A guide to erosion reduction on national forest timber sale areas

Historic, Archive Document

Do not assume content reflects current
scientific knowledge, policies, or practices.

A99.5

F763

A GUIDE

TO

EROSION REDUCTION

ON

NATIONAL FOREST
TIMBER SALE AREAS

U. S. FOREST SERVICE
C AL-1 FORM I A REGIOM
19 5-4

(Reprinted 1955)

Cover Photo

Tractor logged area on National Forest
timber sale Stanislaus National Forest

UF^ITED STATES

DEPARTMENT OF AGRICULTURE
LIBRARY

Book number A99.5
, F763

TO

EROSION REDUCTION
ON

NATIONAL FOREST TIMBER SALE AREAS

BY

R, P, McRorey California Region

N. F. Meadowcroft California Region

C. J, Kraebel California Forest and

Range Experiment Station

U. S. Department of Agriculture
Forest Service
California Region

and

California Forest and Range
Experiment Station

1954

{ ■ ''

August 22, 1955

FOREST SUPERVISORS:

As California’s population continues to grow, we must expect cor-
responding increases in the demand for services from our forest
areas. It is timely to recall, therefore, that the basic policy under
which the national forests were established placed the "securing of
favorable conditions of water flows" on a par with the furnishing of
a "continuous supply of timber for the use and necessities of citizens
of the United States, "

In the California Region we have been steadily increasing our annual
cut of national forest timber. And, as our access roads reach into
the rougher back country, the watershed problems associated with
timber harvesting become more pronounced.

This Guide has been prepared in response to the need for more
specific help for land managers who must deal daily with soil and
watershed protection problems. These guidelines have been de-
veloped primarily by observation of methods and results.

Good results don’t just happen - they come from adequate planning,
good timber appraisals and through the skill and cooperation of the
timber operator who puts the planning into effect. Don’t hesitate to
enlist the aid of your timber operators in planning for a good logging
job which will minimize soil and water damage. Many of the approved
methods or guidelines described were developed with their assistance.

Just remember too, that the objective is always prevention of damage
and by the most economical means with appraisals giving recognition
to necessary costs.

We sincerely hope this set of guidelines will be helpful to you. Those
who have put them together freely admit it doesn’t cover all situations.
It is our hope that as the recommended measures are used they will be
improved or replaced with better innovations to be recorded and illus-
trated in future revisions of this Guide, Our present goal is a compre-
hensive review in two years to be followed by desirable revisions for
improvement.

CLARE HENDEE

Director

California Forest & Range

Regional Forester
California Region

Experiment Station

.'tv

PREFACE

This handbook is the outgrowth of the experience and ideas
of many men. Good ideas in forestry, as in other fields,
often grow into practice without record or even knowledge
of their originators. In California, the record of action
to reduce watershed damages associated with logging is
incomplete, and it is possible to set down only a few inci-
dents that are of record.

In 1946, an informal team, including T, R, Littlefield,

Duncan Dunning and Charles Kraebel, examined a going
sale on the Tahoe Forest, and recommended measures to
safeguard the soil and water resources in a prospective
extension of the sale on an adjacent area. The next year,
in response to a request from the Sequoia Forest, a larger
team, including the same three men plus Russell McRorey
and D'Arcy Bonnett, did a similar but more detailed job
for a proposed sale in the Hume Lake area. Copies of
their recommendations were sent to all R-5 forests by
Regional Forester P, A, Thompson on November 12, 1947.

During 1952 and 1953, a field examination of representa-
tive timber sales throughout the Region was carried on by
N. F. Meadowcroft, McRorey and Kraebel, with a view to
gathering material for a handbook that would have Region-
wide application. In 1953, the Forest Supervisors of the
Region, at their annual meeting, formally requested the
issuance of such a handbook.

♦ \

The Guide was prepared under the direction of T, R,

Littlefield by the last-named three-man team, most of the
photographs were taken by them, and the sketches were
drawn by Jack Serex, The manuscript was reviewed by
several divisions in the Experiment Station and the Regional
Office, Review and revision of the final draft of the Guide
was made by C. N. Strawn and W, R. Howden, Revisions
have been freely made, but all who have had a hand in the
book appreciate that it could well be amplified at many points.
They realize, however, that in many situations a book can be
only suggestive, and that the real job of developing an adequate
technique of watershed protection in logging areas will be done
by the men in the forest.

CONTENTS

Page

I. Introduction 1

II. Principal Factors Influencing Watershed Conditions

A. Natural Physical Factors 2

B. Factors Introduced by Use 5

1. Cutting Practices and Slash Disposal 5

2. Yarding and Skidding 6

3. Road Construction and Maintenance 6

III. Watershed Protection Measures 9

A. Advance Planning of the Logging Operation 9

B. The Cutting and Yarding Operation 15

C. The Road System 37

IV. Suggestions for Further Reading 77

I. INTRODUCTION

In the process of harvesting national forest timber in California,

80, 000 acres are presently being cut-over each year to provide
lumber and other forest products. Removal of the older trees
usually results in timber stand benefits in the form of new tree
seedlings, and of accelerated growth that may accrue on trees
left after a partial cut. By contrast, the disturbances to the
soil and water resources are often harmful. The kind and extent
of damage vary greatly, depending on the amount of timber re-
moved, method of logging, type of soil, roughness of terrain,
and weather conditions.

The injuries to soil and water, collectively termed watershed
damages, are briefly described as follows: Soil is loosened and
often extensively displaced by road construction and skidding. In
places, compaction by heavy machinery, and changes in configura-
tion of the soil surface by roads and landings, cause increased
water movement over the surface and the formation of new water
courses. Eroded soil and logging slash lodged in streams may
cause serious damage to fish life. During high water stages some
of the soil may be carried into water storage reservoirs miles
away from the logging areas.

Not all timber sale operations will involve equally all these forms
of watershed injury, of course, but every sale will involve some
of them. Since most sale operations are located in major water
source areas of the region, special efforts are justified to con-
serve the soils and safeguard the water yield of the sale areas.

It is the purpose of this guide to provide practical aids in the form
of photographs, sketches, specifications, and other information
that will be helpful to those concerned with harvesting timber with
the least possible damage to the soil and water.

1

II. PRINCIPAL FACTORS INFLUENCING WATERSHED CONDITIONS

For purposes of this guide, the chief indicators of watershed
condition are the stability and permeability of soils, and the
quality and regularity of water flow. The principal factors
influencing these characteristics of soil and water are of two
broad types: Those imposed by nature, and generally beyond

man's control; those introduced by man's use, and generally
subject to his control. Both must be considered in planning
a timber harvesting operation to be carried out with minimum
watershed damage.

A. Natural Physical Factors

The principal natural factors which influence soil stability
are geology, soil, slope, precipitation, and vegetation. In
any prospective logging area these factors can be evaluated
to provide a basis for estimating the risks of erosion involved
in harvesting the timber.

To facilitate such evaluation the tabulation on page 3 provides
a rough comparative rating of erosion hazard based on various
combinations of the natural factors affecting erosion. Used
with judgment, this key will serve as a check list in appraising
the erosion potential of any particular area. The map on page 4
showing the broadly generalized geology of the forest areas of
California is to be used with the tabulation.

- 2 -

RELATIVE EROSION HAZARD OF LOGGING AREAS
IN RELATION TO SITE FACTORS

: SITE FACTORS

HIGH

EROSION

HAZARD

MODERATE

EROSION

HAZARD

LOW :

EROSION :
HAZARD :

: Parent rock

Acid igneous

Sedimentary and
Metamorphic

Basic Igneous :

Granite, Diorite,
Volcanic ash
Some schists

Sandstone, schist
shale, slate,
conglomerates
chert

:(Lava rocks) :

Basalt, Andesite:
Serpentine :

: Soil

: (Examples)

II

Light textured, x

with little or
no clay

(Holland, Decom-
posed Granite)

: Medium textured
with considerable
clay

(Hugo and Jose-
phine)

Heavy textured, :
'.largely clay and
adobe ;

(Aiken, Under- :
wood) :

: Slope

Steep

(Over 50%)

Moderate
(20 - 50%)

Gentle :

(0 - 20%) :

: Precipitation

Heavy winter
rains or summer
storms

Mainly snow
with some rain

Heavy snow or :
light rain :

: Vegetation and
'.other organic
: matter on and in
:the soil

None to very
little

Moderate

amounts

Large amounts:

1. To be used in conjunction with accompanying map - "Generalized
Geology of California. "

Soil texture refers to the size and distribution of mineral particles
in soil, the range extending from sand (light texture) to clay
i (heavy texture) .

