by the 

Department of any product or service to the exclusion of others that may be suitable. 

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and 

activities on the basis of race, color, national origin, age, disability, and where applicable, sex, 

marital status, familial status, parental status, religion, sexual orientation, genetic information, 

political beliefs, reprisal, or because all or part of an individual’s income is derived from any 

public assistance program. (Not all prohibited bases apply to all programs.) Persons with 

disabilities who require alternative means for communication of program information (Braille, 

large print, audiotape, etc.) should contact USDA’s TARGET Center at (202) 720-2600 (voice 

and TDD). To fi le a complaint of discrimination, write to USDA, Director, Offi ce of Civil Rights, 

1400 Independence Avenue, S.W., Washington, D.C. 20250-9410, or call (800) 795-3272 (voice) 

or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer.

Robert T. Steinholtz

Bristlecone Trails, Lakewood, CO

Brian Vachowski

Project Leader

USDA Forest Service

Technology and Development Program

Missoula, MT

8E82A3—Trail Treatment for Wet Areas

January 2007

Wetland Trail

Design and 

Construction

Wetland Trail

Design and 

Construction

Wetland Trail

Design and Design and 

Construction Construction

2007 EDITION
ii

Any document concerning trail construction must 

recognize the men and women who do the fi eld work—

whether they are professionals or volunteers. Some of 

the most unforgettable and fun-loving people we have known 

have worked on trail crews.

None of the construction techniques in this document 

are new. Most have been used for decades. Fortunately, 

trail crews took the time to explain and demonstrate the 

construction techniques to us. The techniques described in 

this manual have occasionally been modifi ed slightly to make 

it easier to work with contemporary materials.

Christy Fischer was responsible for the initial editing of this 

manual. Thanks also to the staff at the USDA Forest Service 

Missoula Technology and Development Center (MTDC), 

who obtained additional photographs, scanned fi gures, 

provided review and additional content, and edited, laid 

out, and printed this document. In this revised edition, the 

work involved Bert Lindler, Sunni Bradshaw, James “Scott” 

Groenier, and Jerry Taylor Wolf. Bob Steinholtz drew the 

illustrations used throughout this manual. Thanks also to 

the U.S. Department of Transportation’s Recreational Trails 

Program for funding the revision and additional distribution of 

this manual.

Acknowledgments
iii

Acknowledgments ________________________________ ii

Introduction ______________________________________1

Types of Wetlands _________________________________2

 Wetlands Formed by Glacial Action _________________________ 2

 Wetlands With Organic Silt and Clay Soils ____________________ 2

 Silt and Clay Soils With Some Water _____________________ 2

 Silt and Clay Soils With Considerable Water _______________ 2

 River Deposits and Deltas ________________________________ 3

 Floating Wetlands—Trembling Earth or Quaking Bog ___________ 3

 Wetlands on Mountains __________________________________ 4

 Carrs ______________________________________________ 4

 Seepage ___________________________________________ 4

 Spruce Bogs __________________________________________ 5

 Muskeg _______________________________________________ 5

 Wetlands With Wildlife That Bite Back _______________________ 5

Environmental and Accessibility Compliance ______7

 National Environmental Policy Act and Other Federal Laws ______ 7

 The U.S. Army Corps of Engineers _________________________ 7

 State and Local Agencies ________________________________ 7

 Accessible Trails ________________________________________ 7

Field Work ________________________________________8

 Turned Around _________________________________________ 8

 Trail Layout ____________________________________________ 8

 Reconnaissance _____________________________________ 8

 Preliminary Route—P-Line _____________________________ 8

 Coordination ________________________________________ 9

 Blue Line ___________________________________________ 9

 Final Layout ___________________________________________ 9

 Drawings, Specifi cations, and Cost Estimates ________________ 10

Wetland Trail Structures _________________________14

 Sustainable Design ____________________________________ 14

 Corduroy ____________________________________________ 14

 Turnpikes ____________________________________________ 15

 Causeways ___________________________________________ 17

 Improving Drainage ____________________________________ 17

 Dips or Ditches _____________________________________ 17

 Culverts___________________________________________ 18

Structures Requiring Foundations ________________21

 Sleepers (Sills) ________________________________________ 21

 Cribbing _____________________________________________ 22

 Wooden Piles _________________________________________ 22

 End-Bearing Piles ___________________________________ 23

 Friction Piles _______________________________________ 23

 Bent Construction______________________________________ 24

 Helical Piles (Screw Piles) _______________________________ 26

 Helical Pile Assembly ________________________________ 27

 Special Site Considerations ______________________________ 28

 Puncheon ____________________________________________ 29 Contents
iv

 Type 1 Puncheon ___________________________________ 29

 Type 2 Puncheon ___________________________________ 30

 Type 3 Puncheon ___________________________________ 30

 Puncheon Summary _________________________________ 31

 Gadbury _____________________________________________ 31

 Bog Bridge ___________________________________________ 32

 Bog Bridge on Sleepers ______________________________ 33

 Bog Bridge on Cribbing ______________________________ 33

 Bog Bridge on Piles _________________________________ 33

 Bog Bridge Summary ________________________________ 33

 Boardwalk ___________________________________________ 33

 Stringers __________________________________________ 33

 Boardwalk Summary_________________________________ 34

Finishing Details _________________________________35

 Decks _______________________________________________ 35

 Posts _______________________________________________ 35

 Pedestrian Railing Types ________________________________ 36

 Railing Installation ___________________________________ 37

 Curbs (Bull Rails) ______________________________________ 38

 Bulkheads (Backwalls, End Dams, Faceplates) _______________ 39

Floating Trails ___________________________________40

Construction Materials ___________________________41

 Choosing Materials ____________________________________ 41

 Logs ________________________________________________ 41

 Lumber and Timber ____________________________________ 41

 Decay-Resistant Wood __________________________________ 42

 Naturally Decay-Resistant Wood _______________________ 42

 Preservative-Treated Wood____________________________ 42

 Recycled Plastic _______________________________________ 43

 Hardware ____________________________________________ 43

 Connectors ________________________________________ 43

 Nails _____________________________________________ 44

 Bolts _____________________________________________ 44

 Lag Bolts (Lag Screws) _______________________________ 44

 Washers __________________________________________ 44

 Nuts _____________________________________________ 45

 Wood Screws (Deck Screws) __________________________ 45

 Steel Reinforcing Bars _______________________________ 45

 Staples ___________________________________________ 45

 Hardware Cloth _____________________________________ 45

 Geosynthetics ________________________________________ 46

 Nonslip Gratings and Grit-Treated Mats _____________________ 47

Contents
v

 Roughened Wood Surface ____________________________ 47

 Mineral Paper ______________________________________ 47

 Fishing Net ________________________________________ 48

 Cleats ____________________________________________ 48

Construction Tools _______________________________49

 Measuring Tapes ______________________________________ 49

 Framing Squares ______________________________________ 49

 Plumb Bob ___________________________________________ 49

 Levels _______________________________________________ 49

 String or Line Levels _________________________________ 50

 Stringlines _________________________________________ 50

 Chalklines _________________________________________ 50

 Carpenter’s and Mason’s Levels ________________________ 50

 Torpedo Levels _____________________________________ 51

 Post Levels ________________________________________ 51

 Surveyor’s Transits and Electronic Instruments _______________ 51

 Surveyor’s Levels or Transits___________________________ 51

 Electronic Distance Measuring Instruments _______________ 51

 Saws _______________________________________________ 52

 Handsaws _________________________________________ 52

 Chain Saws ________________________________________ 52

 Hand-Held Pruning Saws _____________________________ 52

 Axes ________________________________________________ 53

 Adzes _______________________________________________ 53

 Planes ______________________________________________ 53

 Draw Knives __________________________________________ 53

 Bark Spuds __________________________________________ 54

 Tools for Drilling Holes in Wood ___________________________ 54

 Bits ______________________________________________ 54

 Braces ____________________________________________ 55

 Battery-Powered Drills _______________________________ 55

 Gasoline-Powered Drills ______________________________ 55

 Clamps ______________________________________________ 56

 Wrenches ____________________________________________ 56

 Chisels ______________________________________________ 56

 Mallets ______________________________________________ 56

 Hammers ____________________________________________ 56

 Claw Hammers _____________________________________ 56

 Sledge Hammers ___________________________________ 57

 Crowbars ____________________________________________ 57

 Tools for Digging Holes _________________________________ 57

 Shovels and Posthole Diggers _________________________ 57

 Augers ___________________________________________ 57

 Gasoline-Powered Augers ____________________________ 57

Contents
vi

 Wheelbarrows ________________________________________ 57

 Compactors __________________________________________ 58

Practicing the Craft ______________________________59

 Working With Logs _____________________________________ 59

 Felling ____________________________________________ 59

 Bucking and Seasoning ______________________________ 59

 Moving Logs _______________________________________ 59

 Peeling ___________________________________________ 60

 Squaring a Log _____________________________________ 60

 Cutting Planks With Chain Saw Mills _______________________ 62

 Working With Timbers __________________________________ 62

 Working With Treated Wood ______________________________ 63

 Pinning Logs and Timbers ____________________________ 63

 Tread Surface _________________________________________ 63

 Slippery Wood Treads ________________________________ 63

 Trail Grade ________________________________________ 64

 Cross Slope _______________________________________ 64

 Soil Conditions _____________________________________ 64

 Surface Treatments __________________________________ 64

 Latex Paint ________________________________________ 64

 Walnut Chips_______________________________________ 65

 Mineral Products ____________________________________ 65

 Nonslip Gratings and Grit-Treated Mats __________________ 65

 Working With Rock, Stone, and Gravel _____________________ 65

 Rock _____________________________________________ 65

 Stone ____________________________________________ 65

 Gravel ____________________________________________ 65

 Uses of Stone and Gravel _____________________________ 65

Appendix A—Field Note Sheets _______________________66

Appendix B—Slope Conversion Table __________________68

Appendix C—Comparison of Round and 

 Rectangular Culverts ________________________________69

Appendix D—Sizes of Hot-Dipped Galvanized Nails _______70

Appendix E—Table of Board Feet _____________________71

Appendix F—Metric Conversions ______________________72

Glossary _________________________________________73

References _______________________________________81

Contents
1

MMost experienced trail crews try to avoid wetlands because

of the construction and maintenance problems they 

pose. Little has been published on wetland trail construction, and materials that are available are often outmoded 

or are too regionally focused. By pulling this information 

together from our experiences, we hope to answer questions 

you didn’t even know you had.

In this manual we have described the common techniques 

for building a wetland trail. We have also included information 

on some of the more unusual materials and tools.

Some of the techniques and tools we describe are suitable 

for wilderness situations where mechanized equipment cannot be used. Others are suitable for urban greenbelts where 

Introduction

a wider range of techniques, material, and equipment can 

be used. Somewhere in between are the back-country sites 

where machines are permitted, but access and logistics are 

challenges. Although this book is written for wetland trails, the 

techniques described can also be used for correcting other 

poorly drained low areas in existing trails.

The manual is written for those who are untrained and 

inexperienced in wetland trail construction, but those with 

experience may learn a few things, too.

The 2007 edition incorporates minor changes to this report, 

fi rst published in 2001 (0123–2833–MTDC). The changes 

primarily involve wood preservative treatments and construction details. The list of references has been updated.
2

Types of Wetlands

WWetland managers and specialists recognize 30 or more 

different types of wetlands. From a trail construction 

viewpoint, there are only six types of wetlands, perhaps 

seven. The basic differences in construction techniques for 

wetland trails depend greatly on the geologic, hydrologic, and 

vegetative factors infl uencing the site and, to a degree, on 

the wildlife species that live there.

Local indicator plants can help identify whether a site may be 

a wetland. Test holes and rod soundings can help determine 

the capability of the soil to support a trail. By studying the 

soil, the wildlife, and the subsurface water at the site, you can 

select the appropriate trail layout and construction techniques.

Wetlands Formed by Glacial 

Action

Generally, trails are easiest to construct in wetlands formed 

by glacial action. As a glacier melts, sand, gravel, boulders, 

and occasional blocks of ice are deposited in a narrow 

area in a mountain valley. The melting glacier creates a 

large creek or river that drains the valley. During spring runoff, 

adjacent wetlands may be underwater, but the ground will still 

be solid. Although you may be working in standing water, 

you will not sink in the soil. As the wetland dries out, the 

surface may be dry and solid. However, water will be just a 

few inches to a few feet below the surface. During the dry 

season, the level of the groundwater will normally drop, but it 

will fl uctuate depending on upstream runoff.

Look for this site condition in northern areas that were glaciated during the Ice Age, or in U-shaped mountain valleys. 

Such valleys indicate previous glaciation (fi gure 1). To avoid 

being misled, dig a 4-foot-deep test hole to see whether characteristic sand and gravel are present.

Occasionally, small deep pockets of organic silt and clay are 

found within wetlands of glacial origin. When these occur 

near a river or creek, the soil mixture becomes saturated 

with groundwater and is extremely fl uid. These pockets are 

rare, usually easily visible, and should be avoided. They can 

be extremely treacherous, especially if covered with a thin 

layer of ice or snow. One such pocket encountered on a trail 

project in the Rocky Mountains was 10 feet long, 8 feet wide, 

and more than 4 feet deep.

Wetlands With Organic Silt and 

Clay Soils

This type of wetland may be the most common. A test hole 

will indicate that the soil is not sand or gravel, but silt or 

clay—soils with fi ne particles. The silt and clay in most wetlands of this type are from organic materials such as leaves, 

bark, and wood. The terrain traps runoff and the soil particles 

hold this water, making the area soft underfoot.

Silt and Clay Soils With Some Water

Anyone building a trail through this type of wetland will fi nd 

that footprints quickly fi ll with water. Hikers may sink up to 

their ankles in the unstable soil.

Silt and Clay Soils With Considerable Water

This type of wetland is similar to the one described above. A 

test hole will indicate that the soil consists of the same silt or 

clay material; however, it has considerably more water mixed 

with it. Work is diffi cult when you immediately sink to your 

knees or even to your waist.

Figure 1—Glacial soils can be expected in U-shaped valleys typical 

of areas shaped by glaciers.

Glaciated U-shaped valley

Glaciated U-shaped valley
3

Your wetland construction 

checklist should include:

• Lace-up boots, hip boots,

 or even waders that are

 suitable for sloshing in water

• A dry change of clothes

Types of Wetlands 

A test hole should be as deep as possible. Due to the excessively wet soil, the sides of the hole will continually slough 

off. It may be impossible to dig deeper than 12 to 18 inches. 

In that case, rod soundings can help determine subsurface 

conditions.

Rod soundings are not too diffi cult to perform or to interpret. 

A 6- to 8-foot-long steel rod is driven into the ground with a 

sledge hammer. If the rod hits something solid, it will stop, 

or slow considerably. The rod may have reached a strata of 

rock or fi rm soil that will support construction, or it may have 

struck a root or an isolated boulder, a misleading indication 

of overall conditions. Take additional soundings nearby to 

determine the overall conditions.

An inexpensive and easily portable rod can be made from 

2-foot lengths of galvanized, 1

⁄2-inch diameter pipe. Screw a 

cap onto one end of one pipe section and screw a coupling 

onto the other end. Continue with 2-foot sections until at 

least 6 feet of pipe is assembled. Screw a T connection onto 

the upper end of the rod so that a 1

⁄2-inch-diameter steel bar 

can be passed through the T for leverage in case the rod 

gets stuck in the ground. Tap the T with a hammer (fi gure 2). 

Figure 2—This sounding rod is inexpensive and easy to carry.

The rod can be made as long as necessary. Usually 6 or 8 

feet of rod is enough to determine whether a soil problem 

exists.

River Deposits and Deltas

Soil deposited along rivers and in their deltas may include 

inorganic clay and an extremely high percentage of water. 

Walking in this type of wetland is almost impossible. This 

type of wetland is found along the Missouri River and in the 

Mississippi River delta, and should be expected along other 

large rivers.

Floating Wetlands—Trembling 

Earth or Quaking Bog

Another type of wetland is the result of water-tolerant sedge 

and sphagnum moss invading lakes. Basically, these wetlands

are areas of land fl oating on water or water-saturated peat. 

Over the years leaves, needles, twigs, and seeds are carried 

into a wetland or lake by wind and runoff, eventually forming a layer of organic soil. In areas where the soil and water 

are extremely acidic, the high volume and acidity of the water 

keeps organic matter from rotting. As this soil layer builds, 

the seeds of less water-tolerant plants will begin to grow. 

After many years a miniature forest of slow-growing, stunted 

trees will be found on the site. Expect plants such as sedges, 

sphagnum moss, pitcher plant, cranberry, blueberry, and 

Labrador tea. Tree species that will tolerate this site condition 

are alders, balsam fi r, black spruce, tamarack, willows, and 

baldcypress.

This soil will support little foot traffi c. Often the ground will 

compress with weight and quake slightly underfoot. At the 

extreme, the ground will undulate as it would if someone 

was walking on a mattress. In the Okefenokee Swamp, this 

type of wetland is referred to as “trembling earth.” In the 

Adirondack Mountains and Canada, a similar site is called 

a “quaking bog.” A test hole may show a thin layer of organic 

soil, perhaps 1 foot thick. Below it will be a layer of sphagnum 

moss and peat. Rod soundings in these layers will meet little 

resistance. When the rod is hit with a 4-pound sledge hammer, people standing 2 to 5 feet away may feel the shock 

through the ground.
4

Types of Wetlands 

Wetlands on Mountains

Carrs

In mountainous areas, wet trail problems sometimes show up

only after the trail has experienced heavy use. The terrain may

slope, perhaps by as much as 10 to 20 percent. Problems 

become evident only when trail traffi c wears through a thin 

layer of soil and exposes a wet, fl uid soil that may be 1 to 3 

feet thick. Trail crews often refer to these sites as carrs.

If test holes and rod soundings had been taken before construction, they would have revealed this thin layer of soil on top 

of fl uid soil. The fl uid layer may be so wet that it would have 

been impossible to dig a test hole without the hole’s side 

walls continually caving in. Once the fl uid layer is reached, 

the weight of the rod can cause it to sink 1 to 2 feet without 

being hit by a hammer. Leaning on the rod might cause it to 

sink 2 to 3 feet. The rod should be hammered until fi rm soil is 

reached or the rod has penetrated 8 feet of soil.

Carrs can often be identifi ed by indicator plants. River birch, 

shrubby willows, and alders growing on what appears to be 

solid ground should alert a trail designer to the potential problem (fi gure 3) and the need for soil testing.

Figure 3—Carrs are characterized by a captive layer of saturated soil

just under the surface that is sandwiched between two impervious 

layers.

Saturated soil

Firm layer of soil

Saturated soil

Rock or impervious soil

Carrs

River birch, willow, or alder

Figure 4—Seepage is sometimes caused by precipitation held in 

perched water tables.

Precipitation

Trail

Saturated soil

Rock

Seepage

R u n o f f

Figure 5—Limestone formations are very porous. Water will percolate

through the limestone and seep out of exposed faces and cutslopes.

Precipitation

Saturated soil

Saturated

soil

Rock

Seepage from limestone

Runoff and

seepage

Seepage

Some mountain wetlands are caused by subsurface water 

that seeps to the surface from a perched water table. A 

perched water table occurs where dense rock or an impervious soil layer is within inches to a few feet below the ground. 

Precipitation that would normally percolate deep into the 

ground is trapped near the surface and follows the slope of the 

impervious material downhill. This condition is common during the spring in high mountainous areas. In the dry season, 

the surface of the ground may be dry, but water will be only 

a short distance below. A trail designed and built in the dry 

season may be unsuitable during the wet season (fi gure 4).

Another more obvious condition occurs near limestone cliffs. 

Limestone covers millions of square miles of the Earth’s surface, and some limestones are extremely porous. Water will 

percolate deeply through certain types of limestone. Other 

types of limestone may be highly fractured, permitting water to 

penetrate. Water will seep out of the exposed faces (fi gure 5). 

This condition also occurs in sandstone formations.
5

Wetlands With Wildlife That Bite 

Back

The last type of wetland has more to do with hydrology, 

climate, and wildlife than geology. Sites in the southeastern 

United States and tropical regions support species of wildlife 

that look upon man as prey. Building a normal wetland trail in 

these areas may be hazardous to the crew building the trail 

and to hikers unfamiliar with the potential dangers posed by 

local wildlife.

Alligators are often found in wetlands in the southern United 

States. Normally, alligators are not a problem to adult humans, 

but they may take an interest in a visitor’s dog or small child. 

Little can be done to permanently keep them off the trail. Alligators may fi nd a way through sturdy barrier fences that are 

improperly maintained, but may have a harder time fi nding 

their way off the fenced trail.

A loop trail should be considered in such areas. The loop trail 

provides the visitor with a route for hightailing it back to the 

trailhead, no matter where the alligator is encountered.

If alligators are the primary attraction for an interpretive trail, 

consider constructing an overlook. An overlook separates 

visitors from alligators and is an alternative to building a trail 

into the alligators’ territory. In open areas, an overlook may be 

an effective way to see alligators. In areas with trees or dense 

brush, an overlook may not be worth the effort or expense. 

Guided boat trips might be another option for heavily-used 

locations.

Wetland trails in northern regions have their own potential 

wildlife challenges. Moose have a fondness for wetlands. 

Although usually docile, moose can be dangerous during 

some seasons. In the spring a cow moose is protective of 

her young. In the fall rutting season, a bull moose can be 

cantankerous and unpredictable. Moose have been known to 

attack people with no provocation and to follow wetland trails, 

including those with a wooden surface. Wetland trails in these 

areas might be designed with few abrupt curves and sight 

distances of at least 75 to 100 feet.

Types of Wetlands 

Spruce Bogs

The spruce bog is a forest type found in the northern United 

States and throughout Canada and Alaska. The forest often 

consists of pure stands of black spruce, a slow-growing tree 

that survives in dense shade where the water table is high. 

Walking through a mature stand of these trees is a unique 

experience. The trees may be 6 to 12 inches in diameter, 25 

to 40 feet tall, 15 to 40 feet apart, and 200 years old. Because they can withstand shade, the trees are often densely 

branched to the ground.

In spruce bogs, roots spread on the surface, presenting a 

problem for trail construction. The roots may be 15 to 20 feet 

long and as big around as the tree. Large tree roots on one 

side of the trail spread out and cross into the root system of 

trees on the opposite side of the trail. Cutting the roots for 

normal trail construction would leave roots on either side 

of the trail and unbalance the trees’ support. Hikers may 

trip over the roots if they are left in place. The surface soil 

is organic and breaks down quickly into ruts and mudholes. 

Hikers detour around these spots, creating a braided trail 

with two, three, or four alternative routes.

Muskeg

Muskeg refers to an area covered with sphagnum mosses 

and tufts of sedges. Muskeg is very common in Southeast 

Alaska, where all relatively open peat bogs with sphagnum 

mosses or sedges are called muskeg. The following information about muskeg is from the Alaska Region Trails Construction and Maintenance Guide (USDA Forest Service 1991).

Soils in Southeast Alaska maintain a thick, living, organic 

surface mat, a high percentage of iron oxides, and are often 

saturated with water. The soil structure breaks down readily 

under stress or disturbance.

Once the protective mantle and root layer are destroyed, the 

soil readily turns into water-muck. In some disturbed muskeg 

soils, there seems to be no limit to how far a person could 

sink. A site can go from solid footing to knee-deep muck after 

the trail crew makes just a few trips back and forth.

The volume of traffi c these highly organic soils can support 

is directly related to the network of roots that exist in the soil. 

This network of roots strengthens the soil just as reinforcing 

bars strengthen concrete.
6

Types of Wetlands 

In the fall bull moose will demolish typical interpretive signs. 

One way to reduce sign damage is to use a vertical format 

for signs and place each sign on a single wide post (fi gure 6).

Wetlands with beaver, or where there is a possibility of 

beaver activity, pose different potential problems. Beavers 

are a natural draw for interpretive trails, but they might chew 

through wooden piles used to support the wooden deck of a 

trail. More importantly, they may change the water level of a 

wetland. A dam built upstream may reduce the fl ow of water 

into the wetland and reduce visitor enjoyment. A dam built 

downstream may raise the water level above the trail. Beavers may also plug culverts, weirs, and overfl ow structures. 

The level of the trail should be set higher to allow for higher 

water. A wetland trail that has been submerged because of 

beaver activity will require maintenance or reconstruction.

