Att 4. SpecificationsForStructuralRangeImprovements_1990.pdf

United States Department of Agriculture

Forest Service

Pacific Northwest Research Station

General Technical Report

PNW-GTR-250

September 1990

Specifications for Structural Range Improvements H. Reed Sanderson, Thomas M. Quigley, Emery E. Swan, and Louis R. Spink

I

This file was created by scanning the printed publication.

Text errors identified by the software have been corrected;

however, some errors may remain.

H. REED SANDERSON and THOMAS M. QUIGLEY are range scientists, U.S.

Department of Agriculture, Forest Service, Pacific Northwest Research Station, La Grande, Oregon 97850. EMERY E. SWAN was range improvement specialist, and LOUIS R. SPINK was project coordinator, Oregon Range Evaluation Project, Malheur National Forest, John Day, Oregon 97845, at the time this research was done. Swan is currently a range conservationist, Malheur National Forest, and Spink is retired.

Authors

Sanderson, H. Reed; Quigley, Thomas M.; Swan, Emery E.; Spink, Louis R.

1990. Specifications for structural range improvements. Gen. Tech. Rep. PNW- GTR-250. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 120 p.

Abstract

Construction specifications and illustrations are provided for several types of barbed wire and pole fences, gates, cattle guards, stiles, spring developments, water troughs, stock ponds, trick tanks, and livestock access trails.

Keywords: Range management, structural improvements, fences, gates, cattle guards, water developments, livestock control.

Contents 1 Introduction

2 Organization of This Handbook

2 Improvement Specifications

2 Fences

4 Guidelines

5 Maintenance of Fences

5 Special Equipment

5 Post-Hole Augers

5 Post Drivers

5 Wire Stretchers

7 Wire-Splicing Tool

7 Barbed-Wire Stringer

7 Tamping Tools

9 Hydraulic Log Splitter

9 Barbed-Wire Fences

26 Standard Post-and-Wire Fence

38 Let-Down Fence

38 Suspension Fence

38 Rock-Jack and Figure-4 Fence

48 Woven-Wire Fences

54 Electric Fences

55 Buck-and-Pole Fences

55 Log-Worm Fences

59 Block-and-Pole Fences

61 Log-Crib Fences

61 Gates

64 Cattle Guards

70 Stiles

70 Water Developments

75 Spring Developments

87 Storage Tanks

87 Water Troughs

91 Round and Rectangular Metal Trough With a Solid Bottom

91 Bottomless Metal Trough

91 Metal Flume Trough

91 Trough Frame

91 Trough Maintenance

91 Water Supply, Overflows, and Outlets

97 Control of Moss

1 04 Small Mammal and Bird Escape Ramps

104 Stock Ponds

107 Pit Tank or Dugout

107 Small Reservoirs

111 Stock Pond Seepage and Repair

114 Trick Tanks and Guzzlers

117 Livestock Access Trails

120 Acknowledgments

120 Conversion Table

120 Literature Cited

Introduction Management of public and private ranges in the Northwest relies on range improve-ments. Structural improvements (for example, fences, water developments, access trails) are necessary for grazing management systems and must be maintained for the systems to operate effectively. The implementation of new grazing systems typ-ically requires construction of new improvements. Structural improvements are also effective in the management and protection of sensitive riparian areas and tree plantations. Improved range conditions can depend on the installation and mainten-ance of improvements. A long-time goal of range management is uniform distribution of cattle. Water developments, stock access trails, and fences have effectively been used to help achieve this goal.

Federal handbooks and a few published technical notes provide guides for construc-tion and maintenance of structural range improvements. Federal agencies have developed range improvement handbooks, which are supplemented by the local management units as circumstances warrant. The USDA Forest Service Missoula Technical and Development Center (1987 and 1988) has published two handbooks on constructing fences and livestock handling facilities. One more handbook is being prepared on water developments. The USDA Soil Conservation Service (1982) also has a fine publication on ponds. Vallentine's (1971) book, "Range Development and Improvements," provides a good introduction to the types of improvements available.

References for the state-of-the-art specifications of improvements are published in many sources. Generally, several sources have to be reviewed to determine the best method to develop a particular site.

Our objective is to provide the best information from the many sources for structural range improvements. The information contained in this handbook was developed through the Oregon Range Evaluation Project (EVAL) (Sanderson and others 1988) and has been applied to the practices implemented by that project.

The EVAL Project was an 11-year study funded through the USDA Forest Service with headquarters in John Day, Oregon. The study was begun in 1976 as an inter-agency effort to implement various range management intensities on private and Federal rangeland. The approach was to develop coordinated resource management plans that included private land and associated Federal lands. Each plan set a prior-ity for improvement opportunities and selected, in cooperation with owners and managers, the range improvements that met goals and objectives consistent with resource conservation and management philosophy.

Through EVAL, coordinated resource management plans were developed for 21 ranches and 18 associated allotments. These plans included the selection and scheduling of more than 1,000 range improvements for implementation during a short period. The objective was to apply "state-of-the-art" range management tech-niques and to monitor a variety of outputs from the sites. An immediate task facing the EVAL management team was to assemble specifications on the state-of-the-art practices. An interagency group was assembled with members from the Soil Con-servation Service and the Forest Service (U.S. Department of Agriculture), the Bu-reau of Land Management (U.S. Department of the Interior), and private ranchers.