- 3 -

National forests of the California Region

- 4 -

B. Factors Introduced by Use

In contrast to the natural physical factors which are beyond
control by man, there are other factors influencing erosion
on every logging operation, which are introduced by man's
use and are subject to his control. These include such things
as cutting practices, yarding of logs, and road construction
and maintenance. Each may create problems of soil and water
damage, but careful planning can minimize their effects and
reduce the amount of corrective work needed after logging.

Specific prevention and protection measures are presented in
the following pages, arranged in the order in which they will
usually be considered or encountered.

1. Cutting Practices (Timber Marking) and Slash Disposal.

There are timber areas where natural conditions are in
such critical balance that any disturbance of cover or soil
would result in irreparable damage, and the land manager
must be alert to recognize and exclude them from cutting
areas. In most cases, however, a cutting practice which
assures the maintenance of proper watershed conditions can
be developed.

The amount of soil disturbance in selective logging has been
found to vary proportionately with the intensity of cutting.

It follows that a light or moderate selection cut is generally
desirable for soil maintenance and watershed protection.

However, in some areas, and in certain forest types, there
are sound economic and silvicultural reasons for heavy
cutting or even clear cutting. This is particularly true in the
coastal Douglas fir type where steep topography and heavy
rains aggravate the hazard of erosion from truck and tractor
roads. In localities where clear cutting in patches is a
desirable silvicultural system, uphill cable logging may cause
less disturbance than a heavy selection cut with tractor logging.

Where clear cutting or exceptionally heavy cutting is employed,
it should be recognized that special precautions for watershed
protection may be required. It should be possible to plan and
execute a clear cutting layout so that roads, landings and
yarding trails are just as satisfactory as in a partial cutting.

- 5 -

Logging slash is an important item in prevention of
erosion and watershed damage. Slash and logging
debris allowed to accumulate in natural drainages can
stop the free circulation of fish and destroy the fish
themselves. By diversion of stream flow, slash tangles
can cause severe erosion damage. On the other hand,
some slash can be used effectively as a mulch on road
fill slopes, skid trails, and other exposed ground sur-
faces to prevent undue soil movement and to promote
stabilization.

2. Yarding and Skidding

This phase of the logging operation must receive special
attention in order to minimize erosion. Skidding or yarding
may cause damage in several ways; Loosening and moving
of soil in ridges at the sides of skid trails, compaction of
soil by movement of equipment and logs, and the "channel-
ling" of the ground surface by repeated passes of equipment
and logs to the landings. The resulting erosion damages
vary with the amount of timber cut per acre, type of equip-
ment used, care in logging, and natural vegetation ground
cover.

3. Road Construction and Maintenance

Properly located, constructed and maintained, roads need
have only a minor adverse effect on watershed conditions.
When location, construction and maintenance are not given
the careful attention they should have, however, roads can
become a major problem in watershed management. Details
of the problems involved and the various methods of solving
them are brought out in Part III, Section C.

For the purposes of this Guide, logging roads are classified
as follows:

Main Roads - The important main access roads

leading from the logging operation
to an outside point, and the main
haul roads within the logging opera-
tion. They are permanent roads,
and usually are on the Forest Road
System.

- 6 -

Secondary Roads

Temporary Roads '

- The principal lateral and more
important spur roads largely
•within the logging operation area.
Usually permanent Forest Road
System projects, but may be
non-system in some cases. If
"on system, " and retired between
timber cuts, they should be given
M4 maintenance classification.

- All other roads within the logging
operation which are used for one
or two seasons only and then re-
tired or "put to bed. " These roads
are seldom Forest Road System
projects, but when on the system
are given M4 maintenance classifi-
cation.

- 7 -

Cut-over area on very steep ground with slopes up to 70 percent.
As the result of careful planning, advance location and construc-
tion of the road and tractor trails, logging has been done without
serious erosion or other damage to the watershed.

Protective strip of vegetation about 50 feet wide left along a
stream to protect banks and preserve natural conditions for fish,
wildlife, and attractive appearance. A very desirable practice
anywhere, but especially so near recreation areas and adjacent to
highways. The surrounding area in this instance was heavily logged.

- 8 -

j 7^p/ca/ P/cm for Loccr / Preo.

- 9a -

III. WATERSHED PROTECTION MEASURES

A. Advance Planning of the Logging Operation

A detailed advance plan coordinating the economic,
silvicultural, engineering, • and protection needs of
the sale area results not only in less damage to the
watershed but also in a more efficient logging
operation. Field examinations made in connection
with this Guide have disclosed that where watershed
disturbance has been least, and the amount of required
erosion control work minor, the logging operation had
been well planned in advance and the plan well carried
out. Photo No. 1. Such planning can best be co-
ordinated with the collection of data for stumpage
appraisal. The finished plan should be put in the
hands of the officer responsible for the administration
of the sale well ahead of the start of road construction,
felling and skidding. Some refinement of generaliza-
tions may properly be left for the project sale officer,
and this should be specified in the plan which forms a
part of his written instructions.

The first step in planning is to evaluate the critical
features of the whole logging and timber harvesting
operation. The proposed timber sale is analyzed in
relation to its effect on site values (soil productivity,
vegetation cover, forage for game and livestock, and
recreation) and on downstream interests (fish life,
reservoirs, irrigation). Watershed protection require-
ments for the logging operation and post logging treatment,
if any, are determined in consideration of the several
natural factors which affect the erosion potential.

Aerial photos, particularly when used stereoscopically,
in conjunction with on-the-ground examination of the
area will be found helpful in selecting landing sites and
road and skid road locations.

The second step is to set up guides or specifications
for erosion prevention or control measures for each
successive stage in the logging operation. The specific
requirements should be set down in text form, and keyed
to a map of the sale area, to guide the project sale officer
in administering the following:

- 9 -

1. Timber marking (cutting) - -including such items as the
designation of areas to be left uncut, or to receive
special marking to minimize erosion or prevent the
clogging of streams.

2. Transportation system- -including standards and
locations of permanent and temporary roads and
stream crossings (bridges, fords, culverts),
construction methods and restrictions thereon,
drainage and stabilization of road slopes or other
disturbed areas, watering and blading of unsurfaced
roads when necessary.

3. Skidding or yarding- -including location or restrictions
on location of skid trails, skid roads, tractor roads,
and landings.

For the purpose of this Guide the several types of
skidding or yarding roads used exclusively by tractors
to move logs from the stump to the landing in logging
operations are described below:

(a) Tractor Road - A road constructed or graded
in advance for the actual log skidding operation.

(b) Tractor Trail - A route not constructed in
advance but developed by much tractor skidding.

(c) Skid Trail - A trail not constructed in ’advance
and used only a few times by tractors.

4. Corrective and preventive measures required of the
operator, or to be done by the Forest Service where
applicable. These include any necessary treatment of
cut-over area, skid roads and trails, disposal or use of
slash in preventing erosion, removal of temporary log and
dirt fills from drainage channels and of logging debris from
streams, cross ditching of roads and skid roads, restoration
of landing surfaces, etc. The disposal of slash not used for
erosion control, should be in accordance with current
Regional slash disposal policy.

10 -

SELECTION OF AREAS TO BE CUT, GIVEN SPECIAL TREATMENT

OR LEFT UNCUT

Protection or "leave" strip along slope adjoining a creek. Area
upslope at left was heavily cut. Protection strips like this help
preserve favorable conditions for fish, wildlife, and recreation
where these values are important.

A clear cut "unit area, " well handled, on a moderate slope at head
of a ravine with intermittent streamflow. After logging, the ground
surface was stripped of competing brush and undesired trees. Most
of the slash was burned, but a small amount was pushed into the draw
to check runoff and trap any eroded material, then the cleared area
was seeded and planted. For good watershed management this method
is not advisable for areas larger than about 5 acres, nor for very
steep slopes, or erodible soil, unless special precautions are taken
to control runoff and erosion.

11

SALVAGE LOGGING IN BURNED AREAS

Washout of fill across a stream in salvage area, after logging,
necessitated reconstruction of the road to give access for planting
and seeding. Such washouts occurred at a score of crossings on
three contour roads in this burn, the eroded material coming to
rest in a power reservoir 3 miles away.

Severe erosion in a burned area aggravated by a timber salvage
operation. Note the rill erosion down the skid trails and edge
of a large gully in foreground caused by a road. In the interest
of good watershed management, careful consideration should be
given as to whether logging in such an area is justified, and
whether adequate treatment can be provided to prevent excessive
damage.

12 -

STREAM CHANNELS

Stream channel heavily obstructed by logging slash and erosion
debris from heavy cutting. Logging waste dumped indiscriminately
in streams in this manner destroys their fishing and recreation
values and creates a severe fire hazard.

