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FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

United States

Department of 

Agriculture

Forest

Service

National

Forest 

Log Scaling

Handbook
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FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

Amendment No.: 2409.11-2006-1

Effective Date: October 30, 2006

Duration: This amendment is effective until superseded or 

removed.

Approved: Gregory Smith Date Approved: 04/20/06

For Joel Holtrop

Deputy Chief

Posting Instructions: Amendments are numbered consecutively 

by Handbook number and calendar year. Post by document; remove 

the entire document and replace it with this amendment. Retain this 

transmittal as the first page(s) of this document. The last amendment 

to this Handbook was Amendment No. 7.

New Document 2409.11-2006-1_transmittal

2409.11_contents

2409.11_zero code

2409.11_10

2409.11_20

2409.11_30

2409.11_40

2409.11_50

2409.11_60

2409.11_70

2409.11_80

2409.11_appendix

 7 pages

 1 page

 2 pages

 30 pages

 15 pages

 76 pages

 27 pages

 6 pages

 7 pages

 6 pages

 18 pages

 66 pages

Superceded Documents(s) by

Issuance Number and 

Effective Date

(Entire Handbook)

Title page thru 247 263 Pages
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Digest:

10 - Corrects minor typographical and technical errors throughout the 

chapter. Substantive changes are as follows:

13 - Clarifies in paragraph 1 that the standard unit for saw timber 

scaling will be in cubic foot log scale, although board foot log scale is 

used under certain circumstances.

17.12 - Changes the caption in exhibit 02 to clarify direction to allow 

full trim in the length measurement and record in 2 foot multiples.

17.18 - Adds new direction and an exhibit for length measurements 

on forked logs.

17.2 - Clarifies scalers will notify the contracting officer when 

improper trim allowance is detected.

17.3 - Adds direction on how to record logs that are further reduced 

to the lower 2 foot multiple, but the diameter increases to the next 

diameter class, the increased diameter will be recorded as the proper 

scaling diameter.

17.33 - Adds a list of butt characteristics to assist in identifying butt 

cut logs.

20 - Corrects minor typographical and technical errors throughout 

the chapter. There are no changes to the substantive direction in this 

chapter.

30 - Corrects minor typographical and technical errors throughout the 

chapter. Substantive changes are as follows:
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Digest-Continued: 

33 - Establishes defect types and new deduction procedures for: 

Burls, Foreign Material, Pecky Rot, Pistol Butt Defect, Pitch Pockets, 

and Spiral Grain. 

Slope of Grain, and Twist have been included in the Spiral Grain 

definition.

Barber Chair and Pull, Stump or Sliver has been included in the 

Breaks and Splits definition.

Bark Seam has been included in the Pitch Seam, Heart Check, Frost 

Crack definition.

Adds new direction and exhibits for crook defect deduction process. 

Combines Knots, large and Knots, clusters into a single new defect 

type, Knots. Establishes new knot size limits and knot deduction 

guide. 

Adds definition of massed pitch and clarification of when a deduction 

in necessary.

Adds clarification of scaling cylinder position when deducting for 

sweep.

Reformats and renumbers entire section to conform to FSH 2409.11a 

- Cubic Scaling Handbook, chapter 20.
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Digest-Continued: 

40 - Corrects minor typographical and technical errors throughout the 

chapter. Substantive changes are as follows:

44 - Changes caption from Stump Scaling to Timber Trespass. 

Provides direction for measurements to be performed by certified 

scalers and cruisers and requires coordination with Law Enforcement 

staff prior to beginning field work.

44.1 - Changes caption from Timber Trespass to Stump Scaling.

44.2 - Changes caption from Scaling when Stump and other Direct 

Evidence is lacking to Stump Cruising. 

44.3 - Established this code and recodes direction formerly at section 

44.2 to this section.

51 - Changes caption to selection of scaling locations. Changes 

responsibility for selection of scaling locations from District Ranger 

to Contracting Officer. Also removes direction on selecting truckscaling locations.

52 - Removes requirement for Forest Supervisor to develop 

additional safety specifications for scaling.
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Digest-Continued: 

53 - Removes the direction which discusses the need for the 

purchaser to keep government logs separate from private logs up to 

the point of scaling and for the use of distinctive marking between 

various sales.

54.1 - Changes the direction for team scaling from “discouraged” 

to “must not be used.” Also removes direction Regional Forester 

to authorize team scaling in limited situations. Changes the 

responsibility for taking corrective action when scalers to not perform 

to standard from District Ranger to Contacting Officer.

54.2 - Removes direction on the benefits of mill visits and specific 

direction concerning various items to be observed while conducting 

a mill visit.

55.2 - 55.4 - Removes obsolete direction, which referenced out of 

date equipment, processes and procedures. 

55.5 - Revises and recodes to section 55.2. Changes the 

responsibility for completing the Scaler Information Form from the 

Forest Service Representative to the Contracting Officer. 

55.61 - Removes section on standard scaling forms.

55.62 - Recodes to section 55.3.

55.63 - Recodes to section 55.4. Removes significant amount of 

instruction, including exhibit’s 01 and 02, on how to fill in scaling 

sheets. Stresses the use of field data recorders to record scaling 

information.
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Digest-Continued: 

55.64 - 55.65 - Removes obsolete direction from handbook.

56.1 - Removes obsolete from handbook.

56.21 - Removes obsolete direction from handbook.

56.22 - Recodes to section 56.1.

56.3 - Removes obsolete direction from handbook.

60 - Corrects minor typographical and technical errors throughout the 

chapter. Substantive changes are as follows:

64 - Increases situations where Regional Foresters may deviate from 

established check scale standards.

65 - Revises to require minimum check scale record and summary 

information. Removes out-dated policy, procedures, and forms.

70 - Reformats chapter.

71 - Updates CFR reference.

80 - Corrects minor typographical and technical errors throughout the 

chapter. Substantive changes are as follows:

82 - Deletes previous documentation which was incomplete and 

adds reference to National Forest Cubic Scaling Handbook (FSH 

2409.11a) for handbook direction. 
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Digest-Continued: 

85 - Adds a cross reference on sample scaling to Forest Service 

Handbook 2409.11a, National Forest Cubic Scaling Handbook, 

chapter 50.

85.5 - Recodes to section 86.1.

85.6 - Recodes to section 86.2.

87.42 - Establishes new direction for Fiber Scaling.

Appendix - Renames exhibits from “Table” to “Appendix.” Removes 

Table 1A, Table VIII, Table IX - Exhibit A, Table XIV. Adds 

Appendix 15 - Factors for Computing Scribner decimal C Volumes 

and Appendix 16 - Scribner Decimal C Recorded Length and 

Segment Lengths. 
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FSH 2409.11 

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Contents

ZERO CODE 

CHAPTER

10 THEORY AND PRINCIPLES OF SCALING

20 DEFECT-DEDUCTION METHODS

30 LOG DEFECTS AND DEDUCTIONS

40 SPECIAL SCALING PROBLEMS

50 GENERAL SCALING REQUIREMENTS

60 CHECK SCALING

70 USE OF INTERNATIONAL LOG RULES

80 OTHER FORMS OF MEASUREMENT

APPENDIX
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FSH 2409.11 

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CHAPTER - ZERO CODE

Table of Contents

01 - AUTHORITY...................................................................... 2

02 - OBJECTIVE...................................................................... 2

03 - POLICY............................................................................. 2

04 - RESPONSIBILITY ............................................................ 2

04.1 - Director of Forest Management .............................. 2

04.2 - Regional Foresters.................................................. 2
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01 - AUTHORITY

Timber use laws are cited in FSM 2400.

02 - OBJECTIVE

The objective of this handbook is to provide standard Service-wide 

procedures and instructions for scaling National Forest timber to be 

sold, for free use, for exchange, and in timber trespass cases.

03 - POLICY

The procedures provided in this handbook shall be used by all 

Regions and Forests when scaling timber for sales, free use, 

exchange, or in trespass cases.

04 - RESPONSIBILITY

04.1 - Director of Forest Management

The Director of Forest Management, Washington Office, is 

responsible for the maintenance of this handbook. Regional Foresters 

may propose revisions to the white pages at any time. These must be 

made in terms of specific wording, additions, or deletions.

04.2 - Regional Foresters

Regional Foresters are responsible for supplementing this handbook 

to accommodate particular Regional and sub-Regional conditions.
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Table of Contents

11 - THEORY OF SCALING..................................................... 2

12 - GENERAL PRINCIPLES OF FOREST SERVICE 

SCALING ................................................................................. 3

13 - COMMERCIAL UNITS USED........................................... 3

14 - AUTHORIZED LOG RULES............................................. 4

15 - SPECIES IDENTIFICATION ............................................. 6

16 - PRODUCT OR PIECE SPECIFICATIONS ....................... 7

17 - LOG MEASUREMENTS................................................... 7

17.1 - Log Lengths ............................................................ 7

17.11 - Maximum Scaling Lengths................................. 7

17.12 - How To Measure Lengths.................................. 8

17.13 - Length in Long Logs.........................................11

17.14 - Scaling 8 1/2-Foot Tie Logs ............................ 13

17.15 - Scaling Odd-Length Logs................................ 13

17.16 - Scaling Short, Even-Length Logs.................... 14

17.17 - Log Volumes, Board Feet................................ 14

17.18 - Length Determination of Forked Logs ............. 14

17.2 - Trim Allowance...................................................... 16

17.21 - Special Trim Provision..................................... 17

17.3 - Log Diameters....................................................... 17

17.31 - Diameter Determination of Crotched 

and Irregularly Shaped Logs........................................ 20

17.32 - Diameter Determination for Caliper Scaling .... 23

17.33 - Determining Butt Logs..................................... 23

17.4 - Taper in Long Logs................................................ 23

17.41 - Distribution of Even Taper ............................... 24

17.42 - Distribution of Uneven Taper ........................... 26

17.43 - Taper in Butt Logs............................................ 28

17.5 - Measurements for Contract Specifications ........... 28

18 - SCALING CYLINDER IN LOGS..................................... 29
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11 - THEORY OF SCALING

Scaling is the determination of the gross and net volume of logs by 

the customary commercial units for the product involved; volume 

may be expressed in terms of board feet, cords, cubic feet, linear feet, 

or number of pieces. Scaling is not guessing; it is an art founded on 

applying specific rules in a consistent manner based on experienced 

judgment as to how serious certain external indicators of defect are in 

a specific locality.

The measuring standard used in scaling logs, called a log rule, is 

a table intended to show amounts of lumber which may be sawed 

from logs of different sizes under assumed conditions. At best, a log 

rule can only approximate salable manufactured volume because of 

constant changes in markets, machinery, manufacturing practices, 

and even the varying skill of individual sawyers. Thus a log rule is 

an arbitrary measure. Its application must not be varied according to 

the mill in which logs are sawed. The scaled volume of logs must be 

independent of variations in manufacture.

The difference between the volume of log scale and the actual volume 

of lumber sawed from the same logs is called “overrun” if the lumber 

tally exceeds log scale, or “underrun” if it is less.

There may generally be an overrun or an underrun when logs are 

scaled by a particular rule in a given locality and sawed by a mill. 

Basic assumptions in the log rules and assumptions in utilization 

practices cause overrun to vary with the size of the average log. 

Experience proves that this is true even for the International 1/4-Inch 

rule, although not to the same degree as for the Scribner Decimal C 

rule. This fact does not change scaling practice. Overrun (or underrun) is estimated in the process of appraising National Forest timber 
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FSH 2409.11 

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CHAPTER 10 - THEORY AND PRINCIPLES OF SCALING

for sale, and presumably by the purchaser in determining what prices 

he will bid. Overrun or underrun is not considered in log scaling, 

even though it is very important to any mill.

12 - GENERAL PRINCIPLES OF FOREST SERVICE 

SCALING

The scaler must be familiar with Forest Service and Regional policy 

on scaling contained in the Forest Service Manual (FSM 2440), 

instructions contained in this Handbook, and utilization and scaling 

specifications of the timber sale contract.

Forest Service scaling determines quantity rather than quality of the 

material. Unless the contract provides for payment on a gross scale 

basis, all defects affecting recovery of sound volumes are deducted. 

No consideration is given to lumber grade recovery.

13 - COMMERCIAL UNITS USED

1. National Forest timber is appraised, sold, and measured 

by customary commercial units for the products involved. Standard 

practice is to scale saw timber by a cubic foot log scale, although 

board foot is used in some Regions under certain circumstances, mining timbers by the piece or linear foot, telephone poles by the linear 

foot or the piece of stated length, piling by the linear foot, pulpwood 

by the solid cubic foot or cord, and fuel wood, shingle bolts, and 

similar material by the cord. Other units may be used when better 

adapted to local trade customs or local situations.

2. As a general rule, the measurement of National Forest 

timber is in the form in which the material leaves the woods rather 

than in the form of products. End-product measurement may only 

be used under special conditions approved by the Regional Forester. 
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Products, such as telephone poles and fence posts, are ordinarily 

finished for market at the stump, and are therefore usually measured 

or counted in their final form.

14 - AUTHORIZED LOG RULES

The Scribner Decimal C Log Rule, the International *-1/4-Inch log 

rule, or the Smalian cubic volume rule as used by the Forest Service 

are authorized under 36 CFR 223.3 for uniform scaling of sawtimber. 

With the exception of the Smalian cubic volume rule, all specified 

rules are board-foot rules. Each board-foot rule is a table showing an 

arbitrary estimate of the amount of lumber a log of given length and 

diameter can produce. Inasmuch as the tables for each rule have a 

different base, the scale of identical logs will differ according to the 

rule used.