Figure 6—Installing signs that are designed to fi t a single post helps 

prevent damage from moose.
7

Environmental and Accessibility Compliance

National Environmental Policy Act

and Other Federal Laws

Laws, regulations, and management practices affect trail construction activities. Congress passed the National Environmental Policy Act (NEPA) in 1969. The purpose of this act is to 

ensure that Federal agencies consider the potential adverse 

effects their activities may have on the environment. The 

preservation of natural resources is the primary intent of this 

act, although the act covers cultural resources as well. The 

National Historic Preservation Act (NHPA) covers cultural 

resources. The Endangered Species Act (ESA) protects rare, 

threatened, and endangered plants and animals.

Trail construction on Federal lands, or lands where Federal 

funds are involved, must conform to these and other laws. 

Proposed trail routes should be walked by specialists knowledgeable about rare and endangered species of plants and 

animals. To avoid disturbing important cultural sites, archeologists and historians should be invited to participate. At 

some locations, cave specialists or fossil specialists will also 

be important. Trail planning needs to be coordinated with the 

land management agency that has jurisdiction over the trail.

Each U.S. Department of Agriculture, Forest Service jurisdiction must complete a formal environmental analysis before 

trail construction or major reconstruction. The process may be 

simple or complex, depending on the nature of the project 

and its affected environment. Checking with the District 

NEPA coordinator is a good fi rst step. Other agencies will 

have similar review processes. Early in the planning stage, 

determine the regulations that govern development in the area 

being considered for construction. Where many agencies 

have jurisdiction, the agency with the most stringent regulations usually governs.

When Federal funds are not involved, professional ethics on 

the part of trail personnel suggests voluntary compliance with

the intent of the NEPA and NHPA regulations.

The U.S. Army Corps of Engineers

The U.S. Army Corps of Engineers governs construction in 

navigable waterways and wetland areas of the United States. 

The agency’s primary concern in wetland areas is to limit the 

volume of fi ll and avoid fi lling that would interfere with normal 

runoff entering the wetland. For a wetland trail the procedure 

generally involves a letter to the local district headquarters, 

perhaps a site visit by a Corps representative, and the issuance

of a Corps 402 or 404 permit. Generally, complying with Corps 

requirements also results in construction that needs minimal 

maintenance.

State and Local Agencies

Many States have enacted regulations controlling wetland 

development, including trails. More States can be expected 

to do the same. Some counties and municipalities have their 

own wetland regulations. More and more trail projects cross 

agency and property boundaries, so Federal project managers need to be aware of other laws and regulations that 

might apply.

Occasionally, large areas have been established with uniform 

regulations applying to many towns and counties. The Adirondack Park Agency is a good example. This agency’s regulations apply to 6 million acres of New York State’s Adirondack 

Mountains. Included are all or parts of 12 counties and more 

than 100 towns and villages. Roughly 45 percent of the land 

is owned by the State; the rest is privately owned.

Accessible Trails

Trails need to be accessible to people with differing physical 

abilities. All trails do not have to be accessible to all people, 

but accessibility is to be considered for new trail construction 

and major reconstruction. It is a legal requirement to do so. 

In May 2006, the Forest Service Outdoor Recreation 

Accessibility Guidelines (FSORAG) and Forest Service Trail 

Accessibility Guidelines (FSTAG) became offi cial direction for 

the USDA Forest Service on National Forest System lands. 

These detailed guidelines are based on the draft accessibility 

guidelines for outdoor developed areas created by the 

Architectural and Transportation Barriers Compliance Board.

To help fi eld practitioners understand the FSORAG and 

FSTAG, the Forest Service produced the Accessibility 

Guidebook for Outdoor Recreation and Trails (Zeller and 

others 2006). This new guidebook is easy to use and is full 

of photos, illustrations, design tips, hotlinks, and valuable 

sidebars. Readers will have an easier time integrating 

accessibility into the outdoor recreation environment. The 

guidebook is available at:

http://www.fs.fed.us/recreation/programs/accessibility/.
8

Turned Around

A legendary Maine guide, so the story goes, insisted that 

he had never been lost, but he admitted to having been 

“turned around real good once—for 3 days.”

A wetland on an overcast day can easily provide an opportunity to get “turned around real good.” Wetland terrain is often 

featureless. There are no hills, ridges, or rock outcrops, and 

no obvious slopes. Vegetation is often uniform. If the vegetation is dense and at least 6 feet high, everything looks the 

same. The problem worsens with fog, rain, or falling snow. 

Maps and even aerial photographs are useless. There may 

be no real danger of getting lost. However, it is frustrating 

and time consuming to lay out a route in the wrong direction 

or to learn that you are not where you thought you were.

In this situation, a compass is essential. Start using the compass before entering the wetland and before getting turned 

around. Bring vinyl fl agging ribbon and a good sighting 

compass to the wetland on the fi rst day. Hand-held global 

positioning systems (GPS) are another way you can keep 

track of your location (fi gure 7).

Field Work

Figure 7—Knowing how to use a compass or GPS unit will help you 

locate the trail.

Sometimes the terrain and vegetation are so uniform you 

have to mark the general area that the trail will traverse. Using the compass and the vinyl ribbon, fl ag a straight line route 

on one particular compass bearing or azimuth. Tie the ribbon 

at shoulder to eye level. When standing at one ribbon, you 

should be able to see the next one (fi gure 8).

Flag the outer perimeters of the general area wherever they 

are not obvious. Use different-colored ribbons as needed to 

help you fi nd your vehicle at the end of the day. Not that you

are likely to get turned around, of course.

Trail Layout

Reconnaissance

Reconnaissance (recon) involves walking over the area the 

trail will traverse and fi nding the places where the trail must 

go and the places you would like it to go. For example, there 

may be only one location where the trail can enter the wetland with minimal construction. This becomes a construction 

control point. There may be just one or two places where it is 

feasible to cross a small stream. These become construction 

control points. One of these points will probably be incorporated in the fi nal route.

What about a location that provides a distant view? This becomes an esthetic control point. A small island in the wetland 

supports a variety of plant life that is of interpretive value. 

The island becomes another control point. A view of a sewer 

plant on the other side of the wetland is something to avoid. 

That location becomes a negative control point.

Preliminary Route (P-Line)

The trail must be laid out on the ground. The objective is to 

tie the control points together in a reasonable route, somewhat like connecting the dots, but on a much larger scale. 

This is normally done with vinyl fl agging ribbon.

Figure 8—Dense, spreading shrubby plants such as willow and alder 

may require two fl agging ribbons, one on each side of the plant.

Flagging ribbons
9

Field Work

Figure 9—Vinyl fl agging ribbon comes in many colors. Striped ribbon

is good for marking the preliminary route.

Few people use striped ribbon, so consider using it to mark 

the preliminary route. Carry at least two different combinations of colors (red and white stripes and orange and black 

stripes or other combinations) (fi gure 9).

If a portion of the route has to be changed, use the second 

color of ribbon. Do not tear down the ribbon for the fi rst route 

that appears to be undesirable; it may prove to be better than 

the alternative route. Tie the new color of ribbon next to the 

piece of the fi rst color where you want to depart from the fi rst 

route. The outcome will be a preliminary route or P-line.

Coordination

The layout of an interpretive wetland trail should be a collaborative effort between people experienced in trail construction and those who will be responsible for the interpretation 

of the completed trail. All parties need to be brought in at the 

planning and layout stage. The interpretive staff is in the best 

position to identify interpretive points. 

On an interpretive trail, the interpretive points will be among 

the control points. Routing any trail through all possible control 

points would result in a long, zigzag trail that would be expensive to build and would look ridiculous. Usually there must 

be a compromise between alignment, the length of the trail, 

construction cost, maintenance problems, and the number of 

esthetic and interpretive control points along the route. One 

600-foot length of trail was built near a beaver dam for its 

interpretive value. Soon, that length of trail was under almost 

2 feet of water and had to be rerouted. That location turned 

out to be a poor compromise.

After agreement on the P-line, the various compliance specialists should be contacted and, if necessary, brought in to 

walk the route. These may include specialists from your own 

agency, perhaps others from the U.S. Army Corps of Engineers and the U.S. Fish and Wildlife Service, and cultural 

resource specialists such as historians and archeologists.

Blue Line

It helps to go back over the P-line and refi ne it with an eye 

toward reducing construction problems, views of the trail by 

other trail users, and views of constructed structures from 

the trail. Refi ne the alignment to avoid sharp turns and long 

straight sections.

Blue ribbon is often a good choice for this more precise 

line. Blue has proven to be the most visible color in areas of 

dense vegetation. Spending time fl agging the blue line will 

make the fi nal layout work easier and faster. In some agencies, specifi c colors of ribbon denote specifi c purposes. Be 

sure your blue fl agged line isn’t going to be confused with 

a logging unit boundary, for example. Sometimes, because 

of vandalism and removal of the ribbon, the proposed route 

should not be too obvious. Solid green or black-and-yellow 

striped ribbon are usually the most diffi cult to see against 

vegetation and less likely to be removed. Sometimes cattle 

and wildlife chew on the ends of the ribbon. You may be able 

to locate the fl ag line by looking for the remaining knots of 

ribbon.

Final Layout

The designer and one or two assistants measure the route 

and keep notes (appendix A) on distances and locations and 

on the lengths of items that will be needed during construction. This information is extremely important for preparing 

accurate cost estimates, ordering materials, tools and equipment, and determining the size of the construction crew.
10

Field Work

Figure 10—This fi eld notebook is a tried and true technology that 

works.

Distances are usually recorded by station, an engineering 

measuring system used for roads, railroads, and utility lines. 

Traditionally, in this system 100 feet is written as 1+00; 1,254 

feet is 12+54. The distances are measured with either a 

100-foot or 50-foot measuring tape and are “slope measured” 

(measured along the slope). Wire fl ags are marked with the 

station distance and stuck in the ground at the approximate 

location that has been measured. Using metric measurements, 100 meters is written as 1+00; 1,254 meters as 12+54.

The trail grade (the slope of the trail route) is measured on 

the ground between stations and between obvious changes 

in slope. At most sites a clinometer or Abney hand level is 

suffi ciently accurate for this work. Precision is not as critical 

for a trail as it is for a road.

Measure the slope as a percentage of grade (the vertical rise 

or fall in feet per 100 feet of horizontal distance, or meters 

per 100 meters of horizontal distance) and record it in the 

notes. Where the route rises, it is shown as a positive or plus 

grade. Where the route drops, it is a negative or minus grade. 

Appendix B has slope conversion information.

A crew of three is more effi cient than a crew of two for doing 

fi nal layout. A crew of three is almost essential in areas of 

dense vegetation.

The fi eld notes can be kept on Rite-in-the-Rain waterproof 

paper and stored in a 4- by 6-inch ring binder (fi gure 10). A 

blank form that you can copy is included in appendix A.

The form shown (fi gure 11) is 41

⁄4- by 51⁄2-inches or a half 

sheet of paper. After the workday, remove the notes from the 

ring binder and leave them in the offi ce or at camp. Normal 

surveyor’s notebooks are awkward for trail fi eld notes—they 

keep trying to close up and they are diffi cult to copy.

The fi eld notes should include important basic information: 

location, project, date, weather, fi rst and last names of the 

crewmembers, job assignments, color of the fl agging ribbons, and the location of the 0+00 station referenced to fi xed 

objects on the ground. Clear and consistent handwriting and 

language skills are important. Standard abbreviations should 

be used and the abbreviations must be explained to others 

on the crew. Provide a legend for unusual abbreviations. 

Sketches and maps are also valuable sources of information. 

Eventually, the fi eld notes will get to the offi ce where someone else may have to interpret them.

What a waste of time it would be to go through all this work 

and end up with notes that are unusable. Paper is inexpensive compared to the time required to gather this information. 

Do not write notes too close to each other. When you make 

an error, put a single line through the mistake. Do not try to 

write over or erase it. Go to the next line and write in the correct information.

It is critically important to note the colors of ribbon that you 

used. Trail construction workers will need to know the color of 

ribbon they will be looking for. Six months after the fi eld layout, even the workers who laid out the trail will not remember 

what colors were used.

Drawings, Specifi cations, and Cost 

Estimates

Regardless of who builds the trail, the fi eld notes must be 

converted to drawings and specifi cations that can be used in 

the offi ce for estimating costs and ordering materials, and in 

the fi eld for construction.
11

Field Work

 Station & Tread Sideslope Gradient

 distance width (percent) (percent) Notes

 Pingree Park—Accessible 

wetland trail. 

 9/10/97—Sunny, warm. 

Bob Pilk, Terri Urbanowski, 

Bob Steinholtz. Red 

ribbon/red fl ags.

 0+00-35’ east of fl ag 

pole/north curb. 

 0+00

 4’ 25 5

 0+50

 4’ 30 5

 0+75 Enter willow brush

 4’ 30 5 Heavy brush clearing

 1+00

 35 5

 1+76 Intersection with wetland

 10 4 loop—rt (south route) 

end willow brush clearing. 

 1+81 Begin bog bridge/piles

 0 4

 2+04 End piles, begin B.B. on 

 0 -2 sleepers

Figure 11—Sample fi eld notes are legible and have the information needed to locate the trail and plan for materials.
12

Field Work

 Station & Tread Sideslope Gradient

 distance width (percent) (percent) Notes

 2+38 End B.B./begin turnpike. 

 0 +2

 2+74 End turnpike/begin B.B. on

 0 +2 sleepers—medium willow 

brush clearing.

 3+06 

 ±10 0 Hummocky/begin B.B. with 

cribbing, some cribbing 

one side only.

 3+58 Timber culvert: 8’ span by 

 4’ 0 0 4’ height

 3+66

 0 0

 3+86 River on rt. Suggest 20 lf 

 10 -1 of Geoweb in turnpike.

 4+19 End turnpike. Begin trail 

on

 4’ 0 +2 solid ground. 

 4+97 Sta. 4+97 = 1+76

Figure 11—(continued).
13

Field Work

The drawings should include the approximate layout of the 

route, indicating landmarks and major items of construction. A second drawing at a larger scale should indicate by 

station or distance where these items begin and end. These 

distances are subject to fi eld adjustment. Several large-scale 

drawings may be needed to show the whole trail route.

Drawings with construction details will also be needed for 

cost estimates and construction. These large-scale drawings 

show the construction materials, their dimensions, how they 

are put together, and how they are attached.

A specifi cation defi ning the quality of the materials and craftsmanship must also be written. For a simple project, this information can be included on the drawings. The specifi cation is 

also needed by the cost estimator, the individual ordering the 

materials, the crew chief, and the project inspector.

Preparing drawings and a specifi cation may sound like a lot of

work, but preparation reduces the questions of the construction crew and the time spent by the designer in the fi eld 

during construction. Such work also reduces the possibility 

that the wrong materials could be delivered to the worksite. 

Written drawings and specifi cations are essential for contracts. Forest Service employees should follow the format of 

Standard Specifi cations for Construction and Maintenance of 

Trails (USDA Forest Service 1996) and Standard Drawings 

for Construction and Maintenance of Trails (USDA Forest 

Service 1996).

If the work is to be done in-house with an experienced crew, 

sometimes the procedures can be simplifi ed. It is still a good 

idea to have drawings and written specifi cations, because 

they can prevent misunderstandings.
14

Wetland Trail Structures

AAt least eight types of trail structures are commonly built in

wetlands. Some of these are built with no foundation. 

Others have sleepers (sills), cribbing, or piles as 

foundations. Most of these structures are built of wood.

The oldest methods for building a wetland trail were corduroy and turnpike, which require no foundation. Turnpike may 

require constructing timber culverts, which involves building 

two small timber walls. The walls must rest on a buried timber sill. Planks span the space between the walls.

The various types of puncheon, gadbury, and the simplest form 

of bog bridge construction may be built on a foundation of 

sleepers, or on log or timber cribbing. Cribbing is more diffi cult 

to construct and is used occasionally where the terrain is 

hummocky (having small mounds of vegetation interspersed 

with depressions that hold water).

Bog bridges and boardwalks are often supported on pile 

foundations. Three types of pile foundations have been used 

for bog bridges and boardwalks: end-bearing piles, friction 

piles, and helical piles. Piles are the most labor-intensive 

foundation. Helical piles and some friction piles require specialized machinery for installation.

Floating trails are another, less common, technique. Where 

they are used, you need some form of anchorage.

In this manual we describe the structures more or less in 

historical order. The oldest are early in the list, and the newest

or most diffi cult to construct appear toward the end. The older

structures can be built without machines, although machines 

make the work go faster. The newer structures are easier to 

build if machinery is available.

Sustainable Design

Sustainable design essentially asks the trail designer or builder:

➥ Can we use the proposed construction technique and 

expect the materials and the various processes to be 

available years from now if we need to replace part of the 

trail?

➥ When the item is no longer usable, can any of the materials be recycled?

➥ Can recycled materials be used in the construction?

➥ Are recycled materials appropriate for the proposed use? 

These criteria should be considered by all agencies, especially conservation agencies.

Corduroy

Corduroy was originally used to provide access through wetlands to areas being logged or mined. Essentially, the technique involved laying a bridge on the ground where the soil 

would not support a road. Two log stringers or beams were 

placed on the ground about 8 feet apart. Small-diameter logs 

or half logs were placed on the stringers, spanning them. 

The logs became the tread or surface of the road. They were 

spiked or pinned to the stringers (fi gure 12).

A variation of corduroy construction was to place the tread 

logs directly on the ground. No stringers were used, and the 

logs were not pinned or spiked to the ground or each other. 

Some excavation was required to ensure the tread logs were 

level. The tread logs eventually heaved up or sank, creating 

severe cross slopes in the tread.

Corduroy construction was often used in areas with deep 

shade and considerable rainfall. The combination of sloping, wet tread resulted in a slippery, hazardous surface. 

The stringers and tread logs soon rotted. With no support, 

the cross slope on the tread logs became worse and more 

hazardous.

When corduroy was laid directly on the ground, it interfered 

with the normal fl ow of runoff. Runoff was blocked in some 

areas and concentrated elsewhere. Erosion and relocation 

of minor streams resulted. No plants grew underneath the 

corduroy, further damaging the wetland resource. Many 

trees needed to be cut to provide the logs for the corduroy. 

In many cases, these impacts would be unacceptable today. 

The useful life of corduroy today is only 7 to 10 years. Corduroy is rarely replaced because suitable trees are even farther 

from where they are needed for the reconstruction job.

Corduroy did not represent sustainable design and required 

considerable maintenance. Corduroy is rarely used today. We 

do not recommend it.
15

Wetland Trail Structures

Figure 12—Corduroy requires a lot of native material, rots quickly to an unsafe condition, and is no longer recommended for new construction.

Turnpikes

Turnpikes are used to elevate the trail above wet ground. The 

technique uses fi ll material from parallel side ditches and 

other areas to build the trail base higher than the surrounding 

water table. Turnpike construction is used to provide a stable 

trail base in areas with a high water table and fair- to welldrained soils (fi gure 13).

A turnpike should be used primarily in fl at areas of wet or 

boggy ground with a 0- to 20-percent sideslope. The most 

important consideration is to lower the water level below the 

trail base and to carry the water under and away from the 

trail at frequent intervals. Turnpikes require some degree of 

drainage. When the ground is so wet that grading work cannot 

be accomplished and drainage is not possible, use puncheon 

or some other technique. A turnpike is easier and cheaper 

to build than puncheon and may last longer. A causeway is 

another alternative where groundwater saturation is not a 

problem and a hardened tread is needed. Figure 13—Trail turnpikes usually cost less than other techniques for 

crossing seasonally wet areas. Occasional culverts are needed for 

cross drainage under the turnpike.

Slope

Leadoff

ditch

Turnpike
16

Wetland Trail Structures

Begin the turnpike by clearing a site wide enough for the trail 

tread and a ditch and retainer log or rocks on either side of 

the trail tread. Rocks, stumps, and roots that would protrude 

above the turnpike tread or rip geotextiles should be removed or at least cut fl ush below the fi nal base grade.

Ditch both sides of the trail to lower the water table. Install 

geotextile or other geosynthetic materials and retainer rocks 

or logs. Geotextile and geogrid should go under any retainer 

rocks or logs (fi gure 14). Lay the geotextile over the ground 

surface with no excavation, then apply high-quality fi ll. An 

alternative method, one that not only provides separation 

between good fi ll and clay, but also keeps a layer of soil drier 

than the muck beneath, is called encapsulation (the sausage technique). Excavate 10 to 12 inches of muck from the 

middle of the turnpike. Lay a roll of geotextile the length of the 

turnpike, wide enough to fold back over the top with a 1-foot 

overlap (fi gure 15). Place 6 inches of crushed stone, gravel, 

or broken stone on top of the single layer of geotextile, then 

fold the geotextile back over the top and continue to fi ll with 

tread material.

Rocks or logs can be used for retainers. Rocks last longer. 

If you use logs, they should be at least 6 inches in diameter, 

peeled, and preferably treated or naturally decay-resistant. 

Lay retainer logs in a continuous row along each edge of the 

trail tread.

Anchor the logs with stakes or, better yet, with large rocks 

along the outside. The fi ll and trail surface keep the retainer 

logs from rolling to the inside.

The practices described above work best on turnpikes in 

mountain bogs or other areas that are not subject to periodic 

river fl ooding. In fl ood-prone wetlands, different techniques 

work better. One turnpike was fl ooded to a depth of 6 to 8 feet 

on two occasions in 1 month. Stones up to 1 cubic foot in an 

adjacent area of riprap were lost in the fl ood. The edges of 

that turnpike were logs pinned to the ground with diagonally 

driven driftpins that helped to keep the logs from fl oating up 

and away. The logs were still in place after the fl ood, but the 

fi ll material between the logs had been swept away. Geotextile fabric that had been installed between the fi ll and the 

ground was still in place. In retrospect, if geocell or geogrid 

had been placed on the geotextile fabric and stapled, nailed, 

or placed underneath the logs, most of the fi ll material would 

probably have remained in place (fi gure 16).

Wood used in turnpike construction should be either a naturally decay-resistant species or treated poles. Pinned as 

described, the logs or poles should survive some fl oods.

Figure 16—Geocell may help keep fi ll in place in areas prone to 

fl ooding.

➛

Geocell

Fill with gravel

Figure 14—Place the geotextile under the retainer logs or rocks 

before staking it.

Underlying boggy soil

Ground line

Slope 1:1

➛

Mineral soil

Side

ditch

CROSS SECTION

➛

➛

Rock retainer option

1 m ➛

Minimum crown 50 mm

➛

➛

➛

Wooden stakes

Log retainers 

150 to 200 mm

Geotextile Side

ditch

➛

➛300

mm

➛ ➛

Turnpike geotextile placement

Figure 15—Sausage or encapsulation method.

Log retainers

➛

Wooden stakes ➛

Side 

ditch ➛

➛

Geotextile

➛

300-mm overlap

Underlying boggy soil

Ground line

Side 

ditch

Rock retainer option

➛

➛

Turnpike sausage or encapsulation technique

CROSS SECTION

Gravel

or rock
17

Wetland Trail Structures

Figure 17—A new turnpike will need additional fi ll as it settles, especially during the fi rst year. This turnpike has a timber culvert.

Improving Drainage

Dips or Ditches

Turnpikes and causeways interrupt the fl ow of water along 

and across the trail. You need to take measures to ensure that 

water fl ows away from turnpikes instead of saturating them. 

The tools to ensure that water fl ows away form turnpikes 

include: dips (or ditches), open drains, French drains or 

underdrains, and culverts.

Firm mineral soil, coarse-grained soils or granular material, 

or small, well-graded angular rock are needed for fi ll. Often, 

gravel or other well-drained material must be hauled in to 

surface the trail tread. If good soil is excavated from the ditch, 

it can be used as fi ll. Fill should not include organic material 

and should have minimal silt and clay components. Fill the trail 

until the crown of the trail tread is 2 inches above the retainer 

or outsloped a minimum of 2 percent. It doesn’t hurt to overfi ll 

initially, because the fi ll will settle (fi gure 17). Compacting the 

fi ll—wet it first—with a vibratory plate compactor will help 

reduce settling.

Fill material imported from outside sources may contain 

seeds of invasive weeds. Instead, it is standard procedure 

to dig a borrow pit near the site. The pit and routes to it 

should be carefully located to avoid resource damage and a 

construction scar that will be seen for many years. The borrow pit should be dug into a slope so that the fl oor of the pit 

can slope out and carry runoff water out of the pit. After the 

trail has been completed, grade back the sides of the pit and 

revegetate the disturbed area with native plant material.