Heavy cutting along this main stream was done with very little dis-
turbance of banks or channel. The trees were felled away from the
stream and hauled out over the tractor road at left, located well
above water level. Most of the logs on the far side of stream were
skidded to a road 200 to 300 feet up the slope at right. Broadleaf
vegetation left along the streambanks, and released by removal of
the conifers, will soon shade the stream.

13 -

STREAM CHANNELS

9.

Stream channel left in good con-
dition after logging. Although
there is a truck road on right
slope and a tractor road on left
slope, the stream- side vegetation
is undamaged, and the overcast
from the road (right foreground)
has caught at a safe distance
above the creek, leaving a clear
undisturbed waterway. (Man in
center stands on stream bank.)

A small stream, choked with silt and logging debris, and with all
riparian vegetation destroyed. Care in logging along the stream
and on the watershed to reduce these damages would have entailed
little additional expense.

- 14 -

B. The Cutting and Yarding Operation

The actual felling and removal of timber need result in only
nominal disturbance of the soil and watershed. To achieve
this requires exercising discretion and judgment, as well as
observing certain practices and restraints in the cutting
operation. The following procedures and practices are
recommended in preparing specific guide lines for the
project sale officer.

1. Selection of areas to be cut, marking, areas to be given

special consideration or left uncut.

(a) Examine critically cutting proposals on light erosible
soils in heavy rainfall country especially where
marking will remove more than 40 per cent of the
volume or where slopes exceed 30 per cent.

Burned areas to be salvage logged require special
consideration. As the normal protective cover of
undergrowth, litter and humus has been destroyed,
a mechanical disturbance of the soil is likely to
increase the erosion and downstream damage.

There may be instances where the proper decision
will be to refrain from logging rather than to
attempt to salvage the fire-killed timber.

(b) Adjust the marking to local conditions of soil, slope
and precipitation so as to provide lighter cuts on
steep slopes or light erosible soils and heavier cuts
(where desirable) in flatter terrain or erosion resis-
tant soils.

(c) Leave an uncut protective strip along live streams
and around the edge of meadows, or carefully remove
only selected trees to attain the same objective.

(d) Fell trees away from drainage channels, both live
and dry, in order to keep slash out of water ways.
(Note a commendable exception in picture number 4.)
Fell trees toward skid roads to limit the haul distance
and to minimize ground disturbance by tractors in
assembling a load of logs.

- 15 -

v5 ^ Lana'/n^ /n ^v'/ne J-^re<7/r?

PJan.

j Lcrr)c//'/7y /n Ory ^ P/an .

- 16 -

2. Selection of landing sites.

(a) Landings should be located on firm dry ground.

In moderate terrain this is easily attained; in
steep country careful reconnaissance of the
sale area and designation of landing sites will
minimize watershed damage.

Some of the best landings observed have been
made by widening the haul roads at some dis-
tance from water courses. Material for the
extra fill may be borrowed from a long stretch
of road rather than a single spot, thus keeping
the cut slope low throughout. Cribbing on the
downhill side with cull or unmerchantable logs
and chunks may also be used to support a landing
fill and thus minimize excavation.

17 -

LANDINGS

Excellent example of large landing in dry ravine at end of road, made
level from road excavation. The road slopes toward landing. Drainage
dip on opposite side, at junction of landing and road, carries local
runoff over edge into logging debris without erosion. The cull logs
and organic matter at right have been well placed to prevent washout
of the landing.

Good small landing on road serving local area of dry ravine at right.
Ditch across far side beyond the car carries winter runoff into debris
below the road without erosion.

18 -

LANDINGS

Combination of skid- road, landing, and temporary road in a stream
channel. No treatment whatever was applied, the result being
erosion of ravine bottom and diversion of winter runoff down road
and over bank in the foreground. If this placement of landing was
necessary, the skid-road should have been treated with slash after
logging, and a sizeable channel constructed across landing with a
levee at the road junction.

Combined landing and water-hole for trucks along secondary road, as
left after logging. Overflow from pool has run down road softening
and eroding it for a long distance. Pool should have been drained
by dip or culvert across road and emptied harmlessly into slash be-
low the road.

19 -

LANDINGS

Landing in disintegrated granite soil below a steep slope that was
heavily cut and tractor logged - with too many skid trails, poorly
located, and not drained after logging. Uncontrolled runoff from
trails gullied the landing, repeatedly blocked a forest highway,
and carried much sediment into a popular fishing stream. With
such site conditions, extraordinary precautions in logging should
have been taken, or the slope left uncut.

Landing above a secondary road and beside a live stream. Logging
slash in channel caused log fill to clog, and subsequent overflow
to damage the road. Removal of the log fill and restoration of
stream channel would have prevented the damage. Such simple
precautions should always be taken where live streams are involved.

- 20 -

LANDINGS

Small landing along temporary road properly cleaned up, and an ade-
quate drainage ditch constructed. Erosion is negligible and area
is well established.

21

Where a landing must be made in the channel of an
intermittent stream, adequate drainage should be
provided for the period of use. Immediately on
completion of logging the channel should be cleared
to its full capacity and the fill material and debris
spread along the road or slopes where it will remain
stable.

Upon abandonment, all landings should be erosion-
proofed by adequate ditching or mulching with forest
litter, as needed, to prevent erosion. Where landings
will be used again in repeated cutting cycles, seeding
to grasses may be desirable if required for erosion
control, otherwise restocking to coniferous species
should be the objective.

3. Yarding and skidding

(a) Limb all logs before yarding to minimize the
damage to reproduction and the soil disturbance
incurred through movement of unlimbed logs.

(b) Consider restrictions or limits on type and size
of equipment to be incorporated in the timber sale
contract (this should be done before the sale is
advertised) with a view to minimizing disturbance
of soil and reproduction.

(c) Ground skidding may be required for sale areas
with heavy reproduction and pole stands, with use
of logging "arches" restricted to selective logging
in more open stands or to patch clear-cutting
operations .

- 22 -

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/////s/a'e o>z. ZVe/i/z. Brass' 7~or> ro Oerr/zv /^oas^nrs

Fij.6, iocaJ-/'or) of Skie/ ^ac/s arF Trai/s ar?F k/a/er-Brea As F^oa/vo
Tbr> ro S^kcsss / G/^rinss.

- 23 -

(d) On excessively steep slopes it may be desirable to
preclude tractor logging and require cable logging.
Cable yarding or ground skidding with tractors uphill
will avoid the converging-trench pattern of downhill
yarding which causes accumulation of water and
concentration of run-off.

In this canyon both soil and stream have taken a "beating"
from the logging operation. This example is not unusual
where steep topography and heavy rains aggravate watershed
damages. Much of this damage could have been prevented
by better planning and greater care in logging but the ultimate
solution might lie in some adaptation of aerial yarding of logs
by cableways.

- 24 -

TRACTOR ROADS

Tractor road in very light (disintegrated granite) soil on 25
per cent slope. Shows erosion and accumulated sand at end of
continuous one-fourth mile run. A water turn-out has since
been constructed in the foreground, but additional water breaks
with outlets should be installed at intervals of 100 feet, including
one at the bend in the road. This skid road could and should have
been constructed with several breaks in the grade.

20.

'Tractor road in light d. g. soil, constructed on long continuous
grade (25 to 30 per cent) across several ravines in steep country.
While general location is satisfactory, complete lack of drainage
caused severe erosion during a very heavy rain. The grade should
have been broken at each ravine crossing and all waterways properly
opened up after logging. Also, water-breaks between ravines, slash
in the road, and reseeding, should have been employed in this case
because of the large amount of bare and highly erodible soil.

25 -

TRACTOR ROADS

Tractor road along creek. Good location, well above high water
level, with a fringe of streamside vegetation, and no unnecessary-
soil disturbance. All logs from a large area were arch-skidded
over this road, and across the creek at a s'ingle crossing just
below this spot. (See Photo 25.)

22.

Tractor road in very steep country and light soil. Good location
roughly on a contour with breaks in grade, localizes drainage and
minimizes erosion. Low points on the grade should always be in
the ravines to prevent diversion of stream flow down the road
during high stages. Photo also illustrates use of cedar (or cull
tree) for a bumper or rub tree where tractor road turns.

- 26 -

TRACTOR ROADS

23.

Tractor road in a salvage logging area sho-wing a well constructed
water-break. This should have been augmented by placement of
slash across the road in foreground to prevent rill erosion. In
parts of this area grass seed was sown broadcast, and trees were
planted. (Looking downhill)

24.

Tractor road on 35 per cent
grade in very rocky soil.