1. The Scribner Decimal C Rule. This is one standard 

rule for Forest Service saw log scaling. This rule rounds contents 

to the nearest 10 board feet. For example: Logs that according to 

the Scribner rule have volumes between 136 and 145 board feet are 

rounded to 140 board feet and shown as 14.

This rule is a diagram rule based on diagrams of circles. These diagrams (ex. 01) show in cross section the number of 1-inch boards the 

small end of a log will produce under assumed conditions.
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14 - Exhibit 01

Diagram Showing the Number of 1-inch Boards 

That Can be Cut From a Specific Log

Table II in the appendix shows the Scribner Decimal C rule volume 

of even- and uneven-length logs from 4 to 20 feet.

The Scribner Decimal C rule is used unless the advertisement and 

timber sale contract specify the International 1/4-Inch rule, the Forest 

Service International 1/4-Inch Decimal rule, or the Cubic Volume 

rule.

2. The International 1/4-Inch Rule. This is another standard Forest Service rule, which probably gives a closer lumber-volume estimate than other log rules in common use. This rule measures 

logs to the nearest 5 board feet. As the name implies, it allows for a 

saw kerf of one-fourth inch. It is a rule based on a formula applied 

to each 4-foot section of the log, and assumes a taper of one-half inch 

in each 4 feet. For practical purposes, the scaling cylinder becomes 

a part of a cone (a frustrum) with a taper of 2 inches in 16 feet. This 
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rule generally results in a log scale relatively close to lumber tally 

when logs are sawed in a reasonably efficient mill. Table X in the 

appendix gives volumes for this rule.

3. The Smalian Cubic Volume Rule. This rule uses the 

Smalian Formula, which is an equation for finding the volume of the 

frustum of a paraboloid. It can be shown generally in the form:

 

 V x L

Where V = Volume in cubic feet (ft3)

A = Large-end cross-section area (ft2) 

a = Small-end cross-section area (ft2) 

L = Log Length (ft)

Table XIV in the appendix chapter gives cubic fiber content of roundwood. 

15 - SPECIES IDENTIFICATION

Since logs of different species may differ in stumpage rates and 

scaling specifications, the scaler’s ability to identify logs by species 

is extremely important, although the logs may be mud- or snow-covered, weathered, or debarked. Species identity is determined by bark 

characteristics, color, amount of sapwood and heartwood, presence of 

pitch, and size and distribution of knots.

Regional Foresters should develop Regional guidelines as needed to 

aid in species identification.

A+a

2
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16 - PRODUCT OR PIECE SPECIFICATIONS

Forest Service timber sale contracts established estimated volumes, 

prices, and minimum tree and product or piece specifications. Contract provisions not only define tree and product or piece minimums, 

but also require the purchaser to vary log lengths to secure the greatest practicable utilization to the minimum top diameter specified in 

the contract. In entering the contract, purchaser agrees to pay for that 

material which equals or exceeds the contract minimums.

Contract terms also determine whether certain classes of material, 

which do not meet the specifications, may be removed at the rate of 

payment, if any, for this type of material. It is most important that the 

scaler adhere to the specifications in the contract. Regional Foresters may develop forms or procedures that will ensure that the scaler 

has the necessary contract information to properly scale any material 

required to be scaled which the purchaser may remove from the sale.

17 - LOG MEASUREMENTS

17.1 - Log Lengths

17.11 - Maximum Scaling Lengths

A maximum scaling length of 20 feet is standard for the western Regions and Alaska; 16 feet is standard for the eastern Regions. Variation from the above standards may be authorized by the Regional 

Forester by special instructions included in Regional supplements.
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The Scaler’s Information Form must show maximum scaling length 

specified in the timber sale contract.

Unless otherwise specified, any further reference to maximum scaling 

length must be to the 20-foot standard. This may require the eastern 

Regions and the Alaska Region to issue special supplements.

17.12 - How To Measure Lengths

Satisfactory devices for length measurements include scale sticks, 

tapes, numbered markers on scaling platforms, or mill decks. The 

method used depends on the type of scaling being performed.

1. Use the following length measuring techniques.

For stump cuts, measure lengths from a point at which the scalingcylinder emerges. For other cuts, make length measurements from

the short side.

2. Determine all log lengths by measuring the shortest 

length between the applicable points at the log ends.

Logs with sweep and crook are particularly difficult to measure. 

Figures a, b, c, and d of exhibit 01 illustrate length measurements.

See “Breaks and Splits” in chapter 30, section 33 for measuring 

broken-end logs.
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17.12 - Exhibit 01

Length Measures

Figure a.

Figure b.

Figure c.
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7.12 - Exhibit 01-Continued

Length Measures

Figure d.

According to timber sale contract provision B6.82, Presentation for 

Scaling (FS-2400-6 - 4/04):

“Trees or pieces presented for Scaling that have not 

been bucked to separate material meeting minimum 

piece standards from material not meeting minimum 

piece standards due to diameter, shall be Scaled as 

though such bucking had been done.”

Determine the measured length from the large end of the piece to the 

full extent of the minimum diameter specified in section A2 of the 

timber sale contract. The minimum diameter can be located with one 

measurement across the short axis of the log. Allow full trim in the 

length measurement and record length in even 2-foot multiples.
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Exhibit 02 illustrates this:

17.12 - Exhibit 02

Scaling Pieces That Do Not Meet Minimum 

Piece Standards Due to Diameter

The measured length of this log would be 47 feet to the contract minimum diameter. Allowing for full trim and 2-foot multiples, record 

and scale it as a 44-foot multiple segment log (sec. 17.13).

Pieces presented for scaling with part of the length (less than the 

minimum length stated in section A2 of the contract) meeting the 

minimum diameter stated in section A2 of the contract shall be noted 

on the scale sheet and the Contracting Officer notified. These pieces 

will be recorded for payment only by written instruction of the Contracting Officer.

17.13 - Length in Long Logs

When logs exceed the maximum scaling length, scale them as two or 

more segments as nearly the same 2-foot length as practicable. When 

it is necessary to divide a log into unequal lengths, make the butt 

segment(s) the longest.
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Exhibit 01 illustrates a 30-foot log divided into one 16-foot segment 

(large end) and one 14-foot segment (small end).

17.13 - Exhibit 01

How to Divide a 30-foot Log

Exhibit 02 illustrates a 44-foot log divided into one 16-foot segment 

(large end) and two 14-foot segments.

17.13 - Exhibit 02

How to Divide a 44-foot Log

Tables IA and IB in the appendix chapter give the proper divisions of 

long logs for scaling purposes where maximum scaling lengths are 16 

feet and 20 feet.

Table III in the appendix chapter shows the division of long logs and 

the Scribner Decimal C volumes for the applicable taper.
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17.14 - Scaling 8 1/2-Foot Tie Logs 

Scale tie logs cut 8 1/2 feet long (plus trim), up to and including 19 

inches in diameter, as 8-foot logs. If diameters are 20 inches or larger, scale tie logs as 8 feet long plus one-half the difference between 

the scales of an 8-foot log and a 9-foot log. If half the difference is a 

fraction, use the next lower whole number.

Example: Scale a 14-inch tie log 8 1/2 feet long as an 8-foot log with 

60 board feet; scale a 17-inch tie log as an 8-foot log with 90 board 

feet. Scale a 20-inch tie log as:

17.15 - Scaling Odd-Length Logs

Scale stick volumes are given for even 2-foot lengths. In the absence 

of tables or a special scale stick, scale odd-length logs by interpolating volumes, rounding 0.5 up or down to the nearest even volume.

Example: For a 15-foot log, use the volume halfway between those 

of 14- and 16-foot logs; then round results like 10.5 and 22.5 to 10 

and 22 and results like 7.5 and 51.5 to 8 and 52.
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17.16 - Scaling Short, Even-Length Logs

When scale sticks are not marked for 6-, 8-, and 10-foot lengths, use 

1/2 the volume for double the length and round 0.5 to the nearest 

even volume or obtain the volume from volume tables II, X, XI of the 

appendix chapter.

17.17 - Log Volumes, Board Feet

Regional Foresters may develop Regional guidelines to provide 

uniformity of log scale volumes. These guidelines must be based on 

Table II, Interpolation, in the appendix chapter or even length factors 

depending upon their applicability.

17.18 - Length Determination of Forked Logs

When a forked log is presented for scaling record only those sections 

that meet the contract minimum piece specification. Do not record 

substandard forks or sections unless specified to do so on the Scaler’s 

Information Form. Measure the length of any qualifying section or 

fork from the large end to the small end. Forking begins at the point 

of daylight. On the piece below the fork, allow full trim and record 

the length to the nearest lower, even, two-foot multiple. Record 

the remaining lengths to the nearest lower, even two-foot multiple 

(Figures a-d - ex. 01).
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17.18 - Exhibit 01

Diagrams of Length Determination of Forked Logs

Figure a - Forked Log With Two Merchantable Forks

Figure b - Forked Log With One Substandard Fork

Figure c - Forked Log With A Substandard Fork at Butt End
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17.18 - Exhibit 01-Continued

Figure d - Forked Log With a Substandard Fork at Top End

17.2 - Trim Allowance

Logs are cut longer than standard lumber lengths because of the 

impossibility of bucking logs squarely and logging damage to log 

ends. This extra length is considered trim allowance and may vary 

between large and small timber, products to be sawed, and logging 

methods. Timber sale contracts list maximum allowances for trim in 

accordance with Regional standards. The Scaler’s Information Form 

should be used to inform the scaler of variations from normal trim 

allowances.

Contract trim allowances are the permissive maximums. Regularly 

measure enough lengths to ensure proper observance of trim. The 

scaler is responsible for accurate length measurements on all logs 

scaled. Scale logs overrunning the trim allowance to the next 1-foot 

scaling length. For example, if 6 inches is the contract trim allowance for logs 8 to 20 feet in length, a log measuring 20 feet 10 inches 

is scaled as a 21; one measuring 24 feet 10 inches, as a 24; but one 

measuring 25 feet 2 inches, as a 25-foot log; 32 feet 0 inches, as a 31; 

or 32 feet 2 inches, as a 32; 41 feet 2 inches as a 41. It is difficult to 

measure log lengths to the nearest inch. Be sure there is actually an 

overtrim before scaling to the next 1-foot length. After the scaling 
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length and trim has been established, as above, divide logs into scaling segments in accordance with instructions in section 17.13 and 

tables IA and IB of the appendix chapter.

Special cut lengths should be taken care of by contract modification and, except for different specifications, should not be a scaling 

problem.

Scalers should notify the Contracting Officer of any improper trim 

they detect. The Contracting Officer should notify the purchaser and 

take necessary action to obtain contract compliance (sec. 17.5).

17.21 - Special Trim Provision

When authorized by the Regional Forester, timber sale contracts may 

provide other provisions relating to trim such as a requirement that 

logs be scaled to the next lower foot.

17.3 - Log Diameters

Scaling requires accurate measurement of log diameters. Common 

tools used to measure diameters are scale sticks, steel tapes, and 

sliding calipers. The steel tape is the primary tool used to obtain the 

diameter of log ends in most regions, the scale stick is used to a lesser 

degree in other regions. The steel tape is versatile and is particularly 

useful for obtaining diameters, which cannot be measured with the 

scale stick, such as recessed logs on a truck. Calipers are useful in 

measuring diameters at points along the log other than at the ends.
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1. Measure log diameters inside the bark at the small end 

of the log.

2. Measure through the true center of the log, not the center of the log as shown by the growth rings and pith.

3. In measuring, avoid abnormal bumps and depressions if 

possible; otherwise, measure as though such conditions do not exist 

(sec. 17.31, ex. 01).

4. Where possible, read the scale stick directly from the 

end of the log, not obliquely from the side.

5. Take a pair of diameter measurements at right angles 

to each other. Measure the short axis first, and then take the second 

measurement at right angles to the first measurement. This is an 

important technique.

6. Take diameter measurements to the nearest inch. Round 

exact 1/2-inch measurements before averaging. Round up when it 

is one of a pair to be averaged. When both of a pair to be averaged 

fall on 2-inch marks, round one up and one down. If the average 

diameter is on a 1/2-inch; for example 23 1/2 inches, round down for 

the final scaling diameter; that is to 23 inches.

In Exhibit 01, measurement “A” is read as 24 inches and measurement “B” as 25 inches. The average, (A + B) ÷ 2, is 24 1/2 inches. 

The one-half inch is dropped to a scaling diameter of 24 inches. 

Note, however, that had measurement “A” and/or measurement “B” 

coincided with the 1/2-inch mark, the measurement would have 

resulted in a final scaling diameter 1 inch larger, or 25 inches.
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17.3 - Exhibit 01

(4) Diameter Measurements (Coconino Scale Stick)

7. Trees or pieces presented for scaling that have not been 

bucked to separate material meeting minimum piece standards from 

material not meeting minimum piece standards due to diameter, shall 

be scaled as though such bucking had been done.

The diameter measurement is exactly that specified in the contract 

and not a diameter class. For example, a contract which lists the 

minimum diameter as 6 inches will be considered to be 6.0 inches. 

Take a single measurement across the short axis of the log. After 

establishing the assumed bucking point, determine diameters by the 

systematic method described in section 17.3, paragraphs 1-6.

Where a length is further reduced to the lower 2-foot multiple, and 

the diameter increases to the next diameter class, the increased diameter is recorded as the proper scaling diameter.
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17.31 - Diameter Determination of Crotched and Irregularly 

Shaped Logs

When diameters cannot be measured accurately on log ends due to 

abnormalities, measure the smallest average diameter above or below 

the abnormality and project the log taper to determine the diameter. 

