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Agriculture Handbook No. 487 -

U.S. Department of Agriculture

Forest Service

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Mechanical Methods

Of Chaparral Modification

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Forestry Sciences Lalxiraiory

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Mechanical Methods

of

Chaparral Modification

George A. Roby, District Ranger,

Arroyo Seco District, Angeles National Forest

and

Lisle R. Green, Supervisory Range Scientist

Pacific Southwest Forest and Range Experiment Station

Agriculture Handbook No. 487

April 1976

U.S. Department of Agriculture Forest Service
Roby, George A., and Lisle R. Green

1976. Mechanical methods of chaparral modification. U.S. Dep.

Agrie, Agrie. Handb. 487, 46 p., illus.

Chaparral modification is undertaken for a variety of land-management purposes. To help land managers in selecting equipment and methods for such work, practitioners in county, State, and Federal modification projects were asked for evaluations of equipment and techniques

they had used. This handbook describes the alternative techniques and

equipment, provides information on operations, reports production

rates and on-site costs, and explains the advantages and limitations of

equipment used for brush crushing, compacting, chopping, and shredding and for grass seeding. Tools for hand methods of clearing and

stump sprout control are also described.

Oxford: 432.17:332.3—087:187x424.5(794). Keywords: chaparral, fuel

modification equipment, fuel management, California.
Contents

Page

PREFACE iv

SUMMARY V

INTRODUCTION 1

CRUSHING AND PILING EQUIPMENT 3

Bulldozer Straight Blade and Tomahawk Crusher 3

Brush Rake 5

Chains 9

Modified Chain Between Two Tractors 11

Ball and Chain 16

CHOPPING AND SHREDDING EQUIPMENT 23

Brushland Disks 23

Roller Chopper 29

Tritter Brush Shredder 31

HAND TOOLS FOR BRUSH CLEARING AND STUMP SPROUT CONTROL 32

Cutting and Piling 32

Stump Treatment 33

GRASS SEEDING EQUIPMENT 35

Rangeland Drill 36

Hand Seeding 37

Aerial Seeding 37

CONTRACT RECOMMENDATIONS 37

LITERATURE CITED 39

APPENDIX A Comparative Specifications of Industrial Track-Laying Tractors 41

APPENDIX B Suggested Form for Summarizing Costs of Chaparral Modification 43

APPENDIX C Relation of Production Rate to Swath Width and Speed of Implement 44

APPENDIXD Contract Specifications for the Modified Chain 45

111
Preface

This handbook brings together the experience

gained in a variety of chaparral modification projects. Such sharing should make for better planning and more efficient use of limited funds. The

handbook is designed to help land managers who

must select equipment and methods for chaparral

management work. It presents the alternatives,

gives advice on operations, reports average production rates and costs, and points out the advantages and disadvantages of the equipment described. All the conclusions are based on direct

consultation with those who conducted projects

on the ground and on the experience of the authors. Most of those who reported were interviewed face to face by the senior author; a few

gave us information by telephone or mail.

Reports were gathered from 19 projects representing five agencies. We are indebted to the following persons for the information they provided:

From the USDA Forest Service, CaHfornia Region, Angeles National Forest: Gilbert H. Easter,

Gordon N. Foster, William Harper, Woody Hite,

Jack Lane, Gordon Rowley, David G. Spiro, Jesse

C. Yarbrough; Cleveland National Forest: Harold

Allum, Lawrence Compton, Thomas E. Lundgren,

Robert Parker, Richard F. Raybould, Robert Robbins, Lowell Smith, Marvin Stout, Richard Wenstrom; Los Padres National Forest: James W. Acton, Mark L. Linane, Robert Nelson, Robert Righetti; Mendocino National Forest: John Lorenzana,

Paul T. Meischke; San Bernardino National Forest:

Donald Adams, Franklin A Gaddy, E. L. Richardson, Daniel J. Swearingin, Patrick L. Wassell; Stanislaus National Forest: Riley Gilkey; San Dimas

Equipment Development Center, Dan W. McKenzie.

From the U. S. Bureau of Indian Affairs: Glenn I.

Ehrlich; the California Division of Forestry: John

W. Gray; the Los Angeles County Fire Department: Russell Stallings; and the San Diego County

Department of Agriculture: Karl Baker, Roy Kepner, Gary Reece.

This report necessarily identifies some equipment

by the manufacturer or trade name. The evaluation

given here is based solely on reports of users in particular projects. Use of trade names is for information only and does not constitute endorsement by

the U. S. Department of Agriculture to the exclusion of other equipment not mentioned.

IV
Summary

Chaparral modification activity has increased in

recent years. This work has among its objectives

reduction of fire hazard, more grazing for Hvestock

and deer, habitat improvement for wildHfe, and

greater water yield. To help resource managers

benefit by the experience of others, we asked workers on 19 chaparral modification projects for county. State, and Federal agencies in California about

the equipment and techniques they used. Data on

production rates and costs were requested, together

with advice on sizes and types of equipment, capability, and safety precautions.

Equipment for land clearing by crushing and

compacting brush, usually in preparation for burning, included the straight-blade bulldozer, the bulldozer with Tomahawk crusher, the brush rake, and

the chain, used between two tractors or with a steel

ball and one tractor.

The tractor with straight bulldozer blade is valuable for crushing brush in preparation for burning.

The "Tomahawk" compactor crusher increases the

production rate by in effect widening the tractor

treads to the full width of the tractor. The tractor

with brush rake is useful for uprooting and piling

brush for burning. Costs in 1973 varied from $25 to

$65 per acre in light brush, depending on steepness

of slope, to $100 with heavy brush on steep slopes.

Costs were nearly doubled when considerable oak

was present.

Brush can be prepared for burning on favorable

terrain by one or more passes of an anchor chain

drawn between two large tractors or between a tractor and ball. Chain length depends on tractor size,

chain and ball weight, and terrain. Best crushing,

chopping, and uprooting of brush occurred when

the chain was modified by welding crossbars across

every link, or every third link. Bars welded only on

alternate links are parallel and uproot less brush.

When the modified chain is used with two tractors,

a swivel at each end is connected to a few feet of

smooth chain attached to the tractor. The modified

chain was found effective in all mature chaparral

types. Two passes, one in each direction, prepared

the brush for safe burning; one pass may be

enough. Two passes can be made at a rate ranging

from 1 to 6 acres per hour, depending on terrain and

brush size and density.

The ball and chain are used on steep side slopes

below a ridgetop. A steel ball, 5 feet in diameter, is

filled with water, or water and gravel. A D-8 size

tractor is generally used. By moving along the ridgetop, towing the ball, the tractor crushes brush on

the slope in a swath about half the length of the

chain. Mature chamise chaparral was found most

susceptible to crushing. Tough species, particularly

oaks, did not crush well. Late summer or fall was

the best season. Production was greatest on slopes

of 50 percent, or steeper.

Equipment for land clearing by chopping or

shredding brush so as to form a mulch included the

brushland disk, roller chopper, and Tritter shredder. In the fighter fuels, prescribed burning is usually not necessary, but in heavy fuels follow-up burning may be indicated.

Brushland disks weighing 8,000 to 11,000 pounds

have impressed observers with their effectiveness

in mulching light brush with one pass, or heavy

brush with two or three passes. Tractors of 130 to

270 net flywheel horsepowers were recommended

for these disks. One pass generally required about

an hour per acre, and subsequent passes, less.

Roller choppers, 8 to 10 feet wide, and weighing

up to 37,000 pounds filled with water, appear useful

in most fuel types if slopes are less than 20 percent.

They effectively mulch light brush fuels, but burning is necessary in medium to heavy fuels unless

several passes are made. Little production data

were available.

Several brush beaters or brush shredders have

been tried over the years. The latest, called the Tritter, was developed in Australia. Considerable modification has been required, but medium manzanita

(about 5 feet tall, and dense) was shredded at a cost

of $35 to $40 per acre on slopes under 35 percent.

Burning is'^not usually necessary following the

shredding, but sprout control with herbicides is indicated, as root crowns are not removed.

Clearing brush by hand becomes necessary under

some situations in spite of the great cost. One hundred to 110 man-hours are required to cut and pile
an acre of light brush, and 250 to 300 man-hours per

acre of very heavy brush. Costs of clearing medium

brush are perhaps $750 per acre;"light brush costs

are half that amount and heavy brush as much as

twice. The Homelite brush cutter, which features a

motor carried in a pack on the operator's back, and

a circular saw at the end of flexible drive shaft, was

credited with speeding up hand cutting. Cut stumps

are usually treated with herbicide to prevent sprouting. The most convenient tool is a sponge attached

to a drip torch. There is no waste and no chance of

drift.

Grass seeding equipment includes the rangeland

drill and Cyclone seeders. The drill is effective

when used on the contour on moderate slopes.

Production rates are from 1 to 3 acres per hour, and

costs from $8 to $25 per acre, depending on conditions. Battery-powered Cyclone seeders may be

mounted on an all-terrain vehicle. For hand seeding,

a Cyclone seeder with metal hopper is generally

preferred, with seeding rates ranging from 1 to 2

acres per hour. Aerial seeding by both helicopter

and ñxed-wing aircraft is economical for large

areas.

VI
Introduction

The modification of chaparral is an increasingly

important land management activity. Chaparral, as

the term is used here, refers to dense stands of evergreen, shrubby vegetation. They are dominated

by species that sprout vigorously after their aboveground parts are removed, and many of these species, as well as nonsprouting species, regenerate

strongly from seed.

Chaparral modification is undertaken for various

reasons, and the term covers operations ranging

from relatively light thinning of brush to a virtually

complete conversion from brush to grass. The information in this handbook was gathered primarily

from projects that are part of an effort to combat

the severe fire problem presented by chaparral

lands in southern California. Modification has other

values, however; it may provide forage and improved cover conditions for wildlife, grazing area

for livestock, and improved conditions of soil cover

and water use. It may also increase recreational

values.

This handbook will be useful primarily to the land

manager who must choose equipment to carry out a

chaparral modification prescription. His choice is

limited by the environmental analysis that has preceded the prescription, and also by the available

funds and manpower. In selecting methods and

equipment, he must recognize that results cannot be

precisely estimated in advance. Even though he

may expect to avoid prescribed burning, for example, he may find eventually that it is necessary after

all. Again, he must realize that no one piece of

equipment or technique is suitable for use over an

entire project. Physical conditions and environmental concerns vary. The best combination to accomplish the desired objectives must be found.

For a long time, various agencies and individuals

in southern California have been engaged in chaparral modification, and the pace of this work has

quickened during the recent past. Much time and

money has been spent, sometimes in a trial-anderror process, to develop tools and techniques that

can accompHsh desired resuhs. Had project workers been able to benefit from others' experience,

costly repetition of mistakes might have been

avoided. This handbook is intended to prevent such

duplication of effort by bringing together information gained at first hand from project workers. The

successes and failures of others will guide the land

manager's thinking and strengthen his decisions.

The plan of this handbook reflects the emphasis

used in gathering data. Those who had used a particular kind of equipment were asked about its usefulness, for helpful advice on techniques they had

employed, and about safety precautions to be observed. Average rates of production were sought

for the various kinds of equipment, because land

managers and planners indicated they could compute their local costs from these rates.

In reporting the results of our interviews, we

have tried to stress the judgment of the majority.

Differences of opinion were noted among project

workers as to objectives and expectations, such as

the definition of an "adequate job" with a certain

piece of equipment. What pleased one manager was

not clean enough to satisfy another. Consequently,

extra passes with the equipment or follow-up burning were required by some managers but not others.

Variance in results was also a reflection of the

operators' and managers' general lack of experience with the different types of equipment. It was

difficult to find contractors and operators experienced with tools such as the brushland disk, ball

and chain, or anchor chain. As we continue to use

this type of equipment under wildland conditions,

effectiveness and efficiency should improve for

each method.

The handbook is devoted primarily to equipment used for land clearing in brushland. Hand

methods are also discussed, including techniques

for stump sprout control. Equipment used for grass

seeding is briefly treated, and some recommendations for contract specifications are made.

The descriptions of the major types of equipment

used in land clearing are grouped broadly according

to the operation they are usually called upon to perform. Although there are no precise limits to the

capabilities of a particular piece of equipment,

some types are used primarily for crushing and piling brush in preparation for burning, and others

1
primarily for chopping and shredding brush to form

a mulch that can be incorporated into the soil.

Because equipment efficiency is frequently linked

to tractor size, information on this point follows the

description of each equipment type. Most contracts

are being written in terms of engine horsepower, or

net horsepower at the flywheel, but horsepower at

the drawbar is sometimes speciñed. This is roughly

20 percent less than flywheel horsepower for tractors commonly used in chaparral modification. A

list of tractors and their horsepower is given as

Appendix A.

The capabiHty of the equipment, including such

considerations as equipment performance under

various conditions of vegetation, slope, and rockiness, and equipment maneuverability, is discussed

in some detail. Then the range of production rates

and costs reported by project workers is given.

Precise data on production rates and costs were

difficult to secure because of the variety in recordkeeping methods. Most users of the equipment

were trying to arrive at some figure for cost per acre

or total job cost, but frequently the rate of production of a piece of equipment or the cost of swampers or of vehicles was hard to separate out of "total or other costs." Sometimes the separate costs

could only be estimated.

The cost data given should be helpful for broad

planning needs. Costs presented are the direct, or

on-site costs in 1973. Not included are indirect costs

such as mileage to and from a job, expense of moving to a work site, supervision and planning, and the

cost of the environmental analysis reports, necessary in most current projects. These were estimated

separately at 40 to 50 percent of on-site costs, and

should be added to the direct costs when total

project costs are needed.

For work planning, good data on rate of production are essential. Included as Appendix B is a form

used for information gathering for this report. This,

or a similar form, could improve record keeping and

work planning.

In computing production rates and costs, percent

slope and the volume of brush must be considered.

A useful indication of volume is the fuel or vegetation type, as classified in the U.S. Forest Service

California Region Fireline Handbook (11), To some

of the types designated, we have added quantitative

estimates as follows:

7— Light to medium chamise, fuel loading generally 5 to 15 tons per acre, dry weight.

8_ Brush mixtures with sage, frequently the

coastal sage type, fuel loading generally 5 to

15 tons per acre.

n_Medium brush and oak, from 10 to 25 tons

per acre, not including oak trees.

12—Heavy pure manzanita, chamise, or buckbrush, 20 to 30 tons per acre.