Keep water from fl owing onto the turnpike by constructing 

a dip, waterbar, or a drainage structure at each end of the 

turnpike where necessary. Keep the approaches as straight 

as possible or widen any curves coming onto a turnpike to 

minimize the chance that packstock or motorbike users will 

cut the corners and end up in the ditches.

Turnpike maintenance, especially recrowning, is particularly 

important the year after construction; the soil settles the most 

during the fi rst year.

Causeways

A more environmentally friendly relative of the turnpike is the 

causeway, essentially a turnpike without side ditches (fi gure 

18). Causeways fi lled with broken rock have been successfully used throughout the Sierra Nevada and elsewhere to 

create an elevated, hardened tread across seasonally wet 

alpine meadows. Often, multiple parallel paths are restored 

and replaced with a single causeway. Causeways create less 

environmental impact than turnpikes because they do not 

require ditches that lower the water table. In highly saturated 

soils the causeway could sink into the ground, a problem that 

geotextiles can help prevent.

Dirt tread

Old ruts

Rocky fi ll

➛

➛

Causeways

Wall rocks

Resodded old ruts

➛

➛

➛

Figure 18—Causeways create an elevated, hardened tread across 

seasonally wet areas. Geotextiles may be added to help prevent the 

trail from sinking into the ground.
18

Wetland Trail Structures

Generally, dips are at least 12 inches deep, have fl at bottoms,

and sideslope ratios of 1:1. In many cases, the dip can be 

extended beyond the wet area to capture water that might 

fl ow onto the trail.

The simplest way to get water across a trail is to cut a trench 

across it. These open-top cross drains, or dips, can be reinforced with rocks or treated timbers to prevent cave-ins. These 

structures are not usually a good alternative because people 

and packstock stumble on them. One way to reduce this risk 

is to make the dip wide enough (at least 2 feet) so that packstock will step into the drain rather than over it (fi gure 19).

An open drain can be fi lled with gravel. Such a drain is called 

a French drain. Start with larger pieces of rock and gravel 

at the bottom, topping the drain off with smaller aggregate 

(fi gure 20). French drains are often used to drain a seep or 

spring underneath a trail bed. A perforated or slotted pipe in 

the bottom of the drain reduces the amount of fi ll material 

needed and drains the area more effectively.

Culverts

Culverts provide better and safer drainage across turnpikes 

than open drainage gaps or ditches.

Historically, culverts were built as small bridges, using stone 

or logs. Stone culverts require large stones and a skilled 

mason. Finding large stones is diffi cult. Today, dry stone 

masonry is almost a lost art. Well-built stone culverts can be 

extremely durable. Some stone culverts that are at least 100 

years old are still in use.

Figure 19—Dips and ditches are a simple and effective way to drain wet areas. The slope angle and depth vary with soil and water conditions. 

Stones help reinforce the dip. Geotextile may be installed under the stone dip to prevent fi ne materials from washing out.

Stone dip

Turnpike ditch

Logs

Saturated soil

Turnpike

Dips 

Figure 20—Wrapping French drains with geotextile helps prevent clogging. French drains or underdrains are used to drain springs and seeps that 

have a low fl ow.

French drain

T R A I L

Stone

headwall

Geotextile fabric wrapped around the 

top, sides, and bottom of this structure

Pitch

4-inch-diameter slotted pipe

Pipe is pitched 1⁄

8 inch per linear foot

Seepage or spring

Capped

end
19

Wetland Trail Structures

Log culverts were used where stone (and stone masons) 

were not as readily available as logs. Construction crews 

may also have been more familiar with log construction. Log 

and timber culverts require less skill to build than stone culverts, but need maintenance. Expect to replace log culverts 

in 20 to 40 years, although they can last much longer.

Building a timber culvert is simple. We typically use 6 by 6 

and 4 by 6 timbers, cutting them to any length suitable for the 

site and trail condition. Although old railroad culverts sloped 

the invert of their culverts, it may be diffi cult to do so in a wetland. In fact, it may be wise to build the invert level. This way the 

rising water from a creek or river can easily fl ow through the 

culvert as the water rises and recedes during a fl ood.

To build a timber culvert, two timber sleepers are placed in a 

shallow trench on each side of the trail, parallel to the trail 

centerline. The sleepers are pinned to the ground with at 

least two driftpins (fi gure 21). A timber wall is constructed on 

each side of the invert, resting on both sleepers. These walls 

can be as high or low as is suitable for the site condition. 

Notched 4 by 6 timbers are placed on the top of the walls 

to become the trail tread. The 4 by 6 timbers are spiked or 

pinned to the walls. Depending on materials available, the 

invert may be lined with stone or with planks resting on the 

sleepers. The invert should be fl ush with the bottom of the 

creek or wetland to allow aquatic organisms to move freely.

Normally, timber walls require deadmen going back perpendicular from the face of the wall into the earth behind the wall.

The deadmen help keep the wall from collapsing. Because 

the walls for a timber culvert are only 6 to 8 feet long, 

installing deadmen is impractical. However, some bracing is 

needed to keep the walls from collapsing. For timber culverts 

with walls retaining 12 to 24 inches of earth, 4 by 6 timbers 

can be used for each side of the tread surface. The bottom 

of each 4 by 6 can be notched 1 inch deep at each end to 

fi t over the two timber walls, forming a brace to support the 

walls. The area between these two 4 by 6s can be fi lled with 

3-inch-wide planks (fi gure 22). Timber walls retaining more 

than 24 inches of earth should have notched 4 by 6s the full 

width of the tread surface.

Most lumberyards carry 4 by 6s only in 8-foot lengths. For 

effi cient use of the wood, the 4 by 6s should be used to span 

distances of 8 feet, 4 feet, or 2 feet, 8 inches. The 2-foot, 

8-inch length would provide a 20-inch-wide open area and 

is the minimum width recommended for timber culverts. The 

minimum clear height of the culvert should be 7 inches. 

Rough sawn 2-inch-wide lumber is adequate for the entire 

tread surface of the 2-foot, 8-inch culvert (fi gure 23).

The trail tread can be the surface of the top timbers of the 

culvert, or a curb can be added on each side and the space 

between the curbs can be fi lled with earth. The height and 

width of a timber culvert can be adjusted to fi t site conditions 

and the expected volume of water. The spacing and number 

of culverts can also be adjusted to reduce the concentration 

of runoff and potential erosion problems. Timber culverts 

have an advantage over round pipe because the top timbers 

can be quite low and still provide the cross-sectional area 

of a large round pipe. Round pipe also concentrates runoff, 

while timber culverts spread the same volume of water over 

a wider area. Timber culverts work well with turnpike construction. Round pipe requires taller structures, a disadvantage.

Figure 21—Timber culvert. The invert (bottom of the culvert) is often built level in wetlands because it is less likely to wash away in fl oods.

INVERT

Trail direction

Sleepers

Timber culvert
20

Wetland Trail Structures

Pipe is not a traditional or visually compatible material for 

some backcountry trail culverts. Also, it is diffi cult to clean a 

small-diameter pipe with a shovel. A typical shovel blade is 

9 inches wide and requires many passes to clean out a 12-

inch-diameter pipe. You can do the job more easily with the 

smaller-diameter combi (combination tool). Make the rectangular opening of a timber culvert 20 inches wide and it will be 

much easier to clean than a round pipe. Pipes as small as 2 

inches in diameter have been used to carry surface runoff beneath turnpike (appendix C compares round and rectangular 

culverts). Such pipes plug up within weeks and are impossible to clean. They should never have been installed.

Corrugated plastic culverts are sturdy, lightweight, and easy 

to cut. Although the culverts are not natural, the colors usually

blend in with their surroundings better than steel. High-density 

polyethylene (HDPE) plastic culverts have become quite 

popular for trail work. However, some trail designers feel 

corrugated plastic culverts look out of place and they may 

not meet Recreational Opportunity Spectrum guidelines in 

remote sites. The ends can be framed by rock so they look 

natural, and plastic does not decay.

Timbers or logs used in culvert construction should be 

naturally decay-resistant or treated wood to help meet 

sustainability criteria. Treated wood should meet best 

management practices for aquatic environments.

Another culvert design that can be effective is an openbottom culvert, essentially half of a round culvert. Openbottom culverts need to be adequately supported under both 

edges.

Figure 22—Notching the deck planks on both ends of the culvert (two planks with notches are adequate for a wall up to 24 inches high) helps to 

brace the walls.

Notched 4 by 6 end deck planks

Unnotched 3 by 6 interior deck planks

Deck planks over timber culvert

Figure 23—Minimum size recommendations for a wooden culvert 

designed to use standard timber sizes effi ciently. Often larger culverts

may be needed. This culvert has no constructed invert.

6"

32"

20"

5"

Saturated soil

Wood culvert component sizes
21

Structures Requiring Foundations

Figure 24—Place sleepers in a shallow trench and pin them at opposing angles so they won’t fl oat away during seasonal fl ooding.

Corduroy, turnpikes, causeways, and improved drainage 

are all constructed directly on the ground and do not 

require a foundation. The remaining techniques—

puncheon, bog bridges, gadbury, and boardwalks—all 

require some sort of constructed foundation to raise the 

structure off the ground.

The type of foundation needed varies with the structure being

constructed, materials available, and the site-specifi c soil and

water conditions. More than one type of foundation may be 

appropriate for each structure, so we will discuss foundations 

fi rst. These foundations include sleepers, cribbing, end-bearing piles, friction piles, and helical piles.

Sleepers (Sills)

The simplest foundation is to rest the tread plank or stringers on sleepers, also called sills, or mud sills. A log of a 

naturally decay-resistant wood or a large-diameter treated 

pole or post is used for the sleepers. Sleepers are used to 

support puncheon, gadbury, and bog bridge construction. 

The notching for each type of structure is different and will be 

discussed later in this chapter.

A sleeper (fi gure 24) is placed in a shallow trench at a right 

angle to the trail centerline. A second sleeper is placed in 

another trench parallel with the fi rst sleeper. The distance between the two sleepers is the span. The span is determined 

with the help of someone with carpentry or structural engineering experience.

Pinning the sleepers to the ground with 24- to 30-inch driftpins is extra work, but it may reduce future maintenance in 

wetlands subject to fl ooding. Pinning is most important near 

streams or rivers where high water velocities may occur during fl ooding. Pinning may also reduce maintenance in areas 

of frequent slack-water fl ooding. The outer driftpins should be 

driven in holes drilled at opposing angles. Driftpins installed 

at these angles will resist fl otation and uplift from frost and 

will also deter vandalism. If rebar is used for pinning, the hole 

can be 1

⁄16-inch smaller diameter than the rebar. Otherwise, 

the hole should be the diameter of the pin.

Drive outer pins at opposing angles

Sleepers
22

Structures Requiring Foundations

Timbers are sometimes used instead of logs for sleepers. 

Timbers are easier to work with because they do not require 

notching. However, timbers do not have the same rustic 

quality as logs. Precast concrete parking bumpers and other 

precast concrete units have been used for sleepers, but they 

are far from rustic. Concrete bumpers weighing 150 pounds 

per cubic foot are diffi cult to bring to the site. In most wetland 

soils, they will eventually sink into the ground.

Sometimes the base for the sleeper can be strengthened by 

excavating deeper, wider, and longer; laying down geotextile; adding several inches of gravel on top of the geotextile; 

and folding the geotextile back over the top of the gravel to 

encapsulate it. Lay the sleeper on top of this foundation.

Cribbing

In hummocky terrain or when crossing a wide, low area, log 

or timber cribbing can be used to support a trail. Usually logs 

are used to construct cribbing (fi gure 25). Dig two parallel 

shallow trenches a few feet apart. Place a sleeper in each 

trench and diagonally pin it to the ground with three 30-

inch driftpins. Drive the outer two pins at opposing angles. 

Depending on the width of the completed trail, the fi rst layer 

(or course) may be 3- to 5-foot-long logs. A second course 

of two more logs is placed on the fi rst course of logs, near 

their ends. Each course of logs is placed at right angles to 

the course below and spiked or pinned to it. The cribbing is 

built up until the proper height is reached. Lay the top course 

perpendicular to the centerline of the trail. Stringers or plank 

can either be nailed to each of the top logs or timbers, or a 

single, large-diameter log can be notched and pinned to the 

top logs (similar to the sleepers described earlier).

If you use logs, saddle notches may be used in the bottom 

of all but the sleepers. This will result in a solid wall of logs. 

A simpler technique is to use a square notch at the ends of 

each log that contacts another. This technique will leave a 

3- to 6-inch gap between the logs (fi gure 26).

Drive spikes or 12-inch-long driftpins into predrilled holes at 

the corners of the cribbing to hold it together. Avoid stacking 

the joints on top of each other. The joints must be offset or the 

driftpins from each course will hit the driftpins in the logs of 

the course below.

Timbers are easier to use than logs because they do not have

to be notched. For greater stability and to prevent the cribbing

from being washed away in fl oods, you can fi ll the open space

in the core of the cribbing with stone.

Wire gabion baskets fi lled with rock also can be used for crib 

structures. Sleepers are placed on top.

Wooden Piles

Piles are another foundation technique. Three types of piles 

have been used for wetland trails. Structural engineers 

refer to these piles as end-bearing piles, friction piles, and 

helical piles (fi gure 27). Geotechnical engineers use a 

hand-operated relative density probe to help determine soil 

conditions. The probe is driven into the ground with a fi xed 

force, allowing resistance to be calculated.

Figure 25—Log cribbing with two sleepers.

Cribbing

Plank

Sleeper Sleeper

Log cribbing with sleepers

Figure 26—Log cribbing with a single sleeper. Do not notch logs that 

contact the ground.

Sleeper

Single sleeper on log cribbing
23

Structures Requiring Foundations

End-Bearing Piles

End-bearing piles are used at locations where fi rm earth or 

solid rock is found 2 to 10 feet below the ground. Although the

soil at these sites may support sleepers, piles can be used to 

support the tread at abrupt changes in grade when the tread 

must be 1 to 5 feet above the ground or water. Piles can also 

support handrails.

To place an end-bearing pile, excavate a hole a little wider 

than the pile to a point below the frostline. If you encounter 

solid rock in the bottom of the hole before reaching the frostline, the pile can rest on the rock. Power augers help make 

digging easier and faster. In wilderness areas or where only a 

few holes are needed, a posthole digger, manually operated 

auger, or shovel will do the job.

Place the pile upright and plumb in the hole. Place the excavated earth (or imported coarse sand or gravel) in the hole 

in 6- to 8-inch layers, equally on all sides of the pile, and 

compact it by tamping. A tamping bar is the best tool for 

compacting earth (fi gure 28).

End-bearing piles can be made from naturally decay-resistant 

or pressure-treated wood, steel, or concrete cast in sonotubes (disposable cylindrical forms). Wood is typically used 

because it is readily available and easier to use than steel or 

concrete. Connections to a wood pile are also much easier 

to make, and the tools needed for the job are lighter and more 

readily available. Timbers are the fi rst choice for end-bearing 

piles because their fl at, squared sides are easier to connect 

to than the round surface of logs. Usually, rough-sawn, pressure-treated 6 by 6s are adequate for this work (fi gure 29).

Friction Piles

Friction piles are normally used when the ground is wet and 

sloppy—areas where you need logs or some kind of a deck 

to stand on while you work. Friction piles for trail work are 

usually at least 12 feet long and 10 to 12 inches in diameter. 

Friction piles are considerably heavier, more awkward to 

transport, and more diffi cult to install than end-bearing piles.

A friction pile should be a naturally decay-resistant log or 

a pressure-treated log or pole. Cut a point on the narrow 

end and dig a shallow hole where the pile is to go. The pile 

must be driven with the wide butt end up and the narrow end 

down. The pile should stand as plumb as possible.

Figure 27—Friction and end-bearing piles. The pile in the middle 

began as a friction pile but became an end-bearing pile because it 

met solid resistance before fetching up.

Friction pile

End-bearing pile

Friction and end-bearing piles

Crowbar

Tamping bar

Earth-compacting tools

Figure 28—A crowbar (rock bar) and a tamping bar. The tamping bar 

is lighter than the crowbar and is best suited for loosening soil in holes

and for tamping around posts.

End-bearing

pile

Squared timbers as end-bearing piles

Figure 29—Using squared timbers for end-bearing piles makes 

connections easier than when round piles are used. Cut the tops at 

an angle so they will shed water.
24

For backcountry wetland trail construction, friction piles are 

driven by hand. Pile driving is done with a “hammer”—a 

21

⁄2- foot piece of 12-inch-diameter steel pipe (fi gure 30). 

A cap is welded at the top and two 1

⁄2-inch-diameter holes 

are cut in the cap to let air out. Two steel handles of 1

⁄2-inchdiameter reinforcing bars are welded to the sides of the pipe. 

At one area where friction pile construction was common, 

two of these hammers were used to drive the piles by hand. 

One hammer weighed 90 pounds and the other 135 pounds. 

Using these tools builds strong bodies. Usually two persons 

work together when operating these manual pile drivers.

The theory of the friction pile is that the surface of the pile 

develops friction against the sloppy soil. The deeper the pile is 

driven, the more friction develops, until fi nally the pile “fetches up” and can be driven only fractions of an inch with each 

blow of the hammer. When that point is reached, pile driving 

stops, normally at depths of 6 to 10 feet. Sometimes fi rm soil 

or rock will be reached before the pile fetches up. At this point 

the driving stops and the pile becomes an end-bearing pile.

If the trail is being built progressively, 12- to 16-foot piles can 

be driven by a small, lightweight machine with a pile driver 

attachment. Building a wetland trail strong enough to support 

the pile driver may be worthwhile in coastal areas that are 

subject to hurricanes, northeasters, or typhoons. If the wetland trail can support the machine, it will probably withstand 

some severe storms. If longer piles are needed, a much 

heavier pile driver can be brought to some sites on a barge.

Structures Requiring Foundations

Bent Construction

Whether wood end-bearing or friction piles are used, once 

a pile is in place, the construction is similar. A second pile 

is placed on the opposite side of the trail centerline so that 

each is the same distance from the centerline. When both 

piles are in place, they are connected by one or two ledgers. 

The combination of ledgers and piles is called a bent.

On a one-ledger bent, the top of each wood pile is cut fl at 

and level with the opposite pile. A 3 by 6 or 3 by 8 timber is 

placed fl at on the top of both piles so that it extends a few 

inches beyond each of them. This timber, or ledger, is spiked 

to the top of each pile (fi gure 31).

When two ledgers are used, one is bolted to the front and one

to the back of each pile, spanning the space between the 

piles. Drill a hole through each pile parallel with the trail centerline. These holes (and ledgers) should be level with each 

other. A 3- by 6-inch ledger is held in place on one side of the 

pile, and the hole in the pile is extended through the ledger. 

This is repeated until each ledger can be bolted to each pile. 

The ledgers should be level and level with each other.

Pile driver

Figure 30—A pile driver (hammer) can weigh 135 pounds or more.

Figure 31—A bent with one ledger. Spike the ledger to the top of 

each pile. The pile and ledger are collectively called a bent.

Ledger

Pile

A pile and a 

ledger equal 

a bent.

One-ledger

bent

Another method for the same type of installation is to determine

the proper height of the ledgers and clamp the pair of ledgers

to each pile of the bent. Drill a hole through the ledger, the pile, 

and the opposite ledger, all at once. This is faster, but requires 

two large clamps that can open at least 1 foot (fi gure 32).
25

Over

41⁄

2 feet

Br Braces aces

Spacer block

is between braces

Double 

brace

Structures Requiring Foundations

After installing a pair of bents, pressure-treated 3- by 12-inch 

tread planks are nailed to the ledger or ledgers as described 

for the bog bridge on sleepers. If the planks are more than 2 

feet above the ground or water, the tread should be at least 

two planks wide for trails that do not have to meet accessibility standards. Collect and dispose of treated wood trimmings 

and sawdust.

Where the deck will be more than 3 feet above the ground, 

diagonal bracing is needed to connect the piles of a bent. A 

single diagonal brace is adequate if the deck is just 3 to 41⁄2

feet above the ground (fi gure 33). If the deck is higher than 

41

⁄2 feet, two diagonal braces are necessary. These braces 

should be installed as a cross brace, forming an X between 

the piles. Diagonal braces are normally wood (fi gure 34). 

The angle of the braces should be between 30 to 60 degrees 

to the horizontal to provide enough support. Angles of 30, 45, 

or 60 degrees, or a 3-4-5 triangle, make the mathematics of 

carpentry easier in the fi eld.

Occasionally, the ground is well below the surface of the 

tread. If the tread is 4 feet or more above the ground and the 

space between the bents is 6 feet or more, diagonal bracing may be needed to connect consecutive bents. Bracing 

between bents is done with wood members from the right 

pile of one bent to the right pile of the next, and the left pile 

of the bent to the left pile of the next (fi gure 35). Keep in mind 

that braces impede waterfl ow and can contribute to debris 

and ice jams.

Figure 32—A bent with two ledgers. Trim the tops of the piles at an 

angle so they will shed water. The bolts go through the pile and both

ledgers.

Ledgers

Tread planks

Pile

Two-ledger bent

Figure 34—Use a cross brace if the deck is higher than 41⁄2 feet 

above the ground. Extra-long braces can be bolted together using a 

spacer block to increase rigidity.

Figure 33—A single diagonal brace is adequate if the deck is no more 

than 41

⁄2 feet above the ground. Alternate braces on successive bents.

Up to 

41⁄

2 feet

Diagonal brace

Brace
26

Structures Requiring Foundations

On national forests, all 

bridges require design 

approval from engineering 

before being constructed. 

Bridges are generally defined 

as structures more than 20 

feet long and higher than 5 

feet off the ground. Some of 

the more elaborate structures 

described in this report meet 

these criteria and require 

 engineering review 

 and approval.

Helical Piles (Screw Piles)

Helical piles, or screw piles, are more accurate terms for 

a recent adaptation of an old construction technique using 

screw anchors. Screw anchors were originally used in poor 

soils, often with cable guy lines. The design of the screw 

Figure 35—Bracing between bents is sometimes necessary.

At least

6 feet

At

least

4 feet

Braces between bents Helical pile

Figure 36—Helical piles are an alternative to friction piles.

anchor was modifi ed to be used as a helical pile. Although 

technically incorrect, the term screw anchor is still used 

(fi gure 36).

Helical piles are now used to support anything from utility 

poles to large buildings built on poor wetland soils. They require 

special equipment and techniques to install. Many certifi ed 

contractors are located throughout the country to allow for 

competitive bidding. Sometimes certifi ed contractors will train 

volunteers to do the work. Helical piles are an excellent 

alternative to friction piles. They weigh less, are easier to 

install with portable equipment, and result in less ground 

disturbance. Their overall cost may be much less than 

friction piles (fi gure 37).

A helical pile includes a helical lead section and a beam 

saddle. The lead section is solid high-strength steel 31

⁄2, 5, or 

7 feet long, pointed at the bottom. One, two, or three solid steel 

helices 8, 10, or 12 inches in diameter and spaced 21

⁄2 to 3 feet 

apart, are welded around a solid steel shaft. The diameter 

and number of helices depend on the loads to be carried and 

the soil conditions at the site. The helices are attached to the 

steel shaft with one edge of the slit lower than the other, 

creating a leading edge and a trailing edge. All the elements 

of a helical pile are hot-dipped galvanized. Bolt holes are provided at the end of each lead section for bolting another helical 

section to the lead section (fi gure 38).
27

Structures Requiring Foundations

Figure 37—Helical piles installed in Colorado. The saddles are not yet 

attached. The ends are covered with temporary plastic caps for safety.

Figure 38—A helical pile was used for this boardwalk. Stringers are 

attached directly to the beam saddle, helping to keep the boardwalk 

close to the ground.

A 12-inch-long, L-shaped beam saddle fi ts into the end of the

steel shaft of the helical pile where the sections are bolted 

together. The beam saddle consists of a steel angle welded to a

pipe sleeve. Two bolt holes in the vertical leg of the steel angle 

are opposite two bolt holes in a steel side lockplate (fi gure 39). 

The side lockplate is held in place by two bolts through the 

steel angle, through a wooden ledger or stringer, and through 

the side lockplate. The beam bracket can be adjusted up to 

31

⁄2 inches by tightening the nuts on the bolt. A custom saddle 

is often used to accommodate larger wood or steel ledgers.

In poor soils, longer helical piles are sometimes used to 

achieve the needed load-bearing capacity. To reach that 

capacity, the pile is augered into the ground until a predetermined torque (the force needed to twist the lead section into 

the ground) is reached. Extensions can be bolted on to the 

lead section and augered into the ground until the correct 

torque is reached.