If calipers are not available, use a scale stick or steel tape at this measurement point, remembering to allow for bark thickness.
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17.31 - Exhibit 01

How to Measure Logs With Abnormal Conditions 

and Average the Diameters
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17.31 - Exhibit 02

Points of Measurement for Log With Crotch

Use the following methods to measure diameters of broken-end logs:

1. When the small end of a log other than a butt cut is broken, measure the large end. Reduce this measurement by the amount 

of estimated taper.

2. When the small end of a butt log is broken, lay the scale 

stick across the top of the small end. Read the measurement (inside 

bark) carefully.

3. When both ends of a log are broken, measure the same 

way as in paragraph 2.
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17.32 - Diameter Determination for Caliper Scaling

Use average diameters in all types of scaling except caliper scaling 

in the woods. In this type of scaling, place the points of the calipers 

directly over the log. Be sure the points are on the widest portion 

on the sides. Measure inside the bark if the logs are scalped. If not, 

measure outside the bark and subtract twice the bark thickness. The 

same basic rules outlined in paragraphs 3, 5, and 6 of section 17.3 

apply, except in caliper scaling in the woods. Keep the calipers snug 

without squeezing them. The recorded measurement is always taken 

from the inside bark diameter.

17.33 - Determining Butt Logs

There are several physical characteristics whose absence or presence 

can assist the scaler in determining whether or not a log is a butt-cut. 

Physical characteristics that are indicative of butt logs are: 

Butt flare, flutes, absence of limbs, thicker bark, actual undercut, 

hinge, stump pull, and shear or circular saw marks left by mechanical 

fellers.

A paint mark showing on the side of a log is only an indicator and 

should not be used as the determining factor in identifying a log as a 

butt-cut. A log that has been long-butted will be considered a secondcut log. 

17.4 - Taper in Long Logs

Scaling diameters of the butt segments are determined by apportioning the taper of the long log. Except for butt logs, taper is the difference between the two end diameters. For butt logs, 

see section 17.43.
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Taper is even when it can be apportioned in an equal amount to each 

segment such as 4-inch taper in a 2-segment log can be apportioned 

2-inches to each segment, and uneven when it cannot.

17.41 - Distribution of Even Taper

Divide the taper by the number of segments, and add the taper per 

segment to the top diameter to obtain the diameter of the second segment. For a 3-segment log, add the taper per segment to the diameter 

of the middle segment. The resulting diameter should differ from the 

butt diameter by the taper per segment.

Exhibit 01 illustrates a 32-foot log with end measurements of 16 and 

20 inches or 4 inches total taper. Scale it as one 16-foot segment with 

a diameter of 16 inches and one 16-foot segment with a diameter of 

18 inches (the mid-diameter).
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17.41 - Exhibit 01

How to Distribute Even Taper in a 32-foot Log

Exhibit 02 illustrates a 46-foot log with end measurements of 16 and 

22 inches (6 inches total taper or 2 inches per segment). Scale it as 

one 14-foot segment with a diameter of 16 inches (2 inches taper); 

one 16-foot segment with a diameter of 18 inches (2 inches taper); 

one 16-foot segment with a diameter of 20 inches (2 inches taper).

17.41 - Exhibit 02

How to Distribute Even Taper in a 46-foot Log

Table III in the appendix chapter shows Scribner Decimal C volumes 

of long logs, 22 to 48 feet, for various total tapers.
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17.42 - Distribution of Uneven Taper

Scale logs with taper in uneven amounts, by applying the excess taper 

to the top segment(s). Trees naturally grow with increased taper in 

top logs, as a check of taper tables or of actual taper measurements 

will demonstrate.

The rule of distribution of taper in long logs is as follows:

1. For two-segment logs with taper not divisible by 2, add 

an inch and divide by 2. This is the amount of taper assigned to the 

top segment.

2. For three-segment logs, raise total taper to a number 

divisible by 3 and divide. This is the amount of taper assigned to the 

top segment. Distribute the remainder of the taper as in a two-segment log.

Exhibit 01 illustrates a 32-foot log with end measurements of 16 and 

19 inches (3 inches total taper). Scale it as one 16-foot segment with 

a diameter of 16 inches (2 inches of taper); one 16-foot segment with 

a diameter of 18 inches (1-inch taper to large end).
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17.42 - Exhibit 01

How to Distribute Uneven Taper in a 32-foot

Exhibit 02 illustrates a 46-foot log with end measurements of 16 and 

23 inches (7 inches total taper). Scale it as one 14-foot segment with 

a diameter of 16 inches (3 inches taper); one 16-foot segment with a 

diameter of 19 inches (2 inches taper); one 16-foot segment with a 

diameter of 21 inches (2 inches taper).

17.42 - Exhibit 02

How to Distribute Uneven Taper in a 46-foot Log
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17.43 - Taper in Butt Logs

The taper in long logs which have the butt cut at one end cannot be 

determined in the same manner as other logs. Average taper can be 

determined by local studies conducted by species.

Uniform butt log tapers as determined by studies may be shown in 

the Long Log Table, Table III in the appendix chapter. Use of this 

table shall be in accordance with instructions issued by the Regional 

Forester. In the absence of authorized taper tables, scale on the basis 

of actual taper.

17.5 - Measurements for Contract Specifications

As described in section 16, the timber sale contract establishes the 

specifications for scaling the products. The Contracting Officer is 

responsible for determining whether or not the material presented for 

scaling is in accordance with the terms of the contract.

Occasionally, a purchaser may cut logs so that material in one product class is attached to material of another product class which may 

have a lower price, or may be removed free of charge. An example 

of this would be where a purchaser chooses to saw small diameter 

logs rather than buck, sort, and haul the smaller logs separately. That 

portion of the log, which meets or exceeds the contract minimums 

would be scaled and charged for in the appropriate product class. 

The smaller portion of the log would be charged for at the rate for 

the appropriate product or removed free of charge depending upon 

contract specifications.

The scaler must be alert for operator actions, which are not within 

contract specifications and report these actions to the Contracting 

Officer. When losses due to stump pull, breakage and damage, exces-
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sive trim, improper bucking, or poor top utilization begin to show up 

in scaling, the scaler must inform the Contracting Officer so that the 

latter may determine if administrative action is necessary. The scaler 

should not alter scaling practices until instructed to do so by the Contracting Officer (ch. 40, sec. 42).

18 - SCALING CYLINDER IN LOGS

The scaling cylinder for the Scribner Decimal C rule is an imaginary 

cylinder extending the scaling length of the log with a diameter equal 

to the measured or small end of the log (ex. 01). Volumes given by 

the rule are the gross board-foot contents of this cylinder.

18 - Exhibit 01

The Scaling Cylinder of a Log—Scribner Decimal C Rule

To visualize the scaling cylinder in a perfectly round log, picture the 

log in a giant lathe rotated against a knife until the entire log is peeled 

to the size of the small-end diameter. The cylinder of wood left is the 

scaling cylinder of that log. The part peeled off is outside the scaling 

cylinder. Make no deduction for defects in that portion of the log (ex. 

02, figures a and b).
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18 - Exhibit 02

Figure a - Defect Both Inside and Outside the Scaling Cylinder

Figure b - Defect Outside the Scaling Cylinder

In the above illustrations, note that the scaling cylinder is independent 

of the pith center of the tree. A good scaler learns to “see” the scaling 

cylinder when he deducts for defect.

The Scribner Decimal C rule also incorporates an allowance for slab 

and edgings, considered for practical purposes to be 1 inch inside the 

surface of the scaling cylinder (fig. a). For this reason, no deduction 

should be made for minor surface defects or blemishes that can be 

eliminated in the slab or edgings.

For International 1/4-Inch log rule or Forest Service International 

1/4-Inch Decimal log rule, refer to chapter 70, section 72.
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Table of Contents

21 - GENERAL......................................................................... 2

22 - SQUARED-DEFECT METHOD ........................................ 

22.1 - Coconino Scale Stick.............................................. 4

22.2 - Shortcut Procedure................................................. 5

22.3 - Application of Squared-Defect Method ................... 7

22.4 - Logs With Defect Showing on One End Only......... 8

22.5 - Logs With Same Defect Showing on Both Ends... 10

23 - PIE CUT METHOD.......................................................... 1

24 - LENGTH-DEDUCTION METHOD .................................. 1

25 - DIAMETER-DEDUCTION METHOD .............................. 
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21 - GENERAL

1. The following defect-deduction methods are approved 

for Forest Service scaling:

a. Squared-defect method.

b. Pie cut method.

c. Length-deduction method.

d. Diameter-deduction method.

2. In applying any of the above methods, the loss is those 

portions of the boards (even feet in softwoods) from the scaling cylinder which must be trimmed off because of defect, provided that the 

remainder of each board has at least the minimum length of 6 feet and 

a minimum width of 4 inches for softwoods. If the remainder of any 

board is shorter or narrower than these limits, the entire board must 

be considered lost, except as provided in chapter 70, sec. 73.

3. All methods must be used with judgment and skill. 

Knowledge of how defects actually cut out must be obtained from 

periodic mill visits. More than one defect-deduction method may 

be used in scaling one log. Good practice is to check one method of 

deduction against another for the same defect. Do not use rules of 

thumb.

4. If defect calculations end in a fraction of 1/2 or more, 

raise the defect to the next whole number. If the fraction is less than 

1/2, reduce the defect to the next lower whole number.
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22 - SQUARED-DEFECT METHO

Defects showing in one or both ends can often be treated as if sawn 

out in squares or rectangles. This deduction method is called the 

squared-defect method.1 It is generally the most accurate method of 

scaling interior defects.

For the Scribner Decimal C rule, the method may be stated by the 

following formula:

 X=

See chapter 70, section 75 and table XII in the appendix chapter for 

defect deductions applied with the International 1/4-Inch rule.

In the preceding formula, W” and H” represent end dimensions of 

the defect in inches plus an allowance (ordinarily 1 inch for each 

dimension) for waste, L’ is the length of the defect in feet, and X is 

the contents of the defect in board feet after 20 percent is deducted 

for saw kerf. X is raised or lowered to the nearest 10. Deductions for 

the various sizes of rectangular and squared defects as computed by 

the formula are shown in tables IV and V in the appendix chapter.

W”xH”xL’

15

1

Originally termed the (Forest Service) Standard Rule.
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Example: A 16-foot log 21 inches in diameter has a gross volume 

of 300 board, feet. The large end shows a spot of heart rot 5 inches 

square. The rot is estimated to go into the log 4 feet.

Stated in terms of the formula above:

 = = 9.6 board feet

Rounded to the nearest 10, the amount deductible for defect is 10 

board feet. Subtracted from the gross scale of 300, the net scale is 

290 board feet (29 Decimal).

Scalers find it difficult and time consuming to use this formula in 

ordinary scaling. As a result, rules of thumb or rough estimates 

have often been used. Such rules of thumb and estimates are 

largely unnecessary. Forest Service scalers should use either a 

Coconino scale stick, or shortcut procedure with its simplified defect 

calculation.

22.1 - Coconino Scale Stick

Defect deductions for squares up to 30 inches are read directly from 

Coconino-style scale sticks for all log lengths. Defect deductions for 

odd or shorter lengths are determined by interpolation. Rectangular 

defects closely approaching squares are ordinarily converted to 

squares. This procedure is permissible in the smaller defects, 

since in the Shortcut Procedure for the Scribner Decimal C rule 

(sec. 22.2), the products of 6x8 and 7x7 would both be raised to 

50 board feet and the products of 10x12 and 11x11 would both be 

raised to 130. The variance in the readings can be extended to 4 

inches without an appreciable difference in volumes; for example, a 

16x20 measurement can be read directly as an 18 x 18 square. Use 

of large rectangular measurements on both ends of a log, requiring 

6x6x4

 15

144

15
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averaging, increases computations and can induce errors. A more 

practicable method is measuring these defects as a square using the 

larger dimension, then averaging, squaring, and making a fractional 

estimate.

Small rectangular defects, as for checks and pitch seams, can 

generally be readily figured using the shortcut procedure (sec. 22.2). 

Where larger rectangular defects are involved, such as 9 x 27, the 27 

can be squared for the length of defect and this figure divided by 3, 

as 9 is a third of 27. Another example would be 13 x 26; square 26 

for the length of defect and use half of this amount. There may be 

occasional answer variances of 10 and 20 board feet from the figures 

in table V (see appendix chapter). These differences can creep into 

the figures through the single and double steps of raising or lowering 

Scribner volumes to the nearest Decimal C figure.

Coconino-style scale sticks marked according to the Forest Service 

International 1/4-Inch Decimal rule are available.

22.2 - Shortcut Procedure

1. For the Scribner Decimal C rule, the shortcut procedure 

for determining the squared-defect deduction may be stated by the 

following formula:

X = W x H to the next higher 10 x L/16 to nearest 10.

The defect dimensions used in this formula are identical to those 

which would be used in the preceding more complicated formula 

(sec. 22); however, the use of a divisor of 16 rather than 15 greatly 

simplifies computations for even-foot multiples of defect. Rounding 

the product of defect height times width to the next higher 10 

effectively cancels the effect of the difference in divisors for defects 

up to and including 12 by 12 inches.
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2. The shortcut procedure is particularly applicable to 

small rectangular defects such as checks and pitch seams.

3. In applying the shortcut procedure, remember these four 

easy steps:

a. Measure both height and width of the defect, 

including the 1-inch allowance for waste.

b. Multiply these two measurements, round off to the 

10 next above, and drop the last zero. Raise results of 

multiplications that end in zero to the 10 next above. 

For example, 10 x 11 = 110, raise to 120 and drop the 

zero for 12.

c. This is the deduction if the defect extended through a 

16-foot log.

d. Estimate the length of the defect in terms of 16 feet. 