Beginning with existing guides for improvements and handbooks, the group extracted

Organization of this Handbook

Improvement Specifications

Fences the most applicable practices under the conditions of the EVAL program. These specifications represent the results that evolved from this interagency effort, including modifications suggested by ranchers and contractors who implemented and main-tained these improvements.

This handbook is divided into major sections by improvement type. Within each type, further subdivisions are provided to separate types according to specifications. In-cluded with each practice specification is a narrative describing when the practice is appropriate, the equipment needed for construction, materials used, and specifica-tions with drawings and diagrams.

The handbook is intended to be used by ranchers, contractors, resource managers, and anyone who plans, installs, and maintains structural improvements. It can be used as a guide during the construction phase of a project, a decision tool during planning, and a source of specifications when contracts are drafted. It has been specifically designed to be copied as needed for inclusion in contract specifications or project design and guides.

Range management grazing systems have become dependent on fencing. Herding, as the primary means of livestock control, has essentially been replaced by extensive fencing patterns. Reasons for the shift toward fencing are many. Vallentine (1971) provides 19 advantages of fencing in livestock management and control. The primary reason for fencing is to keep livestock in or out of a specific area. In either event, the fence specifications are generally the same.

Specifications and descriptions are provided for the following types of fences including four barbed-wire fences:

Barbed-wire fences:

Standard post and wire Let-down Suspension Rock-jack and "figure-4"

Woven-wire fence Electric fence Buck-and-pole fence Log-worm fence Block-and-pole fence

Each fence has characteristics making it desirable for different circumstances. During the planning phase of fence design, consideration should be given to costs, aesthe-tics, kind of livestock, livestock pressure, environment, availability of materials, and accessibility. The location of the fence is determined during this phase of the project.

The location should be marked, taking into consideration property boundaries, vegeta-tion types, wildlife migration routes, available water sources, slope, snowdrift areas, stream crossings, areas of heavy livestock use, gate locations, and road crossings.

Before the fence is constructed, the fenceline should be flagged to mark the location of the fence and to mark all special structures (fig. 1).

Figure 1––-Example of a project map showing approximate location of fence removal, new construction, relocation, and existing and new cattle guards.

Guidelines––The construction phase of fencing cannot be precisely specified for all situations, but a general description of the steps required can be provided. The type and standard of fence to be used in each circumstance need to be coordinated with animal control needs and multiple-use considerations.

Planning fence line location:

1. Survey the boundary where fences occur on property boundaries and construct the fence on the boundary.

2. Locate fences as near to a right angle to the slope as possible to reduce possible damage from logging or snow.

3. Layout the fence as straight as possible between turning points.

4. Locate the fence on ridgetops as much as possible and avoid areas just below the ridge and draw bottoms.

5. Locate fences away from the edges of highly desirable vegetation types, such as meadows, to reduce excessive pressure on the fence by livestock.

6. Provide water gaps across all streams and draws subject to high runoff in the spring.

7. Locate cattle guards at safe sight distance from road junctions, curves, and other visual obstructions.

8. Locate gates at cattle guards; secondary road crossings; major trails; major topographic changes such as ridges, saddles, and draws; and fence junctions with a maximum distance of 0.5 mile between gates.

9. Construct fences with corners more than 900 because corners with acute angles can become "cattle traps."

Preconstruction location of fenceline and special structures:

1. Mark the proposed fenceline with flagging at intervals so that at least two flagged locations are always visible.

2. Mark the location of special structures, such as water gaps, cattle guards, stretch points, corners, and so forth.

3. Mark the location of any change in fence construction specification, such as from three-strand barbed-wire construction to four-strand.

Construction procedures:

1. Set corner posts, gateposts, and stretch posts.

2. Layout a single line between set posts (in item 1) to accurately locate fence line.

3. Clear the right-of-way to permit construction and maintenance. Save trees larger than 8 inches d.b.h. (diameter at breast height) and trees larger than 6 inches d.b.h. in the fenceline that may be used in lieu of fenceposts. Complete brush and debris disposal to meet fire protection standards. Consider aesthetics and wildlife needs.

4. Set fenceposts and layout wire on the side of the post that will receive the great-est pressure from livestock or drifted snow.

5. Stretch and staple or clip fence wire, one strand at a time, between brace points.

Stretch each wire uniformly with the proper tools. Do not stretch wire with a vehicle.

Maintenance of fences––Fences must be maintained to achieve the intended man-agement objective. The objective of maintenance is to keep the fences at, or as near as possible to, the standard to which they were constructed. Annual maintenance consists of thoroughly checking the fenceline. replacing pulled staples or clips, reset-ting or replacing damaged posts, repairing breaks, and adjusting wire tension to bring the fence to as near the original construction standard as possible. Snow damage and fallen trees are the major problems needing attention each year, but damage from wildlife and hunters are also common. Necessary tools generally include smooth-soft wire, fencing pliers, fence tighteners, hammer, saw, clips for steel fenceposts, and staples.

Special equipment––Equipment manufacturers have realized the large market for fencing equipment and have introduced special machinery to aid in the construction of fences. New equipment is frequently made available, so discussion of the subject is somewhat dated. This section includes the basic equipment being used in the main line of fence construction. We have not tried to include all special areas, but those of primary importance in the construction of fences in northeastern Oregon are included.