13— Heavy mixed brush, 20 to 35 tons per acre.

14_ Heaviest mixed brush, 30 to 45 tons per

acre.

These fuel type designations are used in the tables

of production rates and costs.

As a general rule, the production rate of a piece

of equipment can be estimated from the width of its

swath and the speed at which it can be operated. A

graph showing this relationship is given as Appendix C.

Some miscellaneous suggestions made by the

project workers we interviewed have been included

in the section titled "Comments." Special safety

precautions and a comparative listing of the advantages and disadvantages of the equipment type are

included. In this listing, features often mentioned as

affecting choice of equipment were considered.

These include the degree to which the topsoil is disturbed, the amount of soil left in piles, the degree to

which plants are uprooted rather than merely broken off at the surface, the amount of soil left on the

ground to absorb moisture and preserve nutrients,

and the degree to which erosion may be encouraged.

Although every effort has been made to achieve

reliable evaluations of the equipment described, all

land managers will recognize that success with any

piece of equipment depends strongly on field conditions and on the skill of the operator. Proper planning and supervision are essential.
Crushing and Piling Equipment

Under certain conditions of terrain, climate, and

brush type, the indicated treatment for chaparral

modification may be to crush and compact the

brush. Prescribed burning is usually a follow-up

procedure, and the crushing equipment may also

gather the material into piles or windrows for burning. If brush is light, however, burning may not be

necessary.

The most widely used types of equipment are the

bulldozer straight blade, with or without the Tomahawk crusher; the brush rake; the chain between

two tractors; and the ball and chain; all discussed

below. A large I-beam or railroad rail pulled behind

a tractor is sometimes used to crush brush, with the

long axis of the beam at right angles to the direction

of travel. The practice has been recommended for

uprooting big sagebrush (Artemisia tridentata) in

the Intermountain Region, but on the basis of limited information available to us, railing does not seem

well suited for chaparral brush clearing. It may be

effective in mature light fuels such as coastal sage

species. A small area of light chamise in Los Angeles County (Rowher Flat) was railed with disappointing results, however. The practice was suggested as a means for covering seed, but no one in

southern California seems to have used a rail for

this purpose.

Bulldozer Straight Blade and Tomahawk Crusher

The use of straight bulldozer blades for clearing

and piling brush is less frequent today than it once

was in chaparral modification, because they often

disturb the topsoil and mix an excessive amount of

soil with the piled brush. Bulldozers with specialized blades are usually more effective.

The straight blade is sometimes used for compacting and crushing mature brush for broadcast

burning, however, and could be more widely used

for this purpose. The straight blade is raised a foot

or two above the ground to knock the brush over or

break it off just above the ground. The tractor

tracks supply crushing action.

The Tomahawk crusher, which was designed for

breaking up roadbeds, improves the crushing action

of crawler tractors. It has been successful in coniferous forest precommercial thinning, and has been

tried in brushfields in preparation for burning.

The Tomahawk consists of a series of spirally

placed rings on an arbor 10 3/4 inches in outside

diameter (fig. 1). The rings are 24 inches in outside

diameter and are armed with protruding cutter and

crusher segments. The Tomahawk comes in widths

up to 9 feet, but the 6-foot model has been used

more than the others, perhaps because it is the size

needed to crush between tractor tracks. A hydraulic

frame allows mounting on a bulldozer blade, or behind a tractor. The Tomahawk effectively extends

the tractor tracks to the full width of the tractor.

Thus, it can increase the tractor crushing rate by

reducing the number of passes needed.

Tractor size required

The most commonly used tractor for crushing

with the bulldozer blade is the D-7 or D-8 (180-275

net hp at flywheel). The blade width varies from 12

to 14 feet. The wider blades are somewhat more

efficient in good terrain, but transportation may be

inconvenient because of load width limitations.

Capability

The tractor with bulldozer blade is effective in

crushing all vegetative types, except young flexible

brush, on side slopes up to approximately 30 to 35

percent. Effectiveness varies, of course, with the

rockiness of the site.

Small rocks do not interfere with the crushing

operations, but rocks more than a foot high are a

nuisance, can be dangerous, and decrease the

amount of effective crushing. Large scattered boulders and rock outcroppings require special attention

by the operator, but are not ordinarily troublesome.

The Tomahawk is most effective in mature, brittle brush. On the Groveland Ranger District of the

Stanislaus National Forest, where some thinning

slash was crushed, dry slash crushed much better

than green; much of the fines were broken up and

mulched into the soil, thus reducing fire hazard. In

Oregon's ponderosa pine type, Dell and Ward (3)

thought highly of the Tomahawk as a useful tool for

reducing fire spread potential and resistance to control in both green and dry thinning slash.
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Figure 1.—The Tomahawk compactor-crusher effectively extends the crushing action of tractor tracks to the full tractor width.

Production rates and costs

Based on data from the Mendocino National Forest, production rates and costs of crushing with the

bulldozer blade are estimated as follows:

Here the cost of a D-8 tractor and operator was $35

per hour; swamper was not included. The Mendocino experience agrees closely with rates and costs

previously published (7), when these are equated to

1973 costs by a 40-percent upward adjustment.

Percent

slope

0-30

0-30

0-30

Fuel type

12

13

14

Acres per hr

3.0

2.5

2.0

On-site costs,

dollars per acre

12

14

17

Although little information is available as to onsite costs and rates of production for the Tomahawk, these should be slightly better than for crushing with tractor only, because of the increased

crushing area.
Brush Rake

Many sizes and variations of brush rakes, root

rakes, and rock rakes are available {13). Most rakes

are commercially produced but some are homemade. Results reported with the various types are

generally similar, but rakes with the least amount of

blade surface appear to rake cleanest and are most

efficient (fig. 2).

The sizes of rakes used vary from 12 to 14 feet.

The wider rakes increase the production rate slightly, but transporting them may be difficult because of

load width limitations. The wide blades must be

hauled separately from the tractor.

Several types of brush rake attachments are

available for regular bulldozer blades. These attachments are not considered equal to the brush rakes

and rock rakes but have definite advantages over

the straight blade. The rake attachments are helpful

when a single tractor is used for roadwork, drainage, or grading in conjunction with the chaparral

modification. Once the operator finishes clearing

and stacking brush, he removes the attachment and

in a few minutes is ready to use the straight blade

(fig. 3).

Tractor size required

Brush rakes are generally mounted on tractors in

the D-7 or D-8 range (180-275 hp). San Diego County workers reported that in one instance a D6-C

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Figure 2.—Brush rakes with the least amount of blade surface pick up a minimum of soil with the brush.
Fleco Corporation

Figure 3.—Brush rake attachments are generally less effective than brush raises. They are useful, however, in projects where one tractor

must be used for several kinds of work.

equipped with brush rake was better than larger

equipment. It could be maneuvered under and

around large oak trees in county parks with less

damage to soil and vegetation than a D-8, particularly on steeper slopes.

Capability

The brush rake is highly effective in all fuel types,

except perhaps very light brush (light sage and very

light chamise), which tends to slip through the rake.

Welding a root grubber across the rake tips could

possibly overcome this problem (fig. 4). The rake is

superior to the bulldozer blade in that less topsoil is

scalped off and left in the piles. The actual amount

of soil in the piles varies greatly depending on the

skill of the operator.

With the brush rake, as with most other fuel modification equipment, there seems to be a strong

tendency for both the operator and the project foreman to do "too clean" or "too neat" a job. This may

be prompted at times by a desire to avoid follow-up

sprout control treatment, an objective generally not

achieved. In some brush rake projects, too little

debris was left on the soil surface and the jobs were

unnecessarily expensive. There was insufficient

organic material remaining for raindrop energy dissipation and for reduction of overland flow during

intense rainstorms. Much of the nutrients essential

for plant growth in arid situations are tied up in
San Diego County Department of Agriculture

Figure 4.—A root grubber welded across the tips of a brusli ralie uproots or cuts off small or flexible shrubs that would otherwise not be

removed.

small twigs, leaves, and herbaceous plants. Moving

all such material to piles for burning prevents recycling of these nutrients in place, and they are lost in

the atmosphere or in the soil erosion process. A less

productive site and cost escalation are products of

such misdirected zeal.

Small rocks do not appear to cause difficulty.

Larger rocks—those that do not pass through the

rake—slow production and are hard on equipment.

The brush rake can work around large boulders and

trees and can be more selective than some other

types of equipment, such as the modified chain.

Also, it is not difficult to leave an irregular edge, for

visual effect (fig. 5).

Because excessive amounts of soil are left in the

piles when soil is wet, raking should not be done

until soil is dry enough to fall freely as the brush is

moved along.

The maximum sidehill limitation is 30 to 35 percent for most brush rake operations. This limitation

varies with the amount of rock, the soil conditions,

and the prescription dictated by the environmental

analysis.

Production rates and costs

The production rates reported varied from project to project. Rates of production in the lighter

fuels ranged from 0.5 to 1.5 acres per hour, and in
Comments

Advantages and disadvantages of the tractor with

brush rake may be summarized as follows:

Figure 5.—Brush rakes can leave a clean seedbed and brush piles

relatively free of soil. The irregular edge of brushfield is good for

wildlife and for visual effect.

the heavier chaparral fuels from 0.2 to 1.0 acres per

hour, the accomplishment decreasing as the slope

increased (table 1).

On-site costs varied from $23 to $68 per acre in

the Hghter fuels and from $34 to $150 per acre in the

heaviest fuels, not including large oak trees (table

1). These cost figures do not include burning of

brush piles.

Advantages

1. Maneuverable around trees

and boulders, in drainages,

etc.

2. Effective for creating irregular edge effect—scalloping, feathering, etc.

3. Allows varying degrees of

cleanup according to esthetic effects desired.

4. Produces piles or windrows

for burning. Less manpower is needed than for broadcast burning. Piles may be

covered until burning conditions are favorable. Some

piles may also be left for

benefit of wildlife.

5. Leaves less soil in burn

piles or windrows than

straight bulldozer blade

does.

6. Economical to move between jobs, compared with

heavier equipment.

7. Usually leaves a good

seedbed.

8. Removes some roots and

root crowns, reducing

sprouting.

Disadvantages

1. Limited ¡n application by

slopes and soil conditions.

2. Can be relatively costly in

thick brush or in steep or

rocky terrain.

3. Can cause problems in

burning operations; excess

soil in piles makes mop-up

difficult.

4. May stir and loosen topsoil,

compact soil, or channel

runoff water, thereby increasing erosion potential

of heavy, long-lasting

storms.

5. Encourages too thorough

cleanup—not enough debris is left for energy dissipation of rainfall and runoff

and for adequate nutrient

recycling.

TABLE 1.—Estimated production rates and on-site costs¡ for brush rake clearing

on two National Forests, in various fuel types^

Percent

Types 7,8 Types 11, 12 Type 13 Type 14 Type 14, with oaks

Project Acres Dollars Acres Dollars Acres Dollars Acres Dollars Acres Dollars

slope per per per per per per per per per per

hour acre hour acre hour acre hour acre hour acre

Cleveland N.F.

Palomar R.D. 0-25 1.5 23 LO 34 1.0 34

25-35 1.0 34 1.0 34 1.0 34

35+ .5 68 .5 68 .5 68

Trabuco R.D. 0-25 1.3 27

San Bernardino N.F.

San Jacinto R.D. 0-25 0.6 50 .5 60 .4 75 0.3 100

25-35 .5 60 .4 75 .3 100 .2 150

35-1- .4 75 .3 100 .2 150 .1 300

SanGorgonioR.D. 25-35 .4 70

Average 0-25 1.4 25 .6 50 .8 47 .7 55 .3 100

25-35 1.0 34 .5 60 .6 60 .7 67 .2 150

35-1- .5 68 .4 75 .4 84 .4 109 .1 300

'Cost estimate covers tractor, operator, and swamper. To include mileage, planning, overhead, etc., add 40 to 50 percent.

^Fuel type designations are from USDA Forest Service, California Region, Fireline Handbook(i/).
Chains

Chains have been used in some phases of land

clearing for many years, but not until surplus Navy

anchor chain became available were chains used

much in California chaparral modification. Some 12

to 15 years ago, attempts were made to compact

and crush brush for burning by dragging anchor

chains across brushfields between two tractors.

Some good results were reported (4, 8). Recently,

chaining has been more widely used, both with two

tractors and using a metal ball with one tractor on

steep slopes.

Both smooth chains and chains modified by welding steel crossbars across the links are used. In general, users reported that the modified chain is more

effective in dragging brush out of the ground.

Anchor chain, usually available only through

Navy surplus outlets, comes in various weights and

in 90-foot lengths called "shots." If each shot of

chain is cut in half and a Navy master connector

link is inserted, the chain may be lengthened or

shortened by 45-foot increments. The flexibility

thus obtained has made chaining more effective on

some projects, because the chain length and weight

could be adjusted to fit terrain, obstacles, and tractor size. The chain was also easier to handle. In

general practice, various lengths of chain are used,

depending on availability and the requirements of

individual projects.

used to modify chains) and has the great added advantage of being available in long bar lengths of the

correct width and thickness. This eHminates much

expensive cutting necessary with moldboard and

other steel plate.

Ore car rail has sometimes been used for crossbars. This steel is much softer than the other types

used. Bars of this kind must be replaced or have

their worn ends rebuilt much sooner than bars of

harder steels. Ore car rail does not permit as strong

a weld as the harder steels; sometimes the bar is

broken off completely. The softer steel has a possible advantage mentioned by two project leaders: it

is less likely to produce sparks, and therefore decreases the chance for fire starts. No one has observed sparks to be troublesome with anchor chain,

but tractor grousers throw sparks that reportedly

have set fires.

The most frequently recommended crossbar

dimensions are 1 inch thick, 3 to 4 inches wide, and

up to 18 inches long, the length depending on the

size of the chain. There should be an overlap of

approximately 4 to 5 inches on both sides of the

links.

To hold crossbars, a small strip of strap iron

should be welded to one side of the web of each

chain link that takes a crossbar (fig. 7), thus bringing

the level up almost to the height of the outside of

Chain modification

Chain modification with steel crossbars was carried out by the Bureau of Land Management in 1966

(2). Their "Ely" chain, used in Nevada and New

Mexico, was the model for modified chains being

used in California.