In spite of the rocky soil,
erosion has been severe,
owing to the accumulation
of water from the roadway
and adjacent ground. Most
of this could have been
prevented if water-breaks
had been installed after
logging. Due to the flat-
ness of the terrain on both
sides of the road, the breaks
should extend well out into the
adjacent slash.

- 27

TRACTOR ROADS

Excellent tractor road crossing of a perennial stream in good
location with adequate slope on both banks. This prevents stream
diversion into road. All the logs from about 100 acres came out
over this crossing with little or no damage to the stream.

TRACTOR TRAILS

Tractor trail in bottom of a shallow ravine. Even though the
watershed is small, there has been considerable erosion from
one winter's runoff. Skidding down the intermittent waterway
was easy and economical, but after it was done the channel
should have been erosion-proofed by placement of heavy slash.
Under good watershed management the logs from such a basin
would have been skidded out over a tractor road on the slope,
leaving the streambed undisturbed.

- 28 -

TRACTOR TRAILS

Tractor trail on 30 per cent grade in light d.g. soil, completely
stabilized with litter and slash placed by hand. Note the use of
fine material and branches. Water break about 60 feet up slope
turns water out into timber at right.

Tractor trail on 20-25 per cent grade in light d.g. soil, well pro-
tected by a covering of fine litter about one inch deep, and water-
breaks about 100 feet apart, all done by hand. This road withstood
a severe storm without perceptible erosion.

- 29 -

TRACTOR TRAILS

29.

Tractor trail in light
d. g. soil, showing a
stretch of 35 per cent
grade treated by hand
placement of light slash.
With the water-break
visible beyond the men,
and one or two additional
breaks farther up, this
entire trail was effec-
tively erosion-proofed.

Tractor trail heavily
treated with slaslj placed
by hand and crushed into
place by one pass of a
tractor. Erosion control
complete, despite steep
grade of 50 per cent and
light d.g. soil. Such
dense placement of material
is seldom necessary, but it
may be the only practical
treatment for short steep
pitches or trough- shaped
trails .

30.

30

TRACTOR TRAILS

31.

Tractor trail in very-
light d. g. soil down a
steep ravine and across
a live stream, with no
regard for soil conser-
vation practices. Much
material was excavated to
make the fill across the
creek in foreground and
upstream, leaving unpro-
tected slopes and banks.
Erosion has been severe,
is still active, and stream
is heavily silted. This bad
situation could have been
prevented by proper planning,
location, and construction.

32.

Tractor trail on a steep slope
(55 per cent) in light soil,
heavily eroded. Actually,
this is a "bootleg" trail or
shortcut from a well located
tractor road around hill to
right. Treatment now re-
quired consists of water-
breaks (one at top and another
midway down slope), liberal
application of slash, and
possibly seeding to grass.

31

TRACTOR TRAILS

34.

Skid trail "trench" on a
30 per cent slope showing
ineffective treatment.
Erosion has continued be-
cause of poor placement of
short pieces of branch wood
without proper contact with
the ground, and absence of
water turn-outs. Large
material like this should
either be crushed down with
tractors or mixed with finer
material to create effective
water-breaks .

33.

Severe erosion of a short-
cut tractor trail down a 50
per cent slope in very light
d. g. soil. Erosion to bed-
rock at lower end of trail
was caused by water accumu-
lated from one-fourth mile of
undrained trail above. This
trail needed water breaks at
about 100 feet intervals, in-
cluding one at head of this
slope, and a good application
of slash on the steeper pitches.
Moreover, at this spot the
trail should have angled down
the hillside to the right on a
gentler grade.

32

SKID TRAILS

36.

Skid trail on a 30 per cent
slope in compacted granitic
soil, showing erosion which
occurred prior to treatment.
The water-break being dug
in foreground will divert
the water into litter above
logs. The man above is
placing slash in the gully,
but another water-break
farther up the slope at the
turn might be needed.

35.

Skid trail beside a small
water course. This trail
is located well away from
the water course and
crosses it at a point (in
foreground) where it will
not divert stream flow.

A light treatment with
small slash and limbs
has held erosion in check
thus far, but a heavier
application is needed because
the light soil is easily eroded.

33

(e) Tractor roads, tractor trails, and skid trails.

These terms refer to the various routes by -which
logs are tractor- skidded from stump to landing and
differ only as to degree of advance preparation.

Tractor roads, unlike trails, are graded in advance
of use to facilitate the hauling of logs on very steep
ground or other critical areas. Although the standards
of alignment and gradient are much lower than for
truck roads the same general principles of careful
location and construction apply. As the chances for
erosion are higher, the attention given to drainage
and soil stabilization must not be minimized.

It has been found that some of the worst cases of
skid trail erosion encountered could have been
avoided if the trails had been scouted and flagged
before use. Advance location is particularly needed
in rough terrain: The flagging job must be done by a

man on the ground, not by a tractor operator who
cannot see well uphill.

Long steep grades should be avoided and maximum
pitches should be based on local conditions of soil
and rainfall. Grades above 30 per cent should be
the exception rather than the rule. Use natural
undulations in slope to facilitate drainage; on long
grades where no natural undulations exist, introduce
dips at suitable intervals as the major drainage
features. Cross drainage placed just above a steep
pitch or grade is more effective than if placed halfway
down.

In general keep tractor roads out of streambeds, whether
perennial or intermittent. Locate on slopes far enough
above streams so that overcast material will not reach
streams. In steep terrain, where use of a dry channel
will result in less soil movement than grading a tractor
road on the slopes, such channels may be used, provided
the channel is properly regraded and cleared of slash
after logging to permit full stream flow in the wet season.
No logs or chunks should be left in a gulch bottom in such
position that water will be diverted against either bank
and erode the toe of the slope or cause waterfalls that
will gouge out the channel bottom.

- 34 -

(f) Keep bulldozers and other heavy equipment out of
live streams and off of meadows as much as possible.

Stream crossings for tractor skidding should be
carefully selected in places where they will cause
the least disturbance of streambed and streamside
vegetation, such as at bedrock or gravel bottoms.
Occasionally bedding a line of boulders or a log on
the downstream side will support a tractor crossing
for the duration of an operation. When skidding
across a stream is completed, the channel should be
promptly cleared of slash, and the streambed restored
as nearly as possible to its natural shape and grade.

Where skidding across a channel is necessary, the
crossing should be made with enough adverse grade on
the downhill side to prevent any water from being di-
verted into the skid tracks from the streambed. The
interception of even small lateral rivulets on slopes
has often started skid trail rills which were harmless
in summer but became large gullies during the sub-
sequent rainy season. (Photos 31 and 33).

Short cuts between switchbacks on well located tractor
trails have been another source of severe erosion.
(Photo 32). Advance instructions to the cat skinners,
and close supervision during skidding, can eliminate
this trouble.

(g) Meadows: It should be emphasized that, by reason of

their position in most watersheds, unbroken meadows'
perform an important function in storing water to
supply summer flow for springs and streams. This
may equal or exceed their value for grazing, and
justifies the precautions suggested with regard to
logging near them.

Meadow crossings by roads and skid trails have been
responsible for gullying, draining and drying up
meadows that were previously well watered and green.
Tractor and skid trails should not ordinarily be per-
mitted to cross meadows. It is usually possible to
skirt meadows, but where this is not possible they
should be crossed at a narrow point on fill material
which has been hauled in. (Photos 52, 53, 54).

35 -

4.

Treatment after Logging

This is largely a matter of providing drainage and some form of
soil stabilization on the trails. The work should be done promptly
after skidding is completed, and before the beginning of heavy
precipitation. Several examples of bad erosion were observed
which occurred because heavy autumn rain or snow stopped the
logging operations, and the necessary equipment was moved out
before any protective work could be done. In California logging
areas, precipitation after October 1 is always probable, hence
most of the watershed protective work must be completed by
that date.

Slash disposal has generally been considered solely from a fire
hazard reduction viewpoint. Lopping of tops and piling or bunching
and burning are the most frequent methods of reduction of such
hazard. The opportunity of utilizing slash from tops and other
logging debris in positive measures to minimize or prevent erosion
damage should not be overlooked.

In patch clear cutting on erosible soils, the windrowing of slash
along contours may be more desirable than the usual scattering
or piling and burning.

Slash and litter placement in skid trails properly done will pre-
vent soil movement and divert excess water out of trails; improperly
done it is ineffective, wasteful of effort and may even aggravate
the erosion problem. The material must be in good contact with
the soil and the larger pieces at such angles that they will lead
water out of the skidway at many points.