Post-hole augers––Power post-hole augers are of two general types. The tractor-mounted type either rigidly attached to the tractor or is free swinging. The free-swinging type is preferred because it drills vertical holes regardless of slope. The other type is an auger attachment for the two-person chain-saw engine. Neither power auger is well suited for use in rocky ground. All power augers can be danger-ous and should be handled with care. Operators should be well trained. Power augers are available from equipment dealers and equipment rental shops. The different types should be examined and information about their suitability for the intended use should be obtained before they are purchased or used.

Post drivers–– The use of hammers or mauls for driving posts is slow and dangerous and should be discouraged. Several mechanical post drivers are available for mount-ing on tractors, trailers, or skids. Usually, two or three people are required to operate them. When ground conditions are favorable, as many as 100 posts an hour can be set with these machines. One- or two-person hand-operated steel or wood post drivers are also available commercially, or they can be constructed in a local shop (fig. 2).

Wire stretchers––Several types of hand-operated wire stretchers are on the market.

Some of the newer cable-and-ratchet types are preferred to the rope-and-pulley stretchers because they are much safer and more convenient. Commercial fence-building machines may also be used to stretch wire; but vehicles and other machines are not safe because the correct tension on the wire cannot be judged and the wire may break.

Figure 2––Hand-operated fencepost driving tools for wooden and steel fenceposts.

WIre-splicing tool––An effective tool for splicing fence wire has been developed.

This tool eliminates the need for special twists and bends to splice broken wire and can be used to repair rusted wire, which generally breaks when it is bent or twisted.

The tool crimps a special sleeve over the two wire ends to be spliced. Nicopress1 sleeves are available for various types of wire, gauge, and tensile strength (table 1).

Barbed-wire stringer––Barbed wire can be unrolled mechanically or by hand. If done by hand, safety devices such as shields and leather gloves are necessary. One hand method uses a homemade frame that is pulled by one or two people and rolls the wire out on the ground (fig. 3). This method is much easier and safer than carrying a spool of barbed wire and can be constructed for the size of roll being used. If done mechanically, care should be taken to use only machines specifically designed for safety.

Tamping tools––For adequate support of the fence, the soil around wooden posts must be firmed by tamping. Two satisfactory tamping tools are a steel crowbar with a tamping head and a 1-inch galvanized pipe with a T-joint head.

1 The use of trade names in this publication is for the informa-tion and convenience of the reader. Such does not constitute an official endorsement or approval by the U.S. Department of Agriculture of any product.

Table 1––Nicopress sleeve tensile-holding strength

Figure 3––Barbed-wire stringer is pulled behind one or two people to unroll barbed wire.

Hydraulic log splitter––A commercial hydraulic log splitter was modified to split material as long as 8 feet for fence stays, posts, rock jacks, and rock cribs. The main beam was replaced with a 0.25-inch-thick I-beam about 6 inches wide, 7 inches high, and 11.5 feet long. The I-beam was reinforced with a 0.75-inch-diameter rebar weld-ed along both sides of the vertical beam at the lower junction with the horizontal beam (fig. 4). The splitting wedge was modified to split larger material and could be adjusted for different splitting lengths; the plunger-block was enlarged and reinforced (fig. 5). Specific modifications may vary, depending on the design of the commercial model available.

Replacing small tires with 14- to 16-inch-diameter tires may also be desirable. Work crews raised the log splitter to a more convenient work height and constructed a ramp to move material into position to split logs. This effort reduced the need to bend over and pick up material to be split.

Barbed-wire fences–– Description––The typical barbed-wire fence consists of three or four strands of barbed wire stretched between steel or wooden posts. The fenceposts may be braced in several ways, some of which are locally unique, to provide strength and stability. Barbed-wire fences can include gates, water gaps, and cattle guards.

Application––Barbed-wire fences are the most widely used fences in the Western United States. They are suitable for many conditions and are appropriate as perma-nent fences that will receive moderate to heavy pressure by livestock. Barbed-wire fences can cross many different ecosystems and terrain conditions to separate owner-ship and divide interior property. Design specifications may vary depending on snow depth, slope, tree density, and other environmental factors. Construction and main-tenance costs and environmental conditions generally determine the type of fence to be constructed. This guide provides descriptions and specifications for four types of barbed-wire fence: standard post-and-wire, let-down, suspension, rock-jack, and figure 4.

The standard post-and-wire barbed wire fence generally consists of wooden or steel posts and three or four strands of barbed wire. It is relatively inexpensive, easy to construct, and widely accepted. The let-down fence also consists of three or four strands of wire, but it can be detached from the posts––let down––to prevent damage caused by deep snow or wildlife. This type of fence has higher maintenance costs, mostly for labor to let it down and put it up each year, than the standard post-and-wire fence. The suspension fence is suspended across relatively long spans between fenceposts. Such fences are used on relatively flat ground and are particularly successful where blowing weeds are a problem because they twist in the wind and dump the weeds.

Rock-jack and figure-4 barbed-wire fences are designed for areas where setting posts is not practical, such as rocky or swampy areas. The post supporting the strands of wire rests on the ground and is braced and held in place by a rock jack, a wooden crib or platform filled with rocks. Another type of post-bracing system is in a configuration of the number 4 and is referred to as "figure-4."