Best results with the modified chain appear to be

gained when the bars are at 90° angles to each other

on the chain (fig. 6), as they are when welded on

every link or every third link. Bars are parallel if

welded on alternate links. When the bars are at 90°

angles with each other, they tend to "walk" and roll

along, crushing, chopping, digging, and sometimes

pulling out the brush. When they are parallel, they

tend to slide along and over the brush.

The Ely chain used railroad iron, which is soft

and wears away relatively fast, as crossbar material. A variety of harder steels have been used for

crossbars; the best appears to be a material called

Wear-alloy B. This steel wears as well or better

than moldboard steel (the other type commonly

Figure 6.—Crossbars welded onto every link of a chain increase its

effectiveness in crushing brush.
San Diego County Department of Agriculture

Figure 7.—Anchor chain nHxlification usually includes welding a

small bar to the link web, as shown here on the bottom link. This

provides a flat surface across the entire width of the link.

Crossbars are then "tacked" to the link, and a continuous weld

is run around the contact between crossbar and chain link.

the link. This allows the bar to be welded the entire

width of the link with an arc welder. Otherwise bars

may break off.

Contract specifications for the modified chain

from the Cleveland National Forest and San Diego

County Department of Agriculture are presented in

Appendix D.

It is possible that other types of modified chains

may be useful. On one project, steel triangles were

welded on the sides of the links (fig. 8). This proved

to be more effective than the smooth chain but not

as effective as the straight crossbars because the

triangles slid off the brush more readily.

Lead chain and swivels

From 20 to 25 feet of smooth lead chain and then

a swivel should be used between the tractor and the

modified chain. The smooth leafl £hain allows the

tractor to back up and turn around without running

over the swivel and modified chain. The swivel alFigure 8.—A chain modified with steel triangles welded to each

side of links was more effective than smooth chain, but less effective than chain modified with crossbars.

lows the chain to roll and chop, rather than slide

over the brush.

Many large swivels are available commercially.

Swivels are sometimes hard to acquire, however,

even though many equipment companies handle

them. Commercially manufactured swivels sometimes take 2 to 3 weeks to arrive, and their prices

vary from $300 to $1,000, depending on the type

and capacity. Because of these problems, swivels

made from D-9 track rollers and 1 1/2-inch steel

plate (fig. 9) appear to be used almost exclusively

Figure 9.—An anchor chain swivel can be made from a D-9 track

roller and 1 1/2-inch steel plate at a cost of approximately $350.

10
and serve the purpose well (2). The roller can be

drilled and tapped to take a Zerk grease fitting protected by a raised welded ring. This allows the swivel to be lubricated, preferably as often as the tractor

is lubricated. The cover plates should be left on the

rollers to help keep out dust and dirt.

The swivel can be attached to the modified chain

with Navy master connector links, with a 2-inchdiameter pin connecting it to the smooth lead chain.

For safety, all swivel pins and clevis pins should be

threaded and/or fastened in place with a heavy-duty

cotter key or heavy bolt and nut with a cotter key.

All pins and cotter keys should be checked every

morning and evening and at least twice during a

day's operation.

To avoid the danger of pins working out, one project manager had the pins tacked in a few places

with spot welds in addition to the cotter keys. This

appears to be a good safety precaution but frequent

daily inspection is still needed.

On one project, a swivel hook was used to connect the chain to the cable. The swivel hook did not

have a safety snap to prevent the chain from slipping off the hook if the chain became slack.

Although no difficulties were encountered on this

project, any open hook should have a safety snap

installed as a safety feature.

Modified Chain Between Two Tractors

In general, the chains used between two tractors

are modified. They are made from heavy anchor

chain (destroyer or cruiser type), ranging from 40 to

90 pounds per linear foot. The length of chains m

current use varies from 90 to 270 feet (1 to 3 shots),

depending on size of tractor used, terrain, and

number of large trees and boulders. The 180-foot

chain has been found generally useful in mountainous terrain. The effective swath width averages

about half the length of the chain.

The heavier chains, from 60 to 90 pounds per

foot, not including the weight of the crossbars, appear to be the most effective; however, smaller

chains have been used with generally satisfactory

results. Ease in handling is an advantage of the

lighter chains; they can be loaded onto a truck by

one or two men, and smaller trucks can be used.

When the chain is used with two tractors, a swivel at each end allows the chain to turn and "walk"

over rocks, and it effectively crushes and uproots

brush. On a few projects, a third swivel was installed in the center of the chain, and this allowed

each half to turn independently. This did not increase the effectivenesss appreciably, but did keep

the chain from occasionally becoming twisted.

The smooth lead chain may be connected to the

tractor at the drawbar on the rear of the tractor, or

at the cable winch. The cable winch connection

appears to have an advantage.-In heavy fuels or in

steep terrain where the tractors may bog down,

operators found they could winch out 50 to 100 feet,

stop the tractor, and winch the chain up to them.

Wherever the tractors had difficulty getting traction, this proved very effective. Another advantage

of the cable winch connection is greater safety.

Sometimes, in extremely high brush or in rough terrain, operators lose sight of each other. If one tractor is hung up, the other operator may not know it

and may keep pulling, thus twisting or tipping over

the stalled tractor. With the chain hooked to the cable, the operator of the stalled tractor can let out

cable until he or the swamper gets the other operator's attention.

Techniques. Since the modified chain is not very

maneuverable, it is sometimes hard to pioneer the

perimeter of the area to be cleared. With good terrain, flagging the route may be all that is needed, but

on several projects, a tractor with brush rake (usually one of the tractors used to pull the chain)

pioneered the perimeter for the chain. This appears

to be a helpful step, especially in tall brush on difficult terrain. This method is also helpful in defining

the buffer strips along stream bottoms.

Most project leaders reporting believe that pulling the chain in a broad '7" configuration, with a

swath width equal to about half the length of chain,

results in most effective uprooting, brush breakage,

and crushing. Numerous pattern variations are

used, however, depending on tractor size, terrain,

and other conditions. With the "J" configuration,

and a swivel near each end of the chain, there was a

slow turning of the modified chain that seemed to

work bars into tlTe ground and uproot a maximum of

brush plants. In San Diego County, an estimated

three-fourths of the root burls of mature brush were

uprooted from loose sandy soil.

There have been instances in summer, on hard

ground, where the bars did not penetrate and did

11
not uproot brush. A heavy smooth chain might have

accompHshed as much as the modified chain under

these conditions.

Communications techniques. Good communications are essential for most operations where heavy

equipment is being used. With one tractor, visible

hand signals generally suffice. When two tractors

are working as a team with one swamper, however,

hand signals are not adequate. Radio communications are strongly recommended for the modified

chain, for both the operators and the swamper. It is

easy for the tractors to move into areas where they

should not be, especially in tall, heavy cover. If the

swamper has radio communication, he can oversee

and control the operation from vantage points. Radio communications are also essential when an operator gets his tractor in trouble.

On one project, small citizen band radios were

used to good advantage. The radios were mounted

on the tractors and the operators were provided

with headphones. This allowed the swamper and

both operators to be in constant contact even

though they could not see each other. Occasional

difficulties arose; antennas sometimes broke off and

some operators refused to wear the headphones.

There were also complaints about poor quality and

high frequency of repair of citizen band radios. To

remedy this, antennas could be made of more flexible material or spring mountings could be used;

Forest Service net radios could be substituted for

citizen band radios; and perhaps the contract could

specify that the operators wear radio headphones.

Recent improvements such as the bone-conducting

microphone, and small earphones, both of which

can be worn under the hard hat, have made this

equipment more comfortable to wear.

Another communications technique used on a

few projects was attaching dune buggy whips, with

high visibility flags, to the top of the tractor canopies. This allowed each operator and the swamper

to keep sight of the tractors in higher vegetation and

in broken terrain. This inexpensive technique is

recommended for all modified chain operations.

Tractor size required

On most projects using the modified chain, tractors in the D8-46A category (270 net hp at flywheel)

were employed. A few smaller tractors, in the 200

to 230 category, were tried, but most users recommended the 270 range. For good traction, a minimum grouser height of 2 inches is recommended.

The tractors should be of about equal horsepower

so they can switch positions as they make the return

swath. They merely turn around in place and the tail

'tractor becomes lead tractor. On one project, a

small tractor was used for the tail of the chain because the tail requires less pull. This arrangement

proved awkward and inefficient because both tractors had to reposition themselves on the slope to

make the return swath.

Capability

Number of passes. Most project leaders suggest

that two passes with the chain, one in either direction, are needed to prepare brush for burning (figs.

10,11). We have seen two incidents, however, that

suggest one may be enough. On a prescribed burn

on the Palomar District, Cleveland National Forest,

in mature chaparral, fire burned to the ridgetop a

strip that had been crushed with one pass of the

anchor chain. Brush could not be ignited on either

side of the treated strip. Again, on the Los Padres

National Forest, 16-year-old brush that had been

compacted with one pass of a chain near the ridgetop burned, whereas fire could not be induced to

run through the untreated brush below.

During chaining operations there is a tendency,

particularly during the second pass, for a windrow

of brush to build up near the bottom of the loop.

The chain eventually rolls over it and starts to accumulate again. These windrows are easily burned, as

are also the smaller scattered piles.

Vegetative types. The modified chain is highly

effective in all mature chaparral types, except perhaps scrub oak. Young flexible brush may not be

uprooted nor compacted.

Large trees, scattered or in groves, create difficulty. If some trees are to be preserved, narrower

swaths and extra maneuvering are needed, and rate

of production is reduced considerably. Islands for

landscaping and wildlife purposes must be allowed

for in the same way. Maneuvering for such reasons

is easier if the "J" configuration is used rather than

abroad''U".

Slope. The modified chain is highly effective in

uniform slopes up to 30-35 percent. Where the

winch has been used to pull the chain, slopes up to

45 percent have been chained successfully. The

more rugged and broken the terrain, the less effective the chain.

Rocks. In most situations, rocks are only a slight

hindrance to the modified chain. Smaller rocks are

moved easily and the chain tends to walk or roll itself over them. Large boulders with perpendicular

sides will catch the chain, requiring that one of the

tractors back up and go around. This reduces pro12
Figure 10.—When two tractors pull an anchor chain through heavy chaparral, one such pass will usually compact and desiccate brush

enough for later burning.

auction considerably. Most users were impressed,

however, with the good performance of the modified chain in rocky country.

Roads. The modified chain can damage road

berms, fills, and overside drain structures when

roads are crossed by the chain. When roadcuts are

not too high, it is possible to work above some

roads by walking one tractor (usually the lead tractor) along the road. This technique was used quite

successfully on slopes that were otherwise too

steep (fig. 12).

Workers in San Diego County described how

they crossed highways without dismantling their

modified chain hookup. The two tractors approached the road with the modified chain stretched

tightly between them in a shallow U-shape, as nearly a straight line as possible. Flagmen were stationed to stop traffic, and automobile tires were laid

to keep tractor tracks off the road surface. The tractors were then driven across, keeping tension on the

chain. The chain rolled on its swivels, "walking"

across with little marking of the macadam. If the

chain were allowed to assume a deeper "U" or "J"

shape, it would cut up the roadbed. The smooth

chain was taken across roads in a similar manner.

Production rates and costs

The rate of production generally varied from 1.5

to 6 acres per hour for two passes, one in each

direction, in the lighter fuels, and from 1 to 5 acres

13
Figure 11.—During the second pass of an anchor chain, the loosened brush tends to build up ahead of the chain until it is finally dumped as

a rough windrow which can be readily burned.

per hour in the heavier fuels (table 2). In southeastern San Diego County, with gentle terrain, light

fuel, and skilled operators, as much as 10 acres

were double-chained per hour. A less capable contractor did considerably less. The average for about

2,000 acres was 6.5 acres per hour.

Costs varied from $15 to $50 per acre in the lighter fuels and from $20 to $75 per acre in the heavier

fuels for two passes (table 2), except in eastern San

Diego County, where direct costs averaged $12.67.

Comments

Safety. On the steeper slopes, the lead tractor

should be on the downhill side. This puts him out

ahead of rolling rocks knocked loose by the chain

and tail tractor.

The swampers should be behind or above the

tractors and chain and should not ride the tractors

unless a seat is provided.

Use of contractor. Contracts should be written so

that both tractors are provided by the same contractor. On one project, two separate contractors were

used on the same chain, but this can cause difficulty. One contractor may think the other is not doing

his share, and if one breaks down, the other one, of

course, still wants to work. If he is unable to work,

he may put in a claim against the agency or the other contractor. A clause has been used successfully

14
Figure 12.—Some steep slopes between road and ridgetop can be worked with the modified chain. The lower tractor, on the road, should be

leading to be clear of rolling material knocked toose by chain.

TABLE 2,—Estimated production rates and on-site costs^ for crushing brush with

two passes of the modifíed chain between tractors, as used on two National Forests in various fuel types2

Type 14 with

Tractor and

net horse- Percent

Types 7,8 Types 11,12 Type 13 Type 14 large oaks

Project Acres Dollars Acres Dollars Acres Dollars Acres Dollars Acres Dollars

power at

flywheel

slope per

hour

per

acre

per

hour

per

acre

per

hour

per

acre

per

hour

per

acre

per

hour

per

acre

aeveland N.F.

Descanso R.D. Two D-8

235 hp

0-25

25-35

35+

2.5

2.0

1.5

30

38

50

2.0

1.5

1.0

38

50

75

2.0

1.5

1.0

38

50

75

1.5

1.0

.5

50

75

150

Palomar R.D. One AC 21-P

268 hp, with

0-25

25-35

6.0

5.0

15

20

5.0

4.0

20

25

5.0

4.0

20

25

one TD 30

285-300 hp

35+

2.0 35 2.0 35 2.0 35

San Bernardino N.F.

San Jacinto R.D. Two Terex

82-30

230 hp

0-25

25-35

35+

2.3

2.0

1.8

24

28

30

2.0

1.8

1.5

28

30

37

1.8

1.5

1.3

30

37

42

1.2

1.0

.8

44

55

84

Average 0-25

25-35

35+

4.3

3.5

1.8

23

29

43

2.3

2.0

1.8

24

28

30

3.0

2.4

1.5

29

35

49

2.9

2.3

1.4

29

37

51

1.4

1.0

.7

47

65

117

iCosts include two large tractors, two operators, and a swamper. Mileage, cost of anchor chain, overhead, planning, etc., are not included; to estimate total project cost, add 40 to 50 percent.

2Fuel type designations are from USDA Forest Service, California Region, Fireline Handbook (11).