Helical Pile Assembly

Helical pile assemblies for wetland trails usually consist of 

two helical piles opposite each other, one on each side of the 

bog bridge or boardwalk, or they may be located under the 

boardwalk. The two piles may be tied together with a ledger 

or a pair of ledgers placed on edge, resting on the beam 

saddle of each pile. The ledgers are usually solid wood—3 

by 6, 8, 10, or 12 inch, or two or three pieces of 2 by 4s or 2 

by 6s nailed together. Ledgers may also be glulaminated. The 

ledgers are bolted to each beam saddle (fi gure 40).

Screw anchor bracket

Figure 39—Screw anchor bracket for helical piles.

Helical Helical

piles

Helical

piles
28

Structures Requiring Foundations

If the deck is 3 to 41⁄2 feet above the ground, a diagonal brace

is needed between the piles. If the deck is more than 41

⁄2 feet 

above the ground, two diagonal braces are needed, installed 

as cross braces. Diagonal braces may be additional helical 

piles (fi gure 41) or steel angles with diagonal cable attached 

to them. If bents are 6 feet apart or more, diagonal bracing between bents may also be needed. Consecutive bents 

may be braced diagonally from the left helical pile of one 

bent to the right helical pile of the next bent. The procedure is 

repeated to connect the bents’ two remaining helical piles.

Figure 40—Typical ledger confi guration of a helical pile assembly.

Galvanized steel

pipe sleeve with

welded saddle

Batter anchor

with turnbuckle

assembly

11⁄

2-inch-square

steel shaft soil 

anchor

1⁄

4-inch-diameter helix

Helical piles

Helical pile

Figure 41—Typical helical pile assembly.

Special Site Considerations

A trail in a spruce bog requires adapting wetland construction techniques to the site. The most applicable technique is 

the bog bridge on bents. However, unlike construction in most 

wetlands, the location of each pile will have to be adjusted in 

the fi eld to avoid roots.

Although the upper layer of soil is organic, the underlying soil 

may not be. Dig test holes along the proposed route to determine whether end-bearing piles, friction piles, or a combination of both is the best technique.

The spacing between piers will vary, as will the angle of the 

bents to the trail centerline. Some of the tread planks will be 

shorter than normal, and others will be longer. Starting with 

tread planks that are twice the normal length will permit cutting short pieces to fi t one location, leaving longer pieces for 

use elsewhere (fi gure 42).

Figure 42—A bog bridge on a pile foundation. Protecting tree roots 

in a spruce bog requires careful placement of sleepers and piles.

Bog bridge on piles

Although this technique is described for northern spruce 

bogs, it may also have application in cypress swamps in the 

Southeastern United States and elsewhere.

If beaver are a problem, wrap piles with hardware cloth and 

staple it into place. The hardware cloth discourages beavers 

from chewing through the piles, timbers, or logs used in construction (fi gure 43).

Old beaver ponds present something of a problem in bog 

bridge construction, especially in mountainous areas. The 

Anchor

bracket Face 

mount

hanger

Ledger configuration

Helical pile
29

Structures Requiring Foundations

Figure 43—Hardware cloth stapled around piles helps discourage 

beavers.

Hardware cloth

original soil may have been of glacial origin and capable of 

supporting end-bearing piles. However, beaver dams trap silt, 

which drops to the bottom of their ponds. While end-bearing 

piles may work well in some locations in such ponds, friction 

piles are needed elsewhere. When concrete end-bearing 

piles were used at one pond, some settled 1 to 2 feet in 5 

years. After 10 years, all concrete end-bearing piles had to 

be replaced with log friction piles (fi gure 44).

Puncheon

Puncheon are essentially short-span footbridges or a series 

of connected short-span footbridges. The term puncheon 

means different things to different people. Puncheon on the 

Appalachian Trail is not the same as puncheon built in the 

Cascades, Rocky Mountains, or Sierras. Puncheon built in 

easily accessible areas may not be the same as that built in 

the backcountry. Puncheon can be used where the soil is wet 

but does not contain enough water to seriously hamper trail 

work. The one thing common to all puncheon construction is 

the use of sleepers. 

Type 1 Puncheon

On the Appalachian Trail, 3- to 6-foot-long logs are commonly

used for the sleepers. The sleepers are notched to receive one 

or two tread logs and then placed in a shallow trench. The 

tread logs are hewn, split, or sawn, roughly in half, to provide 

a level plane for the walking surface or tread. The tread logs 

are spiked or pinned in the notch of the sleepers (fi gure 45).

If the area to be crossed is longer than the logs available for 

the tread, the puncheon can be built as a series of connecting sections. Hiking any distance on single-tread-log puncheon can be unnerving because the hiker is looking down 

to avoid stepping off the tread. This is especially true if there 

is quite a drop from the tread to the ground or water below. 

Two tread logs placed side by side on longer sleepers will 

help. For two-tread-log construction, the inside face of each 

log should be hewn or sawn to butt closely to the adjacent 

log. A narrow gap between the two logs will help drain water, 

snow, and ice from the tread. This will reduce the chances of a 

slippery tread and retard decay.

Figure 44—Know your soil conditions. Concrete end-bearing piles settled 

1 to 2 feet here and had to be replaced with these log friction piles.

Figure 45—The rustic type 1 puncheon has sleepers and tread logs.
30

Structures Requiring Foundations

Two or three small spacers can be nailed to the inside face 

of one of the logs to control the width of this gap. The spacers can be short, straight lengths of 2- to 4-inch-diameter 

branches or wood scraps, hewn fl at on opposite sides to 

provide a piece of wood about 1 inch thick.

Type 2 Puncheon

In the Western States, puncheon uses log sleepers placed 

in a manner similar to that used on the Appalachian Trail. 

The sleepers are a few feet longer, however, and the space 

between them is spanned by two or three log stringers, or 

beams, spaced 1 to 3 feet apart (fi gure 46). The tread is 

made from 6- to 12-inch-diameter split logs, 4 to 6 feet long, 

or split planks. The split face becomes the tread. The bottom 

of the tread half-log is notched to rest on the stringer log, 

and the tread is spiked in place. If three stringers are used, do 

not spike the tread logs to the center stringer. The top of the 

three stringers will probably not be at the same height. Use 

a long carpenter’s or mason’s level to quickly determine the 

height of each stringer in relation to the others. Ideally the 

tread should be level from one side to the other. Handtools 

normally used in the fi eld for construction make it diffi cult to 

get the tread perfectly level. Adjusting the depth of each 

notch, as needed, will allow for variations in stringer height. 

Shims under the decking also help to level the structure from 

side to side.

Half logs can be placed with their split sides facing up as a 

tread. Smaller half logs are placed split side facing down resting on the stringer and butted tightly against the tread log. 

These logs serve as brace logs, preventing the tread logs from 

wobbling. Succeeding tread log are butted snugly against the 

brace logs (fi gure 47).

If large logs are available, tread plank can be sawn from the 

logs, producing a number of pieces of plank of varying widths

from one log. An Alaskan sawmill can be used at the site 

to produce planks with a uniform thickness. With this plank, 

there should be little—if any—need to notch or shim the 

stringers.

Excessive cross slope will make the surface very slippery. The

meaning of excessive will vary, depending on the climate 

expected when the trail is being used. In a dry climate, the 

cross slope should not exceed 1

⁄2 inch per foot of tread width; 

in a wet climate, or where snow, ice, or frost can be expected, 

the cross slope should be no more than 1

⁄8 to 1⁄4 inch per foot 

of tread width. If the trail leading to the puncheon is wet, no 

matter what the season, hikers will track mud onto the tread, 

making it slippery throughout the year.

Type 3 Puncheon

Type 3 puncheon also uses sleepers to support the structure, 

but the material is sawn timber or lumber, which should be 

treated with wood preservative (fi gure 48). This construction 

is popular at more accessible sites where materials are 

easier to transport. The longevity of treated wood and the 

environmental consequences and labor of cutting trees 

onsite make the use of sawn, treated timbers increasingly 

popular at remote sites as well. Helicopters, packstock, allterrain vehicles, and workers carry in the materials.

The sleepers can be either 6- by 6- or 8- by 8-inch-square 

timbers placed as previously described. Two or three stringers rest on the sleepers and may be toenailed to the sleepers and bolted or nailed to the stringer in the next span. The 

stringers may also be attached to the sleepers with steel 

angles and extended (cantilevered) a short distance beyond 

the sleepers.

Figure 46—Type 2 puncheon has sleepers, stringers, and decking.

Figure 47—Rustic tread or decking made from half logs (logs cut in 

half lengthwise).

Unnotched stringer

Sleeper

Sleeper may be notched

Rustic tread

Type 2 puncheon
31

Structures Requiring Foundations

Figure 48—Type 3 puncheon is constructed from preservativetreated timbers. The nailer bolted to the inside of each stringer helps 

prevent decay by concentrating screw holes and associated decay in 

the easily replaced nailers instead of the stringers.

Nailers

Type 3 puncheon

Figure 49—Gadbury is another rustic structure similar to puncheon. 

Use peeled logs for gadbury.

Gadbury

The size of the stringers is determined by the maximum 

weight they can be expected to support, which may be the 

snow load in snow country. For foot trails, usually the size of 

the stringers is calculated to support a live load of 85 pounds 

per square foot, the maximum weight expected for trail users 

standing on one section of trail. Heavier, wider puncheon is 

needed for horse and mule traffi c.

On foot trails, the tread is often 2 by 6, 2 by 8, or 2 by 10 lumber nailed to the stringers. When three stringers are used, do 

not nail to the center stringer. The nails work their way out and 

pose a tripping hazard. The stringers are the most expensive 

and most diffi cult items to bring to the site. Do everything you 

can to extend their useful life; usually this means keeping 

them dry.

The tread will need replacement more frequently than any other portion of this type of puncheon. In some areas the wood 

tread will require replacement every 7 to 10 years. After three 

or four replacements of the tread, the top of the stringers 

will show signs of decay and wear. Water from runoff and 

condensation will follow the nails down into the wood, and 

repeated nailing in the same vicinity will soften the wood. To 

avoid this, a nailing board (nailer) of 2 by 4s or 2 by 6s can be 

nailed to the top or side of the stringer. A better solution is to 

bolt rough-sawn 2 by 4s or 3 by 4s to the side of the stringer 

with carriage or machine bolts. The bolts can be 21

⁄2 to 4 feet 

apart. The tread is nailed to the nailer instead of the stringer. 

Eventually, the nailer will require replacement, but the nailer 

is much easier to replace than the stringers. Esthetically, it is 

better to attach the nailers to the inside face of the stringers.

Puncheon Summary

The type 1 and 2 puncheon do not represent sustainable 

design. They damage the resource if onsite trees are cut to 

provide construction materials. Offsite timber materials may 

be from more sustainable commercial sources. The type 3 

puncheon meets the criteria for sustainable design because 

the material used is more easily renewed. Although the tread 

may require replacement in 7 to 10 years, the heavy stringers 

have a much longer life expectancy.

All three types of puncheon are raised high enough above 

the ground to provide little interference with the movement of 

fl oodwater. The tread width of types 2 and 3 puncheon may 

affect the growth of plants under the tread.

Type 3 puncheon is the most likely of the three to meet 

accessibility guidelines.

Gadbury

Gadbury (fi gure 49), a structure similar to puncheon, was 

developed in the Pacifi c Northwest. Gadbury uses two half logs,

as described for puncheon, and longer notched sleepers. The

notch cut for gadbury must be about twice as wide as the notch

cut for puncheon. The two half logs are placed on each side of 

the center of the notch with the fl at surface up. Two full logs are 

placed in the notch on the outside of each of the half logs.

An experienced crew can construct gadbury without using 

spikes or steel driftpins. Such construction requires considerable skill and experience with woodworking tools. Lacking 

this experience, the pieces can be spiked or pinned together. 

Earth may be placed on the half logs and held in place by 

the full, outside logs.

Gadbury uses more wood than puncheon. From a standpoint 

of sustainable design, gadbury is less suitable than other 

techniques.
32

Structures Requiring Foundations

Bog Bridge

A bog bridge is a form of puncheon. Normally, bog bridges 

have a single- or double-plank tread surface resting directly on 

mud sleepers (fi gure 50), cribbing, or piles. A puncheon, by 

contrast, will usually have stringers resting on the mud sleepers, with tread decking nailed perpendicular to the stringers.

Figure 50—A simple bog bridge with sleepers. This common 

structure is also called a single-plank boardwalk in coastal Alaska.

Bog bridge with sleepers

Figure 51—The step-and-run technique is a way of keeping planks level as elevation changes. Level planks help reduce slipping in wet climates.

Spacer plank

Step-and-run technique

To add to the confusion over terminology, in coastal Alaska, 

bog bridges are called boardwalks, or step-and-run boardwalks if spacers are used to create steps (fi gure 51). In other 

places, the term bog bridge is synonymous with puncheon. 

In parts of the Rocky Mountains and Sierras, bog bridge 

equates to turnpike, a structure we described as a raised 

walkway of stone and fi ll material. We defi ne bog bridges as a 

series of connected, short-span bridges close to the ground.

The tread of a bog bridge is usually treated, rough-sawn 

3- by 12-inch plank that is 6 to 9 feet long. The plank parallels the centerline of the trail and rests on closely spaced, 

lightweight foundations. This means that the tread of the 

bog bridge can be closer to the ground, perhaps only 6 to 12 

inches above it, providing 3 to 9 inches of clear space below 

the tread. There is little to block the fl ow of water (in either 

direction) below the plank, and little to resist the force of 

fl oodwater going over it. In the backcountry, bog bridges are 

normally one 12-inch plank wide. A plank this narrow does little to interfere with plant growth underneath. The span of each 

of these small bridges will vary with the type of wood used 

for the plank, the thickness of the plank, and the anticipated 

weight on the plank. In areas of heavy, wet snow, the snow 

may be the heaviest weight on the bridge. Snow load may be 

as much as 300 pounds per square foot in such areas.
33

Structures Requiring Foundations

Bog Bridge on Sleepers

In its simplest form, the plank of the bog bridge rests on sleepers. A sleeper is placed in a shallow trench at right angles to 

the trail centerline. A second sleeper is prepared and placed 

in another trench 6 to 9 feet away. This distance is the span, 

which is determined from older installations or with the help 

of someone with carpentry or structural engineering experience. Place the plank fl at in the notches of the sleepers, 

with one cut end centered in line with the centerline of the 

log. Mark the plank where it meets the centerline of the next 

sleeper and saw it to the proper length. The plank is nailed to 

the sleepers at each end with two 50- or 60-penny (appendix 

D), ring-shank nails driven through previously drilled pilot 

holes. This process continues across the wetland.

Bog Bridge on Cribbing

Occasionally, log or timber cribbing can be used to support 

the plank of a bog bridge. Plank can either be nailed to each 

of the top logs or timbers, or one large-diameter log can be 

notched and pinned to the top logs (similar to the sleepers 

described earlier). If the bog bridge is more than 2 feet high, 

the plank should be two planks wide for safety.

Bog Bridge on Piles

Another technique for building bog bridges is to rest the plank

on pile foundations. The three types of suitable piles are endbearing piles, friction piles, and helical piles.

After installing a pair of bents or piers, pressure-treated 

3- by 12-inch planks are nailed to the ledger or ledgers as 

described for the bog bridge on sleepers. The ledgers do not 

have to be notched. When piles are used, the plank may be 

more than 2 feet above the ground or water. In such cases, 

the tread should be two planks wide.

Bog Bridge Summary

Whether a bog bridge is built on sleepers, cribbing, or wood 

piles, it lends itself to backcountry construction. The materials are wood, steel washers, bolts, nuts, and nails. The pieces 

of wood are relatively small and can be carried by hand. Bog 

bridges as described here do not meet Forest Service accessibility guidelines, but are suitable where departures from 

these guidelines are allowed.

Boardwalk

For the purpose of this book, a boardwalk is a structure that 

uses widely spaced bents or piers as a foundation. Stringers, parallel with the centerline of the boardwalk, rest on the 

ledgers of the bents or piers. The stringers support the deck, 

which is usually 2 by 6 or 2 by 8 lumber laid perpendicular 

to the centerline and nailed or screwed to the stringers, or 

to nailers bolted to the stringers. Boardwalks usually have a 

curb or handrail along their edges (fi gure 52).

Basically, a boardwalk is a series of connected bridges, 

each with a span as long as is practical, perhaps 8 to 40 feet. 

At most wetland sites, longer stringers are not practical because they are diffi cult to transport. Also, building adequate 

foundations for the long spans often requires large pieces of 

specialized equipment that cannot negotiate unstable soil.

Stringers

At least two stringers or beams rest on the ledgers and span 

the space between consecutive bents or piers. As the space 

between bents or piers increases, a third stringer, or heftier 

stringers, must be used. Three stringers are always better 

than two. There’s safety in redundancy.

Long, thick stringers are more expensive than smaller ones. 

However, they permit the bents or piers to be farther apart. 

Studies of soil conditions and problems of construction access to the site will indicate the costs for stringers compared 

to bents or piers. Bring in some engineering help to fi gure out 

Figure 52—A typical boardwalk. Boardwalks are expensive 

and somewhat complicated, so seek the help of engineers and 

landscape designers during planning.
34

Structures Requiring Foundations

the most economical spacing of bents or piers. Large stringers should be bolted to steel angles that have been bolted 

to the ledgers. Nailers should be used to attach the deck, as 

described for type 3 puncheon (fi gure 53).

Figure 53—Details of boardwalk construction. Large stringers and 

ledgers connected with steel angles and nailers help increase the 

life of the stringers.

Ledger

Stringer

Steel

angles

Nailer

Deck

Boardwalk

Ideally, the bottom of the stringers of a boardwalk should be 

above high-water levels, but this is often impractical. To reduce

maintenance, the design of the boardwalk should avoid 

interference with the fl ow of fl oodwater and fl oating debris. To 

check for evidence of fl ooding, look for clusters of dead, broken branches stuck in shrubbery or the crowns of trees. Bark 

on the upstream side of trees may be scraped or stripped 

off. The height of anticipated fl oodwater may seriously affect 

the design of a proposed handrail. Joists can be toenailed to 

the ledgers, or steel top fl ange hangers may be nailed to the 

ledgers to support the joists (fi gure 54). Top fl ange hangers 

reduce the distance between the deck and the ground below, 

perhaps eliminating the need for a pedestrian railing.

Pressure-treated wood that is now available is highly corrosive to untreated metal hardware. Hot-dipped galvanized 

treatment is recommended for all fasteners and hardware.

Figure 54—Supporting joists with top fl ange hangers helps keep a 

boardwalk closer to the ground.

Boardwalk Summary

Often boardwalks, as described here, are found around 

visitor centers, heavily used interpretive trails, or at other 

high-use sites. The sophisticated construction and materials 

needed for a boardwalk are less appropriate in the backcountry where the trail user expects simpler, more rustic 

construction and more challenging facilities.

During fl oods, the posts and rails can catch debris and form a

dam. In most situations it is better to build as little as possible 

that will have to resist the force of high-velocity fl oodwaters. A

decision on how much or how little to build should be based 

on the type and age of the visitors who will use the fi nished 

facility—schoolchildren, senior citizens, day hikers, or backpackers. Professional geotechnical and structural engineers 

and landscape architects are needed for effective design of 

these big-budget structures.
35

Finishing Details

Although constructing the basic structure right is most important, often the mark of craftsmanship is most evident 

in the fi nishing details. Most of the following discussion 

applies to boardwalks. However, some fi nishing work can be 

used with other construction techniques.

Decks

Plank used for a deck often contains heartwood and sapwood. If the plank is placed with the heartwood face up, 

alternating moisture and drying—and the effects of freezing 

and thawing—will cause knots and some of the annual rings 

in the wood to lift. To reduce tripping hazards and future 

maintenance, deck plank should be placed “green side up” 

(the heart face down and the bark face up) (fi gure 55).

Posts

A pedestrian railing system may be needed along the edge of

a deck to prevent visitors from falling off. Various building and 

highway codes call these railing systems “handrails,” “guardrails,” or “railings.” If you are planning to install a pedestrian 

railing, the details of the installation of the posts need to be 

thought out before placing the deck. Railing posts need to be 

sturdy. They are a potential liability. Flimsy railings installed as 

an afterthought are the ones most likely to fail. Usually, it is 

the connectors, not the railing, that fail.

The deck, posts, and handrail are all closely related in their 

construction. As a minimum, 4 by 6 timbers should be used 

to support handrails. Actually 4 by 4s that are surfaced 

on all four sides are only 31

⁄2 by 31⁄2 inches. They make a 

fl imsy post. The deck should extend beyond the stringers to 

the back of the post, or at least 4 inches. If this is not done, 

people standing on the deck and leaning on the railing will 

have their feet sticking out beyond the deck (fi gure 56). In 

Figure 55—Place decking with the growth rings facing down to help 

prevent cupping. Cupping causes the wood to decay faster and 

creates a tripping hazard.

Decking

Figure 56—When the handrail post is attached to the stringer below the 

deck, the decking should extend at least 4 inches beyond the stringer.

Minimum

4 inches

Handrail

post

Handrail post construction

addition, the decking helps keep water off the stringers, 

reducing decay.

There are two ways to install railing posts. The most common 

requires the deck to be in place. The posts are toenailed to a 

deck plank. By itself, this is a weak connection and requires 

an angle brace for support. Therefore the plank supporting 

the post must extend beyond the edge of the rest of the deck. 

If the plank is too short, the angle brace will be too close to 

vertical to provide much support (fi gure 57).

Figure 57—Attaching the handrail post directly to the decking requires

long deck pieces to support an angle brace.

Handrail post attached 

to long deck board
36

Finishing Details

The second method is to attach the posts to the outside of the

stringers. It is much easier to bolt the post in place before 

attaching the adjacent deck plank. To provide solid support, 

12 inches of post should contact the stringer. The posts can 

be accurately cut and drilled in a shop and brought to the site. 

To avoid the awkward and time-consuming work of notching 

the planks, the width of the post should match the width of the 

deck planking (fi gure 58).

The top of each post or pile should be cut at an angle to shed

water and to help prevent decay. To avoid a sharp corner 

at the top of the post, a narrow 1-inch area closest to the 

handrail should be cut level, and the sloping portion should 

be pitched away from the boardwalk (fi gure 59). For esthetic 

and safety reasons, the posts should not extend above the 

top of the handrail (fi gure 60).

Pedestrian Railing Types

Safety must be the fi rst consideration in selecting a railing 

system. Safety requirements are primarily determined by 

the relative accessibility of the trail. Railing types must fi t 

the appropriate Recreational Opportunity Spectrum class. 

Railings are of three basic types:

Figure 58—To provide proper support, at least 12 inches of the post 

needs to be in contact with the stringer.

Minimum 12 inches

Handrail

post

Handrail post attached to stringer

Inadequate railing systems 

have high potential for failing and injuring visitors. 

We recommend engineering 

review of railings and their

connections.

Figures 59 and 60—Cut the top of the post at an angle, but leave 

1-inch fl at on the inside edge. The post should not extend above the 

top of the handrail.

11⁄

2 inches

1 ni ch

Post

Finishing

top of post

1⁄

2 inch

Post

Handrail

Post below handrail
37

Finishing Details

➥ Railings attached to buildings (visitor centers, for example), must meet building code requirements such as those 

listed in the International Building Code (IBC). This code 

requires a railing at least 42 inches high that a 4-inch sphere 

will not pass through.

➥ Handrails on bridges need to meet the American Association of State Highway and Transportation Offi cials (AASHTO) 

Standard Specifi cations for Highway Bridges. Although most 

of the structures described in this book are not bridges, we 

offer these specifi cations for information. AASHTO requires 

42-inch-high guardrails on all pedestrian highway bridges. 

Bridges on fully accessible trails usually need this type of 

railing. This code requires handrail at least 42 inches high for 

pedestrian traffi c and at least 54 inches high for bicycle or 

equestrian traffi c. A 6-inch sphere must not pass through the 

railing in the bottom 27 inches, and an 8-inch sphere must 

not pass through the area above 27 inches.

➥ Handrails for more remote trail bridges must be at least 

42 inches high for pedestrian traffi c and at least 54 inches 

high for bicycle or equestrian traffi c. These handrail systems 

must also have at least one intermediate rail so that vertical 

distances between rails do not exceed 15 inches. Threefourths of all Forest Service trail bridges fall in this category.