EamonnMazur Highlight

EamonnMazur Highlight

Table 2––Life expectancy of treated and untreated wooden fenceposts

Equipment––Equipment for constructing barbed-wire fences may include post-hole auger or digger, post driver, wire stretcher, wire-unrolling equipment, tamping tool, fencing pliers, and hammer.

Materials–– Wooden posts––Wooden posts are preferred in areas where significant amounts of snow accumulate because of their strength. They should be of the most durable species available, such as juniper, cedar, larch, or treated lodgepole pine. For treated posts, a preservative should penetrate radically at least 0.75 inch. Commercially pressure-treated posts usually meet this standard. Untreated wooden posts may decay in 1 to 4 years, depending on the kind of wood. Treated fenceposts have a life expectancy of 5 to 25 years, depending on the kind of wood and treatment (table 2).

Standard wooden posts are 6.5 feet long with a 4-inch-minimum-top diameter. In some cases, live trees at least 6 inches in diameter may be used in the fenceline in lieu of posts. Live trees should never have staples driven into them or have wire wrapped around them without being protected. Live trees can be protected by a slab of wood nailed to the side of the tree, with the wires stapled to the slab. Several slabs of wood can be spaced around a tree to protect it if wire is wrapped around the tree. Such slabs of wood prevent injury to the cambium and prevent the tree from growing over the wire. In addition to protecting the tree, slabs of wood also make repair of the fence easier and may prevent damage to saws if the tree is cut down.

Steel posts––Steel posts can be used where strength is not an important factor, or in rocky areas where pounding or drilling is necessary to set a post. Standard T- or U-section posts with a steel anchor plate should be used (table 3). These posts weigh about 1.5 pounds per foot (table 4). Standard length is 5.5 feet. Fence wires should be fastened to steel posts only by steel clips manufactured for this purpose (fig. 6).

Table 3––Comparative strength of U- and T-section posts of the same weight and steel formulationa

- = no data.

a Deflection was measured 36 inches above ground level.

Force was applied 30-1/2 inches above ground level.

Table 4––Approximate weight of steel posts a Standard length.

Stays––Stays can be wooden or 9.5-gauge galvanized, twisted wire. Wooden stays, at least 2.5 by 3 inches, are preferred in areas of deep snow. Wooden stays should be 44 to 46 inches long, should extend at least 4 inches above the top wire, and may be wired to the fence with 16-gauge galvanized wire and a "telephone tie" for added strength. To make a telephone tie, loop the wire over the barbed wire and around the stay. Cross the ends on the back side of the stay and bring each end back around the stay, wrapping the tie-wire ends snugly around the barbed wire. Extra care is needed to tightly snug the wire around green stays (fig. 7). Wire stays may be in-stalled if the cost is less than that of wooden stays; however, they are suited only for areas receiving little snow. Snow bends the stays and damages the fence.

Preferred style

Reason: Easy to install with 5Od spike or fencing pliers.

Less preferred style

Reason: More difficult to install than type shown above.

Figure 6––Steel clips used to fasten barbed wire to standard steel T-posts. Style may be difficult to determine in some catalogs.

Front view

Wire should be wrapped closer together than illustrated.

Figure 7–– Telephone-wire tie.

Rear view

Alternate method of crossing one or both wires over the front of stay.

Barbed wire, staples, and wire tension––Barbed wire should be 2-point, be 12.5-gauge with 4 to 5 inches between 14-gauge wire barbs, and weigh about 1 pound per rod (table 5). Lighter gauge or 4-point wire can increase maintenance. Staples should be 1 .5 inches long. Nails, staples, and smooth wire are generally sold by weight; tables 6-8 give helpful information for buying these items. It is important to buy quality materials to construct a durable and low-maintenance fence.

All line wires should be dead-ended on gate, corner, angle, or line-brace posts. The ends should be wrapped twice around the post, stapled, and twisted back on the stretched wire to prevent the post from twisting. The first few twists around the stretched line wire should be at about a right angle to the line wire for maximum security (fig. 8).

Wire should be tensioned according to ambient air temperature. Wire tensioned too tight on warm days may be stretched beyond the yield point on cold days, and it may sag the next warm season. A good guide to follow is 550 pounds of tension for the coldest day of the year; subtract 2.61 pounds for every degree Fahrenheit between the air temperature at the time it is stretched and the anticipated coldest temperature.

For example, if the coldest expected temperature is -10 °F and the present tem-perature is 80 °F there is a difference of 90 °F. Multiply 90 by 2.61 and subtract the answer, 235, from 550. The proper tension is 315 pounds. The wire should be over stretched on warm days to take out kinks and seat the twist, but not over 500 pounds, and then returned to the proper tension. The wire must be supported on each post by loose staples or a nail during tensioning to relieve the weight of wire and to assure that wire is in the correct position. A simple tension meter can be constructed, which is based on the general static formula for wire tension:

(fig. 9).

Staples should be set at an angle to the post grain and be driven in just deep enough to snug the line wire without bending it (fig. 10).

Braces––Bracing is the key to prolonged life of wire fences. Brace poles should be at least 5 inches in diameter, peeled, and of sound material. Sawed material of least 4 by 4 inches may be used in lieu of round poles. Line braces should be installed at all breaks in alignment, or at least every 1,320 feet.