If the estimate is 8 feet, take 8/16 or 1/2, the originally 

calculated defect. If the estimate is 4 feet, deduct 1/4 

of the 16-foot calculation. If the defect extends about 6 

feet, use 6/16 or 3/8. For a 20-foot length of defect, add 

1/4 of the 16-foot calculation.

4. The following corrections should be made for larger 

defects:

a. Add 10 board feet to the product of W x H for defects 

squaring 13 to 16 inches, inclusive.

b. Add 20 board feet to the product of W x H for 

defects squaring 17 to 21 inches, inclusive.
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Using the same example as for the formula in section 22:

6 x 6 = 36 to the next higher 10 = 40

 40 x or = 10 board feet (1 Decimal C) 

See chapter 70, section 75 for the shortcut procedure applicable to the 

International rule.

22.3 - Application of Squared-Defect Metho

Scalers should acquire techniques for measuring defects in the ends 

of logs. Take measurements in pairs, each at right angles to the other 

as in diameter measurements. If defect is irregular, more than one 

pair of measurements may be needed.

To allow for loss of sound material surrounding a defect, 

always measure end defects for “squaring out” and add an extra inch 

of loss in each dimension.

Consider lumber of even lengths only unless, as in some hardwood 

scaling, lumber of odd length is normally considered merchantable.

When the deduction indicated by the squared-defect method results 

in greater volume deduction than the log scale of the portion affected, 

use the length-deduction method.

The squared-defect method is best adapted to not more than two 

defects in a log end. Applying this method separately to more than 

two defects may cause errors in the several computations required.

See chapter 70, section 75 for exceptions when using the 

International rule.

4 

16

4 

16
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22.4 - Logs With Defect Showing on One End Only

If only one end of a log shows defect, check surface indications to 

determine how far it extends into the log. Surface indications for 

interior rots include conks, scars, catfaces, seams, or rotten knots. 

Look carefully for these on both ends and sides of a log. If a defect 

is found on one end, try to locate its source. Look the sides over 

thoroughly. If defect is found on a side, observe both ends carefully. 

The length of stump rot can often be determined by swells in the log, 

but not all swells mean rot. Breakage sometimes is an indication of 

weakness caused by interior rot. Examine the point of breakage for 

this possibility. When exterior indications are lacking, judgment 

alone must determine its length.

After the extent of the defect has been determined and the squareddefect method judged applicable, use either a Coconino-style scale 

stick or the shortcut procedure. Following are several examples of 

defect calculation using the Scribner Decimal C rule.

Example 1: A 16-foot log 21 inches in diameter has a gross scale 

of 300 board feet. Defect at one end measures 6 by 9 inches and is 

estimated to extend halfway into the log.

Adding 1 inch to each dimension for waste.

7 x 10 = 70 to the next higher 10 = 80

80 x 8/16 or 80/2 = 40

The deduction is 40 or 4 Decimal and net scale is 26 or 260 board 

feet.
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Example 2: A 20-foot log 36 inches in diameter has a gross scale of 

1,150 board feet. Defect at one end measures 13 by 15 inches and is 

estimated to extend 8 feet into the log.

Adding 1 inch to each dimension for waste.

14 x 16 = 224 to the next higher 10 = 230

Add 10 (size between 13 and 16 inches)

240 x 8/16 or 240/2 = 120

(Read on Coconino stick 15 x 15 x 8’ = 12).

The deduction is 120 or 12 Decimal and net scale is 103 to 1,030 

board feet.

Example 3: A 14-foot log 21 inches in diameter has a gross scale 

of 270 board feet. Defect in one end measures 8 by 10 inches and 

extends 6 feet into the log.

Adding 1 inch to each dimension for waste.

9 x 11 = 99 to the next higher 10 = 100

100 x 6/16 or 38 to the nearest 10 = 40

(Read on Coconino stick 10 x 10 x 6’ = 4).

The deduction is 40 or 4 Decimal and net scale is 23 or 230 board 

feet.
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When a defect shows at one end only of a log and is estimated to 

extend to a point within less than minimum lumber length of the 

other end, use the full length of the log as the defect length in making 

deduction. In Western regions the minimum lumber length is 6 feet 

for softwoods and normally 4 feet for hardwoods.

22.5 - Logs With Same Defect Showing on Both Ends

Make careful examination of the log to determine if defects are 

connecting. If the defect is found to extend through the log and the 

squared-defect method is applicable, use either a Coconino-style 

scale stick or the shortcut procedure to determine the deduction. The 

average diameter of the defect will be used in making the deduction 

in 16-foot or longer logs.

Following are examples of defect calculation using the Scribner 

Decimal C rule and a 20-foot maximum scaling length. (See ch. 70, 

sec. 75 for International rule).

1. For logs 8 to 14 feet in length, defect dimensions must 

be taken at large end of defect (in Western regions).

Example 1: A 14-foot log 21 inches in diameter has a gross scale 

of 270 board feet. End defects measure 8 by 10 inches and 4 by 6 

inches. Adding 1 inch for waste:

9 x 11 = 99 to the next higher 10 = 100 

100 x 14/16 = 88 to the nearest 10 = 90 

(Read on Coconino stick 10 x 10 x 14’ = 9) 
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The deduction is 90 or 9 Decimal and net scale is 18 or 180 board 

feet.

2. For logs 16 to 20 feet in length, the average of the 

defect dimensions for both ends of the log must be used (in Western 

regions).

Example 2: A 20-foot log 21 inches in diameter has a gross scale 

of 380 board feet. End defects measure 8 by 10 inches and 4 by 6 

inches. Add 1 inch for waste:

 =7 (H) 

 =9 (W)

7 x 9 = 63 to the next higher 10 = 70 

70 x 20/16 = 88 to the nearest 10 = 90 

(Read on Coconino stick 8 x 8 x 20’ = 9) 

The deduction is 90 or 9 Decimal and net scale is 29 or 290 board 

feet.

3. For logs 22 feet and longer, treat each segment in the 

manner prescribed in paragraphs 1 and 2.

a. For logs 22 to 28 feet in length, average the defect 

dimension at both ends to obtain the size of the defect at 

midpoint and run the larger end of the defect dimension 

through each segment.

9+5 

2

11+7 

2
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Example 1: Defect extends through a 24-foot log that is scaled as 

two 12-foot segments. Defect, including waste allowance, measures 

8 by 10 inches on the large end, 4 by 6 inches on the small end. The 

midpoint defect dimensions are 6 by 8 inches. For one segment, 

use 8 by 10 inches for deduction. For the other segment, use the 

midpoint size, 6 by 8 inches.

b. For 30-foot logs, use large defect dimensions for the 

14-foot segment and average defect dimensions for the 

16-foot segment. See items a and c.

c. For logs 32 to 40 feet in length, average the defect 

dimensions at both ends to obtain the size of the defect 

at midpoint and then use average widths and heights of 

the defect as computed for each segment.

The procedure may be simplified and the same or a comparable 

answer obtained by an alternate method. This modification provides 

for use of the midpoint dimensions as the average defect dimensions 

for each log, but do not use it on marginal logs.

Example 2: Heart check on both ends of a 32-foot log measures 

(including waste) 2 by 10 inches and 2 by 4 inches. The midpoint 

measurements are 2 by 7.

Usual Deduction Method

 =2 =9

 =2 =6

2 x 9 = 18 to the next higher 10 = 20 board feet deduction for 

butt log.

10+7

2

2+2

2

4+7

2

2+2

2
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2 x 6 = 12 to the next higher 10 = 20 board feet deduction for the 

top log.

Alternate Method: Use midpoint measurement.

2 x 7 = 14 to the next higher 10 = 20 board feet for the average 

deduction or 40 for the 32-foot log.

Do not use the alternate method when one segment of a long log is a 

cull or where other indicators cast doubt as to the uniformity of the 

defect.

When the dimensions of end defects are averaged and the result is a 

fraction, round up to the next whole number, as (4 + 3) ÷ 2 = 4.

In regions where hardwoods comprise a significant part of the timber 

volume or where short logs are preponderant, Regional Foresters may 

prescribe different utilization standards and lengths for averaging 

defects.

23 - PIE CUT METHO

Where the defect is deep and V-shaped it can be enclosed in a sector 

of a circle. The deduction bears the same relation to the total scale 

as the sector bears to the circle. Estimates of 1/8, 1/4, 1/3, 1/2, or 2/3 

are used. The deduction is the amount determined by the fraction of 

the scaling cylinder affected, times the scale of a log the same length 

as the defect and the same diameter as the log being scaled.
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23 - Exhibit 01

Pie Cut Method (deep lightning scar affecting 1/4 of log)

Example: A 16-foot log 20 inches in diameter has a gross scale of 

280 board feet. A lightning scar running the entire length of the log 

has been burned out (fig. 14). It can be enclosed in a sector (pie 

cut) equaling 1/4 of the circumference. The deduction is 1/4 of 280, 

which is 70 or 7 Decimal, and the net scale is 21 or 210 board feet.

This deduction method usually applies well to catfaces, fire scars, 

grubworm holes, and rotten knots. It is applicable when the defect 

affects two-thirds or less of the scaling cylinder. To help determine 

the correct fraction to use, mark off the affected portion with a piece 

of keel. Remember to extend the defect the full length of the log if 

the sound portion would be less than minimum merchantable lumber 

length.
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24 - LENGTH-DEDUCTION METHO

This method is useful to deduct for defects which can be confined 

to a portion of the log length. Use this method when the squared 

defect deduction method equals or exceeds the scale of the affected 

log length. Use the scaling cylinder diameter to determine the scale 

of the affected log length. Such defects may include sweep, crook, 

fire scar, knot clusters, large burls and pitch spangles, breaks, crotch, 

massed pitch, and rot.

Example: In a 16-foot log, 16 inches in diameter, scaling 160 board 

feet, with rot 12 inches in diameter affecting 4 feet of the log, the 

squared defect deduction would be 50 board feet. As this deduction 

exceeds a 4-foot cut, or 40 board feet, use a length cut.

In use, this method is often combined with the pie cut method 

(section 23). For example, a deduction for a defect which affects 

one-half the scaling cylinder for 4 feet is equivalent to a 2-foot length 

cut.

25 - DIAMETER-DEDUCTION METH

A diameter cut means reducing the original diameter and scaling 

cylinder of a log. This method is used in deductions for sap rot, 

weather checks (when deductible), shallow catfaces, perimeter rings, 

and knots when they cause a loss of merchantable material.

Example: A log with sap rot measures 20 inches in diameter. The 

rotten sapwood is 1 inch thick on each side. Reduce the gross 

diameter of 20 inches by 2 inches for a net diameter of 18 inches. Net 

scale is that of an 18-inch log. Show the difference between that net 

scale and the gross scale in the defect column.
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Table of Contents

31 - GENERAL......................................................................... 3

32 - DEFECT TYPES AND APPLICABLE DEDUCTION 

METHODS ............................................................................... 4

33 - DEFECT TYPES AND DEDUCTION PROCEDURES...... 6

33.1 - Rots ........................................................................ 6

33.1a - Rot, Conk........................................................... 6

33.1b - Rot, Heart .......................................................... 7

33.1c - Rot, Sap............................................................. 9

33.1d - Rot, Stump....................................................... 12

33.1e - Knots, Rotten................................................... 14

33.1f - Pecky Rot ........................................................ 15

33.2 - Voids..................................................................... 30

33.2a - Catface ............................................................ 30

33.2b - Fire Scar.......................................................... 32

33.2c - Lightning Scar.................................................. 33

33.3 - Breaks and Splits.................................................. 35

33.4 - Checks.................................................................. 40

33.4a - Check, Weather............................................... 40

33.4b - Pitch Seam, Heart Check, Frost Cracks.......... 43

33.4c - Pitch Spangle................................................... 50

33.5 - Pitch Ring, Shake Ring......................................... 51

33.5a - Rings, Pitch and Shake ................................... 51

33.5b - Pitch, Massed.................................................. 58

33.5c - Pitch Pockets................................................... 59

33.6 - Crook, Pistol Butt and Sweep............................... 59

33.6a - Crook and Pistol Butt....................................... 59

33.6b - Sweep.............................................................. 63

33.7 - Knots..................................................................... 65

33.8 - Other Defects........................................................ 69

33.8a - Burls ................................................................ 69

33.8b - Crotch.............................................................. 71
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33.8c - Foreign Material............................................... 72

33.8d - Multiple Defects............................................... 73

33.8e - Spiral Grain...................................................... 74

33.8f – Stain................................................................. 74

33.8g - Wormholes ...................................................... 75
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31 - GENERAL

A scaling defect is any unsound material or abnormal shape in a log 

that reduces its net volume. Defects are grouped in two common 

classes:

1.	 Natural Defects. Natural defects are those which exi

in the log before the tree is felled. These may include all kinds 

interior rot, rotten knots fire scars, catfaces, massed pitch, pitch rings 

and shake, pitch seams and checks, lightning scars, sweep, crook, 

massed grubworm holes, crotch, sap rot, weather checks (snags and 

windfalls), knot clusters, burls, and some types of large knots.

2.	 Logging Defects. Logging defects are those general

occurring after the tree is felled. They include mechanical defect

such as breakage, brooming, tractor damage, and loading damage.

They also include other defects caused by poor logging practices, 

such as sap rot, weather checks, and damage caused by borers after 

trees have been cut.

Forest Service scaling considers deductions for all defects, natural 

and mechanical. All logs shall be scaled as presented, unless 

otherwise instructed by the Contracting Officer. The Contracting 

Officer must make the decision concerning permissive deductions for 

defects caused by the purchaser allowing logs to remain in the woods.