Not all wetland trail structures need railings. If the trail itself 

has more hazardous drops than the trail bridge would have 

without a handrail, a handrail is probably not required. Other 

considerations, such as convenience, may justify installing a 

handrail. Although IBC requirements and AASHTO specifi cations do not govern trail construction, they can serve as 

guidelines. As a general rule, any fully accessible trail with 

a drop of 3 feet or more, or a more remote trail with a drop 

of 8 feet or more, should have a pedestrian railing system. 

All accessible trails require a curb. A wheelchair handrail is 

required for any accessible trail bridge on a grade of 5 percent 

or steeper. Document your decisions with a design warrant 

retained in your fi les.

Railing Installation

Install the railings after the posts and deck are complete. 

Most railings consist of a top and bottom rail, usually 2 by 6s, 

although 3 by 6s make a better splice and a stronger rail. The 

stronger rail permits posts to be spaced more widely than if 2 

by 6s were used for rails. The rail can also be cut and drilled 

in a shop where the splices can be cut accurately and more 

effi ciently.

Often there is no clear direction regarding splicing the railings

if the span exceeds 16 feet, the longest lumber that is readily 

available. It is diffi cult to butt splice a railing to the surface 

of a post that is less than 6 inches wide without an awkward 

splice or a maintenance problem (fi gure 61).

Walking on the top rail is a potential problem. Round logs or 

poles have been used to discourage visitors from walking on 

them, as well as 4 by 4s and 6 by 6s laid diagonally with one 

corner up. Another technique is to cut the tops of all posts 

at an angle and place a 2 by 6, or 2 by 8, on the cut surface. 

This helps to shed water and prevent decay.

Rail splices

Figure 61—Four methods of splicing rails. It is best to cut the rails in 

the shop. Use carriage bolts with the round end on the inside of the 

railing to prevent users from snagging themselves.
38

Finishing Details

The edges of all rails should be “edges eased.” Edges eased 

is a trade term indicating that the corners along the edges of 

the piece of wood are rounded. To reduce splinters, the radius

of the handrail edge should be 1

⁄2 inch or more.

Installing a handrail on a curved bog bridge or angled boardwalk

can be a challenge. One way to do this is to use steel angles. 

Measure the distance between posts and cut the rail to that 

length. Nail or screw the angles at the ends and to the outside

of a 2- by 4-inch or 2- by 6-inch rail. The angles will have to be

bent slightly to conform to the different alignment of the posts.

Hold the rail in place and nail or screw the angle to the side of

the post with the inside face of the board fl ush with the inside 

face of the post. Measure the distance between the centerline

of the two posts and cut a 2 by 6 to that length. Round the ends

slightly and bolt the 2 by 6 to the 2 by 4. The result will be a 

stronger rail than a single piece of material. This technique 

may also be used for straight sections of railing to avoid nailing 

or screwing into the face of the post (fi gure 62).

For rails on curved trails, short wedge-shaped pieces of lumber can be used as shims between the posts and the rails. 

The wedges should be oak or cedar. Wedges are diffi cult to 

cut in the fi eld. You could notch posts to the correct angle to 

accept the rails, but this is also diffi cult.

Cable or wire rope can be used as a railing system in some 

specialized applications (fi gure 63). Often the posts are close,

4 to 6 feet, and the cable is strung through holes drilled in 

the posts or through screw eyes. A single piece of cable may 

be strung through all the holes in the upper part of the posts, 

down the last post to the next lower hole and continuing 

this process back to the beginning through the lower holes, 

reducing the need for many splices. Use cable tensioners as 

needed.

Curbs (Bull Rails)

Curb and bull rail are two names for the same thing. If the 

drop from a boardwalk is about 36 inches or less, a curb 

is usually installed. A curb is required for accessible trails. 

Curbs help to delineate the trail tread (fi gure 64).

Figure 62—One method of installing rails on curving boardwalks 

using steel angles bent to accommodate the curvature of the 

structure.

Steel angle

Carriage bolt

Post 2 by 4 railing

2 by 6 railing

Rail installation on curved boardwalks

Figure 64—Typically, curbs (bull rails) are used when the deck is no 

more than 36 inches off the ground.

36 inches

or less

Curb

Curbs or

bull rails

Figure 63—Wire rope is used here as part of the railing system.
39

Finishing Details

Curbs placed directly on the surface of a wood deck can 

cause the deck planking to decay. Leaves, needles, and dirt 

accumulate against the curb, absorb water, and cause additional decay. During the winter, ice and snow will build up on 

the deck, causing a hazardous condition.

To keep the deck from decaying, place the curbs on blocks. A 

fi nished block of 2 by 4 lumber is only 11

⁄2 inches thick. Leaves 

and dirt can still build up against the curb and under it. With 

just 11

⁄2 inches of space between the curb and the deck, it is 

diffi cult to get a shovel under the curb, making this area almost impossible to clean. A better solution is to use two blocks 

of 2 by 4 lumber, one on top of the other, or one block of 4 by 

4 lumber (fi gure 65) to eliminate the opening under the curb. 

Litter will not be trapped, and melting ice and snow will run off 

more quickly. These openings underneath the curbs sometimes are called scuppers, an old nautical term.

Bulkheads (Backwalls, End Dams, 

Faceplates)

Bulkheads must be installed where wood construction meets 

the earth trail at each end of a puncheon, bog bridge, or 

boardwalk. They function as retaining walls to support the 

earth. They also protect the end grain of the stringers from 

decay and insect damage (fi gure 66). Bulkheads should 

always be treated timber.

Install the top of the bulkhead level with the top of the stringers, covering the gap with a piece of deck plank. This is the 

best way to keep moisture away from the stringer.

Extend the backwall 1 to 2 feet on each side of the structure 

to keep wet soil away from the sides of the stringers.

Figure 65—Having at least 4 inches of clearance under the curb is 

best.

Curb

Spacer block

Clearance under curb

Figure 66—Bulkheads serve as retaining walls to support the earth, 

and they protect the stringers from decay and insect damage. 

Bulkhead

Bulkhead
40

Floating Trails

Figure 67—True fl oating trails need solid anchorages. Often they are 

secured with wire rope.

TT

rails that fl oat on the surface of the water are quite rare. 

They are covered briefl y here. For more detailed information, refer to Floating Trail Bridges and Docks (Neese and 

others 2002).

Most fl oating trails are engineered structures, like docks, 

that fl oat on watertight drums, polystyrene-fi lled corrugated 

plastic pipe, or other specialized fl oating systems. Rely on 

your engineering and landscape architectural staff to help 

you design a functional, attractive system.

A fl oating trail needs solid anchors at each end. Depending on

the length of the fl oating trail and the expected water condition, the anchors may be timber deadmen (buried anchors), 

helical piles, concrete deadmen, or long wooden piles. Two 

cables, connected to these anchors and the opposite ends of 

each fl oat, hold the fl oats in place. The trail must be straight 

between anchor points. Bends in the route require intermediate anchor points for the cables. If there is any current, 

an additional cable brace should be attached to the fl oats 

toward the middle of the span to hold them in place against 

the current. This cable brace must also be anchored on both 

ends. You may need to install cable braces on both sides of 

the fl oating trail to hold it in place (fi gure 67).

A fl oating trail tends to bob around, creating an unsteady 

tread surface. Such trails may not be suitable for all users. 

During periods of rough water, the fl oating trail may have to 

be closed. Sometimes, outriggers extending to the sides of 

the deck can provide additional fl oatation and stability.

Cable brace

Anchor

Intermediate

anchor points

Anchoring floating trails
41

Construction Materials

Choosing Materials

Materials used in trail design should be appropriate for the 

setting. Steel, plastic, concrete, and asphalt may be appropriate in an urban greenbelt, but out of place in the backcountry. 

Log construction, stone masonry, and dirt trails are appropriate in a primitive, backcountry setting, but out of place in a 

city.

The Forest Service recognized this problem in the late 1970s 

and developed a system called the Recreational Opportunity 

Spectrum (ROS).

The ROS system establishes seven types of recreational land

uses and describes the level of development, management, 

and construction materials suitable for each of them. The ROS

principles may appear overly structured, but their application 

should result in construction and management that is compatible with the environment surrounding a wetland trail whether 

that trail is in a remote area, an urban greenbelt, or another 

setting. The ROS concepts are too detailed to include here, 

but they should be understood by anyone planning to design 

and construct wetland trails.

Logs

Wood from logs cut onsite is commonly used in trail construction, but wood is susceptible to attack by insects and fungi. 

Bark separates from the wood. The gap collects water and 

provides shade and protection for insects and fungi. Peeling 

off the bark reduces the likelihood of these attacks. Depending on local conditions, removing the bark may double the life 

of a log.

The bark can be removed by hand or machine. Using a draw 

knife or bark spud is the traditional way of peeling logs. The 

random scrape marks left on the peeled logs gives them a 

rustic appearance. Machine peeling “chews” the bark and 

some of the wood in a spiral pattern. The fi nished pieces are 

almost uniform in size, with a machined appearance that 

lacks the rustic character of peeled logs.

Wood that is exposed to the weather or is in contact with 

the ground will eventually require replacement. In wetlands, a 

fl ood, a heavy snow, a buildup of ice, fallen trees, or animal 

damage may shorten the life of wooden materials. Trees 

growing near a wetland site are unlikely to provide a sustainable source of logs for replacement structures. Even in 

remote areas, logs cut from trees growing in the vicinity may 

not be the best choice of materials.

Using logs cut onsite for trail construction is an ineffi cient use 

of wood and does not represent sustainable design. Tearing 

up areas near a site and destroying the character of the 

wetland makes no sense. Today, responsible trail crews are 

taking commercially obtained logs and other wood materials 

to remote wetland sites by boat, horse, mule, off-highway 

vehicle, by hand, or by helicopter, even when adequate 

material is growing a few feet from where it could be used. 

Sometimes materials can be hauled in more easily over 

snow during the winter for use the following summer.

Lumber and Timber

For the purposes of this text, lumber is wood that has been 

sawed and planed into uniform pieces with a minimum 

dimension of 2 inches or less. For instance, a 2 by 6 is a 

piece of lumber. Timber is wood that has been sawed into 

more or less uniform pieces, with a minimum dimension 

of at least 3 inches. Usually, timbers have not been planed 

smooth.

It helps to understand how logs are processed into lumber 

and timbers. Logs run through a sawmill are typically sawed 

into standard-size pieces, usually 1-inch thick or in increments of 2 inches. Common sizes are: 1 by 4, 1 by 6, 2 by 

4, 2 by 6, 2 by 8, and 4 by 4. The pieces can also be cut into 

3-inch stock. However, such nonstandard timbers would not 

be readily available at the local lumberyard. Most 4-by-4, 

6-by-6, and larger timbers are cut from the center of the log. 

Generally 1- and 2-inch materials are cut from the outside of 

the log.

After the pieces of wood are cut from the log, they are referred to as rough sawn. The fi rst step produces a piece that 

is sawn on its two widest faces. The bark remains on the narrow edges. At this point the piece is described as rough sawn 

and waney edged. The edges are not parallel or square. 

Waney-edged wood is used for rustic siding. Waney-edged 

lumber can be special ordered (fi gure 68).

Next, the piece of wood is run through another saw, the edger,

that trims the edges square and to a standard 2-inch dimension. The piece of wood is now rough sawn on all four sides 

and is full size—a 2 by 4 is 2 inches thick, 4 inches wide, and 

as long as the log.

The pieces are cut to standard lengths. Normally, the shortest pieces are 8 feet long. Longer pieces are cut in multiples 

of 2 feet, up to 16 feet. Rough-sawn lumber or timbers can 

be ordered. A piece of rough-sawn, 2-inch lumber is considerably heavier than the fi nished lumber normally carried at a 

lumberyard. Rough-sawn pieces are not completely uniform. 
42

Construction Materials

Depending on the capability of the sawmill, similar pieces may

vary 1

⁄8 to 3⁄8 inch from each other. The pieces will not have a 

smooth surface, and the edges will be sharp and splintery.

Finally, the rough-sawn pieces are run through a planer. The 

planer removes enough wood to smooth the surface on all 

sides and to produce standard-size pieces. After planing, a 

2 by 4 is 11

⁄2 inches by 31⁄2 inches and is described as S4S 

(surfaced four sides). The size after the lumber has been 

surfaced on all four sides is referred to as nominal size.

Most 2-by-4 material is usually run through a special planer 

to round off the corners. This process is called edges eased 

and reduces the chances of splinters when handling the 

wood. Edges eased can also be specifi ed for other dimensions of lumber and the smallest dimension timbers, but must 

be special ordered.

Waney-edged material should be less expensive than roughsawn because it requires less processing. Rough-sawn material should also be less expensive than nominal-size material 

because it has not been through a planer or had the edges 

eased. If the imperfections of waney-edged or rough-sawn 

material are acceptable, there is no point in specifying the 

nominal size material for a project. Why pay for someone to 

turn wood into sawdust and shavings that you can’t use? Besides, the additional work results in a weaker piece of wood.

Wholesalers sell wood by the thousand board feet. A board 

foot is 12 inches by 12 inches and 1 inch thick, or 144 cubic 

inches. The board footage of lumber and timber is determined at the time the piece of wood is rough sawn. See appendix E for a table of board feet contained in most standard 

sizes of lumber and timber, and for various standard lengths.

Decay-Resistant Wood

Using decay-resistant wood will greatly increase the life of 

the material and reduce maintenance. Some species of trees 

are naturally decay resistant. Wood from other species can 

be treated with preservatives to extend its life. Depending 

on the climate and the location of the piece of wood in the 

fi nished work, construction without decay-resistant wood 

may last only 7 to 10 years, while installations of naturally 

decay-resistant woods may last 70 years or more.

Naturally Decay-Resistant Wood

The most common decay-resistant species include the various 

cedars, redwood, baldcypress, black locust, honeylocust, 

and some white oaks. A tannin found in the wood of these 

trees colors the heartwood and makes it decay and insect 

resistant. The sapwood of the same tree is almost white and 

is not resistant. The wood of Douglas-fi r and the white oaks 

does not contain a toxin, but it is dense enough to repel 

some fungus and insect attacks.

Preservative-Treated Wood

Using chemically-treated wood in wet environments may 

mean the structure lasts 30 years instead of 7 to 10 years. 

It is important to know which chemical treatments are appropriate, and whether or not they cause adverse health or 

environmental effects.

Figure 68—Lumber terminology.

Waney edged Rough sawn Trimmed Planed with edges eased

Lumber cuts
43

Construction Materials

The subject of chemically-treated wood is complex, and is an 

area of continuing research and product development. Follow 

the recommendations in the Best Management Practices for 

the Use of Treated Wood in Aquatic Environments (Western 

Wood Preservers Institute 2006). Another comprehensive 

source of information is Preservative-Treated Wood and 

Alternative Products in the Forest Service (Groenier and 

LeBow 2006).

In a nutshell, there are several good reasons to use preservative-treated wood in wet areas and few reasons not to use 

them. All of the treatments effective in wet areas must be 

applied under pressure in a factory to exacting standards. The 

exception is copper naphthenate, which can be applied carefully and sparingly with a brush and is good for spot treatment. Both oil-type and waterborne preservatives are suitable 

for wet environments from a standpoint of preserving wood, 

but the person specifying materials needs to know the characteristics and effects of each type of preservative before 

deciding which to use. Water-soluble preservatives, such as 

borates, are not suited for wet environments. The borates do 

not permanently “fi x” to the wood.

Workers need to take safety precautions when handling 

or disposing of treated wood. Treated wood should not 

be burned. Some States and other jurisdictions may also 

impose disposal restrictions. Best management practices call 

for proper collection and disposal of treated wood debris and 

sawdust.

Each of the preservatives containing copper imparts a color 

that disappears in time. Normally, the color disappears within 

2 years, but depending on site conditions and exposure, 

the process may take several months to 3 or 4 years. One 

of the most popular preservative treatments, chromated 

copper arsenate (CCA), is no longer used if anyone is likely 

to contact the preservative-treated wood. Replacement 

treatments are more corrosive than CCA, so hot-dipped 

galvanized hardware and fasteners are recommended to 

prevent corrosion.

Recycled Plastic

Many manufacturers of recycled plastic are producing this 

material in the shapes and dimensions of standard wood 

lumber and timber products. Some of these products are being marketed as premium deck coverings. Recycled plastic 

can be worked like wood. It can be sawed, drilled, nailed, 

screwed, bolted, and painted. Although the surface is 

smooth, it is not slippery.

The properties of some recycled plastic may present unexpected challenges and disappointments. The material can be 

up to three times heavier than wood. By itself, 100-percent 

recycled plastic has little strength. It must be reinforced with a 

steel backing or core to have any structural value, increasing 

its weight and introducing another material. 

Plastic is decay resistant. The thermodynamic properties 

of plastic—how much it expands and contracts in the heat 

or cold—are quite different from those of concrete, steel, 

or wood, the materials that would normally be used with 

recycled plastic. The surfaces of some recycled plastic 

severely degrade in sunlight. The problems of strength, thermodynamics, and ultraviolet degradation are being studied. 

These problems have resulted in new, improved formulations 

of recycled plastic. These products have not yet withstood the

test of time.

Some recycled plastics contain sawdust or another form 

of wood fi ber or fi berglass. These composites are usually 

stronger and do not have the same thermodynamic problems 

as most 100-percent plastics. When sawed or drilled, the 

exposed sawdust and wood fi ber may be just as subject to 

fungus and insect attack as untreated wood. However, wood 

fi bers completely encased in plastic will be decay resistant. 

A problem is created when any of the recycled plastics are 

drilled or sawed in the fi eld. Unlike wood, the shavings and 

sawdust will not decompose. This problem can be resolved 

by drilling and sawing over a large plastic sheet and carrying 

the shavings out, the same process that is recommended for 

disposing of treated wood residues.

Recycled plastic is not a traditional construction material. It 

may be inappropriate where a rustic appearance is important. Recycled plastic costs 50 to 300 percent more than 

treated wood. The increased weight of plastic will be refl ected 

in higher shipping and onsite construction costs. One advantage of this plastic is that it does not support combustion.

Hardware

Connectors

The nails, bolts, washers, nuts, and other connectors used 

for outdoor construction should be made of corrosion-resistant

steel. Hot-dipped galvanizing provides more durable protection than electroplating. Products commonly available at 

most building supply stores are electroplated. It is especially 

important to use galvanized or stainless steel connectors on 

wood that has been treated with waterborne preservatives 

containing copper. 
44

Construction Materials

Figure 69—Fasteners (from left): carriage bolt, machine bolt, all-thread

rod, and lag screw.

Nails

Most nails used in trail construction are ringshank nails, barn 

spikes, or occasionally, roofi ng nails. Ringshank nails have 

closely spaced circular rings around the shank of the nail. 

These nails rarely work loose and are very diffi cult to remove 

if driven incorrectly. The steel is quite brittle. It will usually 

break off if it is bent or hit on the side. Nails are sized by the 

penny, an old form of measurement. See appendix D for 

gauge (thickness), lengths, and number of nails per pound 

for each size. Barn spikes are from 8 to 12 inches long, with 

a wide thread making a complete revolution around the 

shank every 4 to 6 inches.

Bolts

Bolts are used for constructing bents. Bolted connections are 

better than screwed connections because the bolt passes 

completely through at least two timbers or a timber and a 

steel plate or angle. Both ends of the bolt are visible and can 

be tightened if the wood shrinks. Three different types of bolts 

can be used: carriage bolts, machine bolts, and long bolts 

that are custom cut from threaded rod (called all thread).

Carriage bolts were used to construct wooden wagons and 

carriages. A square portion of the head of a carriage bolt penetrates into the wood, preventing the bolt from turning when 

it is tightened. Carriage bolts were originally used with oak, 

a hardwood that did not allow the bolt head to turn. Carriage 

bolts are effective with most woods, except for softwoods 

such as redwood and western redcedar. Carriage bolts do 

not require washers between the head of the bolt and the 

wood, but a washer is needed between the nut and the wood. 

Carriage bolts may be up to 12 inches long.

Machine bolts have a hexagonal head that is fl at on the top 

and bottom. Machine bolts require steel between the head 

and the wood and between the nut and the wood. The steel 

can be either a washer or a steel angle or plate. Machine 

bolts may be up to 12 inches long.

All-thread rods are available in lengths of 2, 3, 6, and 12 feet 

and diameters of 1

⁄4 to 1 inch. The rod, threaded for its entire 

length, is useful where long bolts are needed. The appropriate length is cut from the long rod with a hacksaw, and a nut 

and washer are attached to each end. Bolt cutters should not 

be used to cut the rod. They will mash the threads, making it 

impossible to attach the nut (fi gure 69).

Lag Screws (Lag Bolts)

Most people working with these connectors refer to them as 

lag bolts. Manufacturers call them lag screws. Regardless of 

their name, they usually have a square or hexagonal head, 

a threaded tapered shank, and a sharp point. They must be 

tightened with a wrench. They are made in lengths from 1 to 

8 inches and diameters from 1

⁄4 to 5⁄8 inch.

Washers

Four types of washers are suitable for working with wood in a 

wetland trail: fl at washers, fender washers, lockwashers, and 

malleable iron washers. Flat washers are the most commonly 
45

Construction Materials

Figure 70—Two sizes of hardware cloth.

used. They are placed between the wood and nuts and between the wood and the head of machine and lag bolts. The 

washer prevents the bolt head or nut from being drawn into 

the wood. Fender washers are wider than fl at washers, but 

they have the same purpose. Fender washers are used if the 

wood or other material is soft. Lockwashers are not a closed 

circle; they are cut once and the ends are offset on one 

side or the other. They are used with the other washers and 

against the nut to prevent the nut from loosening.

Malleable iron washers are much larger and thicker than 

other washers. These washers were used when large-diameter bolts joined logs and heavy timbers in traditional rustic 

construction. Malleable iron washers can be used with 3

⁄8- to 

1-inch-diameter bolts.

Nuts

Nuts fi t over the threaded ends of carriage and machine bolts

and all-thread rods. They must be used against a washer or 

a piece of structural metal. Nuts are either square or hexagonal, with a round, threaded hole in the center to fi t over the 

bolt or rod. Locknuts fi t more snugly on the bolt than common 

nuts. They are used when vibration may loosen a common 

nut. Locknuts function better than lockwashers, but they are 

not as readily available.

Wood Screws (Deck Screws)

A screw is threaded and tapers to a point. The use of a screw

determines the desired shape of the screw’s head and point, 

and the material from which it is made. There are perhaps 100

kinds of screws, but wood screws are the ones most likely to 

be used in wetland trail construction. Wood screws are used 

to attach tread plank to a nailer, or an interpretive sign to a 

post. The head of a wood screw is wedge shaped to penetrate into the wood without protruding above the surface. 

Most screw heads will either have a recessed slot or cross to 

accommodate a standard screwdriver or a Phillips-head screwdriver. Hot-dipped galvanized steel, stainless steel, and brass 

screws should be used for trail work.

Most stainless steel deck screws are produced with a hexagonal recess in the head to accommodate an Allen wrench, 

which makes them somewhat vandal resistant. Other vandalresistant screws require special screwdrivers for removal. 

These screws are best for installing signs.

Steel Reinforcing Bars

Steel reinforcing bars used for driftpins must be protected 

from the weather and the copper in wood treated with preservatives. Epoxy-coated steel reinforcing bars are available 

from suppliers of heavy construction materials. Usually these 

suppliers sell only to contractors. Epoxy can be purchased 

from some mail-order companies. The crew building the trail 

can cut the uncoated bars to size and dip the ends and paint 

the bars with the epoxy compound. The epoxy coating will 

resist saltwater corrosion. Before epoxy compounds were 

available, steel driftpins were protected with a thin layer of 

heavy automobile grease. The grease also made driving the 

driftpins easier.

Staples

Heavy steel fence staples, 1⁄4 to 1⁄2 inch in size, are useful for 

attaching hardware cloth to wooden piles used for bog bridge 

and boardwalk in areas frequented by beavers. Staples can 

also be used to attach geotextile fabric to wood.

Hardware Cloth

Hardware cloth consists of two sets of steel wires placed 

per-pendicular to each other and welded together. The result 

is a pattern of equal squares. The squares are either 1

⁄4 or 1⁄2

inch. After welding, the hardware cloth is hot-dipped galvanized. It is available in 20- and 50-yard rolls, and in 2-, 3-, and 

4-foot widths (fi gure 70). Hardware cloth is sometimes stapled 

around piles to discourage beavers from chewing on them.
46

Construction Materials

Figure 71—The net-like core of geonet allows drainage.