15
in some contracts that allows the agencies to shut

down the other tractor until a damaged tractor is

repaired.

Advantages and disadvantages

Advantages Disadvantages

Low in cost per acre compared to alternatives.

High in production rate, on

suitable terrain, compared

to alternatives.

Restricted in maneuverability, hence not very selective.

Advantages

3. Creates minimum soil disturbance.

4. Leaves enough debris on

surface to help reduce erosion potential.

5. Facilitates burning; treated

brush burns when surrounding brushfields do not

burn readily.

Disadvantages

2. Limited in application by

slope, irregular terrain, and

brush age and type.

3. Requires special communications techniques in heavy

fuel and broken terrain.

4. Removes few roots and

shrub crowns, so thai

sprouting occurs and herbicides are usually needed.

Ball and Chain

Mechanical brush treatment with anchor chains

between two tractors, or with a bulldozer or brush

rake, is not usually feasible on steep side slopes.

The "ball and chain" technique of crushing brush

was developed to fill this gap.

The equipment usually used for a ball-and-chain

operation is a light-to-heavy anchor chain and a steel

marine net float (buoy), 5 feet in diameter. The

buoys, like the chains, are available through Navy

surplus outlets. The anchor chains are frequently

modified as described earlier. Sometimes, to keep

the chain light enough for the ball to pull it downslope adequately, a reduced number of crossbars

are used.

The working chain usually forms an arc, caused

by the drag of the chain on the ground, brush, and

rock. The width of swath then becomes one-third to

two-thirds the chain length, depending on such

conditions as size of brush, steepness of slope, and

weight of chain in relation to weight of ball.

Various lengths of chain have been used, from 50

to 200 feet. The California Division of Forestry

suggested 120 to 150 feet as a result of their tests (1,

6), and these lengths are typical of chains used on

recent projects reported.

Chains used weigh from approximately 10 to 80

pounds per foot. Weight should be proportional to

weight of ball and length of chain. On some projects, the weight of the chain was so great the ball

would not drop down the slope far enough to work

effectively, particularly on the more gentle slopes.

Long chains should therefore be of fairly low

weight per foot; short chains maV be heavier.

A simple chart may help in determining the size

and length of chain to be used with a 5-foot buoy

filled with water:

Length of chain, ft

60- 90

90-130

130-180

Recommended weight of

chain, lb/ft

50-60

35-50

20-35

Weights do not include the crossbars added to modify chains.

On two projects, a steel cable (7/8 to 1 1/8 inch)

was tried instead of an anchor chain to drag the ball.

This was not entirely successful; the cable was easily damaged and weakened, and the cable did not

crush and uproot brush as well as the modified

chain.

Ball. The buoy or ball is constructed of high-tensile-strength 3/16-inch steel plate and is 58 inches in

diameter. On several projects the buoys tended to

leak water after some use. To prevent leaking, a

second buoy was cut up and welded over the first as

an armor plating. Even so, at least one armor-plated

buoy started leaking after a considerable amount of

use. It is essential to check the buoys for leaks before use and before armor plating.

The empty buoys weigh about 600 pounds each.

Armor plated and filled with water, they weigh

about 5,000 pounds each. When filled with fine

gravel, and then with water, they weigh about 6,700

pounds. Some balls have been filled with gravel or

sand alone, and a few have been filled with concrete. A buoy filled with gravel, sand, or both, is

more difficult to fill and to empty for transporting,

but leakage is avoided. When filled with concrete,

the buoys weigh approximately 9,000 to 10,000

pounds, depending on the density, but of course

16
they cannot be emptied for transportation. San Diego County Department of Agriculture plans to fill a

buoy with concrete, using a 6-sack, 1-inch-mesh,

Class A mix, vibrated into heavy density with a 2-

inch vibrator. They expect the ball to weigh approximately 10,000 pounds. This weight will overcome

the drag of the heavier chain, but transportation will

be difficult.

A water-filled buoy must be completely filled to

prevent severe denting, which increases the chance

of leaks (fig. 13). Because water will not compress,

filling the ball to capacity helps prolong its life.

Hitches. A number of hitching techniques for the,

ball and chain have been reported. Their effectiveness varies, depending on the viewpoint of individual land managers. Some users attach the chain directly to the rear drawbar on the tractor, whereas

some prefer to attach it to the cable winch. On one

project, a hitch was welded on the ripper bar; on

another, hitches were welded on both sides of the

tractor.

If the chain is attached to the rear drawbar, the

center of gravity is kept low and the operator has

good control. When the tractor is working from a

road, however, the low chain can do considerable

damage to berms, fills, revegetation on fills, and

overside drains and aprons. With this hookup, the

ball can be moved up and down the slope only by

moving the tractor. The tractor can change directions without unhooking, however.

With the side hitches, the center of gravity is also

low, and the likelihood of damage to roads is thus

Figure 13.—Denting of this buoy, or ball, would have been much

less severe had it been completely ñlied with water.

present. Again, the tractor must move up and down

slope to move the ball. It is also necessary to hook

and unhook the chain when changing direction.

Attaching the chain to the cable winch allows the

operator to extend the ball and chain various distances by letting out cable. Once some cable is out,

the operator can adjust the ball up or down simply

by using the winch. When the tractor is working

from a road, the cable and chain are above the berm

and also above some of the overside drains. This

attachment raises the center of gravity, but most

operators who have used the method do not consider this a serious difficulty. Attaching the ball and

chain directly to the cable results in considerable

wear on the sides of the winch drum case, because

the weight of the ball and chain pulls the cable off

the drum sideways. A possible remedy is to build a

heavy roller guide on the sides of the drum, but

again, operators do not consider the wear a serious

difficulty. This method allows the tractor to change

directions without unhooking, a definite advantage.

When using a hitch welded on the hydraulic ripper crossbar, the operator can raise and lower the

center of gravity at will. When working from a

road, he can prevent some damage to berms and

fills by bringing the ripper bar up. He can also

change the tractor direction without unhooking.

With the hitch on the ripper bar, however, a winch

cannot be used, and most users consider this a serious disadvantage.

Regardless of the method of hookup used, there

is a definite need for a cable winch. Users reported

that the ball or chain frequently caught on obstacles, and the winch proved helpful in getting it free.

Swivels. A single swivel at the end of the 20 to 25

feet of lead chain appears to be the most effective

swivel arrangement. Then as the ball moves across

the slope, it turns, and turns the chain also, causing

the chain to roll and chop, removing and breaking

more brush. When a second swivel was tried at the

ball, the ball rolled but the chain slid along with less

effectiveness.

Transportation problems. The bulkiness and extreme weight of the ball and chain pose special handling problems. Ideal equipment is a large flatbed

truck with a hoist or A-frame. This allows one man

to load, drive to the job site, and unload.

Frequently the ball was chained to a tractor blade

and then Tifted onto the truckbed (fig. 14).

Unloading is not usually difficult when a tractor is

on the site. The material used to fill the ball significantly affects ease of loading, unloading, and transportation. For short hauls, it is possible to drag the

17
F-522979

Figure 14.—A ball may be chained to a tractor blade for lifting to a

truck and transport to the next nearby work location. This ball

has been armor plated.

ball and chain behind the tractor or to pick the ball

up with the tractor blade and "walk" it along.

Dragging usually causes damage to the road or ridgetop, and ball and chain tracks must be repaired to

control erosion. On one project, the chain alone

was dragged behind a tractor. It sawed 2 to 3 feet

into the ground, leaving a straight-walled gully.

Cutting each shot of chain into 45-foot sections, as

described earlier, was found helpful on some projects.

Tractor size required

A variety of tractors were used for the ball and

chain operations; the majority were in the D-8 category (270 net hp at flywheel). On one project, a

D7-E (180 net hp) was tried. After some time, the

operator and project leader agreed that it was too

small, and a D8-46A was substituted. On another

project, a D6-C (125 net hp) was used on several

ball and chain operations, and its operators judged

it to be adequate. They were using approximately

120 feet of chain weighing 20 to 30 pounds per foot.

This tractor was the only one of its size we found

being used with the ball and chain.

Observations from most field projects using the

ball and chain indicate that a tractor in the D7-E

category is the minimum size recommended, and

one in the D-8 category would be the optimum size.

For this use, most people agree that tractor weight

is probably more important than horsepower, and

that tractor weight must be in proportion to weight

of ball and chain.

Capability

Vegetative types. If the chaparral modification

objective is uprooting and mulching, the ball and

chain is effective only in brush that is light (types 2,

7, and 8) or desiccated. Even in light brush, followup burning is usually considered necessary to reduce fuel concentrations to a safe level. In the medium-to-heavy fuels (types 11, 12, 13, and 14), the

ball and chain appears highly effective as a crushing

technique to prepare brush for burning.

Opinion varied widely as to the necessary number of passes and the desirable amount of flattening

and breaking up of the brush. On some projects, six

to eight passes were made in light fuels with the aim

of eliminating the need for burning, but some users

thought that burning the residue was still necessary

(fig. 15). Elsewhere, three or four passes were being

made and follow-up burning was planned. Where

two passes, in opposite directions, were used, the

crushing proved adequate for compacting and

drying fuels for future burning (fig. 16). Appraisal

was not always favorable at the time work was

completed, but results appeared better after some

weeks had passed.

One pass with a smooth or modified chain, between a tractor and ball or between two tractors, is

apparently adequate to prepare mature brush for

safe burning. The experience of the Palomar District, Cleveland National Forest and the Los Padres

National Forest, described earlier, support this belief. Additional passes increase the costs per acre

and do not appear to improve the burning conditions significantly.

The ball and chain appears to be much more effective when the green fuel moisture is lowest (usually summer and fall). The partially dry brush

breaks up more readily than when moisture content

is high, and treatment results in a higher percentage

of dead and dry fuels for burning. Where the brush

had been treated with herbicide, and brush was desiccated, the ball and chain did an excellent crushing job.

Although this method appears to be most effective during the summer and fall, it was also found

useful when soil moisture was high. On several projects the ball and chain were used during late winter

and early spring and appeared at first to have failed

completely. The brush appeared to spring back

almost unharmed after two or three passes. A few

weeks later, it was evident that much of the brush

was considerably drier than adjacent untreated

brush, and that burning was feasible.

18
Figure IS.—Several passes of the ball and chain may be required to crush brush to the extent shown here. Note the track created by the ball

in this sandy granitic soil. Hand work is usually required to repair the surface and prevent erosion.

When soil was moist, but not too wet for efficient

tractor operation, many plants were uprooted.

Frequently, however, not all roots of a plant were

pulled out of the ground or broken off, and such

plants lived.

Slope. The optimum topographic condition for a

ball and chain operation is a long straight ridge with

side slopes greater than 30 percent (fig. 17).

Production tends to increase as the side slope gradient increases, because the weight of the ball is

then more effective.

Ridges perpendicular to the ridge being worked

are undesirable. Frequent finger ridges, rocky

points, draws, and small drainages cause the ball to

trail up the slope behind the tractor. The chain does

not adequately crush brush on the lateral ridge and

the operator may have to push the ball back down

the slope before he can proceed (fig. 18).

On a few occasions, the ball and chain was used

on flat-to-gentle slopes (0-30 percent) as described

by Gilbert and Schmidt (6). The ball was used as an

anchor and the tractor was driven around the ball in

a circular fashion. Gilbert and Schmidt (6) reported

crushing of 8 to 12 acres per hour, but in our study,

users reported that results were generally unsatisfactory, and that the disk or modified chain between

two tractors should be used on gentle slopes. Best

results in these trials were obtained in old, chamise

19
F-522981

Figure 16.—After the second pass of ball and chain, chamise chaparral may be adequately prepared for burning.

Figure 17.—The optimum terrain for a ball and chain operation is a long, straight ridge with steep uniform side slopes.

20
PLAN VIEW

Figure 18.—Terrain with frequent small ridges, draws, etc., is

undesirable for ball and chain.

chaparral. Heavy brush with tough species did not

crush well.

Edging. The ball and chain in use tends to swing

in pendulum fashion, then "snakes" upslope because of brush drag or terrain, and then swings

loose again. A desirable irregular or scalloped edge

on the crushed strip is thus created.

Rocks and trees. Large boulders and large trees

are troublesome. Because the ball hangs up on such

obstacles, it must be pulled up the slope until it is

clear; then the tractor must move forward and let

the ball roll on down the slope again. Where rocks

and trees are numerous, a winch is very helpful.

Roads. Care must be taken when working from

roads or working across them, and whenever possible, they should be avoided. The chain will damage

berms, overside drains, and roadMs. Dn a few projects, fills on which vegetation had become established only after a long period of time were

stripped. This made the slopes again vulnerable to

erosion, and repeated control work was necessary.

When it is necessary to work from a road, it is advisable to remove drainage structures such as overside drains and downspouts. On one project, it was

necessary for a small tractor to follow along behind

the ball and chain to reconstruct the road and

berms, and to restore drainage.

Production rates and costs

The production rates for the ball and chain on

fuel-break sites varied from 1 to 2 acres per hour in

the lighter fuels, and from 0.5 to 1.5 acres per hour

in the heavier fuels. This was for two or more passes (table 3). Production was greatest on slopes averaging 50 percent or more, and least on gently sloping ridges.

The on-the-ground costs of operating the ball and

chain varied from $22 per acre for three or four passes under good working conditions to $50 per acre

in the lighter fuels, and from $40 to $70 per acre in

the heavier fuels (table 3).

Comments

Soil disturbance. In general, the ball and chain

cause less disturbance to the soil than other methods. An important exception is disturbance near the

tractor where the chain digs relatively deep, especially on road berms, and on other small knobs and

outcroppings. Also, ball tracks are created where

the ball is pushed over the side and where the ball

slides back up the ridge either by intent or accidentally.

This disturbance usually requires erosion control

work. To repair the ball tracks, hand crews are

usually needed to construct water bars and to plant

or seed.

Special hazards. Several balls have been lost

(down canyon) over the past few years. The clevis

pin worked out or became unscrewed, or the swivel

broke, or the clevis spread apart. Breaking of the

chain or cable was not reported.

One project supervisor reported heavy wear on

the pin to which the swivel was directly hooked. To

remedy this, a heat-treated bushing was used

around the pin.

Because there is a potential loose ball hazard, ball

and chain operations above heavily used roads,

trails, campgrounds, and residential areas are not

recommended.