Some defects in logs are caused by abnormal delay in scaling due 

to the fault of the purchaser. Deductions made for sap rot, weather 

checks, or other defect resulting from abnormal delay in scaling are 

chargeable at contract rates. Therefore, these deductions must be 

separately identified.
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32 - DEFECT TYPES AND APPLICABLE DEDUCTION 

METHODS 

Following is a tabulation of common types of defect and the defectdeduction method most applicable to each type. The types of defect 

and applicable procedures are discussed in section 33. Deduction 

methods are described in chapter 20.
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Defect Defect Symbol Diameter Length Pie-cut Squared-defect

Barber chair BK x x x

Bark seam PS x x

Break, straight BK x x x

Break, other BK x

Burl BL x x

Catface, shallow CF X

Catface, deep CF x

Check, heart CH x

Check, weather WC X

Crack, frost FC x x

Crook CR x

Crotch Y x x

Fire scar FS x x

Knots, large K X x x x

Knot cluster KC x x

Knots, rotten RK x x

Lightning scar LS X x x x

Multiple defects MD x x x

Pitch, massed MP x x x

Pitch seam PS x

Pitch spangle, small SF x

Pitch spangle, large SP x

Pull, stump or sliver BK x

Ring, pitch or shake PR or SH X x

Ring, pitch or shake multiple PR or SH x

Rot, conk C x x x

Rot, heart R x x

Rot, sap S X

Rot, stump R x x

Stain 

Sweep SW x x

Wormholes, massed large WH X x x x

Deduction Method

32 - Exhibit 01

Tabulations of Defect

 1Stain is not a defect by itself. If stain is accompanied by rot, refer 

to the appropriate rot. The common rots and fungi found in sawlogs 

are described in table IX in the appendix chapter.

1
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33 - DEFECT TYPES AND DEDUCTION PROCEDURES

Descriptions of common defect types, with applicable deduction 

procedures, follow in alphabetical order. The Scribner Decimal C 

rule is used in examples. The same general scaling practices apply to 

the International rule.

33.1 - Rots

33.1a - Rot, Conk

Sometimes this rot is called red ring or honeycomb rot. In eastern 

species, it is known as red rot. (Should not be confused with red rot 

of ponderosa pine-Polyporus anceps - see table IX, appendix chapter.) 

In incipient stages it is commonly referred to as “firm red heart.” 

This defect varies in color from purple and light red in early stages 

to dark brown in mature stages. In the early stages the wood is only 

stained and requires no deduction. In later stages, the wood breaks 

down to form a honeycomb appearance. Patches of white substance 

called “white pocket” appear. These white pockets indicate that the 

wood is broken down and that a deduction is required.

Deductions for conk rot are particularly difficult. Any one of 

several methods may apply. Effects of the fungus appear to vary 

with species, soil, altitude, and climatic conditions. Mill visits and 

experience are essential for a scaler to interpret what conk indicators 

mean in the timber he is scaling. Record guides applicable to timber 

from specific areas.

Generally, the point of deepest penetration of conk rot is where a 

fruiting body or conk enters the log. Here the rot most commonly 

takes the shape of a crescent. Occasionally, it may be in the form 

of one or more full rings. These may roughly parallel growth rings. 
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When conk stain or conk rot shows in log ends, look with care for 

conks on the log. Use a spud to dig into swollen spots, punk knots, 

and black limbs. Size of conks is sometimes helpful in determining 

the extent of rot in some species. Recognize where conks have 

broken away from logs by punky, yellowish-brown material in the 

holes where the conks were attached.

Make deductions for white pocket (conk) using the squared-defect 

method if the defect occurs as a spot in one end. If 1/4 to 1/2 of one 

end is defective, make a pie-cut deduction of the scaling cylinder 

affected for the estimated length.

A good plan while on a mill visit is to make a rough chart guide such 

as that shown in exhibit A, appendix chapter, for conk rot deductions. 

Use such a chart only for areas and species where it is proved to be 

applicable by repeated mill visits. Note the average length of rot 

spread from the last visible indicator.

WARNING: The effects of conk rot are variable. Widespread or 

uniform use of one chart without essential local modifications and 

repeated checks could- result in erroneous scaling.

33.1b - Rot, Heart

Sometimes called center, circular, dry, or red, this rot is found in logs 

cut from any position in trees. In color it ranges from light brown in 

early stages to reddish brown in its advanced stage. Fruiting bodies 

are usually missing by the time the log is ready to scale. This decay 

is characterized as brittle, dry, crumbly, sometimes with cubical 

patches and usually with white felt like layers between the patches.
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Use the full estimated length of heart rot because it does not taper 

like stump rot. Make deductions by the squared-defect method for 

most heart rot.

Example 1: Exhibit 01 illustrates a 16-foot log with a heart rot 

extending full length through the log. The defect including allowance 

for waste measures 12 by 12 inches on one end, 6 by 6 inches on the 

other. Average of these end dimensions is 9 by 9 inches. Using the 

squared-defect method (ch. 20, sec. 22.5), deduct as follows: 9 x 9 = 

81 to the next 10 = 90 (9 Decimal).

33.1b - Exhibit 01

Example 1 - Heart Rot Both Ends - Squared-defect Method

Example 2: Exhibit 02 illustrates a 16-foot log with heart rot 

extending 8 feet into the log. The defect including waste allowance 

measures 10 by 10 inches on the end showing. The squared-defect 

method gives 10 x 10 = 100 to the next 10 = 110 (11 Decimal). Take 

1/2 of 11 or a 6 deduction for this log.
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33.1b - Exhibit 02

Example 2 - Heart Rot One End Only - Squared-defect Method

Use the length-deduction method where the diameter of heart rot 

equals or approaches the diameter of the scaling cylinder (sec. 24). 

Any regional variance from the instructions above should be based 

on a local guide developed during mill visits. Refer to Rot, Conk, and 

exhibit A, appendix chapter.

33.1c - Rot, Sap

1. Sapwood on logs cut from dead trees, either snags or 

windfalls, often is in advanced stages of decay. If rotten sap extends 

over both the length and circumference of the log and the sapwood is 

still in place, the gross or outside diameter will be measured directly 

and the average diameter determined just as for green logs. When t

rotten sapwood has sloughed away, the gross or outside diameter will 

be determined by measuring the sound wood within the sapwood and 

adding thereto the estimated thickness of the rotten sapwood.

To obtain net scale, determine the average diameter of the sound 

cylinder inside the rotten sapwood (or surface checks) and treat it as 

a special scaling cylinder, considering any other defects that may be 
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present. The difference between the gross scale of the outer scaling 

diameter and the net scale of the inner scaling diameter will be the 

deduction if no other defects are present.

Example: Exhibit 01 illustrates a 16-foot log, 24 inches in diameter 

at the small end, has a gross scale of 40. If the average thickness of 

rotten sapwood is 2 inches, the net scale of the log will be that of a 

16-foot log 20 inches in diameter, or 28.

33.1c - Exhibit 01

Example 1 - Sap Rot - Diameter-deduction Method

2. When portions of the length or circumference of the 

sap are sound, the full log diameter including sap will be the scaling 

diameter and the defect deduction will be treated as follows:

Example: Exhibit 02 illustrates a 16-foot log, 24 inches in diameter 

at the small end, has a gross scale of 40. If the rotten sapwood is 

confined to the side which was lying on the ground and averaged 2 

inches rotten sapwood for 1/3 the circumference for the full length of 

the log the net scale of the log would be 36, derived as:
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33.1c - Exhibit 02

Example 2 - Sap Rot on One Side - Diameter-deduction Method

3. Examine logs with dead sapwood carefully. Rot may 

extend into the heart in the form of pockets. In fire-killed or down 

timber these pockets may be on one side only. This material should 

be looked over with care. Use the Hallin hammer or other type of 

spud to help determine the extent of rot. Deductions for these associated rots should usually be determined by the pie-cut method. See 

ch. 20, sec. 23.

4. Occasionally the top end of a sap-rotted log shows a 

deep rot penetration for a short length only. Make a length deduction 

for this portion and a diameter deduction for the remainder.
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5. Check merchantability specifications of the timber sale 

contract (ch. 10, sec. 16). Some contracts may state that logs with the 

sapwood decayed will be scaled inside the sapwood. In such cases the 

sapwood, like the bark, in disregarded in scaling. Gross scale in such 

a case refers to the heartwood only. Other contracts may provide for 

scaling such logs “gross,” in which case the gross scale is the only

recorded volume.

33.1d - Rot, Stump

Often called butt or ground rot, it is found only in the butt portion 

of trees as the name implies. Color varies from light brown to dark 

reddish brown. Swelling on the outside of a log may be an indication 

of defect length but not always so. Where swellings do indicate rot, 

decay seldom extends far beyond such swelling. The rot may be 

either blunt or conical. Splits on the side of a log, sometimes due to 

weakness caused by rot, aid in estimating decay length. Mill visits 

are the best way to find out whether the local stump rot is generally 

blunt or conical. It may be desirable to develop a local chart guide of 

the type shown by exhibit A in appendix chapter.

The length of penetration of stump rot seldom exceeds 16 feet and 

most commonly runs 2 to 8 feet. If mill visits show that the rot is 

generally blunt at the end, the amount of defect will be determined 

in the same manner as heart rot. If the rot is conical in shape, the 

amount of standard-length lumber which will be recovered along the 

taper of the rot must be considered. Use the squared-defect method 

unless the size of the defect is so large as to approach the diameter of 

the scaling cylinder and a length cut is indicated.
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Example 1: Exhibit 01 illustrates a 16-foot, 24-inch log with stump 

rot averaging 14 inches in diameter. Visible swelling in the log 

indicates total length is 6 feet. Because of the cone shape of stump 

rot, all of the 6-foot portion is not lost. At the point where the rot 

penetrates deepest, the log will not produce longer than 10-foot 

lumber, but along the sides of the rot cone within the scaling cylinder, 

it should produce 12- and possibly some 14-foot lumber. Average the 

defect length. In this example use 4 feet as the average length. The 

squared-defect method (code 22.4) gives 15 x 15 = 225 + 10 raised to 

the next 10 = 240 (24 Decimal), the deduction if the defect extended 

16 feet. The average length, however, is 4 feet, 1 the length of the 

log, or a deduction of 6.

33.1d - Exhibit 01

Example 1 - Stump Rot - Squared-defect Method

Example 2: Exhibit 02 illustrates a 16-foot, 18-inch log with stump 

rot averaging 16 inches in diameter. The size of this defect is so large 

as to approach the diameter of the scaling cylinder and calls for a 

length deduction. In the type of stump rot illustrated, a 4-foot-length 

cut should equal the loss from rot. The difference in scale between a 

log 12 feet in length and 18 inches in diameter and one 16 feet is 5, 

the proper deduction for this log.
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33.1d - Exhibit 02

Example 2 - Stump Rot - Length-deduction Method

33.1e - Knots, Rotten

In some species and areas, rotten knots indicate interior rot. Rot may 

follow the knot into the log, and then spread out one or both ways. 

The length of this spread varies with species, age, and locality. When 

rot shows on one or both ends, make deductions using the pie cut 

method for the length affected. Logs with rotten knots and no end 

indications are a challenge to any scaler. Visit local mills to establish 

a pattern for making deductions for this defect.
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33.1e - Exhibit 01

 Rot in Log End Caused by Rotten Knots—Pie-cut Method

33.1f - Pecky Rot 

Pecky rot does not taper the same as other defects. The following 

rules apply to pecky rot in lieu of averaging defect dimensions 

(Squared Area Methods, sec. 22.31).

1.	 Arrangement of Pecky Rot.

Consider all pecky rot that is less than 2.0” apart as defect. Minimum 

recordable volume for any single pecky rot defect is 10 board feet, 

or 1 Dec C. A 1.0” x 2.0” peck extended through a 16’ log will yield 

1 Dec C defect. (Including 1” for waste; = 6 BF, or 

1 Dec C). 

 2”x 3”x16’

15
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The following exhibit is an example of an arrangement of deductible 

pecky rot:

33.1f - Exhibit 01

Pecky Rot Arrangements

2.	 Defect Deduction Methods

The following exhibit is an example of Squared Area Method:
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33.1f - Exhibit 02

Pecky Rot Squared Area Method

First, calculate largest squared area; taking each subsequent squared 

area at right angles.

When edges of squares result in squared areas closer than 2.0”, use 

the give and take method to obtain squared area dimensions for the 

entire area affected by pecky rot.

Percent Deduction Method:

33.1f - Exhibit 03

Pecky Rot Percent Deduction Method
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3. Extent of Pecky Rot

In the absence of other indicators, use the following rules to 

determine extent of pecky rot.

Single Segment Logs

(1) When only one end contains pecky rot, calculate and 

extend the actual dimensions, including waste, of any

deductible peck through one-half of the segment length 

in even, two foot multiple

For example:

33.1f - Exhibit 04

Figures a & b - Pecky Rot One End, Single Segment Log

Figure a: Figure b:

Butt Log Second Cut

Extended defect dimensions Extended defect dimensions

(10” x 10”) through one-half (10” x 10”) through one-half

of segment (8’). of segment (9’) in even, two

foot multiples, rounding whole.
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(2) When both ends contain pecky rot and the defect 

on each end can be contained using one squared area

dimension, calculate the average squared dimension and

extend through the segment length.

(3) When both ends contain pecky rot and the defect 

dimensions on one or both ends result in two or more

squared areas, extend each defect through one-half of 

the segment length.

For example:

33.1f - Exhibit 05

Pecky Rot Both Ends, Multiple Squared Areas, 

Single Segment Log

Extend defect dimensions, Extend defect dimensions

including waste, through the segment through one-half the onehalf segment the segment length (8’).

length (8’).