Guy wires consist of two complete strands of 9-gauge annealed, or soft, galvanized wire. The brace pole is fitted between the fenceposts near the top wire and double spiked into place. Round or split posts should have a flat surface for the brace pole to fit firmly against the post. The guy wire is double wrapped around the bottom of the post that the fenceline wires will be attached to and around of the top of the brace post, stapled, and tied together so the guy wire forms two long narrow circles.

A stout stick is placed about the middle of the guy wires, and all four wires are twisted together until the guy wires are tight. Additional bracing can be added where extra strength is needed (figs. 11, 12, and 13). Gates are located between two line braces (fig. 14), or one line brace and a corner brace.

Text continues on page 18.

Table 5––Approximate amount of barbed wire needed for fences of various lengths constructed with 1·, 2·,3·, or 4·strand wiresa a Weights assume 2-strand, 12-1/2-gauge barbed wire with 2-point, 14-gauge barbs, 4 to 5 inches between barbs.

Table 6––Number of common nails per pound by size, length, and gauge

Table 7––Number of galvanized fence staples per pound

Table 8––Weights and length of smooth wire per unit of measure, by gauge and diameter

A question frequently arising is, in which direction do the guy wires go? The easiest way to remember is to recall the purpose of the brace pole and the guy wires. The fence wire is attached to a fencepost that pushes against the brace pole and tries to push the brace post over. The guy wires transfer that pushing force from the top of the brace post back to the bottom of the fence post that the wire is attached to. This brace configuration is strongest when the posts, brace pole, and ground form a rectangle.

Text continues on page 26.

CONSTRUCTION

Screw 2 cup hooks into a 44"x3-1/2"x1/2" board 40" apart and 1" down from the top of the board. Place a wire across the cup hooks and mark a line 1/2" below the wire near the center of the board.

HOW TO USE TENSION METER

Run out and stretch all wires. Staple all wires in major dips and rises. Wire should move freely.

Take reading near the middle of the stretch. Place wire on the cup hooks. Attach a spring balance to the wire midway between the cup hooks and pull the wire down until it is deflected to the 1/2" mark.

Read the balance. Multiply this reading by 20. Answer equals pounds of line tension. For example, 15 lb = 300, 16 lb = 320, and 17 lb = 340. (See text for method to determine the correct tension.)

On long spans with 2 or 3 dips or rises, leave 1 or 2 dips or rises unstapled on the end of the wire that the wire is being stretched from. Staple these areas last to evenly tighten the wire. Only experience can judge the correct procedure.

When all wires are tensioned and tied off, staple the rest of the line. First walk the entire line and staple all secondary dips and rises to even out the tension and then staple the rest of the line. Never start at one end and staple through to the other end, unless the stretch is short and flat.

Figure 9––Instructions for construction and use of a simple wire tension tool (Courtesy Waterford Corporation).

Drive staples at an angle in the same direction as the wire is pulling.

Do not drive staples parallel to side of post.

Leave wire loose in staple.

Figure 10–– Techniques for stapling wire to wooden posts.

Corner brace

Line brace Figure 11––Standard corner and line brace detail for wire fences. Sawed material is preferred over round. Notch braces to fit firmly against posts. Install braces every 440 yards and at all changes in alignment.

Line brace for slopes greater than 30 percent Figure 13––Extra-strength braces for normal wire fencelines and for those on steep slopes. Sawed material is preferred over round. Notch braces to fit firmly against posts. Install braces every 440 yards and at all changes in alignment.

Specifications––Spacing line wires is very important, especially in areas where big game are found. The total height should be not more than 42 inches to prevent the top wire from being broken when big game, especially deer, jump over the fence.

The distance between the top two wires is critical for adult deer because their hind legs can become entangled between these wires. We recommend that the top wire be at least 10 inches above the next wire. The bottom wire should be at least 16 inches above the ground to allow fawns and antelope to crawl under the fence (fig. 15).

Grounding of wire fences removes some of the risk associated with lightning and other electrical hazards (fig. 16). Where fencelines are parallel to powerlines, ground-ing should be installed every 1,500 feet. Where the fence crosses under a powerline, the fence should be grounded on each side of the crossing.

The surfaces of posts and braces must be notched or flattened where they are to be joined so that about half the nail will be in each member. Nails should be driven at binding angles to each other (fig. 17). When trees in the fenceline are used to hang wire, wooden strips should be nailed to the tree and the wire stapled to the "nailer" strips (fig. 18). Where trees are within 2 feet of the fenceline, offsets can be used fastening wires to the trees (fig. 19).

Under conditions of heavy snowfall, posts should be spaced at no more than

16.5 feet apart. Otherwise local conditions should be considered and posts spaced according to stock pressures and fence strength. Spacing posts as far apart as 30 feet may be satisfactory under some conditions.

Standard post-and-wire fence––Barbed wire on set or driven line posts is the most commonly used fence construction. Three strands of barbed wire are usually adequate except where livestock pressures are heavy. In such cases, a fourth strand should be added.

Where heavy snow occurs, wooden posts should be spaced 16 feet apart for maxi-mum strength. In areas where moderate snow occurs, posts may be spaced up to 24 feet apart, with two or three stays between posts. Steel posts may be substituted for wooden posts where strength is not a controlling factor; they are usually satisfac-tory except for brace and gateposts, which should be wooden (fig. 20). Usually, at least every fifth post should be wooden.