There is a hazard to the swamper or observer if

he gets below the ball or chain, especially when the

ball has become hung up in trees or rocks. It is not

unusual for the ball to be pulled free very suddenly

under pressure from a winch or other device, dislodging large rocks and trees as it does so.

There may also be a whipping action in a slack

chain as the tractor moves forward suddenly (fig.

19). This has resulted in a few "close calls," and

those nearly injured report that the chain can move

much faster than a man.

21
TABLE 3.—Estimated production rates and on-site costsi of crushing brush with

two or more passes^ of the ball and chain as used on three National Forests in various fuel types^

Percent

slope

Ball and

chain

passes

Types 7,8 Type 12 Type 13 Type 14

Project Acres

per

Dollars

per

Acres

per

Dollars

per

Acres

per

Dollars

per

Acres Dollars

per per

hour acre hour acre hour acre hour acre

Angeles N.F.

Mt. BaldyR.D. 20-30 7-8 1.0 50 0.8 70

30-50 7-8 1.3 45 LO 65

50+ 7-8 1.5 40 1.3 60

Saugus R. D. 30-50

50+

4-6

4-6

2.0

2.0

34

34

Cleveland N.F.

Palomar R.D. 30-50

50+

2

2

1.5

1.5

51

51

Trabuco R.D. 30-50

50+

3-4

3-4

1.2

1.6

30

22

Los Padres N.F.

Santa Barbara R.D. 30-50 2-4 .8 40 0.6 50 .50 60 0.50 60

50+

20-30

2-4 1.0

1.0

30 .8 38 .80 40 .75 40

Average 50 .80 70

30-50 1.3 37 .6 50 1.0 59 .50 60

50+ 1.5 32 .8 38 1.17 50 .75 40

iCosts include tractor, operator, and swamper. For total project costs, including mileage, overhead, planning, etc., add 40 to 50 percent.

2Rates and costs cover total number of passes.

^Fuel type designations are from USDA Forest Service, California Region, Fireline Handbook (11).

When the ball and chain are attached to a winch

line, the cable sometimes becomes twisted, building

up torque in the line, even when there is a swivel.

When the tractor moves the chain, sometimes just

slightly, the cable suddenly untwists and can injure

anyone standing close. This does not happen often,

as the swivels usually prevent it.

Tractor ^^^

l^Vl\1>Tv^"

Person

Figure 19.—A potential whiplash situation is diagrammed here. As

the tractor moves forward suddenly, it snaps the slack chain in

the direction of the arrows—sometimes very sharply.

Advantages and disadvantages.

Advantages Disadvantages

2.

Allows work on steeper

slopes, eliminating or reducing the need for more

expensive hand labor.

Effective in creating irregular edge effect—scalloping,

etc.

3. Allows varying degrees of

cleanup, depending on

number of passes.

Creates minimum soil disturbance, except near the

tractor.

5. Facilitates burning; treated

brush burns when surrounding brushfields do not

burn readily.

4.

1. Not very maneuverable,

especially among trees and

boulders; leaving specimen

trees or clumps is not easy.

2. Creates large ball tracks,

usually requiring erosion

control by hand labor.

3. Removes few roots and

root crowns so that sprouting occurs, and herbicides

are usually needed.

4. May damage road berms

and fills, and small hills and

knobs.

5. Difficult to handle in loading and unloading.

6. Liable to lose the ball,

which would be hazardous,

particularly near residential

areas.

22
Chopping and Shredding Equipment

Where prescribed burning is not planned, equipment is needed to chop or shred the brush, reducing

it to a mulch that can be at least partially incorporated into the soil. The brushland disk is widely used;

the roller chopper is valuable in gentle terrain, and

the Tritter shredder has also been tried. These are

discussed below.

Other types of equipment to chop or shred brush

have been tested by the Equipment Development

Center and by manufacturers in cooperation with

agencies in the field. Results have usually not been

encouraging in the rough, rocky, often steep terrain

where chaparral modification in California is generally attempted. Among the equipment tested is the

Tree Eater, which shreds woody material by beating it with flails or hammers mounted on a drum. It

was found to be high in initial cost, and maintenance was excessive during tests (12); consequently

it has not become part of California chaparral modification. The Trakmac TM-72 is a 4-tracked articulated platform supporting equipment which drives

a cutter at the end of a boom. It has been tested by

the Forest Service Pacific Northwest Region. Costs

were about $45 to cut about 300 stems per acre in a

thinning operation, and $70 per acre to thin and

treat the thinning slash (14). Large rotary mowers

have been tested, but breakage was excessive in

heavy chaparral. It appears that for the near future,

equipment already in use will do most of the chaparral modification work in California.

Brushland Disks

A large variety of weights and sizes of offset harrows and disk tillers, commonly referred to as

brushland disks, are available from manufacturers

such as Rome and Towner. The disks most commonly used have two gangs of blades that can be

opened to offset each other, thus causing a chopping and cutting action as the disk passes over the

brush. This angle of opening can be adjusted by

cable, hydraulic, or mechanical control. With the

hydraulic and cable controls, the disks can be

opened and closed while in operation. To adjust the

mechanically operated disks, it is necessary to stop

the tractor, remove some bolts, move the tractor

forward or backward, and then replace the bolts.

Some disks are available with wheels and rubber

tires that can be raised out of the way during operation and then can be dropped (either manually or

hydraulically) when the disk is to be towed behind a

truck to the next project. (Multiple-ply, punctureproof tires should be specified if disks with wheels

are ordered.)

Almost everyone interviewed was favorably impressed with the overall effectiveness of the large

brushland disks in uprooting, cutting up, and

mulching brush, even in the heavier fuels. Users

were especially pleased by the number of roots and

root burls brought to the surface. Nearly all felt this

would reduce maintenance costs considerably by

reducing the number of sprouts. Additional observation is needed to establish the range of sprout

control, but results were particularly good on chamise chaparral.

The disk does not remove the topsoil, but does

stir and loosen it to a depth of 8 to 16 inches, depending on the disk weight and the size of blades.

This loosening may increase the infiltration and

percolation rate of the soil temporarily, but may

also leave it vulnerable to rain and runoff during

storms of high intensity or long duration. Personnel

on several projects maintained that rainfall on freshly disked land resulted in little erosion. Such estimates are relative, however. Possibly, the surface

had been hard and crusted, with little vegetative

cover, or had been made water repellent by hydrophobic substances from shrubby plants, the effect

sometimes being intensified by earlier burns.

Disking could improve both conditions.

Disks in use today weigh from 6,000 to 12,000

pounds and may be 8 to 12 feet wide. Blades vary

from 28 to 38 inches in diameter. The most commonly used disks at present are the 9-foot 6-inch

Towner (Model 801-144) and the 12-foot 2-inch

Towner (Model 801-184), both with 36-inch blades

(fig. 20). ^

The California Division of Forestry reported

good results in using disks 8 to 9 feet wide and

weighing only 5,100 to 5,300 pounds, with 28- to 32-

inch blades, near San Luis Obispo, California.

One pass of the disk prepared heavy brush for

broadcast burning; a second pass produced a

23
Figure 20.—This 9-foot 6-incli Towner disic witli 36-incli blades is tlie most popular size brush disk presently used on southern California

wildlands.

seedbed suitable for drilling with the rangeland

drill, without burning(5).

On one project, two disks of similar weight were

used-one with 36-inch blades and the other 32-

inch blades. The project supervisor and the operators could find little difference in the results. These

disks were used in both light and heavy fuels. Other

users felt the larger blades brought more roots and

root burls to the surface, so that there was lower

sprouting potential. Some users reporting felt the

weight of the disk was more important than the size

of the blades in achieving the desired results.

Control mechanisms

The hydraulic control mechanism appears to be

much superior to both the cable and mechanical

method. Many project supervisors and tractor operators were emphatic on this point. With the hydraulic control, the operator can adjust the cutting angle

of the disk (open and close the gangs) while the

tractor is working and while it is stopped. Many

operators found that if the angle of cut was adjusted

slightly, the disk would cut better under different

conditions of soil and brush species and size. Also,

when the tractors became stuck (wedged in or high

centered), as they occasionally did, with the hydraulic control the operator could close the disk,

and maneuver to free the tractor. With a cable or

mechanical control, this would be impossible, as

the tractor must be moving forward or backward

for the disk to be opened or closed.

Operators also reported that sometimes, especially in heavy fuels, the brush "balled up" under the

disk, even lifting it completely off the ground.

When the gangs were opened and closed, the disk

usually cleared itself and started cutting again.

24
Tractor size required

Opinion varies on optimum tractor size or horsepower rating for pulling each disk. Most users interviewed believe that for chaparral type conversion,

the disk manufacturers' recommended horsepower

ratings are low, by perhaps 15 percent.

The following horsepower ratings (fig. 21) were

recommended for the various disk sizes:

Weight of disk (lb)

8,000-9,000

9,000-10,000

10.000-11.000

Net horsepower at flywheel

i ___^__

125-145

150-180

185-270

Rough terrain and tough heavy brush require more

horsepower than light brush on gentle terrain.

Therefore, under such adverse conditions, equipment at the upper horsepower range should be chosen. (For comparative tractor specifications, see

Appendix A.)

Capability

The brushland disks have proved effective in all

chaparral fuel types. Effectiveness depends on the

weight of the disk and the number of passes, as well

as on the density and composition of the brush

stand.

Figure 21.—This 12-foot, 10,500-pound disk requires a tractor of 185 to 270 net flywheel horsepower such as this HD-21. The disl( has

made two passes.

25
Brush should be disked on the contour and not

parallel with the slope. Parallel disking can result in

severe erosion. Efficient contour disking is limited

to approximately 30 to 35 percent side slopes, and

some environmental analysis statements have limited work to lesser gradients.

A few scattered rocks do not greatly affect the

disk operation. Large numbers of scattered rocks

will prevent the disk from penetrating and thus decrease the amount of cutting and mixing with the

soil.

The disk can be worked around scattered large

boulders or trees. In areas where the large boulders

and outcroppings of trees are close together, it is

impossible, of course, to use the disk. In general,

the disk is considered highly selective and maneuverable.

In its open, working position, the disk should

only be turned to the left, because of the angle of

the gangs when open. If the disk is turned to the

right while working, there is increased strain on the

tongue and drawbar and other parts. Several drawbars and tongues have been bent and broken as a

result of turning in the wrong direction.

The disk can be operated under a variety of soil

texture and moisture conditions, as long as the soil

is not wet. During wet weather, if the tractor tends

to bog down at all, work should be stopped. Some

soils become extremely hard when dry and penetration of the disk blades is poor.

When soil is moist, or sandy, the disk blades penetrate readily, uprooting shrub root crowns. Also,

the disk incorporates twigs and branches deeply

into the soil. Some operators pointed out, however,

that under moist soil or sandy conditions not all

roots are severed, and such uprooted plants frequently survive. In contrast, if disking is done when

soil is nearly dry, plant crowns are apt to be broken

loose from all roots, and these shrubs die. Also,

moisture content of the brush is lower when soil is

dry, and brush is more readily broken and mulched.

It is sometimes convenient to attach a seeder to

the disk. Results with various types of seeders are

described in a later section.

Production rates and costs

Rates of production varied from 0.5 to 2.0 acres

per hour in the lighter fuels and from 0.2 to 0.6 acre

per hour in the heavier fuels (table 4). They are representative of the rates for the 9-foot 6-inch Towner

disk with 36-inch blades (Model 801-144). For the

smaller disks, the rate is slightly lower and for the

larger disks, slightly higher. The rates apply for

more than one pass of the disk in most fuel types;

repeated passes are necessary to uproot most brush

plants, mulch the small stems into the soil, and reduce fuel continuity for fire control. The site can be

seeded with the rangeland drill without additional

preparation after such disking.

In fuel type 7 (chamise), one or two passes of the

disk incorporated 85 to 95 percent of the brush into

the soil (fig. 22). In fuel type 14 (heaviest brush), an

average of four passes was required to do an adequate job. The first pass of the disk was generally at

the rate of about an acre per hour, which was considerably more time—up to three times as much—as

second, third, or fourth passes required. This economy on second to fourth passes sometimes encouraged unnecessary passes of the disk in an effort to

leave the disked brushfield "clean."

On-site costs varied from $26 to $70 per acre in

the lighter fuels, and from $60 to $175 per acre in

the heavier fuels (table 4).

Comments

Mechanical failures. On several projects, the

tongues and drawbars on the Towner disks failed;

tongues required reweldiiig, reinforcement, or replacement. The most frequent failures were breaking of the main weld near the back of the tongue,

and bending of the tongue or swivel. Some of these

failures were probably due to equipment abuse

(turning wrong direction under stress, too much

horsepower, etc.) but there appears to be a definite

weakness in the design of the tongue assembly.

Until the manufacturer improves the tongue design,

we recommend that these points be watched closely

during operation or preferably reinforced before

the equipment is taken into the field.

A few instances of failure of the hydraulic ram

cylinder on the Towner disk were reported. These

were attributed to metal fatigue. Many times, during more than a year of use, the hydraulic ram forcibly struck the end of the cylinder when the gangs

were opened or closed suddenly. The cylinder wall

eventually cracked, leaking the hydraulic fluid. On

some projects, this problem was overcome by attaching a heavy safety chain between the ends of

each gang. The chain was adjusted so that when the

disk snapped open, the strain was on the chain and

not on the hydraulic ram. When the gangs were

closed, the swamper had to drape the slack chain

over the frame to prevent it from getting tangled in

the blades. The Saugus Ranger District solved this

by adding an upright bracket and garage door spring

to keep the chain slack out of the disk.

26
TABLE 4.—Estimated production rates and on-site costs for one or more passes^ of the

brushland disk, as used on four National Forests in various fuel types^

Project Percent

slope

Types 7, 8

(1 pass)

Types 11, 12

( 1-3 passes)

Type 13

(2-4 passes)

Acres Dollars Acres Dollars

per per per per

hour acre hour acre

Acres

per

hour

Dollars

per

Type 14

(3-5 passes)

Acres

per

hour

Dollars

per

acre

Angeles N.F.

TujungaR.D. 0-25 2.0 50

Saugus R.D. 0-25

25-35

35+

1.0

.8

.5

30

45

60

Cleveland N.F.

Descanso R.D. 25-35 1.0 40 0.5 70

Palomar R.D. 0-25

25-35

1.0

.5

26

52

.5

.2

52

156

0.3

.2

78

156

Trabuco R.D. 0-25 0.7 53

Los Padres N.F.