Best results have been obtained by using a mixture of large and
fine material, first placing the large pieces such as branch wood
and small logs diagonally across the trail, then tossing twig
and litter material between them, and finally passing a tractor
down the trail to press the slash into contact with the soil (Photo 30).
Where the tractor pass is not made greater care should be used
in placing the slash, and more fine material should be placed
between the large pieces.

Slash should be placed only where needed. Not all skid trails
require it, and most trails need it only in spots. Mulching with
slash is particularly adapted to trough- shaped trails in which it
would be difficult and very costly to build water-breaks, to short
trail-ends where slash mulch will do the necessary control more
cheaply than dozer-built ditches, and to places where the maneu-
vering of a tractor would damage surrounding young trees.

- 36 -

In general, the combination of well-placed water-breaks,
interspersed with slash placement in critical spots, will
give the most effective protection to tractor and skid trails.
How much of this to do by hand and how much by machine
will be determined by conditions on each project.

Water-breaks or cross-ditches are most economically built
by a bulldozer working down- slope. If the tractor passes
over them after they are shaped they usually require some
hand work to open the ditches and reshape the down-slope
berms (Photo 23). Cases have been observed where the
bulldozer work was wasted because the berms and ditches
were not reshaped. The breaks should be spaced closely
enough to prevent development of gullies between them.

No fixed spacing will apply everywhere. On steep grades
and very erodible soils they should be closer than on gentle
slopes and rocky clay soils.

Thoughtful and timely application of preventive measures
will minimize damage from timber harvesting. Each forest
officer must be alert to develop and apply additional measures
which will meet local needs. One measure that still needs
serious attention is the safeguarding of streamside vegetation.
This has been touched on in the discussion of cutting practices,
but it needs emphasis. With care, mature trees can be cut
from the very bank of a stream without excessive damage
(Photo 8). But there is needed a determined effort to log
more carefully in the vicinity of streams for the purpose of
maintaining more natural streamside conditions, even though
this will occasionally require leaving some merchantable trees
uncut.

C. The Road System

The logical development of a road system in a working circle or
operating area follows these steps in order:

1. Planning, Reconnaissance, and Location

2. Construction

3. Maintenance

4. Retirement or "putting to bed. "

- 37 -

The first step is actually three important steps, but these are
so closely, related that for the purpose of this Guide they are
treated as one.

To insure proper attention to watershed problems in planning
logging road systems, and in the reconnaissance and location
of roads, there can be no substitute for sound engineering
procedures and methods carefully applied by skilled personnel.
The details of these engineering procedures are beyond the scope
of this Guide.

1. Planning, Reconnaissance, and Location of Roads

The following pictures (37-54) together with the related
descriptions and text, illustrate some of the more trouble-
some points in connection with planning, reconnoitering and
locating logging roads.

a. Locate the roads to serve the type of logging planned,
i. e. , tractor, cable, etc.

Picture 37 illustrates a typical satisfactory road system
layout for a tractor logging job. In this case the terrain
is somewhat broken but on the whole is not too steep for
efficient tractor logging. The road system layout would
work equally well for a timber sale in which the terrain
was not so broken.

Picture 38 illustrates a marginal type country between
that which should be tractor logged to contour roads,
and that which can best be logged uphill by high-lead
cable methods. The area was logged by tractor to three
contour roads. With a high-lead system, one road--the
lowest one, which involved the most excavation and
erosion- -would have been eliminated. The two upper
roads would have been spaced farther apart, and the
whole area logged with much less soil disturbance.

- 38 -

Aerial view of burned area on steep varied terrain showing
road and tractor skid trail system used in timber salvage
operation.

Aerial view of burned area in steep country, with roughly
parallel ravines. Parallel contour roads are located to
facilitate yarding of logs up or down tractor trails on ridges.
This is a normal system layout for tractor logging.

39

Temporary road properly located along a creek.

40

I

Picture 39 illustrates a secondary road on a good
contour location in typical tractor logging country.
Alignment is good, cuts and fills well balanced and
grades within desirable limits, as evidenced by the
lack of roadbed erosion. It is possible in country
of this type and on a road of this kind to locate
landings and spur road take-offs so as to minimize
erosion damage. A location of this kind with proper
drainage provided will not create a watershed problem.

Picture 40 shows a good canyon bottom location for a
temporary road in tractor logging country. Note that
streamside conditions have been left largely undisturbed,
overcast material caught well above water level, and
screen of trees and shrubbery has been left between
the road and the stream. Fill slopes have been pro-
tected by a raised shoulder. Spur or tractor road
take-offs at intervals can be selected which will cross
to the opposite slope with minimum streambed disturbance.
Although this is a temporary road the location principle
holds good for main or secondary locations as well.

- 41

b. Limit gradients on permanent system roads to non-
eroding values for the soil type.

Picture 41 illustrates a secondary road built on a
location which evidences consideration for the
erosion values of the soil type - in this case a
sandy soil. The gra'des were held to 6% and below,
and ample drainage was provided. No erosion in
evidence. Incidentally, other good features are
illustrated by this picture: Machine shaped back

slopes, ample inside ditch, raised shoulder
(proper for this soil type), and clean roadside.

Picture 42 illustrates use of excessive grade (10% it
for the soil type, a very light decomposed granite soil
Grades in this type soil should be held to 6% or below
if possible. If absolutely necessary to use steeper
grades, the erosion can be minimized by providing
frequent and adequate cross drains (culverts or dips)
to remove ditch water, paving ditches with hand laid
rock riprap, and mulching fill slopes with forest
litter. This picture illustrates another bad feature -
undercut back slope - which results in bank sloughing,
ditch plugging, and accelerated erosion of the road.

- 42 -

Excellent stretch of secondary road on hillside location
in sandy soil.

Temporary road in very light d. g. soil showing deep
ditch erosion.

43

Main road on hillside location in rocky shale soil.

Well constructed temporary road through rolling country.

Abandoned temporary road showing severe erosion of the roadbed.

- 44 -

c. Use undulating or broken grades where possible to
reduce erosion control and drainage work.

Picture 43 illustrates use of undulating grade in a
main road. Although the undulations are long and
rolling, they serve the purpose of providing low
points where water can be taken across the road,
thus reducing ditch and roadbed erosion.

Picture 44 illustrates correct use of undulating or
broken grades on a temporary road. Roads located
and constructed in this manner will require little
in the way of permanent drainage structures - chiefly
those at main stream crossings.

Picture 45 shows the bad results of locations using
long sustained heavy grades unrelieved by grade
breaks or other means of cross-drainage. Grade
breaks at intervals of two to three hundred feet on
this road would have helped to prevent much of this
severe roadbed erosion which has washed away
cushion material down to bedrock in many places.

- 45 -

d. Locate on solid ground above high water levels and,

where possible, well back frora natural water channels.

Picture 46 illustrates a temporary road location along
a live stream. The roadbed is about 25' above stream-
bed - in this case a sufficient distance for excavation
overcast to catch above high water level, A screen of
trees and reproduction has been left between the road
and the stream. This location retains a good appear-
ance of the scenery. It also avoids pollution of the
stream by silt and debris and maintains shade on the
stream, both of which are vital to fish life.

Picture 47 shows the results of a location too close to
the stream channel. In the background the road is
almost in the streambed. There is no apparent reason
why this location had to be so close to the stream. The
cross slopes are light and no rock is in evidence, A
location above and away from the streambed, such as
shown in the preceding picture would avoid this vmsightly
condition and maintain stream conditions largely undis-
turbed. The situation here could have been alleviated to
some extent by clearing and slash disposal in advance of
excavation.

- 46 -

Temporary road in steep country and shale soil,
showing location along live stream.

A small creek polluted with silt and debris from a road
constructed too close to the channel.

47

Main road in difficult location across wet slide area in serpentine-
shale formation.

Main road constructed in a wet location at the crossing of
three ravines.

48

e.

Avoid wet areas or unstable ground.

Picture 48 shows some of the problems introduced
by location through a wet slide area in serpentine.
The outside shoulder has slumped and a slide has
occurred in the cut slopes. The road location
should avoid such areas if possible. Where they
can not be avoided, it is essential to plan de-
watering systems of perforated pipe, and careful
placement, compaction, and stabilization of fill
materials. In this instance a line of perforated
pipe laid in a deep trench in the inside ditch line
with coarse rock or gravel backfill would serve
to intercept the ground water.

Picture 49 illustrates another type of undesirable
location which introduces difficult drainage problems.
The crossing should be made either above or below such
wet areas if possible. If necessary to cross such areas,
the location should include plans for a deep intercepting
ditch, substantial raised shoulder berms with outlets
and application of forest litter to the large fill slopes.
Unless such areas are very large, usually some ad-
justment of grades in adjacent sections will make it
possible to avoid them.