Where construction crosses dry draws, all fence strands should be anchored to heavy rocks, logs, or other durable material with 9-gauge galvanized smooth wire (figs. 21 and 22). Several methods may be used for crossing live streams or very deep draws. The fence should be dead-ended on each side of the crossing with line braces. The section of the fence crossing the stream may be constructed so it can be removed or can swing with high waterflow (figs. 23, 24, and 25).

Text continues on page 38.

Three-Wire spacing

Four-Wire spacing Figure 15––Barbed-wire spacing for three- and four-wire fences.

50d or 6Od driven at binding angles

Sound wood against sound wood (no bark)

Figure 17––Nailing techniques for fence construction. Bend exposed ends of nails that extend through a member so they are flat and parallel with the timber surface.

Nearly flat surfaces

Alternate post and stay spacing for moderate conditions.

Figure 20––Spacing recommendations for steel or wooden posts and wooden stays for standard wire fences.

26. 27.

CONSTRUCTION DETAILS

Pickets are 2-1/2" x 6" material suspended on 2" x 10" strap iron "U" clamps over 1" diameter pipe.

A 5/B"-diameter cable is inside the pipe and anchored at either end with a deadman. The structure is supported by 12"-diameter, treated posts set 5' deep, rock-jacks, or trees at least 10" d.b.h. Pickets are spaced with lO"-long sections of 1-1/4" pipe that is placed between the clamps and slipped over the I" pipe. The clamps may be greased to reduce wear. Because of the weight of the pickets, this design is recommended for spans 25' or less. Longer spans require heavier cable and pipe.

Figure 24––Swing picket fence designed for water gaps on larger streams. (A.) Pickets hang down into the stream and "float" on the water. (B.) Pickets may be lifted out of the water to prevent ice damage by two stands of no. 9 wire attached to brace posts on either side of the stream.

Let-down fence––Let-down fences are designed for areas with heavy snow and where seasonal movements of big game must be considered. The tension-cable anchor is critical because it supports the span that will be let down. The anchor can be fastened to a tree or to a permanent fenceline brace (fig. 26). Let-down-fence spans should be planned as straight stretches (fig. 27). Posts may be wood or steel.

Line posts may be spaced as far apart as 30 feet, but two or three wooden stays are usually needed for longer spans. Line braces should be set at least each 180 feet.

Construction should allow each section between anchor points to be laid down.

Wooden stays are used to attach wire at each steel post (figs. 28 and 29), tree (figs. 30 and 31), or rock-jack (fig. 32). Wire loops are used to hold the stay to the line structure during the grazing season. Wire strands should not be stretched as tightly as in regular post-and-wire fences. Wire supports can be used on tree nailers or rock-jack members (fig. 33). A useful tool to let down and put up fence spans can be constructed with a board 30 inches long, or a maul handle, and about 5 feet of chain (fig. 34).

Suspension fence––Suspension fences work well on open, level area but have limited use in mountainous terrain. Such fences are not recommended for sites with deep snow. The advantages are low costs for construction and maintenance.

Wooden line posts are spaced 80 to 128 feet apart with two-piece wire stays 16 feet apart. Three to six strands of barbed-wire are stretched taut between line braces (no more than a 3-inch sag between posts) and fastened to posts with nailed clips or ''telephone staples." The wires must be free to move back and forth through the clip, and the stays must not touch the ground. Treated wooden posts are preferred to steel posts.

Suspension fences work well on smooth ground where small depressions or gullies are not prevalent. In areas where windblown weeds are a problem, the suspension fence gives less trouble than conventional fences because they are flexible and can "dump" weeds that pile up against the fence.

Rock-jack and figure-4 fences––Rock-jack and figure-4 fences are very functional and usually have low maintenance requirements. These fences are useful in areas where setting wooden or steel posts is difficult; for example, in swampy or rocky areas.

They should also be considered in areas where native material is available on the site and where construction and maintenance costs are less than the cost for fences with set posts. This type of fence is very flexible. Rock-jacks provide the primary support; figure-4's, steel posts, and wooden stays, used in combination to suit site conditions, provide secondary support.

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Pigtail has enough slack to allow free movement of stay when fence is put up and let down but will not move stay along fenceline and will be parallel with the steel post when the fence is up.

Figure 28––Side view and recommended spacing of steel post and stay structure used to support let-down fences.

Steel fenceposts are not suitable for areas that receive heavy snow.

Cold shut - attach to nailer or rock-jack with 5Od or 60d spike. Leave last 1” of spike out to lock wire. Bend over protruding spike ends that extend through timber.

Figure 33––Detail of cold shut used as a wire support on tree nailers or rock-jack supports.

Rock-jacks (fig. 35) and figure-4's (fig. 36) are constructed from split wood. Corner or gate rock-jacks are designed to hold more stress (fig. 37). Rock-jacks are spaced from 50 to 160 feet, depending on snow conditions and the type of intermediate supports. On rocky and moderately level topography, rock-jacks may be spaced every 50 feet with wooden stays every 12.5 feet between jacks. On level forested sites with light snowfall, rock-jacks may be spaced every 100 feet and figure-4's every 25 feet with wooden stays between each span. Steep, rocky slopes or sites with heavy snow loads need to have the rock-jacks spaced closer together to support the fence (fig. 38). On sites where steel posts can be used, rock-jacks may be spaced every 160 feet and steel posts every 20 feet with wooden stays between each span. For areas with moderate snow loads, wooden stays can be used to prevent steel posts from settling into the soil (fig. 39).