OjaiR.D. 0-25

25-35

35+

1.0

.8

.5

35

45

70

.7

.6

.3

50

60

117

.6

.3

.2

60

117

175

Santa Lucia R.D. 0-25

25-35

35+

1.5

1.0

.5

40

45

50

Santa Barbara R.D. 0-25

25-35

35+

.8

.7

.5

43

50

68

.7

.5

.3

50

68

113

.5

.3

.2

68

113

170

San Bernardino N.F.

SanGorgonioR.D. 0-25

25-35

1.0

.8

35

45

Average 0-25

25-35

35+

1.3

.8

.5

35

46

65

.8

.7

.5

48

50

68

.9

.6

.4

45

74

93

.5

.3

.2

69

129

173

iThe rate for the first pass was generally about 1 acre/hr. Rate of subsequent passes was 2 or 3 acres/hr. Rate and cost data cited

were for the total number of passes made, and are direct costs of tractor, operator, and swamper. Total costs were about 40 to 50 percent more than on-site costs.

2Fuel type designations are from USDA Forest Service, California Region, FireUne Handbook (11).

Occasionally the hydraulic hose caught in brush

or trees and broke. This difficulty was overcome for

the most part by running the hydraulic lines through

old cotton-jacket firehose and threading it through

the eye of a 3- to 4-foot-long rod welded vertically

from the disk tongue. This kept the hose up out of

the way and still provided enough slack in the hose.

There was only one report of a disk blade breaking. A large section of a blade broke out after hitting

a large rock at considerable speed. Breaking of

blades does not appear to be a difficulty, even in

rocky country, if reasonable care is taken by the

operator.

Safety precautions.—A canopy over and around

the operator is essential for all tractor work in irregular mountainous terrain, and it is especially needed

with the brushland disk. Because the disk has a

double-action swivel hitch, it can tip over forward

as well as sideways. On one project, a 10,000-pound

disk rode up onto "balled" brush, and tipped over,

27
"^'Tf .

"^ '\^ígiA»

F-522984, 522985, 522986

Figure 22.—In light chamise chaparral, one pass of the disk incorporated most brush into the soil (top). In moderately heavy Ceanotbus

with scattered manzanita, two passes left more fuel on the ground than desirable for fire control (left). Three passes (right) in similar

brush incorporated most of the brush into the soil.

28
forward. It put a large dent in the canopy about the

level of the operator's head. Obviously this operator strongly recommends the use of canopies in

towing brushland disks (fig. 23).

F-522987

Figure 23.—During chaparral modification, the tractor operator

needs to be protected from whipping branches, and from the

disl( itself. It rode up over a brush pile, then tipped forward,

leaving the dent on the canopy post.

On several occasions disks tipped over sideways.

Nearly always this was after the disk rode up off the

ground on the balled brush. The narrower 8-foot 2-

inch disk appeared to be quite topheavy compared

to the wider 10- and 12-foot models and was more

prone to tip. Swampers should be conscious of the

danger that the disks may suddenly roll over sideways, and should stay clear, especially of the downhill side.

Care should also be taken when repairs are made

on these large pieces of equipment. The disk should

always be on as nearly level ground as possible, and

should be securely chocked in place while repairs

are made.

Advantages and disadvantages

Advantages

1. Maneuverable around trees

and boulders, in drainages,

etc.

2. Effective for creating irregular edge effect—scalloping, feathering, etc.

3. Allows varying degrees of

cleanup according to desired esthetic effects.

4. Incorporates debris into the

soil, allowing nutrient recycling.

5. Digs out many roots and

root crowns, reducing or

eliminating need for herbicides.

6. May increase percolation

and reduce runoff.

Disadvantages

Limited in use by slopes,

soil, and rock conditions.

Disturbs and loosens soil,

making it more vulnerable

to detachment and transport by high-intensity or

long-duration rainfall and

running water.

Roller Chopper

The roller chopper is basically a large drum, lying

on its side, around which a dozen or more steel

blades have been bolted or welded parallel to the

long axis. It is similar to the large sheepsfoot rollers

used to compact road fills, but has blades rather

than "feet." An axle through the drum, and a drawbar attachment, enable it to be towed, either singly

or double in tandem (fig. 24). Several models are

available from manufacturers such as Fleco, Marden, and Rockland.

Widths range from 4 to 16 feet, and weight, when

roller is filled with water, ranges from 1,350 to 50,000

pounds. Most practical for our work and conditions are 8- to 10-foot-wide models. The singledrum models weigh 18,000 to 28,000 pounds when

filled with water, and the tandem (double-drum)

models weigh 37,000 pounds or more.

In use, the roller tends to lift itself up onto a

blade, then fall forward onto the next blade. This

lifting and falling is responsible for part of the cutting action, and efficiency increases as the speed

increases. The drums are aligned so that each drum

cuts or shears the brush from a slightly different

angle.

Models with replaceable and reversible blades

appear to be most desirable. With permanent

blades, it is necessary to build up the edge by welding, or to cut off the blades with a torch and weld

new ones on. Replaceable blades can be changed in

3 to 4 hourST

Like the offset brushland disk, the double-drum

offset roller chopper must be turned to the left only.

Its design makes turning to the right difficult and

subjects the equipment to structural strain and pos29
San Diego County Department of Agriculture

Figure 24.—The offset tandem roller chopper appears to be useful

in most vegetation types provided slopes are gentle and the chopper is pulled as rapidly as conditions allow. In medium-to-heavy

brush, follow-up burning is usually considered necessary.

sible damage. The single-drum roller choppers can

be turned in either direction.

Tractorsize required

Generally, a tractor in the D-8 range is recommended, but a small roller chopper or favorable terrain may allow use of a smaller tractor. For roller

choppers 10 feet wide, weighing 27,000 pounds

empty, and 48,500 pounds filled with water, a tractor of at least 270 hp (net at flywheel) is needed.

Manufacturers' recommended horsepower ratings

appeared to be low for most mountainous terrain.

Capability

The only recent brushland experience with the

roller choppers was reported by the San Diego

County Department of Agriculture. A Marden Duplex brush cutter 8 was used in light-to-medium

brush with stems up to 2 inches in diameter. The

roller chopper made one pass over the chamisecoastal sage brush, and burning was not considered

necessary. Observers felt the roller chopper could

handle denser brush, provided stem size did not

increase much, or could handle larger stems provided the stand was sparse. In denser brush, burning

would probably be necessary as a follow-up treatment to reduce fuel volume. Also, in the dense fuels

with larger stems, two passes might be necessary.

California Division of Forestry tests reported by

Ritchie and Dodge (10) indicated that a Marden

Duplex brush cutter chopped about 70 percent of

medium-density chamise chaparral, 4 to 8 feet tall,

into the ground in one pass. In dense, heavy Ceanothus, two passes chopped about 80 percent into the

soil. In manzanita-chinkapin-snowbrush, the Marden readily crushed the brush satisfactorily for prescribed burning, but not for drill seeding without

burning. In San Diego County, the roller chopper

effectively cut and broke up willows up to 5 inches

in diameter around a large reservoir.

Because the roller chopper tends to slide sideways in a skiing fashion, the maximum side slope

appears to be approximately 20 percent. It is possible, however, to work it up and down slopes estimated up to 35-40 percent. A single drum can be

lowered and raised, in yo-yo fashion, on much

steeper slopes, where large rocks or trees are not a

hindrance. This technique would be similar to using

a sheepsfoot roller for compacting long fill slopes.

The roller chopper makes depressions the length

of the blades. Therefore working it up and down

slope instead of on the contour, when slope exceeds

10 or 15 percent, may be desirable. On the contour,

the blades leave depressions up and down slope and

encourage rivulets and gullies. If the tractor works

up and down, the trenches on the contour act as

water bars and small check dams.

A few rocks are easily avoided, as reported by

San Diego County personnel, but this leaves uncut

brush. Large numbers of rocks also result in uncut

brush because they hold the blades above the

brush. The roller chopper is considered maneuverable and selective, the single drum more so than the

double-drum models.

Production rates and costs

Little information is available on the production

rates of the different-size roller choppers. We estimate, however, that an 8-foot roller chopper, working under average conditions in medium brush,

could make two passes over 1.25 to 1.75 acres in an

hour.

Assuming a tractor with swamper rental rate of

$40 per hour, on-site costs in medium fuels would

be approximately $23 to $32 per acre for the two

passes. Some workers suggested the swamper is

unnecessary in light brush or on good terrain.

Comments

The advantages and disadvantages of the roller

chopper are as follows:

Advantages Disadvantages

I. Maneuverable around trees 1. Limited in use by slope

and rocks, in drainages, gradient, and by excessive

etc. rockiness.

30
Advantages

2. Effective for creating irregular edge effect (scalloping,

etc.).

3. Leaves debris on or near

the surface, reducing eroDisadvantages

2. When worked on contour,

creates small trenches up

and down slope, increasing

erosion potential.

Advantages

sion potential and allowing

nutrient recycling.

4. Creates water bars across

slope when worked up and

down slope, reducing erosion potential.

Disadvantages

Removes few roots and

shrub crowns, so that

sprouting occurs.

Tritter Brush Shredder

Several types of brush shredder have been used

in the past, but these generally have not proved

practical for California conditions, primarily because they were not sturdy enough. The Yeomans

Tritter land conditioner, manufactured and used in

Australia for many years for range type conversion,

has recently been introduced to our West Coast. It

appears to have some application in chaparral conversion.

The Tritter Model 260 weighs approximately 3,300

pounds. It uses 28 hammers or flails, each weighing 6 pounds, rotating at 1500 r/min on a heavy-duty

shaft in the direction of travel to clear a swath 5 feet

wide (fig. 25). The hammers can be adjusted to cut

from 1/2 inch to 8 inches above the ground.

The machine is available with a power-takeoff

drive shaft, or an independently mounted diesel

engine to drive the hammers may be purchased.

The power-takeoff unit does not appear satisfactory

in chaparral. On the Saugus Ranger District, Angeles National Forest, there were four universal joint

failures during shredding of half an acre of chamise

of relatively flat, uniform slope. A power-takeoff

unit was used behind a rubber-tired tractor on the

Groveland Ranger District, Stanislaus National

Forest, to clear manzanita from pine plantations.

The old and new growth 2 feet to 4 feet high was

shredded in one pass. Larger manzanita required

two passes; however, the rubber-tired tractor

bogged down in the larger fuels. The operator felt a

crawler tractor would have had no problems pulling

it througl^ the heavier brush, but there are very few,

if any, crawler tractors available with a live power

takeoff that is independent of the tractor drive. The

Tritter is designed to run at a constant speed, feasible only with an independent drive system.

The optional independently mounted diesel power source is expensive and adds considerable weight

to the Tritter. Rear visibility is impaired, making

backing difficult. The most practical power source

appears to be a hydraulic motor, 60 hp at 2500 r/

min, mounted on the Tritter. The Groveland Ranger

District, with the help of the San Dimas Equipment

Development Center, has converted a Tritter with

such a hydraulic motor. The land-clearing contractor was required to provide and mount on his tractor the pump, heat exchanger, filter, control valve

and hydraulic fluid storage which met the specifications to drive the motor. When interviewed, Groveland District people were still making minor changes

and adjustments, but were sure that the right combination of pumps,motors, and pressures will make

the Tritter fully effective for their needs. Costs of

the Groveland conversion were approximately

$1,500 to purchase and install the hydraulic motor

on the Tritter, and from $1,500 to $2,000 to set up

the pumping system on the tractor.

The Tritter leaves an evenly distributed cover of

finely shredded material over the soil, thus providing soil protection and nutrient recycling. Brush

Figure 25.—One pass of the Yeomans Tritter land conditioner

reduced medium manzanita brush to shreds on the Stanislaus

National Forest. Heavy chaparral required two passes.

31
species that sprout will do so vigorously following

use of the Tritter shredder, because the crowns and

sometimes the lower stems of the plants are not

damaged. Nonsprouting brush must be shredded

below the lowest green branches, or growth will

continue.

Tractor size required

Because of the light equipment weight and narrow swath, tractors delivering from 90 to 125 net

engine horsepower should be adequate.

Capability

The Tritter appears to perform well in all fuel

types, but the rate of production is considerably

lower in the heavier fuels.

Small rocks do not appear to interfere with performance; they are pulverized by the hammers. In

larger numbers, however, rocks, particularly igneous rocks, shorten the life of the hammers by

excessive wear. Large rocks and boulders must be

avoided. Because it makes a narrow swath, the Tritter is considered maneuverable and very selective.

It will perform on side slopes of up to 30-35 percent.

The Tritter comes equipped with rubber tires

which are liable to puncture, and steel wheels or

multiple-ply puncture-proof tires should be substituted. A foam is available from some rubber manufacturers for use in conventional tires. Inside the

tire, the foam sets up into a solid that will not leak

when the tire is punctured. If much highway travel

is required, the steel wheels are not practical.

Production rates and costs

An estimate, based on limited use from theGroveland District, is 0.5 to 0.75 acre per hour in

medium manzanita on slopes up to 30 percent gradient. The drier and more brittle the vegetation, the

more efficient the Tritter appears to be •

The Groveland District estimates, again on limited information, the direct, on-site costs to be approximately $35 to $40 per acre in medium manzanita on slopes where the tractor can operate efficiently.

Comments

The advantages and disadvantages of the Tritter

are as follows:

Advantages

1. Selective and maneuverable.

2. Provides a uniform protective cover over the soil,

reducing erosion and providing for adequate nutrient recycling.

Disadvantages

1. Limited in application by

slope, soil, and rocky conditions.

2. Incorporates little debris

into soil.

3. Does not remove any roots

or shrub crowns, so that

sprouting occurs.

4. Low in production rate

compared to other alternatives.

Hand Tools For Brush Clearing and Stump Sprout Control

Hand labor is the most costly method of clearing

brush, but it may be the only way under some conditions. When steep slopes, loose soil, or rock outcrops make clearing by mechanical methods impractical, and when prescribed burning is not suitable, hand clearing is the only alternative. Hand labor is also desirable for clearing around or through

special interest areas such as archeological or historical sites, areas containing distinctive plants, or

areas where visual effect is of critical importance.

Size of hand crews varies from a few men to 20 to

25. The crew most commonly used, and apparently

most practical, consists of 15 to 20 men. Such a

crew is productive and easily transported, and a

good foreman can provide the necessary supervision for efficiency and safety.