Geosynthetics

Geosynthetics are synthetic materials used with soil or rock 

in many types of construction. Geosynthetics can improve 

construction methods and offer some alternatives to traditional trail construction practices.

The Missoula Technology and Development Center produced

a detailed report, Geosynthetics for Trails in Wet Areas: 2000 

Edition (Monlux and Vachowski 2000), about these versatile 

products. The following information is summarized from that 

report. MTDC plans to update the report in 2007.

Geosynthetics perform three major functions: separation, 

reinforcement, and drainage. Geosynthetic materials include 

geotextiles (construction fabrics), geonets, sheet drains, 

geogrids, and geocells. All these materials become a permanent part of the trail, but they must be covered with soil or 

rock to prevent ultraviolet light or trail users from damaging 

them.

Geotextiles, sometimes called construction fabrics, are the 

most widely used geosynthetic material. They are made 

from long-lasting synthetic fi bers bonded to form a fabric. They 

are primarily used to separate trail construction materials 

from wet, mucky soil and to reinforce the trail. They have the 

tensile strength needed to support loads and can allow water, 

but not soil, to seep through. Nonporous geotextiles can be 

used in drainage applications to intercept and divert groundwater. Felt-like geotextiles are easier to work with than heatbonded, slit-fi lm, or woven products that have a slick texture.

Geotextiles are often used in trail turnpike or causeway construction. They serve as a barrier between the silty, mucky 

soil beneath the fabric and the mineral, coarse-grained, or 

granular soil placed as tread material on top of the geotextile. 

The importance of separation cannot be overemphasized. 

Once mineral soil contains about 20 percent of silt or clay, 

it takes on the characteristics of mud—and mud is certainly 

not what you want for your tread surface. Most geotextiles 

commonly used in road construction work for trail turnpikes. 

The fabric should allow water to pass through it, but have 

openings of 0.3 millimeters or smaller to prevent silt from 

passing through.

Geotextile is sensitive to ultraviolet light. It readily decomposes when exposed to sunlight. When geotextile is not exposed 

to sunlight, it lasts indefi nitely. Always store unused geotextile in its original wrapper.

Geonets or geonet composites (fi gure 71) have a thin polyethylene drainage core that is covered on both sides with 

geotextile. They are used for all three functions—separation, 

reinforcement, and drainage. Since geonets have a core plus 

two layers of geotextile, they provide more reinforcement for 

the trail than would a single layer of geotextile.

Sheet drains are a form of composite made with a drainage 

core and one or two layers of geotextile. The core is usually 

made of a polyethylene sheet shaped like a thin egg crate. 

The core provides separation, reinforcement, and drainage. 

Since sheet drains have greater bending strength than geotextiles or geonets, less tread fi ll is often needed above them.

Geogrids are made from polyethylene sheeting that is formed

into very open grid-like confi gurations. Geogrids are good for 

reinforcement because they have high tensile strengths, and 

because coarse aggregate can interlock in the grid structure. 

Geogrids are normally placed on top of a layer of geotextile 

for separation from saturated soil.

Geocells (fi gure 72) are usually made from polyethylene 

strips bonded to form a honeycomb structure. Each of the 

cells is fi lled with backfi ll and compacted. Geocells are good 

for reinforcement, reduce the amount of fi ll material required, 

and help hold the fi ll in place. Geocell usually has geotextile 

under it to provide separation from saturated soils. The grids 

need to be covered with soil so they will never be exposed. Exposed geocells present a substantial hazard to vehicles due 

to loss of traction, and can cause hikers or packstock to trip.
47

Construction Materials

Nonslip Gratings and Grit-Treated 

Mats

Gratings are normally used for walking surfaces at industrial 

sites and boat docks. They may be useful where a slippery 

tread in a wetland trail has become a problem, or where this 

problem can be anticipated because of deep shade, heavy 

rainfall, or icy conditions.

Gratings are made in a variety of sizes from steel, stainless 

steel, aluminum, and fi berglass. Some manufacturers use 

fi ne serrated teeth on the surface of the grating to prevent 

users from slipping; others use small, round, raised knobs 

on the surface; still others embed silica grit. The gratings can 

be attached to an existing deck or used by themselves in the 

original construction.

Other options to reduce the likelihood of users slipping on the

trail include the use of strips of rubber-like material with a 

non-skid surface. The strips adhere to clean decking. When 

wood is painted, stained, or sealed, a nonskid additive (sold at 

paint stores) can be mixed with the paint, stain, or clear sealer 

before they are applied.

Silica-treated fi berglass mats are available from some of 

the grating manufacturers. They come in thicknesses of 1

⁄8 to 3

⁄4 inch and in panel sizes of 5 to 12 feet. Fiberglass can be 

sawed to size. Holes can be drilled for nailing or screwing 

fi berglass to wood planks.

Most gratings are extremely expensive, well beyond the budgets of most trail projects. The exceptions would be for wetland trails at very heavily used sites such as visitor centers or 

for short interpretive trails.

In Alaska, slippery surfaces are a reality on miles and miles of

boardwalk. The Forest Service Alaska Region’s Trails Construction and Maintenance Guide (1991) offers several ways 

of dealing with this problem. These methods are described 

next.

Roughened Wood Surface

Use a saw or adz to cut grooves perpendicular to the line of 

travel. Make the cuts deep enough to be effective, but not so 

deep that they hold enough water to cause decay.

Mineral Paper

Mineral paper is available in a 9-inch width in 50-foot rolls. 

This tar-fi berglass material is tacked down every 3 to 4 

inches along each edge with galvanized roofi ng nails. Mineral 

paper should be used on pressure-treated wood because it 

will hasten the decay of untreated wood. If properly installed, 

it has given good service for up to 10 years. Mineral paper is 

inexpensive and easy to replace.

Figure 72—Geocell being laid in courses for a bridge approach. 

When the approach is completed, the geocell will not be visible.
48

Fishing Net

Nylon fi shing net (No. 96 Bunt Web) has been used successfully in the Alaska Region and has been found to be durable 

and effective. Make sure the net is properly stapled to each 

pressure-treated plank before delivering and installing the 

planks. Use an air-driven pneumatic stapler (that can be 

rented with an air compressor) to drive galvanized staples. 

Staple at 4-inch intervals to keep the net from bunching and 

creating a tripping hazard. The netting can be applied in the 

fi eld using hand-driven galvanized fencing staples.

Neatly hide all edges underneath the walking surface of the 

plank or logs. Black 1- to 2-inch mesh netting has been used 

successfully on trails in Alaska. The color blends into the landscape. Used net material can usually be obtained free from 

net hangers in most Alaska fi shing towns.

Cleats

Cleats, narrow boards screwed or bolted perpendicular to the

tread at step-sized intervals, are an effective way to reduce 

slipping, especially on slopes. Metal cleats are common on 

steep gangways leading to docks subject to tidal fl uctuations.

Construction Materials
49

Construction Tools

Figure 73—Framing square.

Figure 74—Use a clinometer to set grades for preliminary trail layout.

The standard tools used for trail construction are also needed for building a trail in a wetland. Standard trail tools are 

not described here. Instead, this report focuses on tools 

specifi cally needed for wetland trail construction. Find out 

more about handtools in MTDC’s Handtools for Trail Work

report (Hallman 2005) and two-part video (98–04–MTDC).

Measuring Tapes

Measuring tapes are a necessity for estimating and constructing a wetland trail. Construction measurements for wetland 

trails are often taken from the trail centerline. It is frequently 

necessary to divide by two. Metric measurements offer an 

advantage over English measurements in such cases. In addition, there is a move from the English system of measurement to the metric system (appendix F). Buy new tapes that 

are graduated in both systems.

Tapes 50 feet and longer are made of fi berglass, cloth, or 

steel. Fiberglass is best for the wet, brushy environment of 

wetlands. Cloth is not recommended because it will wear and 

rip easily. Long steel tapes may rust, kink, and break when 

used in wetlands. Short steel tapes, 6 to 30 feet long, are 

essential.

The longer tapes are best for estimating quantities of materials and hours needed for construction and for laying out centerlines of sleepers, bents, and other structures. The shorter 

steel tapes are handy for the actual construction.

Framing Squares

Framing squares (fi gure 73) are thin, L-shaped pieces of steel

with a 90-degree angle at the corner. Each leg of the L is 1 to 

2 inches wide and graduated in inches (or centimeters) from 

both the inside and outside corners of the L. The legs may 

be 8 inches to 2 feet long. Framing squares are used to mark 

hole centers and timbers to be cut at a 90-degree angle and 

to provide a straight, fi rm edge for marking angled cuts.

Plumb Bob

A plumb bob is a solid steel or brass cone, 3 inches long by 

11

⁄2 inches in diameter. The plumb bob accurately transfers 

measured points above the ground to comparable points on the

ground. It is useful for locating the centers of holes to be dug.

Levels

Specialized levels are useful for wetland trail work. An Abney 

hand level or a clinometer is accurate enough to be used for 

setting grades during the preliminary layout of most wetland 

trails (fi gure 74). String or line levels and carpenter’s and 

mason’s levels are needed during construction.
50

Construction Tools

Figure 75—String levels and a chalkline.

String or Line Levels

There are two types of string or line levels: one establishes 

percent of grade easily, the other does not. Each level is about 

3 inches long by 1

⁄2 inch in diameter and has a hook at each 

end to hang the level on a string. The string is pulled tight 

between two points in an almost horizontal line. One of the 

points must be at a known elevation. The string level will be 

used to establish the elevation of the other point.

The most common type of string level has two marks on the 

level tube. These marks are equidistant from the high point of 

the level tube. Center the level bubble between the two marks

on the tube by raising or lowering the string at the second 

point. When the bubble is centered, the string is level. If the 

tread is to be level, this is the elevation to be met. If the tread 

is to be sloped, the difference between the two points must be

calculated; the elevation to be met is established by measuring the difference needed, up or down, from the level line.

In the second type of string level, the high point of the level 

bubble is off center. The level tube has fi ve graduations. The 

fi rst two are widely spaced. The rest are closer together, but 

evenly spaced. When the bubble is centered between the two

widely spaced marks, the string is level. When the edge of 

the bubble touches the third mark, the string is at a 1-percent 

grade, the fourth mark is at a 2-percent grade, and so forth. A 

string level is accurate enough to begin to establish relative elevations and slopes for small wetland trail projects (fi gure 75).

Stringlines

Almost any type of string can be used for a stringline, but 

for repeated use a professional stringline is best. This type of 

stringline is a tightly braided string wound around a short, 

narrow piece of wood, plastic, or metal. Usually there is a 

metal clip, or a loop, tied on the end.

The stringline extends a straight line to reference the location

of the next section of construction. The stringline can also 

be used with string levels to establish relative elevations and 

slopes.

Chalklines

A chalkline is another type of stringline used to mark a straight

line between two points on a fl at surface. The marked line is 

commonly a guide for sawing.

Professional chalklines come in a metal case that holds the 

coil of string and the chalk dust. One end of the chalkline 

is held tightly at a fi xed point on the surface of the object to 

be marked. The chalkline is stretched to the mark at the opposite end and held tightly at that point. Hold the chalkline at 

about midpoint, pull the chalkline straight up from the surface 

and release it. The chalkline will snap back into place, leaving a sharp, straight line of chalk between the two points.

A chalkline is useful for marking the centers of sleepers 

and bents for a deck that needs to be in a straight line, or the 

edges of a deck to be trimmed uniformly, or the edges of a 

log to be cut with a fl at face.

Carpenter’s and Mason’s Levels

There used to be a distinction between carpenter’s levels and

mason’s levels. Carpenter’s levels were wood or wood with 

steel strips to protect the edges. The mason’s level was all 

or mostly steel. Today, wood, steel, aluminum, and plastic are 

used in either type of level.

These levels are available in lengths of from 2 to 6 feet. 

Given the abuse trail tools take, steel or aluminum levels are 

best. A 3- to 4-foot-long level is more accurate than a shorter 

level. These levels are easier to pack than 5- to 6-foot-long 

levels. Plastic levels are also available and cost less.
51

Construction Tools

Figure 76—Post level.

The levels have three tubes mounted in the body of the level. 

One level tube is parallel with the length of the level, one 

is perpendicular to it, and one is at 45 degrees to the other 

two. When a level bubble is centered, the edge of the level is 

either level, vertical, or at 45 degrees.

Torpedo Levels

A torpedo level is steel or aluminum and plastic and only 8 to 

12 inches long and 1 to 2 inches wide. It is used to determine

if a surface within a confi ned area is level, for example the 

surface of a notch. Although the torpedo level is not as accurate as the longer levels, it can be used to check whether 

an item is out of level, or out of plumb. If so, a more accurate 

level can be used to make the corrections.

Post Levels

Post levels save time when setting posts and piles. They are 

basically plastic right angles that are 4 inches long in three 

dimensions. Two level tubes are mounted in the two faces of 

the level. Set the level along the side of the post or pile, and 

use a crowbar or shovel to adjust the post or pile until it is 

plumb (fi gure 76).

Surveyor’s Transits and Electronic 

Instruments

Hand-held tapes and levels are adequate for short destination or loop trails in a wetland, or for low, poorly drained 

sections of existing trails. However, for trails longer than a 

quarter mile or over undulating terrain, more precise measurements might avoid future problems. Control points for 

elevation and slope can be established using surveyor’s 

transits or a variety of electronic instruments.

Surveyor’s Levels or Transits

Old surveyor’s levels or transits may be hiding in a closet or 

storage area at some agency offi ces. Blow the dust off and try to

fi nd someone who knows how to run the instrument. A builder’s

level or transit may be less accurate, but should work. A surveyor’s

level rod will be needed to obtain distances and elevations. 

Distances can be quickly measured optically using stadia.

Electronic Distance Measuring Instruments

Two types of electronic distance-measuring instruments 

(EDMs) are available. The least expensive type is hand held 

and can measure distances across a fl at surface to a point 

from 2 to 250 feet away. This type of instrument does not provide elevations of points or information needed to determine 

slopes and relative elevations. It will not provide accurate distance measurements if vegetation impedes the line of sight.
52

Construction Tools

More expensive instruments can measure distances up to 

12,000 feet with an accuracy of 0.02 to 0.03 feet. A direct, 

clear line of sight is required.

Global positioning systems (GPS) provide horizontal positioning through the use of coordinates and can provide elevations. This equipment may cost from a hundred dollars to 

several thousand dollars depending on the quality. The skills 

needed to operate GPS equipment vary depending on the 

equipment’s sophistication and accuracy.

The accuracy of small hand-held instruments can be close to 

1 meter (3.28 feet), in open, relatively level terrain, suffi cient 

accuracy for trail work if frequent points are taken along the 

route.

Survey-grade GPS instruments also are available for more 

precise work. These instruments require extensive training 

and experience in their use. They are also very expensive.

GPS technology changes quickly. Technological advances, reduced costs, and increased accuracy have resulted in many 

practical and affordable GPS trails applications.

Saws

Handsaws

Most timbers and logs used in wetland trail construction are of

relatively small diameter. Usually the largest are the piles, 6 to

10 inches in diameter.

If only a few pieces must be cut, or if wilderness regulations 

require, a one-person crosscut saw can do the job. This is 

an old-fashioned large handsaw. The blade is 3 to 4 feet long 

and heavier than a carpenter’s handsaw, with much larger 

teeth (fi gure 77).

Chain Saws

If many pieces of wood need to be cut, and if regulations 

permit them, chain saws do faster work for cutting the small 

sleepers, piles, and planks used for some wetland trails. A 

small, lightweight saw designed for tree pruning is better for 

cutting horizontally on vertical piles, posts, and other items. 

Pruning saws are available weighing 8 pounds, with a 12- to 

14-inch bar.

The sawyer should be adequately trained and experienced in 

the use of the chain saw and the safety equipment. Most government agencies, the Forest Service included, require workers 

to receive special training and certifi cation before they are 

allowed to use a chain saw.

Figure 77—A one-person crosscut saw is a good choice for backcountry settings.

Figure 78—Pruning saws.

Hand-Held Pruning Saws

Small hand-held pruning saws are used on most projects. 

Most types have a curved blade 12 to 26 inches long. For 

wetland work, the shorter saws are adequate. Some saws 

have a wood or plastic handle that the blade folds into when 

it is not being used. Small pruning saws with a straight blade 

6 to 8 inches long are available. The short saws with the 

straight blade work well for cutting shallow notches in log 

sleepers. When the saws are folded, they can be carried in a 

pocket (fi gure 78).
53

Construction Tools

Figure 79—Using an adz safely requires that the adz has a razorsharp edge and that the worker use the utmost control and concentration when making the swing.

Axes

Three kinds of axes are commonly used in trail work: singlebit, double-bit, and broad axes. The hatchet is not included in 

this tool list. A Maine guide once wrote that the hatchet is the 

most dangerous tool in the woods. He may have been right. It 

takes only one hand to use a hatchet. The other hand is often used to hold the piece of wood to be cut—not the safest 

thing to do. Few trail crews include a hatchet in their toolbox.

Proper ax selection, care, and use is described in MTDC’s 

videos and reports: An Ax to Grind: A Practical Ax Manual

(Weisgerber and Vachowski 1999) and Handtools for Trail 

Work (Hallman 2005).

Adzes

If the hatchet is the most dangerous handtool in the woods, 

the carpenter’s adz is the second most dangerous. A person 

getting hurt with a hatchet has usually been careless. It is 

not necessary to be careless to get hurt using an adz. The 

carpenter’s adz is used for cutting a level surface on a log 

for some types of puncheon and gadbury and for removing 

knots and bulges on log surfaces.

The blade of a carpenter’s adz is 5 inches wide and similar to

an ax except that it is mounted perpendicular to the line of the

handle, similar to a hoe. The edge must be sharp. The handle

is curved, similar to a fawn’s-foot handle on a single-bit ax.

Workers using an adz normally stand on a wide log (16 

inches or more in diameter) and swing the adz toward their 

feet, almost like hoeing a garden. An adz can be used on 

smaller-diameter logs by a worker standing next to the log and 

chopping sideways along the length of the log. When one face 

of the log is cut to a level plane, the log can be turned and 

another face can be cut. It is extremely diffi cult to use a longhandled adz to cut anything but the upper surface of a log.

Two other types of carpenter’s adzes have short handles. 

They are not suitable for shaping large logs, but work well for 

removing knots and bulges and for cutting notches. Shorthandled adzes are made with a straight or concave blade, 

about 3 inches wide. Striking the back of the adz head with a 

hammer will eventually crack the head (fi gure 79).

Planes

Small block planes can be used for shaping bevels and 

chamfers, for removing unevenness where two pieces of 

wood butt together, and for smoothing splintery edges that 

visitors might touch. Block planes are small, about 2 inches 

wide and 4 inches long, and easily packed to the worksite 

(fi gure 80).

Draw Knives

Draw knives are often used to peel the bark off logs. Logs will

last longer without the bark. Draw knives work best on logs 

with thin bark.
54

Construction Tools

Figure 80—A small block plane is useful for fi nish work on wood 

structures.

Figure 82—A bark spud works well when peeling green logs.

Figure 81—Straight and concave draw knives.

Draw knives have either straight or concave steel blades that 

are 12 to 15 inches long with a wooden handle at each end. 

The draw knife is pulled toward the worker. The straight draw 

knife does not put as much of the edge against the wood as 

the concave knife, making the concave knife more effi cient 

and more popular (fi gure 81).

Bark Spuds

Bark spuds are better suited for removing the bark from thickbarked or deeply furrowed logs and logs with many knots or 

large knots. Normally, logs are most easily peeled when the 

tree is still green, but this characteristic varies by tree species. Bark spuds are from 18 inches to 6 feet long. All have 

a steel head that is 2 to 3 inches wide and 3 to 5 inches long, 

sharpened on the end and both sides. The wooden handle is 

15 inches to 51

⁄2 feet long (fi gure 82).

Tools For Drilling Holes in Wood

Bits

Bits are used to drill holes in wood for bolts and for pilot holes

for nails and screws. Some of the types of bits available are 

twist bits, chisel bits, augers, and ship augers.

Twist bits are intended for use on steel, but the smaller bits 

can be used for drilling pilot holes in wood for nails and 

screws (see appendix D for appropriate pilot hole sizes). 

Chisel bits resemble a chisel with a point in the center. Chisel 

bits tend to tear up the wood around the hole on the top and 

bottom surfaces of the wood, but they are readily available in 

diameters of 1

⁄16-inch increments. Augers resemble a widely 

threaded screw with a sharp end and sharp edges. Augers 

do not tear up the wood like chisel bits do. A normal auger 

bit is 6 inches long and readily available in 1

⁄4- to 11⁄2-inch 

diameters, in 1

⁄8-inch increments, less readily in 1⁄16-inch 

increments. With a 6-inch-long auger, it is diffi cult to get the 

holes to line up when two 3-inch ledgers are on each side of 

a 6 by 6 pile. Ship augers help in this situation because they 

are longer. Ship augers are 15, 17, 18, 23, and 29 inches long 

and are indispensable when working with timbers and logs.

Old auger bits were made with a four-sided shaft to fi t into a 

manually powered brace or drill. A six-sided shaft is designed

for use in a power drill and will spin uselessly when used in 

a manually powered brace or drill. Today, most bits are made 

for power drills. When selecting a bit from a maintenance 

shop, check to see that the shaft of the bit matches the brace 

or drill to be used at the worksite (fi gure 83).
55

Construction Tools

Figure 83—Ship augers are longer than normal 6-inch augers.

Figure 84—A traditional brace and bit.

Figure 85—Gasoline-powered drills are great for backcountry work if 

regulations allow their use.

Braces

Braces and bits are the traditional tools for drilling holes in 

wood. The brace, a handtool suitable for wilderness use, is 

extremely slow. Old braces require an auger bit with a foursided shaft (fi gure 84).

Some braces are made with a ratchet, which is helpful when 

working in close situations where the brace cannot be turned 

a full circle. People have a tendency to lean on the brace to 

speed up drilling. This practice bends inexpensive braces. 

Buy a good brace or don’t lean on it. Keep the bits sharp.

Battery-Powered Drills

Small battery-powered drills are useful for drilling holes 1⁄16

inch to 3

⁄8 inch in diameter. Some heavy-duty drills can drill 

holes up to 1 inch in diameter. Battery-powered drills may be 

practical for backcountry use where only a few holes are to 

be drilled, where the crew returns to the shop after work, or 

where a generator or photovoltaic power source is available.

Gasoline-Powered Drills

Many trail crews use gasoline-powered drills. These tools can

drill holes up to 1 inch in diameter and weigh from 10 to 12 

pounds, plus fuel (fi gure 85).

Only the more expensive heavy-duty drills, whether battery 

or gasoline powered, have a reverse gear. A bit can become 

stuck if it does not go all the way through the wood. To avoid 

getting a bit stuck, lift the drill up a few times while drilling 

each hole. If the bit does get stuck, disconnect the bit from 

the brace or drill and use a wrench to twist the bit backward.

If you have a generator at the worksite, another alternative 

is to use a 1

⁄2-inch-diameter electric drill. Most of these drills 

have a reverse. An annoying drawback is stepping over 

a long extension cord and getting it tangled in brush and 

timbers. If the operator is standing in water, electric shock is 

a possibility. Generators are heavy and require fuel. Although 

some generators have wheels, most are awkward to transport to wetland sites.
56

Construction Tools

Figure 87—Socket slicks can be hard to fi nd.

Figure 86—Large jaw clamps.

Clamps

A pair of large jaw clamps can speed the installation of two 

ledger bents. The clamps should have at least a 12-inch opening. These clamps are used for making furniture and may 

be all steel or part steel and part plastic. Both ledgers are 

placed roughly in position and clamped loosely to each pile. 

The height of each ledger is adjusted, the clamps are tightened, and the bolt holes are drilled (fi gure 86).

Wrenches

At least one wrench is needed to securely fasten carriage 

bolts and lag screws. Two wrenches are needed to fasten 

machine bolts and all-thread rod. Specialty wrenches or 

screwdrivers are needed to install vandal-proof screws. 

Closed-end and open-end wrenches, and a set of socket 

wrenches, may all be needed. Tying one end of a cord to the 

wrench and the other end to your belt may help keep the 

wrench from getting lost in the water or mud.

Chisels

Wood chisels are needed for wetland trail structures. The 

blade may be 1

⁄4 to 21⁄2 inches wide. Wood chisels are typically 

made with short handles, which often contribute to scraped 

knuckles. It is worthwhile to repair or replace the handles of 

old, long-handled chisels.