- 49 -

f . Avoid very steep slopes when possible.

While it is often necessary to cross steep mountain
slopes with logging roads, such locations should be
avoided whenever possible. Steep slopes introduce
difficult construction and maintenance problems;
roads built across them require heavy soil distur-
bance and result in aggravated watershed erosion
problems.

Pictures 50 and 51 illustrate some of these
problems. Excavation of roadbed on slopes
above 65% results in long "sliver” fills which
are very difficult to compact satisfactorily.

This results in shoulder settlement, loss of
shoulder berm, and serious fill slope erosion.
The long cut slopes also increase the a’rea
exposed to erosion. Road construction on
such locations frequently calls for special
features such as retaining walls, intercepting
ditches above cut banks, extra large raised
shoulder berms, more frequent drainage
structures, fill compaction and fill stabiliza-
tion. Berm outlets require long down spouts
or paved outlets. Special care is necessary
in providing for drainage to insure that a
minimum of water reaches the exposed surfaces.
Heavy mulching of fill slopes with forest litter
is also usually necessary to prevent erosion
damage. All of these features add to the cost
of the road and emphasize the desirability of
avoiding such locations when possible.

- 50 -

Main road in difficult location, through decomposed granite in
very steep terrain (over 80 per cent), resulting in sloughing and
settlement of overcast fill.

51.

Main road in a problem
location on a very steep
mountain side (80-90
per cent) in light decom-
posed granite soil.

51

Main road well located and constructed. Location around edge
of meadow avoids damage to this important grazing resource.

Secondary road, showing poor location and construction features;
crossing through center of meadow instead of skirting its edge,
and cutting through meadow sod to place the roadbed on mineral
soil below the sod level. This is a certain way to start a gully
across the meadow, by diversion of natural channels.

52

g. Keep stream and meadow crossings to a minimum.

Pictures 52, 53 and 54 illustrate good and bad road locations,
and an example of meadow damage that resulted from improper
road location and construction. It is usually possible to skirt
a meadow by locating the road at the toe of the adjacent slope,
as shown in picture 52. When a crossing through a meadow
is necessary, it should be located at a narrow point in the
meadow, and should be built as a low through-fill with borrow
material from outside the meadow. Ample culverts should
be provided for drainage through the fill.

54.

Example of meadow damaged by road construction. The
roadside ditch, originally formed by excavation of material
for the road, has eroded deeply and drained the meadow,
thus favoring the spread of sagebrush at the expense of grass.
Several check-dams have helped to stabilize the gully, but
have not remedied the damage.

It is also bad location practice to follow a stream, crossing
and recrossing frequently. Each crossing requires a
structure, and maintenance of numerous structures adds
much to total road costs.

53 -

h. Avoid successive switchbacks above each other.

The "Jacobs Ladder" type of location up the face of a mountain,
with successive switchbacks above each other, is very un-
desirable and should be avoided if at all possible. Roads built
on this kind of location cause more disturbance of soil in a
given area than any other type of construction, and as a direct
result cause excessive watershed damage. Maintenance of the
road is much costlier than normal, drainage difficulties are
multiplied, and the road is very unsatisfactory because of the
severe alignment. Avoiding these switchback locations
frequently introduces added construction costs. Considerable
increased cost in construction, however, is usually justified
in the long run by the lower maintenance and damage costs on
the better location.

Every possible alternate location should be thoroughly explored
and considered before resorting to switchback location. Money
spent in reconnaissance and location study will more than pay
off in ultimate savings.

2. Construction of Roads

If careful attention has been given to the planning, reconnaissance
and location of a road project, the construction is made much
easier. It is not within the scope of this guide to deal in detail
with road construction methods. The Forest Road Handbook and
other publications supply such details. The purpose here is to
discuss some important features of road construction which
have a direct bearing on watershed protection and management.

In some cases these features are illustrated by pictures.

a. Clearing in advance of excavation.

Clearing and slash disposal should always be done in
advance of excavation work. This holds true even
though part or all of the clearing is done by bulldozer
or other machine methods. When clearing is done
concurrently with excavation, logs, slash and other
debris are inevitably mixed in with fill material.

This prevents proper compaction of the fill and often
results in erosion of fill material.

Pictures 55 and 56 illustrate this point better than words.

- 54 -

Main road through area with heavy cover constructed without
advance clearing of construction zone. Much slash and logs
are covered by excavation overcast and incorporated in the
roadbed. As this material rots, the road shoulder settles,
disrupting the drainage system, and resulting in serious
erosion.

Main road constructed with slash in fill has resulted in serious
roadbed failure. This is the result of failure to clear the con-
struction zone in advance. The damage is three-fold: road out

of service, high cost of repair, and downstream siltation. All
could have been prevented.

55 -

b.

Excavation and fills.

Correct location in the first place will avoid any large
volume of excess yardage, by careful balancing of cuts
and fills. When excess yardage occurs, however, care
should be exercised to place it where it will not erode
into stream channels. Much waste yardage can be
avoided during construction by moderately rolling the
grade, or slightly shifting the center line to reduce
the excavation needed.

Picture 57 illustrates a case in which poor road location
resulted in badly unbalanced cuts and fills, and poor
construction practice aggravated the situation by dis-
posing of excess material downslope to constitute an
erosion problem. Moderate adjustments to grade and
center line during construction would have prevented
much of this.

Main road in very light decomposed granite soil and heavy
terrain built under very poor construction standards.
Excavation is excessive, with much waste into stream
channel, large areas are exposed to erosion, and
drainage control is wholly inadequate. Result is severe
erosion, with damage to road and siltation of a reservoir •
just downstream.

- 56 -

Picture 58 illustrates an example of carefully
balanced cuts and fills. There is no excess waste
yardage spilled over into the stream channel. A
careful location job followed by correct construction
practice has resulted here in a well balanced stream
crossing and no serious erosion problem. The logs
and slash in the stream channel, however, should
have been cleaned up.

Main road along and across stream, representing good
location and construction practice. Overcast and fill
are retained well above high water level, and shoulder
berm is ample.

57 -

c. Drainage for the road.

A properly planned and located road will have provision
for drainage adequate to the rainfall and run-off conditions
of the locality it serves. The drainage system may be
of permanent or temporary type, depending upon the life
of the road and economic factors affecting road construc-
tion. (See RHB R-5 Supplement, pages 108a and 108b of
9/10/53.)

Picture 59 shows a road which is otherwise well designed
and constructed but, because the cross drainage culverts
are too far apart (500 - 700 feet), the inside ditch is
eroding. In this case culverts spaced at approximately
350 feet would have prevented the ditch erosion, and
resulted in a thoroughly satisfactory road.

Main road on hillside location in rocky soil. Good
features are moderate grade (5 per cent), gravelled
surface, and sloped cut-banks. Although ample in
capacity, drainage ditch tends to erode due to excess
distance between culverts (500 - 700 feet).

- 58 -

Picture 60 illustrates a more aggravated example of
insufficient cross drainage culverts. In this case the
culvert spacing was 700-800 feet on an 8% grade.

Culvert spacing should not have exceeded 250-300 feet
in this case. The excessive spacing has resulted in
volumes of water beyond the culvert capacities. Culverts
were by-passed and serious ditch erosion developed.
Remedial measures for this situation will now require
installation of properly spaced and installed culverts
and filling of the eroded ditch with gravel or other
erosion resistant material. Cut-off walls or dykes
of impervious material will have to be provided im-
mediately below each culvert intake to prevent further
by-pas sing.

Main road at crossing of shallow ravine, showing severe
ditch erosion, drainage failure, and some road surface
damage.

- 59 -

Picture 61 illustrates another type of road drainage fault
frequently found on poorly located and constructed roads.
The curve superelevation (not common on logging roads)
results in an outsloped road surface. No raised shoulder
berm and drainage outlets have been provided at the low
inside edge of the curve. This has resulted in all roadbed
water running down the erosible fill slope, with results
shown in the picture. In this situation, with highly
erodible decomposed granite soil, forest litter mulch and
fill slope planting should have been installed in addition
to raised shoulder berms and paved spillways. Forest
litter mulch treatment is illustrated by Picture 62.

Main road in highly erodible decomposed granite soil,
showing severe erosion of the fill slope, the consequence
of the lack of drainage control.

- 60 -

62.

A mulch of forest litter, in this case mostly pine needles, applied
to a depth of 2 inches to this road fill slope has provided immediate
protection against erosion. The seeds of trees and shrubs which
such litter usually contains will provide permanent cover. This
inexpensive treatment is suited to all classes of logging roads
where erosion proofing is required.