As with standard barbed-wire fence construction, log or rock tie-downs should be used to hold the fence. in position at draws, depressions, and streams (figs. 21, 22 23, 24, and 25).

Woven-wire fences–– Description––Woven-wire fences consist of woven wire stretched between line posts, generally with one or two barbed-wire strands above the woven wire. The mesh of the woven wire differs, depending on the animals the fence is designed to control. Some fence construction requires woven wire of smaller mesh in the lower portion of the fence and larger mesh in the upper part. Some designs do not call for barbed wire above the woven wire, and the height of the woven wire ranges up to 8 feet to control wildlife. The line posts are similar to those of standard barbed-wire fences, depending on the height of the fence.

Application––Woven-wire fences are generally used to control livestock, such as sheep and goats. An effective fence consists of 26-inch woven wire hung 2 to 4 inch-es above the ground with one or two strands of barbed wire above the woven wire.

Barbed wire above the woven wire is not necessary if sheep are on both sides of the fence. Woven-wire fences are suited for gentle and rough terrain but generally are not suited for snow country because heavy snow will pull the fence down.

Equipment––The equipment used for. barbed-wire fences can be used for the con-struction of woven-wire fences, except that woven wire must be stretched as a single unit. This can be done by bolting two 2 by 4's together with the end of the woven wire between them to form a clamp. Bolts should be at 8-inch intervals and tightened to prevent slippage. The wire should be stretched reasonably tight, but not over-stretched, because the mesh will collapse. Staple both ways from the center of the stretched section to maintain equal tension between posts.

Materials––Materials needed for woven-wire fences are woven wire, barbed wire, posts, nails, staples, and 9-gauge galvanized smooth wire.

Specifications––The woven-wire fence should be constructed with 12.5-gauge-mesh wires and 10-gauge top and bottom wires and should be galvanized. Horizontal wires may be closer together at the bottom than at the top. Vertical wires are usually about 6 inches apart. Woven wire comes in 20-rod.(330-foot) rolls of different heights.

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Crossing at least 40· above ground.

Rock

Overlap all joints 8”

Place legs in shallow holes to prevent slipping on slopes.

Front view

Floor:

Sound Wood 2” thick by any width ( larch preferred) Nail only this floor board. The rest usually are not nailed but are held in place by rocks.

Jack legs and supports:

Six 3·x6·x5-1/2'

Side view Figure 35-Construction details for rock-jacks used in fenceline. commonly called line-jacks.

Drive two 50d or 60d nails at binding angles in each joint and bind with No.9 wire.

Rear leg is placed between two front legs.

Figure 36-Construction details for figure-4 fence supports.

Standard 26-inch-high woven wire, hung 2 to 4 inches above the ground, should be used to control sheep. No barbed wire is necessary below or above the woven wire when sheep will be on both sides of the fence. If cattle or horses may be in the area, one or two strands of barbed wire are needed above the woven wire. Smooth wire is preferred for horses to prevent injuries. The space between the woven wire and the barbed wire, or wires, is critical for safe passage of wildlife. Special structures, similar to a cattle guard, are needed to allow antelope to pass through woven-wire fences.

Posts should be spaced 16.5 feet apart; wooden stays may be needed in areas where snow may damage the fence.

Electric fences- Description- There are two types of traditional electric fences.-single-wire and two wire. The hot wire, or wires, is supported by fiberglass posts or by insulators attached to steel or wooden posts. Posts are spaced 30 to 50 feet apart, depend-ing on vegetation and topography. The single-wire fence uses one charged wire and uses the earth for the ground circuit. Both wires of the two-wire type may be charged, or only the top wire is charged and the bottom wire is used for the ground.

The single-wire fence costs less, but also has the highest risk of failure. The two-wire fence (one charged wire and one ground wire-generally the lower wire) over-comes the disadvantages of the single-wire fence to complete the ground circuit on dry or rocky sites. Best results are obtained on moist ground by charging both wires separately with individual charging unit. This overcomes potential battery failures and provides maximum security.

A recent development in high voltage and high-tensile-strength smooth wire is a "permanent" New Zealand electric fence. High-tensile-strength smooth wire has also been used to construct nonelectrical fences. These types of fences have been in-stalled in a few areas; however, we do not have any experience with them and have not included them in this handbook. Distributors of "New Zealand" fence material should be contacted to obtain specifications.

Costs for other fencing techniques should be compared with costs for electric fencing. It may be cheaper, and perhaps more satisfactory, to install a standard three-wire, barbed-wire fence that can be used to permanently control distribution of livestock.

Equipment- The tools used to construct barbed-wire fences can be used for electric fences. Because these fences are temporary, it is not as necessary to clear the right-of-way beyond what is needed to keep the hot wire from being grounded.

Application-Electric fences are most often used for temporary fences to control livestock on a nonpermanent basis. They have been used successfully to protect new seedings, plantations, construction sites, and research plots, and to temporarily divide meadows into smaller pastures. They are most effective on moist sites and least effective on dry, rocky sites. For the fence to be effective, vegetation should be kept from contacting the hot wire. Electric fences should never be built under high-voltage powerlines

Materials––Special electric fence wire may be used for electric fences; however, smooth 9-gauge wire or barbed wire may be preferred because it can also be used for later fence construction. If wooden or steel posts are used, insulators are needed to support the charged Wires. Fiberglass posts do not need insulators and are usually pushed into the ground by hand. Fence chargers, or circuit controllers, should be installed according to manufacturer's specifications.