For a small amount of close work, the wood chisel can be 

hit or pushed with the palm of the hand. If this technique is 

impractical, use a wooden mallet. Hitting a wood chisel with a 

steel hammer will damage the chisel’s handle. A good wood 

chisel should not be used close to nails, screws, or bolts. The 

cutting edge should be kept sharp.

The socket slick, an oversized chisel, is a diffi cult tool to fi nd. 

However, if considerable notching or other accurate work 

is required, obtaining a slick will be worth the extra effort 

and expense. The blade is 33

⁄8 inches wide with an 18-inch 

wooden handle. The slick weighs 3 pounds. A 2-inch-wide 

chisel weighs just 10 ounces. The advantages of the slick are 

its wide blade and long handle. The slick can remove wood 

twice as quickly as a wide chisel. The long handle keeps the 

hands farther from the wood being cut (fi gure 87).

Mallets

Mallets are made with plastic, wooden, leather, or rubber 

heads. Mallets with plastic or wooden heads should be used 

for hitting wood chisels.

Hammers

Claw Hammers

A carpenter’s claw hammer is helpful for nailing log culverts, 

bog bridges, boardwalks, and geotextile fabric. A 28-ounce 

framing hammer is better than the lighter models, although 

the heavy hammer may be awkward for workers who are 

unaccustomed to it.
57

Construction Tools

Figure 88—A hand auger.

Sledge Hammers

A variety of different weight sledge hammers should be available at the worksite. A 4-pound sledge is good for starting 

driftpins and spikes. A 6- or 8-pound hammer is better for 

driving them. The 8-pound hammer is better suited for moving heavy timbers and logs fractions of an inch when they 

are almost in place. Surveyor’s sledge hammers have shorter 

handles. They are better for driving long pieces of steel because they provide better control.

Crowbars

A crowbar is indispensable for building trails in rocky terrain. 

For most wetland trail work, the crowbar is used to move 

fallen trees and logs out of the way and to align piles, logs, 

and timbers. A crowbar, also called a rock bar or pry bar, is 

much stronger than a hollow-pipe tamping bar. The two are 

often confused.

Tools for Digging Holes

Shovels and Posthole Diggers

The sharp-pointed shovel can be used for digging a narrow 

deep hole, but a posthole digger or manual auger is more 

effi cient. The posthole digger with its clamshell-like blades is 

most common, but it is slow and awkward to use. The auger 

is more expensive, but more effi cient.

Augers

The auger blade consists of two pieces of immovable curved 

steel set at opposing angles to each other. The wooden 

handle is turned in a horizontal plane while the blades drill a 

hole in the ground. In most soils an auger is more effi cient 

than a posthole digger (fi gure 88).

Gasoline-Powered Augers

Gasoline-powered augers are available. These can usually be

rented from local equipment rental companies. A one-person 

auger weighs 18 to 140 pounds. A two-person auger weighs 

35 to 75 pounds. These augers are easily moved to a site. 

The heavier one-person augers have an engine mounted on 

wheels that is separate from the auger. Power augers usually 

make fast work of drilling holes in almost any soil. Problems 

occur when the auger runs into a boulder, a large root, or soil 

containing 4- to 6-inch pieces of gravel. The bit will stop, and 

the torque of the engine may cause back injury.

Wheelbarrows

Wheelbarrows are an underrated and often forgotten piece 

of equipment for trail work. A wheelbarrow is a necessity for 

moving fi ll for most turnpike construction and can be helpful 

for moving tools, materials, and supplies. For big jobs, two 

wheelbarrows are handy. One can be loaded while the other 

is being dumped.

Steel and fi berglass are the most common materials for the 

body. Steel is heavier and stronger, but fi berglass is cheaper 

and more easily repaired.

Wheelbarrows commonly available at most local building supply stores do not withstand the rigors of trail work. Contractor’s wheelbarrows are made with stronger steel, and the 

handles are made of heavier, better quality wood. Although 

more expensive, a contractor’s wheelbarrow will far outlast 

the fl imsy backyard variety. Contractor’s wheelbarrows can 

also be rented.
58

Figure 89—A vibratory tamper.

Construction Tools

Figure 90—Vibratory plate compactor.

The solid-body wheelbarrow is the type that comes to mind 

when we think of wheelbarrows, but the gardener’s wheelbarrow also has a place in trail construction. This wheelbarrow, 

without sides, is easier to use when loading large stones, 

short timbers and logs, and bags and boxes of materials. 

Gardener’s wheelbarrows are more expensive than contractor’s wheelbarrows and are diffi cult to fi nd. Most have steel 

wheels. Pneumatic rubber tires are better for trail work. The 

frame of a standard wheelbarrow can easily be converted to 

a gardener’s wheelbarrow. Temporary fl at-tire repair sealants, 

sold in aerosol cans, help prevent pneumatic tires from going 

fl at. Motorized carriers could greatly ease the burden of moving materials, where their use is allowed.

Compactors

Compactors should be used when placing fi ll for turnpike 

and for backfi ll around end-bearing piles. Several companies 

make a vibratory tamper type of compactor that is suitable for 

compacting small areas of fi ll. These companies also make 

vibratory plates, which are better suited for larger areas, such 

as turnpike and accessible surfaces. Vibratory tampers have 

an area 8 inches square that contacts the ground. Vibratory plates have an area 15 inches square that contacts the 

ground (fi gures 89 and 90).

A third type of compactor is an attachment to the Pionjar rock

drill. It can be used for compacting backfi ll in narrow spaces 

around end-bearing piles, fenceposts, and signposts.
59

Practicing the Craft

Working With Logs

You learn some time- and labor-saving procedures after working with logs a few times. Here are some tricks that can make 

your work easier.

Felling

Trees needed for log construction should be felled during 

the growing season, mid-April to early September in most 

regions. The bark is easier to remove from trees cut during 

this season.

Ideally, fell trees uphill from the construction site, and out of 

sight of trail users. Select straight trees free of obvious defects. 

Often defects are not noticeable until the tree is down, but outward signs of decay, fungus growth, and insect attack indicate 

a tree to be avoided. Special training and agency certifi cation 

are required for fallers, a very hazardous occupation.

Bucking and Seasoning

After felling, the tree is bucked, or cut, into log lengths. The 

logs can be peeled, which will reduce their weight and permit 

them to dry out, or season. Leaving the bark on the logs will 

protect the surfaces when the logs are moved, especially 

if the logs are dragged. Whether the logs are peeled or 

not, they should be stacked off the ground on two or three 

stringers of low-quality logs. Stickers should be used between 

layers of usable logs to allow uniform seasoning. Stickers can 

be 2 by 4s or small-diameter logs placed across a layer of 

logs at the ends and midpoints of a layer (fi gure 91).

Moving Logs

Logs are heavy. Footing is uneven and often slippery. Accidents can happen easily, and the emergency room is far away. 

When logs are carried by hand, the tendency is to pick up the 

logs and carry them on the shoulder or at the waist. If workers 

holding the log slip, the log will come down on them. The result 

can be a serious injury to the ribs, hip, ankle, or foot.

To avoid or reduce the severity of this type of injury, use 

two or more log carriers. Log carriers are large steel tongs 

mounted in the center of a 2- to 3-inch-diameter wooden 

handle that is 4 feet long. Two workers can use one log carrier to drag a log. At least two carriers are needed to lift a log, 

one carrier at each end. Each carrier requires one worker on 

each side of the log.

Log carriers are awkward to pack, heavy, and serve only one 

purpose. The teeth of log carriers indent the wood half an 

inch or so on each side of the log. The indentations mar the 

appearance of the log and provide a place for decay to begin.

A cheaper and lighter method for moving a log is to use 

rope slings and the removable handles of mattocks or adzes 

(or small-diameter logs that are 3 to 4 feet long). The slings 

are made by taking 6 feet of 1,000-pound-test nylon rope 

and tying a fi sherman’s knot, double fi sherman’s knot, or a 

grapevine knot at the ends, forming a loop.

Roll the log onto the slings and slip the handles over the 

log and through the loops of the slings. With one worker on 

each end of the handles (four workers total), lift the log off the 

ground. The log should be about ankle high. If anyone slips 

and drops the log, the most serious injury will be to the ankle 

or foot, and the log will not have fallen far enough to develop 

much force (fi gure 92).

Figure 91—Stickers placed between layers of logs help the logs dry 

faster and reduce decay.

Stickers for stacking logs

Figure 92—Slings are a good way to move logs and timbers, 

bundles of steel bars, wheelbarrows that must be carried over soft 

ground, or bags of cement carried on plywood.

Nylon ropes

Handles

Slings to carry logs
60

Practicing the Craft

Peeling

Peeling is a tedious process. There is little reason to peel 

the bark off a log if you plan to hew or plane it, unless the 

bark is dirty and likely to dull your cutting tools. Pine, fi r, and 

other evergreen trees may develop pitch pockets just under 

the bark. On freshly cut trees, pitch may be runny rather 

than thick or sticky. The cutting edge of a drawknife is never 

more than an arm’s length from a worker’s face, and the 

drawknife is pulled toward the worker’s body. Cutting into a 

pitch pocket splatters pitch on the worker. A drop of pitch in an 

eye results in the same burning effect as a drop of turpentine. 

Wear safety glasses or goggles when peeling logs of most 

evergreen species.

Squaring a Log

It is not easy to cut a uniform plane surface on a log. That diffi -

culty plus the desirability of using treated timbers for longevity is the reason less work is being done with native logs on 

site. However, if you are determined to use logs because of 

their availability and their rustic appearance, here is how to 

do so. The fi rst step is to place the log on nearly level ground 

and roll it over to determine which face is easiest to work 

with. Avoid areas with many knots or large knots. The crook 

of the log, if any, should be in the direction that will cause the 

least problem when the construction is completed. Roll the 

log until the best face is up and in a roughly horizontal position (fi gure 93).

Determine the width of the plane surface that is needed. Put 

a carpenter’s or mason’s level in a horizontal position against 

the end of the log. Use a measuring tape or framing square to

measure the distance between the solid wood and the inside 

of the bark at the edge of the level. By trial and error, move 

the level up or down until its upper edge is level and on a line 

that measures the dimension needed. Draw a line across the 

end of the log on the edge of the level. Without moving the 

log, use the same process to draw a line across the other 

end.

Drive a nail into the bark where each horizontal line meets 

the bark. Stretch a chalkline or stringline between the two 

nails on one side of the log. If the bark is thin or has been 

removed, a chalkline can be used and snapped, leaving a 

chalk mark to work to. A chalkline will not leave an accurate 

or discernible mark on thick, deeply furrowed bark or on a 

log with an inch or more of crook. In this situation, drive nails 

to hold the string every 2 feet or so along the line of the string. 

Repeat the process on the other side of the log.

After scoring parallel cuts down to the chalkline with a chain 

saw or ax, use an adz to remove the wood from the top of 

the log down to the chalklines. Use small-diameter logs, 2 

by 4s, or log dogs to hold small logs in place while doing the 

adz work. To control how much wood is removed, cut with the 

grain of the wood. This technique reduces the likelihood of 

breaking out deep chips of wood. The direction of the grain 

will be obvious after the fi rst few cuts.

A chain saw will do the work much faster. A helper is needed 

to make sure the sawyer doesn’t cut below the chalkline on 

the far side of the log (which the sawyer cannot see). Otherwise, you will end up with a wavy surface. If the wavy surface 

is used as a tread, it will cause hikers to slip and fall when the 

tread is wet or frosty.

If you are not using a chain saw, the technique described 

above is practical only on small logs. The adz is considered 

a fi nishing tool for surfaces that have already been hewed to 

size. If a lot of wood must be removed and power equipment is 

not available, hewing with a broad ax is more common and

Figure 93—Steps to square a log.

Squaring a log

Level

1—Roll the log so the best 

face (without knots or other 

defects) is on top. 

2—Use a level on the end 

of the log, mark out the 

width of the planed 

surface you need. Do 

this on both ends 

of the 

log.

3—Snap a chalkline the 

length of the log on both 

sides.

4—Score parallel cuts 

with an ax or chain 

saw down to the 

chalkline. Remove 

the remaining 

wood with an 

adz or chain 

saw.
61

Practicing the Craft

more effi cient. The process starts out much like that described for adz work, but instead of horizontal cuts, broad 

ax cuts are made vertically, for the length of the log along 

the chalkline. This technique is spelled out in more detail 

in An Ax to Grind: A Practical Ax Manual (Weisgerber and 

Vachowski 1999).

Check the surface with a straightedge, a framing square, or 

a long level. Check across the log and also along its length. 

Mark any high spots and remove them. It is easier to detect 

high spots by kneeling on the side of the straightedge in 

shadow and looking between the straightedge and the wood 

(fi gure 94).

After the fi rst surface is complete, a second surface can be 

marked and cut. If the second surface is perpendicular to the 

fi rst, a framing square can be used to mark the ends of the 

log. Repeat the marking procedure with the chalkline or stringline and nails. The log can be rolled over so that the second 

surface is horizontal and can be adzed, or the log can be left 

in place so the second surface can be shaped with a broad 

ax. This method is suitable for making log puncheon that 

must be two logs wide (fi gure 95).

If the second surface needs to be parallel to the fi rst, place 

the log with its ends resting on two other logs with the fi rst 

surface facing up and the log level (fi gure 96). Determine 

either the thickness of the log needed, or the width of the 

second surface needed. Using the level, mark a line along 

the log’s edge parallel with the fi rst surface. Roll the log until 

the fi rst surface is facing down and repeat the chalkline or 

stringline procedure for the second surface. Use an adz or 

saw to level the second surface. This technique is suitable for 

situations where one surface must be level for a tread and 

the bottom at each end must rest on log or stone piers.

Figure 94—Use a long level to fi nd high spots that need to be 

removed.

Smoothing the surface of a log

Figure 95—Use a framing square to mark a perpendicular cut.

Perpendicular cuts

Figure 96—Use this procedure when a second fl at surface must be 

parallel to the fi rst.

Parallel surfaces
62

Practicing the Craft

Figure 97—An Alaskan sawmill works great for creating planks from native logs. The mill requires a powerful chain saw (at least 3.8 cubic inches 

of displacement, more is better) and a special ripping chain.

Cutting Planks With Chain Saw 

Mills

Where chain saws are allowed, native logs are available, and 

distance or other factors preclude hauling in treated timbers, 

consider using an Alaskan sawmill (fi gure 97). This is about 

the only way to effectively channel the power of the saw to 

create uniform, square planks. Several sizes of mills are 

available. A basic mill costs less than $200. You also need a 

powerful chain saw, one equipped with ripper teeth.

Working With Timbers

Rough-sawn timbers are splintery, and some species of wood

are more prone to splinter than others. To avoid a handful of 

splinters, wear good-quality, heavy work gloves.

Timbers to be used in a horizontal plane, (ledgers, stringers, 

and culvert inverts) should be checked for camber, a slight 

bend in the length of a piece of wood. Although camber usually is slight—less than 1

⁄2 inch per 10-foot length—it should 

be used to your advantage.

Camber can usually be determined by sighting along all the 

surfaces of the timber from one end. Sometimes a stringline 

held to each end of the timber helps to identify camber. Many 

timbers will not have any camber.

If camber is present, the convex face should be placed up 

and the concave face placed down, even if this contradicts 

the “green-side up” general rule of placing growth rings down 

to reduce cupping. Weight on a timber will cause the timber 

to defl ect or sag. With the convex surface up, defl ection will 

act to straighten the timber. If camber is ignored and the 

timber is installed with the concave surface up, it is already 

sagging. Additional weight will cause the timber to sag even 

more.
63

Practicing the Craft

Working With Treated Wood

At a preservative treatment plant, freshly treated wood is 

stacked on areas of concrete where excess preservative drips 

from the stack and is collected and recycled. The treated 

wood is air dried, which works well in a dry climate. However, 

the wood is sometimes dry at the surface but wet below the 

surface when it is shipped. This wood will weigh more because of the moisture. You need to consider this factor when 

transporting the wood to remote locations. The high moisture 

content of newly treated wood will also cause tools to bind 

and tear the wood. This is not intended to deter you from using treated wood, but it is something you need to be aware of.

Treated wood may be kiln dried if that process is specifi ed. 

Kiln drying to 19-percent humidity can be required. However, 

the minimum order for large plants may be a truckload. Most 

small local plants probably cannot do this at all. Kiln drying 

does cost more.

Pinning Logs and Timbers

Driftpins (usually 1⁄2-inch-diameter steel reinforcing bars, 

also called #4 deformed rebar) are used to pin logs and 

timbers. Some trail crews prefer to use driftpins cut from 

1

⁄2-inch-inside-diameter galvanized steel pipe. The length of 

the driftpins will vary. When driftpins are used to anchor a log 

or timber to the ground, about 12 to 18 inches of the driftpin 

should be in the ground. If rock or boulders are encountered 

before the driftpin is driven its full length, it will have to be 

cut off with a hacksaw. When pinning one log or timber to 

another, the driftpins should be long enough to go through 

the upper piece and all the way through the lower piece, or at 

least 12 inches into it.

First, drill holes in the wood 1

⁄16 inch smaller than the diameter 

of the rebar. Before driving the driftpins, dip the end of the 

driftpin in heavy automobile grease. The lubricant will make 

it easier to drive the driftpins, will protect the driftpin from the 

weather, and will provide a thin, protective fi lm between the 

steel and the copper in treated wood. Driving the driftpins is 

much easier if you make a striking plate out of a short piece 

of pipe with a 2- to 3-inch round plate welded to one end.

The top of the driftpin should be countersunk (fi gure 98). 

Countersinking can be done neatly by placing a 4- to 6-inch 

piece of steel pipe around the driftpin and a 12-inch piece 

of a smaller diameter rebar inside the pipe. With the pipe 

resting on the log or timber and the smaller diameter rebar 

resting on the driftpin, hit the rebar with a sledge hammer 

until the top of the driftpin is below the surface of the wood. 

This depression can be fi lled with grease to protect the steel 

from rusting. Wipe any surplus lubricant off of the wood. 

Tread Surface

Slippery Wooden Treads

We are frequently asked how to correct a slippery wooden 

tread. Often, the surface is not the source of the problem. The 

slippery surface usually is the result of overlooking factors 

such as trail grade, cross slope, or soil conditions.

Figure 98—Countersinking the driftpin is a good practice easily 

accomplished by striking a short piece of rebar inside an even 

shorter piece of pipe.

Pipe

Rebar

Countersinking driftpins

Grease

to protect

rebar

1⁄

2-inch

rebar

driftpin
64

Practicing the Craft

Trail Grade

If the grade of the trail surface is too steep, there is little that 

can be put on the tread to eliminate slipperiness. A wooden 

surface that has been installed at an 8-percent grade will be 

slippery with only a heavy dew. Pedestrians will fi nd a wooden surface built at 5-percent grade slippery with frost or light 

rain. Shaded and north-facing sites aggravate the problem. 

The maximum grade for a trail with a wooden surface should 

be 2 percent (1

⁄4 inch per foot).

Cross Slope

Another cause of a slippery tread is a cross slope that is 

too steep. To prevent excessive cross slope on a trail, use a 

simple carpenter’s, mason’s, or torpedo level to identify any 

difference in elevation between parallel stringers, the notch 

in sleepers, and ledgers attached to the piles. To eliminate 

or reduce cross slope, shim up the stringers or ledgers, 

excavate the high end of the sleepers, redrill the bolt holes, 

or replace the ledgers (fi gure 99).

It is much cheaper to build the foundation correctly than to 

try to correct problems later through maintenance.

Soil Conditions

Another factor that can create a slippery tread is settlement, 

a problem that occurs when soil settles after a trail has been 

constructed. The trail may have been built properly, but all or 

part of the trail may have settled over time. Perhaps sleepers or a bent on end-bearing piles were used instead of a 

bent on friction piles. That part of the foundation settled over 

time, causing the trail to sag. The result is that one or both 

sections of trail on each side of the sag are steeper than 

intended.

One part of a trail support may settle. For example, one end 

of a sleeper may settle and the other end may not, or one pile 

in a bent may settle and the other may not. Both piles may 

settle, but one may settle more than the other. This type of 

settling will affect cross slope.

Cross slope of 1⁄4 inch per foot (2 percent) is common for concrete and asphalt surfaces, but is excessive for wood. The 

cross slope should be level or 1

⁄8 inch or less per foot (0 to 1 

percent). Settlement can be corrected by shimming the low 

side, notching the high side, or a little of each. This is extremely diffi cult to do after construction and can be avoided to a 

degree by taking ample rod soundings and digging a number 

of test holes during the design phase. During construction, 

the crew should be alert for changes in soil conditions and 

should take remedial actions when necessary.

Surface Treatments

If the hazard of a slippery tread cannot be corrected by shimming, notching, or adding steps, a few surface treatments 

can be applied. These treatments will require maintenance.

Latex Paint

A nonskid latex paint is made for boat decks. This paint is 

opaque, unlike a clear wood stain, but it can be tinted. As 

with all painted surfaces, peeling, scraping, and periodic 

repainting must be expected.

Excavate to level

Shim stringers

or ledgers

Eliminating cross slope

Drill new bolt hole

Figure 99—Eliminate cross slope with shims, by excavating the high 

side of sleepers, or by drilling new bolt holes on the ledgers.
65

Practicing the Craft

Walnut Chips

Walnut chips are a hard, angular material produced in various sizes. The number 4 size is suitable for nonslip surfaces. 

Walnut chips can be applied to a wooden surface by sand 

painting (using chips and paint mixed at the factory), using 

chips mixed into the paint at the site, or by painting the wood 

and sprinkling on chips while the paint is wet.

Mineral Products

Nonslip products are also made from pumice and aluminum 

oxide. Some are premixed. Others are sold as a gritty powder

that is mixed with paint.

Nonslip Gratings and Grit-Treated Mats

Another method for correcting a slippery trail tread is to replace a wooden plank tread with nonslip gratings or to apply 

grit-treated fi berglass mats to the planks.

Working With Rock, Stone, and 

Gravel

The construction industry recognizes differences between 

rock, stone, and gravel. It helps to understand the differences 

in the materials so you will know what to specify or order.

Rock

Rock is the parent material in and under the ground. Sometimes it is called bedrock or ledgerock. Moving rock usually 

requires drilling and the use of explosives.

Stone

When rock is broken or crushed, the pieces are referred to as

stone. Stone, when used in construction, describes usable 

pieces of what once had been rock. Stone may be large enough

to use for walls, or it may be small pieces that have been 

through a rock crusher for use as aggregate in concrete or as

a base course in a road. Stone is angular on all sides.

Among the byproducts of rock-crushing operations are 

“crusher fi nes,” screened material smaller than 1

⁄4 inch that is 

not suitable for most crushed stone contracts. This material is 

often sold at a discount at crusher operations and makes a 

fi ne trail surface when it is wetted and compacted.

Gravel

Small pieces of rock that have broken naturally and have 

been subject to glacial action or tumbled in a river or creek 

are called gravel. The glacial action or the effect of water has 

rounded and removed all the corners of the original piece of 

rock.

Uses of Stone and Gravel

Rock is rarely found in a wetland. Stone can be brought to the

site for use as riprap. Crushed stone can be used for walking 

surfaces. Because crushed stone is angular, when it is compacted it will knit together to form a solid mass. Gravel cannot

be compacted to produce a solid mass. Gravel’s rounded shape

is useful because water can move through the spaces between

the gravel particles. Crushed stone should not be used for 

drainage (around perforated pipe or to carry water from one 

point to another). Use gravel for drainage (fi gure 100).

Figure 100—Crushed stone has angular edges and compacts well. 

It is good for tread surfacing. Gravel does not make good surfacing 

because it has rounded edges. Gravel is good for subsurface 

drainage because water fl ows freely through it.