It should be remembered that streams in logging areas frequently
carry trash. The construction of strong and sufficient trash racks
above culvert inlets should be given high priority to prevent
clogging of culverts.

When temporary drainage structures are installed on a temporary
road, the log bridges or culverts should have ample capacity to
carry expected flood flows during the period of use. Removal of
the temporary structures and restoration of the stream channels
should always be required at the end of the term of use.

Picture 63 shows a temporary log bridge on a temporary road.

- 61 -

Because green unpeeled logs were used, this bridge will have
a short life. At h^e enu of the period of log hauling this structure
should be removed and the channel restored. Such structures
should never be built on permanent roads except as an emergency-
measure.

Log bridge on temporary road will accommodate high flows without
damage. Where use of road is known to be for a limited period
this type of structure is preferable to earth-fill crossings which
will wash out every winter.

Picture 64 shows what happens when temporary fills at stream
crossings are not removed and the stream channels restored
over winter. When this type of construction is permitted on
temporary roads, the fills across streams or dry water-
courses should always be removed at the end of the logging
season or period of use. (See Maintenance).

- 62 -

Through fill of a temporary road washed out and carried downstream
during first winter after logging. This damage should have been
prevented, the soil saved, and streambed restored by removing the
fill and spreading it along road in each direction from stream.

Although seldom used during the period of log trucking, and especially
on main roads, drainage dips are an excellent method of removing
road- surface water and discharging it at points where the flow will
not result in erosion. Frequently, at the end of the period of logging
use, drainage dips are installed because they serve very satisfactorily
for other types of traffic. In areas which receive considerable rain-
fall during logging season, properly constructed drainage dips can
serve satisfactorily on secondary or temporary spur roads. One
advantage of drainage dips is that they can be readily removed by a
grader when not needed. Picture 65 and Figure No. 7 show examples
of correct drainage dip construction.

- 63 -

An excellent example of dip construction, showing long roll and
outslope to culvert (at stick left). Drainage dips of this type
kept several miles of road open under very severe rainfall and
ground conditions. The shape of dip should be modified to suit
vehicle, speed, and load.

- 64 -

d. Meadow crossings.

When necessary to cross mountain meadows with logging
roads considerable care is required in construction to
avoid meadow damage. Crossings should be constructed
as low through-fills with material borrowed from outside
the meadows. Ample culverts should provide for drainage
through the fills. Great care should be taken to avoid
breaking the meadow sod. Picture 66 illustrates a good
construction job in crossing a meadow, with the exception
that clearing debris should not have been deposited on the
meadow alongside the road.

66 .

Good example of road crossing a meadow with minimum
disturbance. Crossing is located at a narrow point of the
meadow and has a metal culvert (hidden by log at far side)
large enough to carry run-off from local watershed. Note
that fill is raised above meadow level, the fill material
having been hauled in, and that no excavation has been made
in the meadow.

- 65 -

e. Back slopes

Avoid undercut back slopes during construction. Cut slopes
should never be steeper than 1/4 horizontal to 1 vertical
even in solid rock, 1/2 to 1 in stable mixed rock and earth,

3/4 to 1 in ordinary-stable earth and 1 to 1 or even flatter
in erosible type soils. Cut slopes should be entirely machine
constructed with the bulldozer or grader. No hand polishing
should be done beyond cutting off protruding large roots and
prying loose rocks down off the slope. Hand polishing of
cut slopes is usually a waste of time. Undercutting the cut
slope causes slides which block drainage ditches and divert
water onto the road surface with resulting erosion.

f. Fills

Fills over 10 feet in height in erosible soils usually require
special treatment to secure good compaction. Before placing
the fill all duff and slash should be removed down to firm
mineral soil. The fill should be placed in successive layers
not over 12 inches deep, and each layer compacted by passes
of a bulldozer, carryall scraper or other equipment. In
extreme cases rolling with sheepsfoot roller may be necessary.
Rock and other coarse material should be placed on the edge
of the fill to help protect the fill slope from eroding. Such
careful construction, followed by mulching of the fill slopes,
with forest litter, and in some cases planting of the fill slopes,
will^ result in stable fills with little danger of erosion. Under
no circumstances should end dumping of fills over 10 feet high,
in erosible soils, be allowed.

g. Cushioning material

On permanent roads provide ample road cushioning material.
Require that roadbeds be ripped, and rocks over 6 inches in
diameter be removed from the top 10 inches of the roadbed.

This is one of the most frequently neglected features of
logging road construction and contributes heavily to equipment
maintenance, damaged tires, etc. In case the roadbed material
is predominantly rock and boulders, it may be necessary to
import select borrow material to supply the cushioning surface
to the required depth on the roadbed.

- 66 -

3. Maintenance

The maintenance of logging roads is usually performed by the
timber purchaser under the terms of the timber sale contract.
However, the purchaser can elect to deposit money in the
Cooperative Work fund with which the Forest Service performs
the road maintenance work. In either event the Forest Service
has the responsibility of seeing that the maintenance work is
properly performed.

Regular maintenance as a watershed and road protection measure
cannot be over- emphasized. It should be regular and thorough.
For permanent and secondary roads the following items deserve
special attention:

a. Repair and clear out all drainage ditches, dips, culverts,
and bridges, etc., in the fall and as necessary again in
the spring.

b. Keep damaging traffic off soft roads in the fall and spring.

c. See that the road surface is in good condition as the winter
season approaches.

d. During the hauling season the roads should be bladed fre-
quently enough to maintain a reasonably smooth driving
surface.

e. Earth and gravel surface roads should be sprinkled
frequently enough to keep the roadbed firm and avoid
"dust" erosion of the surface.

In the case of temporary roads that are to be eventually
abandoned, the following work should be done before
winter sets in to prevent erosion and encourage stabiliza-
tion:

a. Install waterbreaks with outlets through the berm, if any,
at 50 to 200 feet intervals, depending on the steepness of
grade, soil type, and precipitation. Such waterbreaks are
readily removed by a grader at the beginning of the next
season's logging.

b. Locate water outlets where growing vegetation, rocks, or
tangles of slash will break the force of the water and thus
prevent the formation of gullies.

- 67 -

Figure 8 and Picture 67 illustrate the proper method of in
stalling waterbreaks for winter when some traffic is
expected to use the road in the "off" season.

- 68 -

Secondary road in decomposed granite, with good surface drainage
for the winter season provided by numerous rolling dips about one
foot deep, at 45° angle, and with a slight outslope.

Picture 68 shows a waterbreak built at right angles to the road.
Such a waterbreak is not self-cleaning; it tends to fill up and
become ineffective.

Temporary road in very light decomposed granite soil showing
improperly built waterbreak, with obstructed outlet and a berm
that is too high and is placed squarely across the road instead
of at an angle of 40 or 45 degrees.

- 69 -

Remove temporary fills and culverts at stream crossings,
making sufficient channel to carry high water.

c .

Picture 69 illustrates the correct fill removal treatment
at the end of the logging season or at final termination of use.

Temporary road crossing of a small stream showing the
channel properly cleared out after logging. Both fill and
logging debris were removed. Erosion on road beyond car
should be stopped by water breaks to drain off surface water.

4. Retirement or "putting the road to bed. "

Putting the temporary roads to bed is one of the most important
erosion prevention measures in a timber sale operation. If
correctly done, very little, if any, damage to the watershed will
result. If incorrectly done or neglected, serious erosion scars,
polluted streams, and silted reservoirs will result.

The methods used will depend upon the soil type, steepness of
terrain, grade of road, precipitation (especially whether it is
mostly rain or mostly snow), road exposure, and other factors.

- 70 -

Following are some very important points to observe in
putting roads to bed:

a. Remove temporary fills and drainage structures in
water channels and clear the channels to allow full
flow of water without erosion.

Picture 69 illustrates the proper method of removing
temporary fills from a stream channel.

b. In porous soils such as volcanic cinders, rocky shale,
etc. , removing the berm and giving the roadbed an
outslope will serve the purpose.

Picture 70 shows a retired road treated in this manner.

Temporary road, on steep hillside (about 60%) in porous rocky
shale soil, "put to bed" after completion of logging. Constructed
on variable grade, with sloped cut-banks and slight outslope, this
proved a very satisfactory road and required little treatment after
use. The break in grade near car, and outslope, together pre-
vent serious erosion in this soil type, thus maintaining the road-
bed for possible future use.

- 71 -

c. In more erosible soils, install water breaks at 50- to 200-foot
intervals, depending upon soil type and steepness of road
grade, to intercept water running down the roadbed. Breaks
should be placed so as to discharge on rock outcrops, in
natural water channels or in heavy brush.

Pictures 71 and 72 show examples of water break construction
in temporary roads.