Two Segment Second Cut Logs

(1) When only the small end is affected by deductible peck, calculate and extend the actual dimensions, 

including waste, through the small end segment only.
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(2) When only the large end is affected by deductible peck, calculate and extend the actual dimensions, 

including waste, through the large end segment only.

(3) When both ends contain pecky rot and the defect 

on each end can be contained using one squared area

dimension, calculate the average squared dimension

including waste, and extend through the length of each

segment.

For example:

33.1f - Exhibit 06

Pecky Rot Both Ends, One Squared Area, 

Two Segment Second Cut Log

(4) When both ends contain pecky rot and defect dimensions on one or both ends result in two or more squared

areas, extend each defect through the length of the

segment.
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For example:

33.1f - Exhibit 07

Pecky Rot Both Ends, Multiple Squared Areas, 

Two Segment Second Cut Log

(5) Exception:

When in the scaler’s judgment the pecky rot is clearing up or when 

the individual pecks are small and not expected to extend through the 

segment length, extend actual dimensions through one-half segment 

only.

c. 	Two Segment Butt Logs

(1) Merchantable Butt Logs

(a) When both ends are affected by deductible peck, 

calculate and extend the actual dimensions including

waste, of the small end deductible peck through the 

length of the small end segment and one-half the length 

of the butt (large) end segment. Extend the actual dimensions including waste of any deductible peck on the 

butt through the remaining one-half length of the butt 

(large) end segment.
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For example:

33.1f - Exhibit 08

Pecky Rot Both Ends, Merchantable Two Segment Butt Log

Extend actual dimensions (10” x 10” on small end), plus waste, 

through the length of the small end segment (16’), and one-half the 

length of the butt (large) end segment (8’). Extend actual dimensions 

(4” x 5” on the butt end) plus waste, through on-half the length of the 

butt (large) end segment.

(b) When only the butt (large) end segment is affected 

by deductible peck, calculate and extend actual dimensions of any deductible peck through the length of the 

butt (large) end segment only.

(2) Cull Segments, Butt Logs

(a) When the small end is affected by deductible peck, 

covering an area large enough to result in less than the

contract minimum net scale recovery, cull the small

end segment and one-half the length of the butt (large) 

end segment. Extend the actual dimensions, including waste, of any deductible peck showing on the butt 

through the remaining length (one-half) of the butt 

(large) end segment. To determine if the butt (large) 
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end segment is cull, compute the volume for each defect 

[include culled one-half butt (large) end segment], and 

then add them together. If the combined defect resul

in a net volume in the butt segment that is less than

the contract minimum net scale recovery, cull the butt

(large) end segment.

For example:

33.1f - Exhibit 09

Pecky Rot Both Ends (Cull Small End Segment), 

Two Segment Butt Log

(b) When the large end segment is affected by deductible peck covering an area large enough to result in less 

than the contract minimum net scale recovery, cull the

large end segment. Extend the actual dimensions, plus 

waste, of any deductible peck showing on the small end 

through the length of the segment.
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For example:

33.1f - Exhibit 10

Pecky Rot Both Ends (cull large end segment), 

Two Segment Butt Log

d. 	Three Segment Second Cut Logs

(1)When only the small end is affected by deductible 

peck, calculate and extend the actual dimensions, plus 

waste, of any deductible peck through the length of the 

small end segment and one-half the length of the middle 

segment.
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For example:

33.1f - Exhibit 11

Pecky Rot Small End Only, 

Three Segment Second Cut Log

Extend actual dimensions (10”x 10” on small end), including waste, 

through the small end segment (16’), and one-half of middle segment 

(8’).

(2) When only the large end is affected by deductible 

peck, calculate and extend the actual dimensions, plus 

waste, of any deductible peck through the length of the 

large end segment and one-half the length of the middle 

segment.

(3) When both ends are affected by deductible peck 

and the defect on each end can be contained using one

squared area dimension, calculate the average squared

dimension for each segment and extend through the

length of each segment.
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For example:

33.1f - Exhibit 12

Pecky Rot Both Ends, One Squared Area, 

Three Segment Second Cut Log

Average squared dimension for each segment and extend through the 

length of each segment.

(4) When both ends are affected by deductible peck and 

the defect on one or both ends results in two or more

squared areas, calculate and extend the actual dimensions of each deductible squared area through the length

of each end segment and one-half the length of the 

middle segment.

(5) Exception:

When in the scaler’s judgment the pecky rot is clearing up or when 

the individual pecks are small and not expected to extend through the 

segment length, extend actual dimensions through one-half segment 

only.

e.	 Three Segment Butt Logs

(1) Merchantable Butt Logs
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(a)When both ends are affected by deductible peck, 

calculate and extend the actual dimensions, including

waste, of any deductible peck on the small end through 

the length of the small end and middle segments. Extend the actual dimensions of any deductible peck o

the butt through the remaining length of the butt (large) 

end segment.

For example:

33.1f - Exhibit 13

Pecky Rot Both Ends, Merchantable Three Segment Butt Log

Extend actual dimensions (10” x 10” on small end, plus waste) 

through the length of the small end segment (16’) and middle 

segment (16’). Extend actual dimensions (4” x 5” on the butt end, 

plus waste) through the length of the butt (large) end segment (16’).

(b) When only the butt (large) end is affected by deductible peck, calculate and extend the actual dimensions, 

plus waste, of any deductible peck through the butt 

(large) end segment only.

(2) Cull Segments, Butt Logs

(a) When the small end is affected by deductible peck, 

covering an area large enough to result in less than the

contract minimum net scale recovery, cull the small end

segment and the middle segment.
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For example:

33.1f - Exhibit 14

Pecky Rot Small End Only, 

Three Segment Butt Log With Cull

Cull small end segment (16’), middle segment (16’0).

Extend any other defects showing on the butt (large) end through the 

remaining length of the butt (large) end segment.

(b) When the butt (large) end is affected by deductible 

peck, covering an area large enough to result in less than 

the contract minimum net scale recovery, cull the large

end segment only.
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For example:

33.1f - Exhibit 15

Pecky Rot Large End Only, 

Three Segment Butt Log With Cull

(c) When both ends are affected by deductible peck, and 

the butt end has deductible peck covering an area large 

enough to result in less than the contract minimum net

scale recovery, cull the large end segment only. Calculate and extend the actual dimnsions, plus waste, of an

deductible peck on the small end through the length of 

the small end and middle segments.
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For example:

33.1f - Exhibit 16

Pecky Rot Both Ends, Three 

Segment Butt Log With Cull

33.2 - Voids

33.2a - Catface

Scars or wounds, often caused by falling objects scraping against 

a tree, are generally called catfaces. When shallow in depth and 

removable with the slab, they need no deduction. When they 

penetrate deeper into the log, use the pie-cut method.

For catfaces similar to sap rot, determine how much of the surface of 

the scaling cylinder is affected and apply a diameter cut.

Exhibit 01 illustrates a 16-foot log with a deep and partially grownover catface. The defect is 10 feet long and is confined to a quarter 

section of the log. The diameter at the small end of the log is 17 

inches. The gross scale of a 10-foot log, 17 inches in diameter, is 

120 or 12 Decimal. The deduction for defect would be 1/4 of 12 or 3 

Decimal.
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33.2a - Exhibit 01

Catface - Pie-cut Method

Exhibit 02 illustrates a 16-foot log with a catface extending the 

entire length. The catface is 2 inches deep and covers 1/3 the 

circumference. The small diameter of the log is 15 inches and the 

gross scale 140 or 14. The defect is determined by subtracting the 

scale of an 11-inch log (diameter of core) from the gross scale and 

dividing by 3. Example: (14-7) ÷ 3 = 2.

33.2a - Exhibit 02

Catface - Diameter-deduction Method

Watch for massed pitch, wormholes, and rot in conjunction with 

catface. If ants are present, they are usually an indication of a deep 

dry rot somewhere within the log. 
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33.2b - Fire Scar

Fire scars are usually found only in butt logs, but occasionally extend 

into the second 16-foot log. In some species this defect may be 

accompanied by massed black or red pitch; sometimes by weather 

checks and wormholes or rot. Part of the scar at the top end may be 

healed over; consider possible defect here in measuring its length 

within the scaling cylinder. Mill visits will show how fire scars affect 

recovery of lumber from local species, timber of different ages, and 

scars of different ages. Fire scars may also be called catfaces. (See 

catface.)

Exhibit 01 illustrates a 16-foot log with fire scar extending 8 feet 

from the butt. Fire scars of this type always have a part of the defect 

outside the scaling cylinder (not deductible) and therefore appear 

more serious than they are actually.

Use a combination of pie cut and length of defect. First, estimate 

what part of the end of the scaling cylinder is affected, then what 

length is lost by defect. In the illustration half of the cross section of 

the scaling cylinder might be affected for 8 feet in length. Deduct 1/2 

of the 8 feet or 4 feet in length. Net scale is that of a log 12 feet long.
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33.2b - Exhibit 01

Fire Scar in Butt Log - Combination 

Pie and Length of Defect Method

33.2c - Lightning Scar

The spiral effect of lightning scars, sometimes with shatter, massed 

pitch, wormholes, and weather checks, presents a difficult scaling 

problem. The degree of spiral and volume loss varies. Give 

consideration to short-length lumber the log will produce.

The following alternate method may be used for the more difficult 

problems:

1. Determine degree of spiral over the entire log (as 1/4, 

1/3, 1/2, 2/3). Consider recovery of short-length lumber and taper.

2. Obtain gross scale of the lo

3. Measure depth of scar. Include massed pitch and other 

defects if present.

4. Double the scar depth (for both sides, sec. A) and subtract from log diameter. This result is diameter of section 
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33.2c - Exhibit 01

Lightning-scar Deduction

5.	 Obtain volume of section B and subtract from gross

volume of the log for the gross deduction if the entire collar, section

A, were lost.

6. Judge how much of this collar is lost. If the spiral went 

1/3 the way around the log, only 1/3 would be affected in some way. 

Short-length-lumber recovery might also reduce the amount lost.

7.	 Subtract net deduction from gross scale for net scale.

Exhibit 12 illustrates a 16-foot by 26-inch log with lightning scar spiral of 1/3 and 6 inches in depth. When the above formula is applied 

to these figures, the results are:

a. Gross log scale of 16-foot by 26-inch log = 50

b. Depth of scar doubled = 6 plus 6 inches = 12

c. Diameter of unaffected section B = 26 minus 12 

inches or 14
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d. Volume of section B = (16 feet by 14 inches) = 11

e. Gross deduction = 50 minus 11 = 39

f. Scar affects 1/3 of this “collar” 1/3 of 39 = 13

g. If short-length-lumber recovery and taper allowance 

in that 1/3 is about 25 percent, reduce the amount of loss 

25 percent or about 3. 

13 minus 3 = 10

h. Net log scale = 50 minus 10 (Decimal) = 40

Some logs have shallow scars on all sides that are deep enough to 

cause some loss in the scaling cylinder. Treat this defect the same as 

sap rot by making a diameter deduction.

Use the pie cut method when lightning scars are deep and affect one 

face.

33.3 - Breaks and Splits

Breaks and splits are mechanical defects which require special 

consideration. Modern-day logging, much of it in steep country, will 

generally result in some damage to the logs when felled, bucked, 

transported, and handled by various mechanical devices. In many 

instances this damage may result in a considerable loss of sound 

timber. Refer to codes 17.5 and 42 if abnormal amounts occur. 

Broken-end logs (shatter breaks) caused by falling, split or slabbed 

ends caused by poor bucking or falling, and slivers (stump pull) 

pulled from logs in falling are the most common types.
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Breakage may occur regardless of what precautions are taken; or 

may result from improper bedding, felling trees across stumps, logs, 

rocks, or ridges. Accurate determination of the extent of lengthwise 

shattering is often difficult as it may be hidden by bark. Remove 

enough bark to insure inclusion of the entire defect in the deduction.

Buckers should usually leave some breakage in a log to avoid waste.

Lengths of broken-end logs are determined as follows:

1. Where the broken end is wholly or partly bucked, measure the log from saw cut to saw cut and make any required deduction

(ex. 01, figure a).

2. When only one end is bucked, determine the most applicable scaling length and make the required deduction (ex. 01, figure 

b).

3. When neither end is bucked, determine the applicable 

scaling length and make any required deduction for defect (ex. 01, 

figure c).

4. When applicable scaling length is determined and the 

length due to breakage is less than the minimum length stated in the

contract, the log is considered unmerchantable due to size. It shall be

considered as substandard. Refer to section 55.63 for recording.
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33.3 - Exhibit 01

Broken End Partly Bucked

Figure a

Figure b

Figure c
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The following deduction procedure should be used to simplify and 

standardize treatment of broken-end logs:

1. Logs under 16 inches. If a quarter to a half of the end 

section within the scaling cylinder is gone, deduct half the length

affected (Exhibit 02 - figure a). If more than half the end section is 

gone, consider the entire end lost and deduct for the full length affected (33.3, ex. 02 - fig. b).

33.3 - Exhibit 02

End Break - Small Log Deduction When Half 

or Less of Log End is Broken

Figure a

End Break – Small Long Deduction When Over 

Half of Log End is Broken

Figure b
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2. Logs 16 inches and over. When any portion of the end 

section is broken, use a combination of pie-cut and length deduction. 

See Ex. 03, Fig. a - c.