Cutting and Piling

The tools most commonly used are the chain saw,

brush hook, and Pulaski, and sometimes the doublebit axe. On occasion, long- and short-handled pruning saws and pruning shears are used. These pruning tools have been very useful on shaded fuelbreaks for removing the lower twigs and branches

from trees.

The Homelite brush cutter was used in place

of or in conjunction with chain saws on several

projects. A motor carried on the operator's back

drives a flexible drive shaft that runs through a 3 1/2

to 4-foot-long metal tube and turns a circular saw.

The operator controls the saw on the end of the

tube with handlebars. Some users felt this saw in32
creased their production rate several times over the

chain saw.

In hand clearing, the brush is placed in piles

or windrows for later burning. The piles should

not be placed too close to vegetation that is not to

be removed, to avoid scorching when piles are

burned. If the piles are covered with heavy construction paper, it is possible to burn them under

very wet conditions.

While working extremely steep slopes, the crews

of one project found that as they worked up the

slope they could allow the brush to roll downhill,

where it formed a windrow against uncut brush.

This technique eliminated some of the strenuous

effort required to drag the brush to a pile or windrow.

Stump Treatment

On many projects, the freshly cut brush stumps

were treated with herbicide to prevent future

sprouting. Generally, undiluted 2,4-D amine (4

pounds per gallon, acid equivalent) was applied to

the fresh cuts. Occasionally 2,4-D ester at the same

concentration was used.

Among the tools used to apply herbicides to the

cut brush stumps are paint brushes, plastic spray

bottles, large (1- to 2- quart) oil squirt cans, Hudson

sprayers, and drip torches (the type used to burn

out and backfire). All theie have been used effectively, but the Hudson sprayer appears to be the

least desirable method because it encourages application of more herbicide than necessary.

Perhaps the safest and most efficient method of

applying herbicides to the stumps is the drip torch

technique developed on the Cajon District, San

Bernardino National Forest (fig. 26). A floor flange

of a thread size matching that on the end of the drip

Figure 26.—The best tool for applying herbicides to freshly cut

chaparral stumps was a drip torch with a heavy sponge attached.

torch (usually 3/8-inch iron pipe), was attached to

the end of the looped tube. Next, one half of a

coarse-textured sponge (GSA No. 7920-884-1115),

approximately 3 by 4 by 2 inches, was attached to

the flange with from two to four 3-inch bolts with

wing nuts. The sponge absorbed the herbicide, aiid

when it was pressed against the surface of the

stump, the herbicide was squeezed out, covering the

surface very well. The flow to the sponge can be

regulated with the air adjustment on the tank of the

drip torch, and dripping prevented. There is little

waste and no chance of drift. If the torch is

dropped, it will not spill. Where large stumps were

treated, the uncut sponge (6 1/4 by 4 1/4 by 2 1/2

inches) was used to advantage. Personnel of the

Cajon District estimate they can cover an acre with

approximately 1 to 1 1/2 gallons of herbicide, depending on the number of stems per acre.

A coloring agent in the herbicide temporarily

dyes the stumps and helps keep track of those that

have been sprayed. Tujunga District personnel

found 1/2 to 1 teaspoon of Rhodamine B liquid dye

sufficient for 5 gallons of amine solution. The liquid

dye in plastic squeeze bottles is much cleaner and

easier to use than the powder form. Eight ounces of

Rhodamine B dye for 250 gallons of foliage spray

solution has proved effective. Food coloring at a rate

of 1 to 2 ounces per 5 gallons of amine solution was

used to good advantage on the Ojai District. Green

was considered more visible than red. Either dye

will last for a few days or more depending on the

weather conditions.

Although good sprout control has been achieved

with both amine and ester solutions, the water soluble amine solution has given the most consistent

stump kill. In virtually all instances, the effectiveness of the herbicide increased as the time lag between cutting and treating decreased. All stumps

should be treated as soon after cutting as possible,

and always the same day they are cut.

On some projects, the stump treatment method

was not used, but new sprouts were later sprayed

33
with a solution of 2,4-D ester (4 pounds per gallon,

acid equivalent), 1 gallon of diesel oil, and about 100

gallons of water. The cut stump method appeared

to be superior to the foliage spray treatment.

Foliage spraying becomes necessary if the stump

treatment is not successful. If properly and promptly applied, the 2,4-D amine stump treatment frequently resulted in more than 90 percent kill. This

was true even of scrub oak on Los Padres National

Forest test plots. The stump treatment method also

eliminated the need to drag awkward hoses or make

frequent trips with portable sprayers, as required

for the foliage spray method. To eliminate the few

sprouts that resulted from successful stump treatment, one man can cover several acres a day using a

Hudson or similar-type sprayer.

It is reportedly common for stumps to sprout

shortly after treatment. The sprouts sometimes

reach a height of 1 to 2 feet before the plant dies.

On some Los Padres test plots, in scrub oak treated

with 2,4-D amine, sprouting continued for 2 years

before plants died.

Production rates and costs

The rate of production for hand cutting, piling,

and stump treatment varied from 70 to 178 manhours per acre in the lighter fuels (5 to 15 tons per

acre), and from 215 to 370 man-hours per acre in the

heavier fuels (20 to 40 tons per acre) (table 5).

TABLE 5.—Estimated production rates and on-site costsi of hand cutting and piling brush for burning,

and treating cut stumps with herbicide, on four National Forests, in various fuel types^

Percent

slope

Types 7 ,8 Types 11, 12 Type 13 Type 14

Project Man-hours

per

acre

Dollars

per

acre

Man-hours

per

acre

Dollars

per

acre

Man-hours

per

acre

Dollars

per

acre

Man-hours

per

acre

Dollars

per

acre

Angeles N.F.

Arroyo Seco R.D. 0-50

50+

150

178

3550

3650

205

240

3750

3875

220

275

3800

31,000

Mt. Baldy R.D.

Tujunga R. D.

Cleveland N.F.4

Descanso R.D.

0-50

50+

0-50

50+

0-50

50+

88

100

350

400

201

215

775

825

250

275

150

175

227

234

1,000

1,100

600

700

875

900

275

300

234

252

1,100

1,200

900

970

Palomar R.D. 0-50

50+

70

80

280

320

200

225

800

900

225

250

900

1,000

Trabuco R.D. 50+ 70 280

Los Padres N.F.

Ojai R.D. 0-50

50+

85

95

350

390

250

275

1,000

1,100

275

300

1,100

1,200

San Bernardino N.F.

San Jacinto R.D. 0-50

50+

160

175

632

700

200

220

800

880

240

290

960

1,160

300

370

1,200

1,480

Cajon R.D. 50+ 180 720

San Gorgonio R.D. 0-50

50+

70

80

280

320

180

190

720

760

215

225

860

900

Average 0-50

50+

104

HI * •

407

437

200

218

788

853

213

232

838

913

249

282

980

1,107

iFor total project costs, add 40 to 50 percent to cover mileage, small equipment, planning, and overhead.

2Fuel type designations are from USDA Forest Service, California Region, Fireline Handbook (11).

3lncludes an estimated $20 per acre cost of burning piled brush.

"^No herbicide treatment costs are included for projects on this forest.

34
On-site costs varied from $280 to $700 per acre in

the lighter fuels and from $800 to $1,480 per acre in

the heavier fuels. The overall average crewman salary is estimated at approximately $3.85 per hour,

and ranged from $3.45 to $4.00 per hour.

Comments

Advantages and disadvantages of hand clearing

are as follows:

Advantages

1. Usually not limited by

slope.

2. Highly selective.

3. Effective for creating irregDisadvantages

1. Very costly.

2. Removes no roots or shrub

crowns, so that sprouting

occurs.

Advantages

ular edge effect—scalloping.feathering, etc.

4. Allows varying degrees of

cleanup according to desired esthetic effects.

5. Does not disturb topsoil.

6. Effective in very rocky

areas.

7. Does not leave soil in burn

piles and windrows.

8. Produces piles or windrows

for burning.

9. Leaves roots in ground

where needed to help hold

soil in place while new

cover is established.

Disadvantages

Little or no debris is incorporated into the soil.

Grass Seeding Equipment

Chaparral modification may or may not include

seeding of desirable grasses, once the brush has

been cleared. The equipment most commonly used

for seeding is the rangeland drill. Hand methods are

frequently practical, and aerial seeding is sometimes economical for large areas.

Seeding attachments have occasionally been

tried. Use of an attachment called the Holt Seeder,

installed on the back of the brushland disk, was

reported, but it was not considered satisfactory in

any trial. The squirrel-cage-type blower did not

supply sufficient air velocity to disperse the seed.

Attempts made to modify the equipment for better

seeding were not successful, and unmodified seeders were being returned to the manufacturer for

refund.

The Cyclone Company makes several types of

electric seeders that can be attached at the front or

rear of a vehicle. The San Diego County Department of Agriculture has used an electric Cyclone

seeder on an all-terrain vehicle and has been well

satisfied with the results (fig. 27). On one Forest

Service project, a battery-powered Cyclone seeder

was mounted on the frame behind the disk. Seed

was broadcast, and covered by dragging a smooth

light anchor chain. With the seeder mounted about

3 feet above the ground, wind was not a serious

problem; at greater elevations it was. Distribution

was not satisfactory if the seed was broadcast from

less than 3 feet.

San Diego County Department of Agriculture

Figure 27.—The San Diego County Department of Agriculture has

used to good advantage an electric Cyclone seeder on an all-terrain vehicle. Chaining preceded the seeding. Goggles are essential equipment for the operator.

35
Rangeland Drill

Over the years, a drill has consistently been the

best method of getting seed established. Several

types of seed drills are available, but the one most

commonly used, and found most rugged and dependable, is the rangeland drill designed for the

Rangleland Seeding Committee (9) by the Forest

Service Equipment Development Center at San

Dimas, California. This drill is available in full and

half sizes. The full-size drill has a 10-foot planting

swath.

The rangeland drill can be adjusted to apply a variety of seed mixtures at desired rates per acre, or

can be modified with a small-seed attachment. It

can also be equipped to apply commercial fertilizer.

The drill is effective on slopes from 0 to 30 percent and should only be used on the contour. The

drill rows then act as small water bars and check

dams, slowing down the flow of surface water. The

drill is capable of being used effectively on ground

strewn with considerable debris and rocks. Because

the disk arms are independently suspended, they

are free to ride separately over rocks and debris.

The drill can be transported from one area to another by suspending it in the rangeland drill carrier designed for it, and towing with a 3/4- to 1-ton truck.

Travel routes should be scouted because the carrier

width is greater than some truck trails and gates.

Tractor size required

Tractors with 60 to 90 net flywheel horsepower

are adequate to pull the rangeland drill, and larger

tractors should not be used except to carry a wide

bulldozer blade if clearing ahead of the drill is needed. Probably more damage to the rangeland drill

results from the use of excessive horsepower than

from any other cause (fig. 28).

F-522990

Figure 28.—A 10-{oot rangeland drill is towed here by a tractor with a horsepower rating of only 42 (net flywheel). Large tractors are not

necessary nor recommended for pulling the drill.

36
Production Rates and Costs

The rate of production of the rangeland drill

varies from 1 to 3 acres per hour depending on

gradient, irregularity of terrain, rockiness, and

brushiness. If drilling is done after wildfire, clearing of stiff unburned brush stems with a dozer

blade ahead of the drill results in only 50 to 60

percent of production on previously cleared, gentle terrain. The Mendocino National Forest averaged 20 acres per day on good terrain, including

down time.

Assuming a cost per hour for tractor and swamper of $25, the direct drilling costs range from as

low as $8 to $10 per acre, not including seed, to as

much as $25 per acre under adverse conditions.

Hand Seeding

When steep terrain, small areas, or other conditions prevent the use of the rangeland drill, seeding

by hand is a commonly used practical alternative.

Several hand seeders are available, but the Cyclone

seeder is used most frequently. These seeders can

be calibrated to broadcast seed at approximately

the prescribed rate. FertiHzer can also be applied.

The Cyclone seeder is available with either a metal

or a cloth hopper to hold the seed. The metal hopper appears to be superior and is preferred by most

workers. One man can seed from 1 to 2 acres per

hour with a hand seeder, depending on the terrain.

Aerial Seeding

Seeding is done by both rotary-wing (helicopter)

and fixed-wing aircraft. For large areas close to airports, or areas of uniform terrain, seeding with

fixed-wing aircraft is usually cheaper. Helicopters

are usually better for seeding small or remote or

irregularly shaped areas, such as some fuel

breaks, especially if terrain is rough and irregular.

For conditions common to most fuel breaks, the

estimated cost range for seeding with rotary-wing

aircraft is from $2 to $2.50 per acre. The cost range

for fixed-wing is estimated at $1 to $2.50 per acre.

The size of the project strongly affects the cost.

Contract Recommendations

A high percentage of fuel break construction and

other chaparral modification work is done by contract, and most project leaders feel that contracts

could be made more effective. The following recommendations are based on suggestions received.

1. Include a clause to limit the amount of down

time without penalty for contract equipment.

Excessive down time was detrimental to the accomplishment of several projects because in working

under strict seasonal, fiscal year, or other time restrictions, only a short period was available for

work. A limitation of 10 to 15 percent down time

was suggested, with down time in excess of this

resulting in a penalty assessment on the contractor.

This would encourage speedy repair, and would

discourage contractors from bidding on jobs with

rundown or wornout equipment.

The clause allowing the contractor 48 hours to

either repair or replace the equipment was generally

considered too generous, as a breakdown might

recur a day or two later and the contractor would

again be covered for 48 hours.

2. Require a minimum of 2 inches grouser height

on tractors. Traction is important with all the types

of equipment and techniques described in this handbook. Most contracts now used specify horsepower, but even if a tractor has adequate horsepower,

wornout grousers will result in poor performance.

3. Specify maximum horsepower requirements.

Most contracts specify horsepower minimums, but

not maximum horsepower requirements. Sometimes equipment such as the disk and rangeland drill

has been damaged because the tractor used was too

powerful. It is not uncommon for a contractor to be

37
the low bidder with a piece of equipment that greatly exceeds the minimum.

4. Write into the contract sufficient flexibility to

allow a tractor, and other equipment as far as possible, to be kept busy even if plans change somewhat

because of breakdown, weather, or managerial decision. For example, if a tractor is hired to pull a

brushland disk, and the disk breaks down, the contractor might be required to switch the tractor to the

ball and chain or to a brush rake clearing and piling

job. Anticipating such a situation might require the

contractor to have the brush rake available. This

kind of planning helped several projects.