Secondary road with well built water break, installed at a
good angle and of sufficient size to provide effective pro-
tection for winter conditions. However, if road is to be
traveled during the winter, the break is too abrupt. Both
ditch and berm should be broadened into a dip-and-mound
profile so that vehicles will roll rather than bounce over
them.

- 72 -

Drainage ditch and -water break in abandoned temporary road
functioning effectively after one winter. It would be more
dependable if both ditch and cross ditch were somewhat deeper.
Another water break exists just beyond trees. There is no
erosion, and vegetation is becoming established in the road.

Pictures 73, 74 and 75 illustrate what happens when badly
needed water breaks are not installed.

Abandoned logging road in decomposed granite soil severly
eroded as the result of inadequate drainage. Upon abandonment
water-breaks, at least, should have been constructed. Prefer-
ably the roadbed should have been scarified and planted, since
this is site lA sugar pine land. The gully should now be checked,
because the eroded material is being deposited in an irrigation
reservoir downstream.

73

74

Abandoned temporary road
in rocky soil showing severe
erosion of outside shoulder
and berm by accumulated
water from one-eighth mile
of road. Heavy bank slough
forced water over against the
outside berm, causing the
washout. In this case, the
treatment after logging
should have included removal
of the berm and installation
of frequent water breaks.

Diversion of winter flow of an intermittent stream down this
abandoned temporary road cut out much of the road and de-
posited the debris on a small meadow. The direct cause was
the excavation of the stream bank in foreground and failure to
replace it, and failure to clean out and deepen the stream
channel after logging. Heavy water-breaks at close intervals
would also have helped the situation.

- 74 -

d. Where natural revegetation of an abandoned road -will be slow,
it is sometimes advisable to scarify the roadbed and seed or
plant with trees. When vegetation is firmly established in
the roadbed the erosion problem will be largely cured. Fre-
quently scarifying the roadbed will give enough aid to natural
regeneration to complete the job without seeding or planting.

e. Plating slash or other debris in close contact with the
abandoned roadbed will impede the flow of water and reduce
erosion. This treatment is especially good when, because of
road location, it is difficult to construct water-breaks as
frequently as desirable to prevent erosion. Picture 76 shows
an example of this treatment.

Temporary road protected from erosion after logging by
felling a partly rotted snag, and placing slash in the roadway.
Good contact with ground was obtained by passing tractor
over the fallen snag and slash after placement.

- 75 -

CONCLUSION

When the foregoing methods of logging and road construction are
neglected, the results to watersheds are frequently disastrous
and long lasting. Pictures 77 and 78 illustrate some of these
unfortunate results.

77.

Slash barriers in this stream have
stopped the circulation of fish;
erosion deposits have killed their
food and covered their gravel
spawning beds; removal of stream-
side shade trees has admitted
full sun to warm the shoaled water
above optimum temperatures for
trout. Result: a nearly dead trout
stream.

Spring floods may open some of the
barriers, or pile them into fewer
and higher "dams, " and streamside
trees will grow again. But, unless
the barriers are removed by man,
it will be many years before this
stream becomes once more a
suitable environment for trout.

78.

This large stream, once deep and clear, is now heavily choked
with sediments and debris from improperly logged areas. Each
year during high water much of this material moves down into an
irrigation reservoir, a case in which the watershed damages extend
far beyond their source.

- 76 -

SUGGESTIONS FOR FURTHER READING

Forest Service Manual References

TIMBER MANAGEMENT - TITLE 7.

Sets forth official policy and standards for Forest Management
and Utilization. Sections specifically relevant to watershed
protection are:

102.8 Prohibition of Destructive Methods of Logging

106.6 Timber Management and Protection of Water Resource

203. 11 Transportation Plan

203. 16 Restoration, Repair, or Protection Work by Purchasers

203. 17) Maintenance

203.18)

212. 53 Requirements to Reduce Erosion

ROAD AND TRAIL SYSTEM - CHAPTER 1 OF TITLE 13.

Presents general policies concerning roads and trails. Of special
interest are the sections dealing with Timber Haul Roads: 106.21

through 106.27, and the R-5 Supplement to Section 106.24.

WATER MANAGEMENT - R-5 SUPPLEMENT IN VOLUME III.

Sets forth the objectives and policies of Region 5 concerning the
water resource, its management, utilization, and protection.

Handbooks and Directives

I • .

FOREST ROAD HANDBOOK, By Division of Engineering, Forest Service,
Washington, D.C. Presents forest road design standards, surveys,
plans, construction, maintenance, structures, transportation system
planning, records and reports, construction contracts and specifica-
tions .

DRAINAGE PRACTICE, REGION 5, By Division of Engineering, Forest
Service, San Francisco. Compiled in 1940 as a supplement to the
1940 Truck Trail Handbook. Revision expected within next few
months but old edition has much good material in it,

TIMBER SALE CONTRACT FORM

Contains standard contract terms, including provisions relating to
watershed protection. (Although the contract form does not appear
in the Manual, it is referred to in Sections 203. 58 and 203. 59).

SPECIAL INSTRUCTIONS FOR THE GUIDANCE OF THE FOREST OFFICER
ON THE TEN MILE UNIT SALE, KINGS RIVER WORKING CIRCLE,
SEQUOIA NATIONAL FOREST, CALIFORNIA. Contained in
Memorandum to Supervisors (R-5) from Regional Forester
P. A, Thompson (S-SALES-General) Nov. 12, 1947. (Mimeo.)

THE DESIGN OF MOUNTAIN ROADS AS INFLUENCED BY SOIL TYPES.

By C. L. Young. U. S. Forest Service, Region 5. December, 1953.
(Mimeo.) This paper contains an evaluation of soil series classifi-
cations as they pertain to road location and construction.

- 77 -

Logging Plans and Methods

REDUCING LOGGING DAMAGE. By R. D. Cosens. California Forest and
Range Experiment Station. Research Note No. 82. February 21,

1952. Describes measures taken to reduce logging damage on an
experimental logging project in sugar pine-fir type in California.

SKID ROAD EROSION CAN BE REDUCED. By S. E. Weitzman and

G. R. Trimble, Jr. Jour. Soil and Water Conservation. July, 1952.
Presents results of a study of the effects of location, grades, and
drainage of skid roads on an experimental logging operation in the
Appalachian Mountains.

SOME WATERSHED ASPECTS OF LOGGING ON NATIONAL FOREST LANDS
IN REGION ONE (WITH SPECIAL REFERENCE TO THE SPRUCE
PROGRAM). By C. A. Friedrich. U. S. Forest Service Region 1.
December, 1953. An illustrated booklet dealing with the effects of
"highball" operations on watersheds and stream conditions. Copy
obtainable on request from Regional Forester, Missoula, Montana.

APPLIED FOREST MANAGEMENT IN THE DOUGLAS-FIR REGION. By
Philip A. Briegleb. Pacific Northwest Forest and Range Experiment
Station. Research Note No. 71. December, 1950. Describes
specific measures necessary to avoid excessive erosion and to
maintain watershed conditions.

SUGGESTIONS FOR GETTING MORE FORESTRY IN THE LOGGING PLAN.
By R. H. Ruth and R. R. Silen. Pacific Northwest Forest and Range
Experiment Station. Research Note No. 72. Decerhber, 1950. A
detailed study of the factors involved in making a logging plan.

PRACTICAL GUIDES FOR SEEDING GRASS ON SKID ROADS, TRAILS, AND

landings following logging on east-side forests of

WASHINGTON AND OREGON. By J. O. Gjertson. Pacific Northwest
Experiment Station. Research Note No. 49. January, 1949.

General References

THE FRASER EXPERIMENTAL FOREST. Rocky Mountain Forest and Range
Experiment Station. Station Paper No. 8. May, 19 52. Includes re-
sults of studies of the effects of logging on runoff and erosion.

RELATION OF RUNOFF AND WATER QUALITY TO LAND AND FOREST
USE IN THE GREEN RIVER WATERSHED. By W. A. Kunigk. Jour.
Amer. Water Works Assn. 37:21. January, 1945. This article
reflects the growing concern of water works administrators in the
condition of water source areas.

WATER AND TIMBER MANAGEMENT. By M. D. Hoover. Jour. Soil and
Water Conservation. April, 1952. Explains why our steadily growing
water needs require special care in logging and other activities in
mountain watersheds.

VEGETATION AND WATERSHED MANAGEMENT. By E. A. Colman.

Ronald Press, N. Y. 1953. 412 pp. An appraisal of vegetation
management in relation to water supply, flood control, and soil
erosion.

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AGRICULTURE— FOREST SERVICE— SAN FRANCISCO