33.3 - Exhibit 03

End Break - Large Log Deduction When 

Half or Less of Log End is Broken

Figure a

End Break - Large Log Deduction When Over 

Half of Log End is Broken

Figure b

Falling and bucking breaks are generally avoidable, but may be 

caused by rot, by heavy leaning trees on steep slopes, or by some 

factor not readily apparent to the scaler. Deductions for these defects 

are generally made by the squared-defect method. Refer to chapter 

40, sec. 41.2 for scaling of chunks and slabs.
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33.3 - Exhibit 03-Continued

Left, Stump Pull - Squared-defect Method Right, 

Bucker Break (straight) - Squared-defect Method

Figure c

33.4 - Checks

33.4a - Check, Weather

Also known as wind and sun checks. They occur (1) in logs left in 

the woods or cold decks for an extended period before scaling and 

(2) in dead trees (snags). Make no deductions for logs that weather 

check when left in the woods (by the option of the purchaser) or in 

cold decks. However, make deductions for such logs if the purchaser 

was not responsible for the condition of the logs as in sales of 

right-of-way logs already piled, or logs resold to a new purchaser. 

Instructions to scalers should cover proper procedures when this 

condition occurs.

Exhibit 01 illustrates a 32-foot log cut from a live tree. End 

dimensions are 24 and 28 inches, respectively. Weather checks 

occurred after the tree was felled and bucked in a right-of-way 

clearing. Such checks usually are about twice the depth at the ends of 

a log than elsewhere. If these weather checks are deductible (that is, 

not due to delay in removal by the purchaser), deduct as follows:
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33.4a - Exhibit 01

Weather Checks - Diameter-deduction Method

1. Top segment.

a. Measure the small end diameter of the 32-foot log 

(24 inches in the illustration).

b. Measure one-half of the depth of the checks on the 

small end (3 inches) and multiply by 2 for both sides 

of the segment (6 inches); this is the gross diameter 

deduction.

c. Reduce the diameter of the segment (24 inches) by 

6 inches to obtain a net diameter of 18 inches. The net 

scale then is that of a 16-foot log 18 inches in diameter, 

210 board feet or 21.

2.	 Butt segment. In the top segment the gross diameter 

deduction was 6 inches or a net scale of a log 6 inches less than the 

diameter at the small end. Do the same thing with the butt segmen

but use the midpoint diameter of the long log.

a. Find the midpoint diameter by use of the taper in the 

long log. In the illustration the taper is 4 inches from 

butt to top. Thus the midpoint diameter is 26 inches.
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b. Reduce the segment diameter by 6 inches for a net 

diameter of 20 inches. The net scale then is that of

16-foot log 20 inches in diameter, 280 board feet or 28.

Where only a fraction of the log surface or end is affected and the 

checks are deep, use the pie cut method, as shown in figure 14. 

Where (1) only a fraction of the log surface or end is affected and (2) 

the checks are confined to the outer surface and are deductible use a 

percentage or fraction of a diameter deducted for the length affected 

(fig. 24).

Weather checks found in logs cut from dead trees often are different 

from those described previously. These checks usually occur before 

a tree is felled. The depths of the checks in the sides of logs and at 

midpoint are about as deep as those in the ends. However, because of 

moisture retained in butts of standing trees, checks in the large end of 

a butt log may not be as deep as those in the top.

Weather checks often penetrate deep into the center of dead logs. If 

spiral grained, the log may be cull for sawtimber. However, if the log 

is straight grained, or the spiral is not severe, consider the possibility 

of cutting merchantable length lumber between the checks. By mill 

visits, determine the seriousness of weather checks. The statements 

above are guides to help in making deductions. To be merchantable, 

the log must meet net percent of gross stated in the contract. Exhibit 

02, figures a and b, illustrate the recovery of merchantable length 

lumber from spiral-checked logs.
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33.4a - Exhibit 02

Log is Cull because 6’ Lumber Cannot be 

Recovered Between Checks

Figure a

Log is Merchantable Because of Recoverable

Lumber Between Checks

Figure b

33.4b - Pitch Seam, Heart Check, Frost Cracks

1. Heart check is an opening or separation across the log 

heart at right angles to the annual rings. When filled with pitch, it is 

called a pitch seam. Frost cracks are similar to heart checks, except 

that they are usually visible in the bark and extend from the outside

of the log to the heart. Often these defects run farther lengthwi

than do pitch rings. Normally make deductions for seams, checks, 

and frost cracks by the squared-defect method.
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A word of caution in measuring the width of this type of defect; 

Search for “breakouts” or branches from the main check or seam. 

These are sometimes difficult to see, especially when log ends are 

wet. The minimum width of a check is 1 inch. This results in a width 

of 2 inches for squared defect calculations when the inch is added for 

waste.

33.4b - Exhibit 01

Heart Check - Squared-defect Method

Exhibit 01 illustrates a 16-foot butt log with a heart check in the large 

end. Top diameter of the log is 21 inches. The actual height of the 

check is 23 inches, but do not add an inch for waste to this dimension. 

Use 21 inches (the diameter of the scaling cylinder) for the height and 

3 inches for the width. The width measurement includes the 1 inch 

allowed for waste. The estimated depth of penetration in the log is 

8 feet. The squared-defect method (sec. 22.4) then gives 3 by 21 = 

63 or a deduction of 7 for a 16-foot length. One-half of this gives 4 

(Decimal), the deduction for 8 feet of penetration.

2. When the check shows on both ends and apparently 

extends straight through the log without twisting, deduct as for heart

rot: For 16- to 20-foot logs, average the end defect dimensions. For 

logs shorter than 16 feet, use the large end dimensions unless the 

Regional Forester prescribes otherwise. For logs longer than 20 

feet, follow the deduction rules described under section 22.5. Th

includes the use of the alternative method explained under section 

22.5, item 3c.
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33.4b - Exhibit 02

 Heart Check in 32-foot Log - Squared-defect Method

This exhibit illustrates a 32-foot butt log with heart check showing 

on both ends and in the same position. Small diameter of the 32-foot 

log is 23 inches, and midpoint diameter 25 inches. End dimensions 

of the defect in the 32-foot log are 2 by 15 inches and 3 by 25 inches, 

respectively, including waste. When dimensions of 15 and 25 inches 

are averaged the midpoint dimension is 20 inches.

Use 3 inches for the estimated width at the midpoint. For the butt 

segment, average 3 by 20 inches and 3 by 25 inches; result, 3 by 23 

inches. For the top segment, average 2 by 15 inches and 3 by 20 

inches; result, 3 by 18 inches. The squared-defect method (code 

22.5) then gives the following deductions: Butt segment, 3 x 23 = 69 

or 70 or 7. Top segment: 3 x 18 = 54 or 60 board feet (6 Decimal).
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33.4b - Exhibit 03

 Method for Making Deductions for Cross-checking

3. Deductions for two cross-checks are made as explained 

in item 2 preceding. In measuring height of the second check, do 

not include the width of the first check measured. Diagram separate 

checks at right angles. The “give and take” procedure explained 

in item 4 may also be used in determining the deduction for two

cross-checks. Use the “give and take” procedure when diagramming 

at right angles creates a loss of recoverable material in the squared

defect area of the checks.

4. Deductions for more than two, cross-checks (called 

multiple checks or spangle) are usually made using the squared-defect method unless the defect is large and results in a length-deduction. Some recovery might show between the ends of the check. U

the “give and take” procedures when squaring out this type of defect. 
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In exhibit 04 below, note that some recovery appears between the 

square (the “give” area). This is offset by the loss in the check ends 

outside the square (the “take” area).

33.4b - Exhibit 04

Multiple Checks and Pitch Spangles - Squared-defect Method

5. Heart checks and pitch seams showing on both ends of a 

log at different angles indicate twist. Obviously the loss here is greater than when the check is straight  The twist causes the production o

short-length lumber, some of it less than 6 feet. Consider the amount 

of twist when deducting for this defect. If the twist is 45o, use 1

times the deduction for a straight check. If the twist is 90o, double 

the deduction for a straight check.

On one log end, place a small stick in the bark parallel to the check. 

This helps determine if any twist is present when you are at the other 

end.
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This exhibit illustrates a 16-foot log with a 2- by 20-inch heart 

check showing on the butt end. The same check at the top end is 1 

by 16 inches, but shows a 90∞ twist. After adding 1 inch for waste 

and averaging the defects (3 by 21 and 2 by 17), the squared-defect 

method (code 22.5) gives 3 x 19=57, or a deduction of 6 for a 16-foot 

log with a straight check. Adjusting for the 90∞ twist, the actual 

deduction for the log will be 6 x 2 or 12.

33.4b - Exhibit 05

 Heart Check With 90o Twist - Squared-defect Method

The next exhibit illustrates a 32-foot log with a heart check showing 

on both ends. End measurements of the defect are 3 by 21 inches and 

2 by 12 inches, including waste. The check on the top end indicates a 

90∞ twist from that showing on the butt end. By using the squareddefect method (sec. 22.5), the defect is computed as follows:

Average end defects (3 by 21 and 2 by 12 inches) to obtain 

dimensions of defect in the center of the log (3 by 17 inches).

Determine defect for each scaling length by averaging end defects 

and adjusting for twist (45 degrees in each segment).
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3 by 21 and 3 by 17 average 3 by 19 inches. 

Use 3 x 19 = 57 or a deduction of 6 for the 16-foot length for the butt 

segment if the check was straight.

33.4b - Exhibit 06

Heart Check With 90o Twist in 32-foot Log; 45o Twist 

in 16-foot Log – Squared-defect Method

Adjusting for the twist, the actual deduction for the butt segment will 

be 6 x 1.5, or 9.

3 by 17 and 2 by 12 average 3 by 15 inches.

Use 3 x 15 = 45 or a deduction of 5 for the 16-foot length of the 

top segment if the check was straight. Adjusting for the twist, the 

deduction for the top segment will be 5 x 1.5 or 8. The total defect 

deduction for the 32-foot log is 17.

6. When logs are exposed to the sun and wind for an 

extended period, weather or seasoning checks often occur in the ends. 

The scaler must learn to detect this type because he makes no deduction for them (see Checks, Weather). Such checks often increase in 

length due to weather. Use a thin wire or knife blade on doubtf

checks to determine the type. Look for sawdust in checks. Sometimes this is an indication of a natural heart check.
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7. For multiple frost cracks, see Pitch Spangle.

33.4c - Pitch Spangle

When more than two pitch seams occur in the large ends of butt logs, 

the defect is called a pitch spangle. Douglas-fir and western larch are 

species commonly affected. Breakouts from the seams often occur. 

Sometimes pitch rings occur in connection with pitch seams. Defect 

of this type causes heavy loss in lumber manufacture. Sometimes a 

part of the defect extends into the second log.

33.4c - Exhibit 01

Pitch Spangle Deductions in 32-foot Log; Butt Segment - Lengthdeduction Method Top Segment - Length-deduction Method 

for Large End; Squared-defect Method for Small End

Make length-cut deductions for pitch spangles in the butt 16-foot log 

when the size of the spangle approaches the scaling diameter. For 

other logs, use the squared-defect method, as you would for multiple 

checks. 

This exhibit illustrates a 32-foot, 20-inch log with pitch spangle. The 

entire scaling cylinder is affected because the seams extend beyond 

its edges. Some defect shows on the small end of the 32-foot log 

indicating the defect is greater at the 16-foot point and not as great as 
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in the butt end. In the illustration the butt 16-foot segment is highly 

defective, more than 50 percent. If the contract merchantability 

clause specifies 50 percent, this log is cull. If 33 1/3 percent, this log 

may be marginally merchantable.

If mill visits indicate that pitch spangle cuts out this way, treat the top 

16-foot log as follows: Judge the large end defect as 50 percent of 

the scaling cylinder and the length of penetration as 8 feet. Deduct 

half of the 8 feet affected or 4 feet for the large end. For the small 

end, apply the squared-defect method and use 8 feet for the length. 

Compute the deduction for each, add, and then compute the net scale 

of the log.

Refer to examples included under Pitch Seam, Heart Check, Frost 

Cracks for alternate procedures for determining the volume of a top 

log.

33.5 - Pitch Ring, Shake Ring

33.5a - Rings, Pitch and Shake

1. Ring shake defect is the separation of one or more 

annual rings sufficient to cause a volume loss in manufacture. This 

separation is known as a pitch ring when it becomes filled with pitch, 

often a characteristics of species like Douglas-fir and larch.

2. 	Shake ring defects follow the annual rings. Somet

they stop where knots start, for knots tend to hold the annual rings together. On some logs the length of pitch rings is shown by a narrow 

scar or pitchy seam running lengthwise in the bark. A scaler must 

look closely at log ends to locate rings and determine their size and

shape. He should bear in mind that a ring that opens wide may have 

deep penetration into the log and that numerous rings may penetrate 
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deeper than one or two rings. Make no deductions for rings outside 

the scaling cylinder, but rings in the large end of logs that enter the

scaling cylinder will need defect deductions. It is important for the 

scaler to make sawmill visits to develop judgment in making ring 

shake deductions.

3. 	The need for considering the number of rings, ring location, ring class, ring taper, and the scale of any solid core often make

pitch and shake rings a complex scaling problem.

4. The basic procedure for scaling pitch and shake rings 

is to square the defect and replace a sound core. Rings are measured 

and averaged for size in the same manner as log diameters (sec. 17.3).

This rule in formula is: 

Logs to 14 feet inclusive: (large ring +1)2 - (core ring scale) 

Logs 16 to 20 feet inclusive: (average ring + 1)2 - (core ring scale)
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33.5a - Exhibit 01

Shake Ring in Large End

Example 1: A 14-foot log 21 inches in diameter has an 8-inch shake 

ring showing in the large end. The defect extends an estimated 8 feet.