Specifications––All electric fences should have signs securely attached to the top wire at frequent intervals to warn people that the fence is charged. Because of possi-ble hazards to humans, electric fences should be used only in areas not frequented by visitors.

Buck-and-pole fences- Descrlption––Buck-and-pole fences have a scenic, rustic appearance and are con-structed almost entirely with wooden poles.

Application––Buck-and-pole fences are suitable for administrative sites, camp grounds, wilderness, and other sites with high scenic values. These fences are also suitable for areas with high snow accumulation. They have a tendency to sink into the ground on very moist sites: however, and are recommended for drier, more rocky areas where the fence material, mostly pole-size trees, is readily available near the proposed fenceline. Buck-and-pole fences are generally more expensive to construct, but they require less maintenance than barbed-wire fences.

Equipment––Chain saws are needed to clear the right-of-way for buck-and-pole fences and for falling and trimming poles. Bucks and poles are usually cut on or near the construction site, and the bark is stripped off. Other equipment includes hammers and hand saws. A miter box with a 30° or 40° angle, constructed out of 2- by 10-inch lumber, is convenient to cut the correct angle to join the buck members.

Materials––Well-seasoned lodgepole pine or yellow pine pole material is best for buck-and-pole fences, although other straight species, free of knots, are satisfactory.

All material should be peeled or have the bark stripped from at least two sides for quick seasoning.

Specifications––Poles should be cut 12 feet long and have a minimum 3-inch dia-meter, which allows the bucks to be spaced 10 feet apart. Fir poles should not ex-ceed 12 feet in length with buck spacing at 10 feet. Brace poles (4-inch-minimum diameter) should be placed on every fifth buck, except in steep or heavy snow areas where every panel may need to be braced (fig. 40). Buck sticks are mitered for a close fit and strength (fig. 41).The buck-and-pole fence can be modified for wildlife by using three instead of four poles per panel and reducing the total height (fig. 42).

On exposed areas with severe winds, we recommend that buck sticks be spread farther apart (80°).

Log-worm fences- Description––Log-worm fences are constructed with poles and treated wooden stays and have a zig-zag, or "worm," appearance because each section is at an angle to the previous section. The angle may vary, depending on the strength and stability needed-the sharper the angle, the greater the stability.

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Figure 41––Construction details for buck-and-pole fence–– rider-pole-spacing recommendations for livestock and detail for buck sticks. A cross-brace is needed to prevent the bucks from spreading in areas with heavy snow conditions.

Figure 42––Construction details for buck-and-pole fence–– rider-pole-spacing recommendations for wildlife and detail for buck sticks where fences are subjected to severe wind. A cross-brace is needed to prevent the bucks from spreading in areas with heavy snow conditions.

Application––The log-worm fence is well suited for areas of high snow accumulation and timbered sites. These fences are rustic and are also used for administrative and recreation sites. Maintenance cost is very low, and the fence lasts a long time when it is properly constructed. Log-worm fences can be a barrier to young deer and elk, and care should be taken in selecting locations for long stretches of this fence. Sec-tions of wire let-down fences may be necessary to allow free passage of big game, especially on migratory routes.

Equipment–– The equipment needed for log-worm fences is similar to that used in constructing buck-and-pole fences. No miter box is needed, but tools are needed to dig post holes and to cut wire.

Materials––Seasoned lodgepole pine logs are preferred, although other species may be used, including split larch rails. Bark should be stripped from two sides of logs to hasten seasoning. Logs with minimum taper are best; logs should be at least 6 inches in diameter and up to 18 feet long. All tie wires should be 9 gauge and galvanized.

Treated wooden stays with a minimum 4-inch diameter or treated 4 by 4's are needed to support the logs.

Specification––Log-worm fences are usually at least 5 feet high. Rocks should be used to keep the bottom logs off the ground. Spans are generally 12 to 14 feet, with 2 feet extending beyond the crossing point. Spans may be longer, depending on the diameter of the logs and the snow depth. As the snow depth increases, larger mate-rial is needed to support the heavier snow load. Stays should be treated wooden material at least 4 inches in diameter and buried 18 inches in the ground (fig. 43).

Smooth 9-gauge galvanized wire is used to hold the stays together; it should be looped twice around and twisted to tighten.

Block-and-pole fences- Description––The block-and-pole fence is similar to the log-worm fence, except that short (2-foot) fence sections are at right angles to the main sections and the material is usually larger. These fences are relatively maintenance free and have a rustic appearance.

Application––Like the log-worm fence, the block-and-pole fence can be used in areas of deep, drifting snow and where appearance and durability are important.

Availability of materials on site is an important concern because large poles and rocks are needed.

Equipment–– The size of the material needed for block-and-pole fences necessitates the use of hoisting equipment capable of handling large logs and rocks; also needed is the equipment used for constructing log-worm fences.

Materials––Logs used for constructing buck-and-pole fences should have at least an 8-inch diameter; larger logs are preferred. Span lengths should not exceed 12 feet.

Treated stays are needed to support the logs, and large rocks are…