5. Specify that tractors which must work as a

team, as in chaining, should be of approximately

the same size, horsepower, gear ratio, and physical

condition, because production will be limited to that

of the least efficient unit.

38
Literature Cited

1. Brown, Robert D.

1973. Pre-burn treatment of oaks with the ball and

chain. Calif. Div. For. Range Improv. Stud. 21,6p.

2. Cain, Don.

1971. The Ely chain. USDI Bur. Land Manage. Ely,

Nev. 32 p.

3. Dell, John D., and Franklin R. Ward.

1%9. Reducing fire hazard in ponderosa pine thinning

slash by mechanical crushing. USDA Forest Serv.

Res. Paper PSW-57, 9 p. Pacific Southwest Forest

and Range Exp. Stn. Berkeley, Calif.

4. Dodge, Marvin, and Cecil Pierce.

1%2. Anchor chain improves brush range land. Calif.

Div. For. Range Improv. Stud. 7, 8 p.

5. Frank, Franklin F., Richard H. Bawcom, and W. James

Clausen.

1970. The brush disc-an effective tool for brushland

range improvement. Calif. Div. For. Range Improv. Stud. 20, 6 p.

6. Gilbert, Richard, and Jef Schmidt.

1970. Ball and chain brush crushing. Calif. Div. For.

Range Improv. Stud. 19, 8 p.

7. Green, L. R., V. E. White, and T. R. Plumb.

1%3. Some brush conversion costs on southern California fuel-breaks. Fuel-Break Rep. 12, 18 p. Pacific Southwest Forest and Range Exp. Stn.

Berkeley, Calif.

8. Lind, Carl.

1960. Anchor chain, new conservation tool. USDI.

Our Public Lands 9(3): 7-9.

9. Rangeland Seeding Committee.

1970. Range seeding equipment handbook, 156p.

Washington, D.C.

10. Ritchie, Roy W., and Marvin Dodge.

1962. Marden brush cutter trials. Calif. Div. For. State

For. Notes 11, 6 p.

11. USDA Forest Service, California Region.

1971. Fireline handbook. San Francisco, Calif.

12. USDA Forest Service, Equipment Development Center.

1970. Results of field trials of the Tree Eater-a tree

and brush masticator. Equip. Dev. and Test Rep.

7120-1, 26 p. San Dimas, Calif.

13. USDA Forest Service, Equipment Development Center

1971. Tractor attachments for brush, slash, and root

removal. Equip. Dev. and Test Rep. 7120-3, 78 p.

San Dimas, Calif.

14. USDA Forest Service, Pacific Northwest Region.

1973. Trakmac tested for thinning and slash treatment

on Eastside. R-6 Fuels Manage. Notes 1(5): 3.

Portland, Ore.

39
Appendix A

Comparative Speciñcations ofIndustrial Tracií-Laying Tractors

Make and

model

Approx.

bare weight

(lb)

Net engine

horsepower

at flywheel

Maximum speed (mi/h)

1 St gear 2d gear 3d gear 4th gear

Allis-Chalmers:

H-3

HD-3

HD-4

HD-6B

HD-6E

HD-6EP

HD-llB-DD

HD-llB-PS

HD-llE

HD-HEP

HD-16B-DD

HD-16B-PS

HD-19

HD-21-A

HD-21-B

HD-21-P

HD-41

J. I. Case:

350

450

750

850

lOOOD

1150

Caterpillar:

D4-D

D4D-DD

D4D-PS

D4-SA

D5

D5-DD

D5-PS

D5-SA

D6-8U

D6-B

D6-C

D6C-DD

D6C-PS

D6C-SA

D7-3T

D7-C

D7D-17A

D7-DD

D7E-47A

D7-PS

7,100 48 1.2 2.1 3.1 5.2

7,300 43 1.2 2.1 3.1 5.2

8,800 59 1.8 2.8 4.9 —

12,600 69 1.5 2.7 3.5 4.2

13,500 69 1.5 2.6 3.5 4.2

14,100 75 3.0 5.9 — —

23,650 125 1.4 2.1 2.9 3.7

24,500 140 2.8 5.2 — —

22,000 123 — — — —

23,000 140 — — — —

36,100 172 1.4 2.1 3.0 3.9

37,200 195

163

252

3.0 6.3 — —

47,900

57,100 273 2.5 4.2 6.4 —

50,000 268 — — — —

104,000 524 2.6 4.5 6.5 —

5,905 39 2.0 3.2 5.4

8,850 51 1.6 2.8 3.2 5.8

11,720 70 — — — —

13,000 72 2.1 3.0 4.1 5.7

13,450 93 — — — —

15,357 85 1.7 2.9 3.4 6.0

13,100 65 2.0 3.6 5.8

13,100 75 1.7 2.5 3.4 4.5

13,700 75 2.0 3.6 5.8 —

15,100 — 2.5 2.9 3.5 4.0

18,600 93 1.7 2.6 3.6 5.0

18,500 105 1.7 2.6 3.6 5.0

19,100 105 2.2 3.8 6.3 —

20,400 — 2.5 2.9 3.5 4.0

17,195 93 1.7 2.6 3.6 5.0

18,300 93 1.7 2.6 3.7 5.2

23,000 120 1.5 2.1 3.0 4.2

23,000 140 1.7 2.5 3.5 4.9

23,500 140 2.3 4.1 6.4 —

26,100 — 2.5 3.0 3.5 4.0

25,1^0 93 1.4 2.2 3.2 4.6

26,355 128 1.5 2.2 3.2 4.6

26,555 140 1.5 2.2 3.2 4.6

30,400 180 1.5 2.2 3.1 4.6

32,590 160 1.5 2.2 3.1 4.6

31,300 180 2.2 3.9 6.0 —
Comparative Specifications of Industrial Track-Laying Tractors—Continued

Approx.

bare weight

Net engine

horsepower -

Maximum speed (mi/h)

Make and

model (lb) at flywheel 1st gear 2d gear 3d gear 4th gear__

Caterpillar (con.):

D8-2U 34,160 144 1.7 2.3 2.7 3.1

D8-DD 49,000 270 1.6 2.1 2.9 3.7

D8-H35A 46,032 235 3.0 5.1 7.6

D8-H36A 47,180 235 1.5 1.9 2.7 3.5

D8-H46A 48,210 235 2.4 4.2 6.5

D8-PS 49,900 270 2.4 4.2 6.5 ~

D9D-19A 57,990 320 4.1 5.6 7.8

D9E-50A 59,506 335 4.2 6.0 8.2

D9-PS 68,000 385 2.4 4.2 6.5

John Deere:

JD350-B

JD450-B

8,163

11,600

42

65

1.4

1.8

1.9

2.8

3.3

4.3

6.5

6.7

International Harvester:

TD-6 (62)

TD-7C-GD

8,872

12,410

50

50 1.4 1.9 2.0 2.6

TD-7C-PS 12,510 56 1.9 3.2 5.5 ~

TD-8C-GD 15,400 63 1.4 1.9 2.0 2.6

TD-8C-PS 15,500 69 1.9 3.2 5.5

TD-9B-GD 12,540 66 1.7 2.5 3.4 4.4

TD-9B-PS

TD-9B-CA

12,765

12,481

75 2.6

1.9

4.2

2.7 3.7 4.5

TD-15B-GD 23,093 125 — — "~

TD-15B-PS 23,217 125 — — — ~

TD-15C-GD 24,507 140 1.6 2.1 2.8 3.9

TD-15C-PS

TD-15C-CA

24,163

24,762

140 2.7

2.1

3.5

2.9

4.6

3.7

6.0

4.4

TD-20B-PS 30,876 160 — —

TD-20C-PS

TD-20C-CA

32,191

32,024

170 2.4

2.2

3.2

2.7

4.7

3.2

6.1

3.7

TD-25B-PS 50,000 230 2.6 3.3 5.0 6.3

TD-25B-GD 49,565 230 1.7 2.1 2.6 3.3

TD-25C-GD 52,095 285 1.5 1.9 2.2 2.9

TD-25C-PS 52,495 285 2.6 3.3 5.0 6.3

Komatsu:

D50-15 20,280 90 1.6 2.2 3.4 5.8

D50P-15 27,120 90 1.6 2.2 3.4 5.8

D50PL-15 27,340 90 1.6 2.2 3.4 5.8

D60-6 27,670 140 1.6 2.2 3.1 4.3

D60E-6 28,620 155 1.6 2.3 3.3 4.6

D60P-6 36,160 140 1.6 2.2 3.1 4.3

D60PL-6 35,050 140 1.6 2.2 3.1 4.3

D65-6 28,110 140 2.2 4.0 6.4 —

D65E-6 29,060 155 2.3 4.0 6.6 —

D80-12 37,920 180 1.5 2.1 3.2 4.6

D85:12 38,360 180 2.0 2.8 4.2 5.9

D150-1 57,300 300 1.6 2.2 3.0 4.7

D155-1 57,300 300 2.3 4.2 7.3

Massey-Ferguson:

MF 200 7,715 44 1.7 2.3 3.4 5.7

MF 300 14,700 65 2.2 4.0 —

MF 400 20,585 85 2.2 4.0 — ~

MF 2244 6,600 44 — —

42
Comparative Specifications of Industrial Track-Laying Tractors—Continued

Approx.

bare weight

Net engine Maximum speed (mi/h)

Make and

model (lb) at flywheel 1st gear 2d gear 3d gear 4th gear

Massey-Ferguson (con.):

MF 3366 18,464 75 2.1 4.0 ~

MF 500 25,800 136 2.4 4.1

Terex:

82-30 44,500 225 1.9 3.8 7.3 —

82-30T 44,500 225 1.9 3.8 7.3 —

82-40 53,170 275 2.1 3.7 6.1 ~

82-40T 54,200 290 2.1 3.7 6.1

82-80 73,000 440 1.7 3.5 6.9

Appendix B

Suggested Form for Summarizing Costs of Chaparral Modification

APPROXIMATE RATES AND COSTS OF FUEL MODIFICATION OPERATIONS

Project Name

Name and Title

Location .

Fuel Type

Agency

Tons per Acre

Tractor Number Direct OTHER PER ACRE COSTS

Type and model, of Acres cost:

size of horsepower acres Slope per dollars Mileage Planning Environmental Supervision Other

equipment rating treated percent hour per acre statement

0-20

20-35

35+

0-20

20-35

35+

0-20

20-35

35+

Remarks: (Include any helpful information such as soil types, plant species composition, rockiness, rental rates of equipment, use of swampers, etc.)

43
Appendix C

Relation ofProduction Rate to Swath Width and Speed ofImplement

30

25

^ 20

CD

C 15

o

Ö. 10

\ 1 1 /

^"t ;^v / y

r/ ^7- f

/

t n A ^y /

-^j— V

/ / ^./

1 / ^/

r

\ / /

(X y

\ / / y

r

y

\ / / / y

/

\ >

r-

/ /

/

S^/

\ / À

/

/

-<o \ / / /

r

4,

y

/ / / / y y

/

r

/

f

/

/

y\' y^

/ / / /

Kl

/ / /

/

y ~yr

/ /

f.

/ —^ / y

y^

/ i / /

/ y >

y

/ / / / y

/^ /

/ / / À

/

/y

/ / / /y y

/^

/ .

/ / ^j/./.y

/

/ //./

/

/

//

/

/

X

/

Á /

/^

/V/

/ V ^yy

/ /A/y 1////>

^

Wáf^<

Wr 1

5 6 7 8 9 10

Acres per hour

M 12 13 14

Source: Rangeland Seeding Comm. (9).

44
Appendix D

Contract Speciñcations for the Modified Chaiifi

Technical Specifications

Material Specifications

Cross bar: 1 by 4 by 18 inches

Hardness (B.H.N.) 350/380

Yield strength 170,000 P.s.i.

Tensile strength 180,000 P.s.i.

Reduction in area 40 percent

Elongation in 2 inches 15 percent

Spacer: 1/4 by 1 by 4 inches; hot rolled steel or

better

Welding rod: 7018 or better

Welding

Each spacer and cross bar must be welded to a

chain link in a professional manner.

The objective is to weld the cross bars to the

anchor chain in such a manner as to take severe

use without breaking the weld.

All areas of contact between cross bar, spacer, and chain link must be welded. All areas of

close proximity between cross bar, spacer, and

chain link must be welded. Exhibits 1,2, and 3

show relationship of cross bar and spacer to

chain link with weld areas. All welds are to be 3/4

inch 7018 fillet welds.

Cutting Specifications

Remove the center link on each shot of chain.

This will result in eight sections approximately 45

feet long.

3/4 7018 Fillet Weld

All Sides

i/4"xl"x4"Hot Roll

Steel Plate

UA

Typical Chain Link

EXHIBIT 1

V^^ J^F^ffr—^"^ 7^^

21/4"

Section B B

l"x4"xl8" As Per Specification 211

'/4"l"x4" Hot Roll Steel.

Fornn to Curve of Chain

74 7018 Fillet Weld

All Sides

EXHIBIT 2

Multiple Chain Unit

EXHIBIT 3

Inspection and Acceptance

The Government may make periodic inspections

to insure that specifications are being met.

Final inspection and acceptance will be performed after chain is returned to the F.O.B. point.

Measurement and Payment

Method of Measurement

The actual number of bars accepted by the

Government.

Basis ofPayment

Payment at the unit price for the number of

bars accepted.

1 Adapted from specifications drawn up by the Cleveland National Forest, based on suggestions from the San Diego County

Department of Agriculture. Material specifications are those of

Wearalloy B heat-treated bars manufactured by Ford Steel Co.,

Maryland Heights, Mo.

45
This publication reports research involving pesticides. It does not contain recommendations for

their use, nor does it imply that the uses discussed here have been registered. All uses of pesticides

must be registered by appropriate State and/or Federal agencies before they can be recommended.

CAUTION: Pesticides can be injurious to humans, domestic animals, desirable plants, and fish or

other wildlife—if they are not handled or applied properly. Use all pesticides selectively and carefully.

Follow recommended practices for the disposal of surplus pesticides and pesticide containers.

FOLLOW THK LASKL

U.S. »irAITMtNT OF AGIIICUITUIE

U.S. GOVERNMENT PRINTING OFFICE: 1976 0—579-942

46