Crushed stone Gravel

Compaction comparison
66

Appendix A—Field Note Sheets
Stat oi n &

Tread S di es ol pe Grad ei nt

distance w di th (percent) (percent) Notes

Stat oi n &

Tread S di es ol pe Grad ei nt

distance w di th (percent) (percent) Notes
68

Slope Conversion Table

 Percent

 grade 1Slope 2Pitch

 0.5 1 ft per 200 ft 1⁄16 in per 1 ft

 1 1 ft per 100 ft 1

⁄8 in per 1 ft

 2 1 ft per 50 ft 1

⁄4 in per 1 ft

 2.5 1 ft per 40 ft 5

⁄16 in per 1 ft

 3 1 ft per 33 ft 3

⁄8 in per 1 ft

 3.3 1 ft per 30 ft 7

⁄16 in per 1 ft

 4 1 ft per 25 ft 1

⁄2 in per 1 ft

 5 1 ft per 20 ft 5

⁄8 in per 1 ft

 6 1 ft per 16.5 ft 3

⁄4 in per 1 ft

 7 1 ft per 14.3 ft 7

⁄8 in per 1 ft

 8 1 ft per 12.5 ft 1 in per 1 ft

 8.33 1 ft per 12 ft 1 in per 1 ft

1 One unit of climb or descent per 100 units of horizontal distance.

2 Number of vertical inches per horizontal foot. Vertical inches shown are 

rounded off to the nearest 1

⁄16 of an inch.

Maximum grade recommended for wood surface trails = 2 percent.

Appendix B—Slope Conversion Table
69

Rectangular Timber Culverts

 Clear width (inches)

 20 24 30 36 48 60 72 84

 5 0.7 0.8 1.1 1.3 1.7 2.1 2.5 2.9

 11 1.4 1.8 2.3 2.8 3.7 4.5 5.5 6.4

 17 2.1 2.9 3.6 4.3 5.0 7.1 8.5 9.9 

 23 2.9 3.8 4.8 5.8 7.7 9.6 11.5 13.4

These tables show the open-end area of round culvert pipe and the open-end 

area of rectangular timber culverts.

Height

(inches)

End area

(sq. ft)

Round Pipe Culverts

 8 10 12 15 18 24 30 36

 0.4 0.6 0.8 1.2 1.8 3.1 5.0 7.1

End area (sq. ft)

Appendix C—Comparison of Round and Rectangular Culverts

Diameter

(inches)
70

 2Penetration 1

Penny Length required Nails per Gauge Bit size for pilot

 (d) (inches) (inches) pound (inches) holes (inches)

 10 3 2 75 10 NA

 12 31

⁄4 21⁄8 69 10 NA

 16 31

⁄2 21⁄4 54 9 3⁄32

 20 4 25⁄8 33 7 1⁄8

 30 41⁄2 3 29 7 1⁄8

 40 5 31⁄4 22 51⁄2 1⁄8

 50 51⁄2 35⁄8 20 51⁄2 1⁄8

 60 6 4 18 51⁄2 3⁄16

1 Nails are sold by the old English system of pennyweight. The value of the penny has changed since the system was devised, and today there seems to be no 

relation to the size and weight of the nail to the penny. The standard symbol for penny is “d.”

2 The “penetration required” column shows the minimum depth the nail must penetrate into the second piece of wood to make a sound connection. The penetration 

must be increased by one-third when nailing into the end of the piece of wood (end nailing).

Appendix D—Sizes of Hot-Dipped Galvanized Nails
71

 Size Finished size

 of board Length of board (ft) (inches)

 6 8 10 12 14 16

 1 x 6 3 4 5 6 7 8 3⁄4 x 51⁄2

 2 x 4 4 5.33 6.67 8 97 11 11⁄2 x 31⁄2

 2 x 6 6 8 10 12 14 16 11⁄2 x 51⁄2

 2 x 8 8 10.67 13.33 16 19 21 Normally rough sawn

 2 x 10 10 13.33 16.67 20 23 27 Normally rough sawn

 2 x 12 12 16 20 24 28 32 Normally rough sawn

 3 x 4 6 8 10 12 14 16 Normally rough sawn

 3 x 6 9 12 15 18 21 24 Normally rough sawn

 3 x 8 12 16 20 24 28 32 Normally rough sawn

 3 x 10 15 20 25 30 35 40 Normally rough sawn

 3 x 12 18 24 30 36 42 48 Normally rough sawn

 4 x 4 8 10.67 13.33 16 19 21 31⁄2 x 31⁄2

 4 x 6 12 16 20 24 28 32 Normally rough sawn

 6 x 6 18 24 30 36 42 48 Normally rough sawn

The most common sizes of boards used for boardwalk and bog bridge construction.

Yield (board ft)

Appendix E—Table of Board Feet
72

M E T R I C C O N V E R S I O N S

To convert from this unit To this unit Multiply by

 inch millimeter 25.4*

 inch centimeter 2.54*

 foot meter 0.3048*

 yard meter 0.9144*

 mile kilometer 1.6

 millimeter inch 0.039

 centimeter inch 0.394

 centimeter foot 0.0328

 meter foot 3.28

 meter yard 1.09

 kilometer mile 0.62

 acre hectare (square hectometer) 0.405

 square kilometer square mile 0.386*

 hectare (square hectometer) acre 2.47

 ounce (avoirdupois) gram 28.35

 pound (avoirdupois) kilogram 0.45

 ton (2,000 pounds) kilogram 907.18

 ton (2,000 pounds) megagram (metric ton) 0.9

 gram ounce (avoirdupois) 0.035

 kilogram pound (avoirdupois) 2.2

 megagram ton (2,000 pounds) 1.102

 ounce (U.S. liquid) milliliter 30

 cup (inch-pound system) milliliter 247

 cup (inch-pound system) liter 0.24

 gallon (inch-pound system) liter 3.8

 quart (inch-pound system) liter 0.95

 pint (inch-pound system) liter 0.47

 milliliter ounce (U.S. liquid) 0.034

 liter gallon 0.264

 liter quart 1.057

 degrees Fahrenheit degrees Celsius (°F – 32) ÷ 1.8

 degrees Celsius degrees Fahrenheit (°C x 1.8) + 32

*These items are exact conversion factors for the units—the others give approximate conversions.

Appendix F—Metric Conversions
73

Glossary

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.

Baluster—One of many vertical pieces between the top and 

bottom rails of a guardrail.

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.

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).

Borrow pit—An excavation used to obtain fi ll 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.

Camber—A slight bend in a timber.

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

Chamfer—Similar to a bevel but done at the end of the piece 

of wood and across the grain.

Balusters

Balusters

Beveled edge

Cantilever

Amount

of batter

Batter

Amount

of batter
74

Glossary

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 decay if the hole is exposed 

to moisture.

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.

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 decay.

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.

Dap—A shallow hole or slot drilled or routed in a piece of 

wood. A dap is usually drilled to fi t 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.

Chamfer

Chamfered

edges

Countersinking

Screw head is

countersunk

in the wood

Cross slope

Level

Cross slope

Cupping
75

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.

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 piece of 12- to 30-inch rebar or steel pipe used to 

keep logs and timbers in place.

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.

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.

Dap

Space

notched

in upper

board

Froe

Footing

Footing

Deadmen

Concrete

deadman

Timber

deadman

Glossary
76

Glossary

Heartwood

Heartwood

Invert

Frostline—The maximum depth that frost can be expected to

penetrate into the ground.

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 fl at 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.

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 defi nition, 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-fi r 

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 baldcypress 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.

Helical pile—A solid steel shaft 11⁄2 to 21⁄2 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.

Invert—The bottom surface of a pipe, ditch, or culvert over 

which water fl ows.

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 sleeper (sill) or ledger, 

toenailed into place, supporting a fl oor or deck.

Joist hanger—A steel angle or strap nailed to the side of a 

ledger and shaped to hold a joist. If a top fl ange hanger or 

face mount hanger is installed, the joist is placed within the 

hanger and the two are nailed together.

Ledger—A horizontal piece of wood attached to, and supported by, piles or concrete or stone masonry piers. The ledgers 

support stringers or tread timbers.
77

Top fl ange

hanger

Nailer

Log dogs

18 to 30 inches

A smaller 

log dog 

that is easier 

to pack.

Log dogs—The fi rst type of log dog is a broad U-shaped 

steel bar 18 to 30 inches wide, with pointed ends, which is 

used to temporarily hold two logs at right angles to each other.

The second type of log dog is smaller and easier to pack. It 

consists of a 6-inch to 12-inch-long steel plate that is 2 to 3 

inches wide and pointed at each end. A second steel plate 

(3 to 6 inches long, identical width, pointed at one end and 

straight on the other) is welded across the center of the fi rst 

to form a T.

Loop trail—A trail route that forms a closed circuit connecting a number of points of interest. The trail returns to the 

trailhead where it began but the trail user does not cover the 

same route twice.

Lumber—As used in this text, wood that has been sawed 

into a square or rectangular cross section that is 2 inches 

thick or less.

Moraine—Moraines are made of debris deposited by 

glaciers. The most common moraines are end (or terminal) 

moraines and lateral (or slide) moraines. Rock that the glacier 

has broken out of the valley is deposited in the moraines. 

Rock in moraines has been broken up and ground into boulders and various sizes of gravel and sand.

Mortar—A mixture of sand, lime, Portland cement, and 

water. Mortar is used in masonry construction to bind bricks, 

concrete blocks, or stone to form structural elements such 

as retaining walls and piers. Mortar may also be used when 

constructing riprap.

Nailer—A strip of wood attached to a stringer that tread 

planks are nailed or screwed to.

Glossary
78

Glossary

Piers

Piers

Saddle notch

Sapwood

Peen—To strike a piece of metal with a hammer, denting the 

surface, or mashing the threads of a bolt after installing a nut,

to prevent the nut from being removed.

Pier—Piers are used to support one or both ends of a beam 

or stringer. Piers may be timber or log cribbing or piles, helical piles, stone masonry, or concrete.

Pile—For wetland construction piles may be wooden logs, 

poles, or timbers, steel helixes, or concrete that is cast in 

place. A pile is usually no more than 12 inches in diameter. 

The pile is either placed in a hole dug to the depth required 

(end bearing pile), driven with a heavy weight (friction pile), 

or screwed into the ground by a machine (helical pile).

Pilot hole—A small hole drilled in wood or steel to guide a 

nail, screw, or drill bit.

Pinning—Driving driftpins through a log or timber into a log 

or timber, or into the ground.

Plank—A 2 by 4, 2 by 6, 2 by 8, 3 by 6, or wider board or 

timber. In wetland construction, planks are usually used as a 

walking surface or tread.

Plumb—A line or plane perpendicular to the Earth’s surface.

Ponding—Water that has accumulated in a low area.

Portland cement—A gray powder made from limestone 

that is mixed with sand and water to make mortar, or mixed 

with sand, small stones or gravel, and water to make Portland 

cement concrete. In this text Portland cement concrete is 

referred to as concrete.

Puncheon—Short-span footbridges or a series of shortspan footbridges supported by sleepers.

Riprap—Stones placed to prevent fast water from scouring 

and eroding a surface. Large stones (12 by 12 by 6 inches or 

larger) are hand placed on a setting bed of either aggregate 

or mortar. With an aggregate setting bed, adjacent stones 

are butted tightly together. Because of the irregularity of the 

stones, spalls are used to prevent them from moving. If the 

stones are placed on a mortared setting bed, the stones may 

be 1

⁄2 to 3 inches apart.

Rod sounding—Driving a steel rod or pipe into the ground to

determine the location of fi rm soil or rock.

Saddle notch—A half-circle notch cut in the bottom of a log 

to fi t over a log in the course below.

Sapwood—Wood just under the bark of a tree. Sapwood is 

only a few years old. This wood is usually a light color and not

as strong or as dense as the heartwood.

Square notch—A notch cut in a log to fi t snugly against a 

square notch cut in another log, the square cut end of another log, or a plank. The portion of the notch in contact with 

the other log is cut as a fl at, uniform plane. The end or ends of 

the square notch are perpendicular to the fl at plane.
79

Square notches

Toenailing

Setting bed—A layer of aggregate (either crushed stone or 

crushed gravel), or mason’s sand, mortar placed on solid 

rock, or a compacted subgrade of existing ground or fi ll. Depending on the setting bed, material, and subsurface conditions, the setting bed may be from 4 to 12 inches deep.

Shim—A short, thin piece of wood, usually oak or redcedar, 

used between two pieces of wood or between a piece of 

wood and steel, earth, or rock. The shim is used to bring a 

ledger, stringer, or tread to level.

Slackwater—Floodwater with little or no velocity. Slackwater 

is formed when water in creeks, streams, and rivers backs up

into low terrain, creating a temporary ponding condition.

Sleeper ß—A horizontal log or timber laid in a shallow trench

to support a plank or logs.

Slope measurements—Measurements taken on the ground 

or parallel with the slope of the ground. Slope measurements 

provide a true indication of the quantities of materials needed

for construction. Maps and construction drawings for roads 

and utility lines are measured horizontally. Measurements 

taken electronically are also measured horizontally. Slope 

measurements can sometimes be as much as 10 percent 

greater than horizontal measurements.

Sonotubes—Hollow cardboard cylinders used for forming 

round concrete columns. The sonotube is removed after the 

concrete sets.

Spalls—Small angular pieces of hard, durable stone. Spalls 

are wedged between stones that have been placed without 

mortar. Spalls have a function similar to that of shims used in 

wood construction.

Stringer—One of two or more beams placed parallel with 

the centerline of the tread that supports the tread plank.

Tamping—Using a narrow machine compactor, a tamping 

bar, the handle of a shovel, or other tool to compact earth 

backfi ll around a post, pole, or pile.

Test boring—A deep, narrow hole drilled into the ground with

a power auger. A record is kept of the types of soils encountered and their depth. Test borings are usually done by 

geotechnical engineers (see test holes).

Test holes—Frequently, soil information does not require the 

sophistication and accuracy of test borings. A test hole can be

dug by hand, or it can be dug with a backhoe. Test holes are 

wider than test borings, allowing the soil strata on the sides of

the hole to be easily seen. Test holes can be no deeper than 

the equipment can easily and safely dig. The information provided by test holes is usually suffi cient to determine construction

techniques needed for wetland trails in areas where there is 

no previous wetland construction experience. It is simpler and 

cheaper to dig test holes than it is to drill test borings.

Timber—As used in this text, wood that has been sawed or 

hewed into a square or rectangular cross section that is at 

least 3 inches thick.

Toenail—Joining two pieces of wood by driving nails at an 

angle to the surface of one piece and into the second piece.

Tread—The walking surface of a trail. Applied to wetland 

trails constructed of wood, tread refers to the portion of the 

timber, log, or plank that the user steps on.

Twist—A defect in lumber and timber caused by a tree growing with a twisted grain. The result is a piece of lumber or timber with surfaces at one end that are not in the same plane 

as the surfaces at the other end. Occasionally, usable short

Glossary
80

Glossary

lengths with little twist can be cut from the original piece. 

More commonly, the original piece is useless.

Twist

Wane—A defect in a piece of lumber or timber, caused by 

bark that was not removed or a beveled edge.

Waney edge—A term used at the sawmill to describe a 

board, plank, or timber of nonuniform width when one or two 

edges contain bark or irregular sapwood just below the bark. 

A waney edge is considered a defect, but the board or plank 

may be suitable for rustic construction.

Warp—Severe bend in a piece of lumber or timber making 

it unusable in its original length. Sometimes the warp occurs 

mostly at one point, usually a knot, and short usable pieces 

can be cut on either side of that point.

Waney edge

Water table—The level below the ground surface where 

groundwater will fi ll a test hole.

Warp

Weir—A depressed channel in a dam providing an outlet for 

the overfl ow water in a pond when the water level exceeds 

a desired height. Weirs are usually concrete or timber, or a 

combination of the two.

Water table

Wetland indicator plants—Various species of plants that are 

tolerant of wet soils. When many specimens of these species 

are present at a site, they indicate a wetland environment.

Weir
81

User name (t-d) and password (t-d) are required for publications on the T-D Internet site (http://www.fs.fed.us/t-d).

Groenier, James Scott; Eriksson, Merv; Kosmalski, Sharon. 

2006. A guide to fi ber-reinforced polymer trail bridges. Tech. 

Rep. 0623–2824–MTDC. Missoula, MT: U.S. Department 

of Agriculture Forest Service, Missoula Technology and 

Development Center. 98 p. Available electronically at: 

http://www.fs.fed.us/t-d/pubs/htmlpubs/htm06232824/

Groenier, James Scott; LeBow, Stan. 2006. Preservativetreated wood and alternative products in the Forest Service. 

Tech. Rep. 0677–2809–MTDC. Missoula, MT: U.S. Department of Agriculture Forest Service, Missoula Technology 

and Development Center. 44 p. Available electronically at: 

http://www.fs.fed.us/t-d/pubs/htmlpubs/htm06772809/

Hallman, Richard. 2005. Handtools for trail work: 2005 edition. 

Tech. Rep. 0523–2810–MTDC. Missoula, MT: U.S. Department 

of Agriculture Forest Service, Missoula Technology and 

Development Center. 26 p. Available electronically at: 

http://www.fs.fed.us/t-d/pubs/htmlpubs/htm05232810/

Lebow, Stan T.; Tippie, Michael. 2001. Guide for minimizing 

the effect of preservative-treated wood on sensitive environments. Gen. Tech. Rep. FPL–GTR–122. Madison, WI: U.S. 

Department of Agriculture Forest Service, Forest Products 

Laboratory. 18 p. Available electronically at: www.fpl.fs.fed.

us/documents/fplgtr/fplgtr122.pdf

Meyer, Kevin G. 2002. Managing degraded off-highway 

vehicle trails in wet, unstable, and sensitive environments. 

Tech. Rep. 0223–2821–MTDC. Missoula, MT: U.S. Department of Agriculture Forest Service, Missoula Technology 

and Development Center. 48 p. Available electronically at: 

http://www.fs.fed.us/t-d/pubs/htmlpubs/htm02232821/

Monlux, Steve; Vachowski, Brian. 2000. Geosynthetics for 

trails in wet areas: 2000 edition. Tech. Rep. 0023–2838–

MTDC. Missoula, MT: U.S. Department of Agriculture Forest 

Service, Missoula Technology and Development Center. 18 p. 

Available electronically at: 

http://www.fs.fed.us/t-d/pubs/htmlpubs/htm00232838/

References

Neese, Jasen; Eriksson, Merv; Vachowski, Brian. 2002. 

Floating trail bridges and docks. Tech. Rep. 0223–2812–

MTDC. Missoula, MT: U.S. Department of Agriculture Forest 

Service, Missoula Technology and Development Center. 26 

p. Available electronically at: 

http://www.fs.fed.us/t-d/pubs/htmlpubs/htm02232812/

U.S. Department of Agriculture Forest Service. 1991. Alaska 

Region trails construction and maintenance guide. Tech. 

Rep. R10–MB–158. Anchorage, AK: U.S. Department of 

Agriculture Forest Service, Alaska Region.

U.S. Department of Agriculture Forest Service. 1996. 

Standard specifi cations for construction and maintenance 

of trails. Eng. Man. EM–7720–103. Washington, DC: U.S. 

Department of Agriculture Forest Service. ISBN 0–16–

048802–8. 108 p. 

U.S. Department of Agriculture Forest Service. 1996. Standard 

drawings for construction and maintenance of trails. Eng. 

Man. EM–7720–104. Washington, DC: U.S. Department of 

Agriculture Forest Service.

Weisgerber, Bernie; Vachowski, Brian. 1999. An ax to grind: 

a practical ax manual. Tech. Rep. 9923–2823P–MTDC. 

Missoula, MT: U.S. Department of Agriculture Forest Service, 

Missoula Technology and Development Center. 60 p. 

Available electronically at: 

http://www.fs.fed.us/t-d/pubs/htmlpubs/htm99232823/

Western Wood Preservers Institute. 2006. Best management 

practices for the use of treated wood in aquatic environments. 

Vancouver, WA: Western Wood Preservers Institute. 36 p.

Western Wood Preservers Institute. [no date]. Guide to the characteristics, use and specifi cations of pressure-treated wood. 

Vancouver, WA: Western Wood Preservers Institute. 13 p.

Zeller, Janet; Doyle, Ruth; Snodgrass, Kathleen. 2006. 

Accessibility guidebook for outdoor recreation and trails. 

Tech. Rep. 0623–2801–MTDC. Missoula, MT: U.S. 

Department of Agriculture Forest Service, Missoula 

Technology and Development Center. Available 

electronically at: 

http://www.fs.fed.us/t-d/pubs/htmlpubs/htm06232801/
82

Notes
You can order a copy of this document using the order 

form on the Federal Highway Administration’s (FHWA) 

Recreational Trails Program Web site at:

http://www.fhwa.dot.gov/environment/rectrails/trailpub.htm

It is also available electronically at:

http://www.fhwa.dot.gov/fspubs/

Fill out the order form and fax it to the distributor listed 

on the form. If you do not have Internet access, you 

can send a fax request to 301–577–1421 or send a mail 

request to:

 FHWA R&T Report Center

 9701 Philadelphia Ct., Unit Q

 Lanham, MD 20706

Produced by:

 USDA Forest Service

 Missoula Technology and Development Center

 5785 Hwy. 10 West

 Missoula, MT 59808

 Phone: 406–329–3978

 Fax: 406–329–3719

 E-mail: wo_mtdc_pubs@fs.fed.us

This document was produced in cooperation with the Recreational Trails Program of the Federal 

Highway Administration, U.S. Department of Transportation.

This document is disseminated under the sponsorship of the U.S. Department of Transportation 

in the interest of information exchange. The United States Government assumes no liability 

for its contents or use thereof.

The contents of this report refl ect the views of the contractor, who is responsible for the accuracy 

of the data presented herein. The contents do not necessarily refl ect the offi cial policy of the 

Department of Transportation.

This report does not constitute a standard, specifi cation, or regulation. The United States 

Government does not endorse products or manufacturers. Trade or manufacturer’s names 

appear herein only because they are considered essential to the object of this document.

U NITE D STATES OF A M E RIC A

DEPARTMENT OF TRANSPORTATION
You can order a copy of this document using the order 

form on the FHWA’s Recreational Trails Program Web site at:

http://www.fhwa.dot.gov/environment/rectrails/trailpub.htm

Fill out the order form and fax it to the distributor listed 

on the form. If you do not have Internet access, you can 

send a fax request to 301–577–1421 or a mail request to:

 FHWA R&T Report Center

 9701 Philadelphia Ct., Unit Q

 Lanham, MD 20706

Forest Service and Bureau of Land Management employees may obtain additional copies from:

 USDA Forest Service

 Missoula Technology and Development Center

 5785 Hwy. 10 West

 Missoula, MT 59808

 Phone: 406–329–3978

 Fax: 406–329–3719

 E-mail: wo_mtdc_pubs@fs.fed.us

Robert T. Steinholtz is a principal of Bristlecone Trails, a trail 

work consulting fi rm in Lakewood, CO. Bob was a landscape 

architect and trails specialist for many years with the National 

Park Service Planning, Design, and Construction Center in 

Denver, CO. His experience includes building 125 miles of 

new trails in 23 States from coast to coast. Bob has often been 

called on for his expertise by various Federal, State, and 

municipal agencies. He has been a coordinator or instructor at 

20 hands-on courses covering trail-related subjects.

About the Authors

Brian Vachowski has been a project and program leader 

at the Missoula Technology and Development Center since 

1993. He received a bachelor’s degree in forestry from the 

University of Massachusetts and a master’s degree in outdoor 

recreation from Utah State University. He has worked for the 

Nez Perce, Bighorn, Winema, and Routt National Forests in 

recreation, wilderness, lands, planning, rural community assistance, special uses, fi re, and timber positions.

Library Card

Steinholtz, Robert T.; Vachowski, Brian. 2007. Wetland trail 

design and construction: 2007 edition. Tech. Rep. 0723–

2804–MTDC. Missoula, MT: U.S. Department of Agriculture 

Forest Service, Missoula Technology and Development 

Center. 82 p.

Describes materials and techniques used to construct trails 

in wetlands. This manual is written primarily for workers who 

are inexperienced in wetland trail construction, but it also 

may be helpful for experienced workers. Techniques suitable 

for wilderness settings and for more developed settings are 

included. Drawings by the author illustrate all important points. 

A glossary is included, as are appendixes with material 

specifi cations.

Keywords: boardwalks, bogs, carrs, corduroy, drainage, 

maintenance, marshes, muskeg, piles, puncheon, recreation, 

swamps, tools, trail crews, trail planning, turnpikes

Electronic copies of MTDC’s documents are available on 

the Internet at:

http://www.fs. fed.us/eng/t-d.php

For further technical information, contact Brian 

Vachowski at MTDC or Bob Steinholtz.

Brian Vachowski:

 Phone: 406–329–3935

 Fax: 406–329–3719

 E-mail: bvachowski@fs.fed.us

 Bob Steinholtz:

 Bristlecone Trails

 10350 W. 14th Ave.

 Lakewood, CO 80215

 Phone: 303–233–4522

 E-mail: brstlcn@aol.com