Using the shortcut procedure (sec. 22.4), deduct as follows:

9 x 9 = 81 to the next higher 10 = 90 board feet 

90 x 8/16 = 45 to the nearest 10 = 50 board feet

Replace 7-inch core (allow 1-inch taper), 8 feet long

Deduction = 50 - 10 or 40 board feet (4 Decimal)

(This is easy to compute with the Coconino scale stick.)

Example 2: A 16-foot log has a 6-inch shake ring showing at 

the small end and an 8-inch shake ring showing at the large end. 

Adding 1 inch for waste and averaging the defect (sec. 22.5): 

8 x 8 = 64 to the next higher 10 = 70 board feet

Replaced 6-inch log = 20 board feet
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Deduction = 70 - 20 or 50 board feet (5 Decimal)

(This is easy to compute with the Coconino scale stick.)

33.5a - Exhibit 02

Shake Ring in Both Ends

5. Following are instructions for varying the above procedure in accordance with the circumstances encountered.

a. For one-quarter rings, use the squared-defect method 

as for checks and do not consider core.

b. 	For a half ring, take half the deduction for a full ring

for the length affected.

c. For a three-quarter ring, take three-quarters of the 

deduction for a full ring for the length affected.

d. When 2 full rings are not more than 2.5 inches apart, 

measure diameter of the outside ring. Add 1 inch. Apply squared-defect method for gross deduction. Reduce 

this by the scale of a log with a diameter of the inner

ring.
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e. When 2 full rings are over 2.5 inches apart, measure 

diameters of both rings. Compute separately as per 

preceding examples and add deductions together.

Example 3: A 16-foot log has 6-inch and 16-inch shake rings 

showing at the small end and 8-inch and 18-inch rings showing at the 

large end. Adding 1 inch for waste and averaging the defect:

18 x 18 = 324 + (sec. 22.2) to the next higher 10 =

330 + 20 (For 17” to 21” squares) = 350

Replaced 16-inch log = 160

Deduction for large ring = 350 - 160 or 190 (19 Decimal)

8 x 8 = 64 to the next higher 10 = 70

Replaced 6-inch log = 20

Deduction for small ring 70 - 20 or 50 (5 Decimal) 

Total deduction 240 board feet or 24

(This is easy to compute with the Coconino scale stick.)
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33.5a - Exhibit 03

Two Full Rings Over 2.5 Inches Apart

f. When multiple rings occur with no recovery between 

them, square the overall defect and allow for the scale

of any inside log surrounded by the rings.

g. For a full or partial ring 2.5 inches or less from the 

outside at the top end, a perimeter ring, deduct by the 

diameter deduction method for the portion of the circumference and length affected.

Example 4: A 16-foot log 21 inches in diameter has a 22-inch shake 

ring showing in the large end. The defect extends an estimated 8 

feet to where the estimated ring diameter is 19 inches. It is thus a 

perimeter ring at this point and a diameter reduction is used. An 8-

foot log 21 inches in diameter scales 150 board feet; an 8-foot log 19 

inches in diameter scales 120 board feet. The deduction is 30 board 

feet or 3.
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33.5a - Exhibit 04

Perimeter Deduction in Stump Cut

h. Make a length deduction if deductions by the 

squared-defect method exceed the log scale of the part 

affected.

i. Do not replace the core in determining the defect 

when the core is too small (normally less than 6 inches) 

to yield standard-sized lumber.

6. The scaler must remember to follow instructions for 

application of the squared-defect method (sec. 22.3) in determining 

which measurements to use. They should also be aware that ring defects follow annual rings and taper, and remember to treat each cor

as a new scaling cylinder.

7. A Pitch and Shake Ring Deduction Table for 16-, 18-, 

and 20-foot logs with rings showing on both ends (table VI in the 

appendix chapter) can be used instead of making the several calculations normally required. The table is for use in scaling with t

Scribner Decimal C rule and provides for taper up to 8 inches.

8. Breakouts from a shake ring sometimes occur. These 

numerous short radial seams usually are found in a “collar” on the

outside of the ring. Obtain the average length of the seams. If 2
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inches or less (the collar thickness) follow the deduction rule as 

explained in the preceding item 5. If seams are over 2.5 inches long, 

determine how much of the collar is affected-a third, half, or all-and 

use the multiple-ring rule as explained in item 5.

9. Sometimes pockets occur in annual rings. In some 

softwood species they are called pitch pockets.

In some hardwood species they are referred to as gum pockets. 

Usually there is a separation present but the pockets are too short to 

cause a volume loss. Make no deduction for these pockets unless 

they are long enough to square out for a deduction of 10 board feet or 

are so numerous as to cause an actual loss in lumber recovery.

10. In white fir and hemlock a combination of ring and radial shake is common in some areas. The combination often requir

a length deduction. Frost cracks, splits, or seams on the outside of 

the log often indicate the extent or condition.

33.5b - Pitch, Massed

Massed Pitch is defined as an accumulation of solid pitch. Often 

massed pitch occurs in connection with fire scars and may extend 

beyond the scar at the top end. The concentration of pitch must be 

sufficient enough to cause an actual loss of merchantable lumber 

before any deduction is made. No deduction is made for wood lightly 

saturated with pitch because such material can be utilized in certain 

grades of lumber.
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33.5c - Pitch Pockets

Defined as small, scattered crescent shaped areas of pitch (usually 1 

or 2 inches in length) that are occasionally present in some species 

of logs. This condition is rare, but when it does occur, it is usually 

found in the butt logs of pine species.

No deduction is made for this condition because scattered pitch 

pockets rarely if ever result in a volume loss of merchantable lumber. 

Certain grades of lumber allow for the presence of pitch. A deduction 

may be made if an extreme concentration of pitch pockets is enough 

to cause an actual loss of merchantable lumber.

33.6 - Crook, Pistol Butt and Sweep

33.6a - Crook and Pistol Butt

When a log has an abrupt curve or bend, the defect is called crook. 

When crook is present in the butt end of the log, the defect is called 

pistol butt defect. Deductions are made for void, cross grain and any 

portion that will not produce 6-foot lumber recovery on either side of 

the crook. 

One type of crook is found in logs from upper portions of trees. 

Snow or falling trees that break off tops of other trees can cause this 

defect. Before a new leader starts, rot and black massed pitch may 

enter the wound. The new leader may die, leaving a large suckertype dead knot. Breakage may occur at this point due to weakness 

caused by cross grain. 

Cross grain material is defined as grain deviation that exceeds 3 

inches per foot from straight. Measure grain deviation by projecting a 

straight line down the center of the segment starting from the longest 
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straight portion. Measure the distance between the projected straight 

line and the centerline of the crook portion for the length affected. If 

the deviation exceeds 3 inches per foot it is considered cross grain 

and the entire length affected by crook is deducted using a length 

deduction. 

If cross grain material is not present, determine the percent loss for 

void and include the portion of the log that will not produce standard 

length lumber in the manufacturing process for the deduction. 

33.6a - Exhibit 01

Crook - Length Deduction for Cross Grain

In this exhibit, 4 feet of length is affected by crook. Grain deviation 

measures 20 inches in 4 feet, or 5 inches in 1 foot, which exceeds 3 

inches per foot. Due to cross grain, the length deduction is the full 4 

feet.
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33.6a - Exhibit 02

Crook - Length Deduction for Void

In this exhibit, 4 feet of length is affected by crook. Grain deviation 

measures 12 inches in 4 feet, or 3 inches in 1 foot, which does not 

exceed the allowable deviation. Void and loss due to manufacturing 

process affects 25% of 4 feet. Length deduction of 25% of 4 feet is 

taken for void.

If grain deviation had exceeded 3 inches per foot, it would be 

considered cross grain and a length deduction of 4 feet would be 

taken for the crook.
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33.6a - Exhibit 03

Crook - Length Deduction for Cross Grain

In this exhibit, 2 feet of length is affected by crook. Grain deviation 

for the affected 2 feet measures 12 inches, or 6 inches in 1 foot, 

which exceeds 3 inches per foot. A 6-foot portion and an 8-foot 

portion remain on either side of the crook and are parallel to, or on 

the same plane, as each other. The length deduction is the full 2-foot 

portion containing cross grain. If the remaining portions on either 

side of the defect would not produce 6-foot lumber recovery or were 

not parallel and on the same plane, the deduction would include those 

portions.

33.6a - Exhibit 04

Crook - Length Deduction for Cross Grain and 

Portion Not on the Same Plane

In this exhibit, 2 feet of length is affected by crook. Grain deviation 

for the affected 2 feet measures 11 inches, or 5.5 inches in 1 foot, 

which exceeds 3 inches per foot. A 6-foot portion and an 8-foot 
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portion remain on either side of the crook but since they are not 

parallel to, or not on the same plane as each other, the defect 

deduction includes the 6-foot portion. The length deduction is 8 feet; 

2 feet for cross grain and 6 feet for the portion not on the same plane.

Trees growing on steep slopes and/or in locations of heavy snowfall 

are susceptible to pistol butt defect. This condition often results in 

cross grain material in the affected area. 

33.6a - Exhibit 05

Crook - Pistol Butt Defect

In this exhibit, pistol butt defect affects 6 feet of the butt end of this 

log. Grain deviation measures 24 inches in 6 feet, or 4 inches in 

1 foot, which exceeds the allowable 3 inches per foot. The length 

deduction for pistol butt defect in this example is the entire 6 feet.

33.6b - Sweep

Sweep compared with crook is less abrupt and more continuous. 

Sweep is often long enough to affect more than one segment. 

Varying the bucking lengths of logs will often reduce the loss due to 

sweep. If logs presented for scaling indicate poor bucking practices 

the scaler will report this to the Contracting Officer. Scalers will 

deduct for sweep in logs by scaling as presented unless otherwise 

instructed (sec. 17.5).
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Make deductions for sweep as follows:

1. 	Position the scaling cylinder in the log segment to maximize volume recovery. The scaling cylinder may extend from eith

end of the log segment or may be positioned in the center portion. 

2. Measure the length of the log affected by sweep.

3. 	Deduct the fraction of this length lost in sawing, considering standard length lumber recover

4. Make a length deduction accordingly.

33.6b - Exhibit 01

Sweep

Exhibit 01 illustrates a 16-foot, 20-inch log with sweep affecting 

6 feet of the scaling cylinder. It is estimated that one-third of the 

affected area will be lost in sawing. In this case a 2-foot-length 

deduction is made.
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Sweep in combination with an interior defect such as rot or shake is 

likely to cause a cull log.

33.6b - Exhibit 02

Sweep in Combination With Shake

33.7 - Knots

Knots are normally a grade defect and are not considered a scaling 

defect until the knots are oversized where they enter the scaling 

cylinder, and their numbers and location cause a volume loss in 

the manufactured product. An extremely knotty log does not 

automatically create the need for a defect deduction.

Live knots begin to taper immediately under the log surface, whereas 

dead knots begin to taper at a point where the limb actually died. 

Volume loss associated with oversize knots occurs in the growth ring 

area of the knot. Logs with larger knots may produce grain distortion 

in and around the collarwood area causing additional volume loss due 

to cross grain material. A volume loss may also occur when oversize 

knots occur in knot whorls, knot clusters or bunch knots.

Knot clusters may consist of a group of small limbs developed from 

adventitious buds. It does not affect the volume of lumber produced 

and is not treated as a defect.
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Live and dead knots are considered oversize when they exceed the 

maximum knot size limit for the diameter ranges shown below. 

Maximum knot sizes are based on the small end diameter, or scaling 

cylinder size, of the affected log or segment.

Knots are measured at the surface of the log and size is determined by 

averaging the narrow and wide measurements of the hardened area of 

the knot showing growth rings, excluding the collarwood surrounding 

the knot, as shown in Exhibit 11.

33.7 - Exhibit 02

Determining Knot Size

Make deductions for oversize knots using the Knot Deduction Guide 

when the entire scaling cylinder is affected with oversize knots. 

Consider knot location, log taper, percent of circumference and length 

affected and adjust the deduction outlined in the Deduction Guide to 

KNOT SIZE LIMIT

Small End Diameter Max. Live Max. Dead

 5” to 10”	 2”	 1”

11” to 20”	 3”	 2”

21” & up 4” 3”
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reflect only the loss within the scaling cylinder due to oversize knots. 

A few scattered oversize knots on a log does not create a volume loss. 

These deductions for oversize knots are not applicable to Ponderosa 

Pine, Sugar Pine, and hardwoods.

33.7 - Exhibit 02

Mostly Live Oversize Knots

Given:

Recorded log length = 20 feet

Small end diameter = 26 inches

Live knot size limit = 4 inches. 

Live knots, 5 to 6 inches in size, are affecting 

the entire surface of the log.

KNOT DEDUCTION GUIDE

Small End Diameter *Diameter Deduction

 5” to 15”	 1”	

 16” to 25” 2”

 26” to 35” 3”

 36” to 45” 4”

46” & up Scaler’s judgment

* Reduce the defect volume if entire scaling cylinder or length

is not affected.
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Using the Knot Deduction Guide, a 3-inch diameter deduction is 

indicated. Log taper is considered and it is determined that the 

knots would be 5 inches where they enter the scaling cylinder so no 

adjustment is made to the deduction.

When oversize knots do not affect the entire surface and/or length of 

the log, the amount of defect deduction will be reduced to represent 

only that portion of the log that is affected with oversize knots.

33.7 - Exhibit 03

Mostly Dead Oversize Knots

Given:

Recorded log length = 20 feet

Small end diameter = 17 inches

Dead knot size limit = 2”

Mostly dead oversize knots affect two faces, 

50%, for 6 feet.

Using the Knot Deduction Guide, a 2-inch diameter deduction is 

indicated. Adjust the deduction to 1” for 6 feet for the percent and 

length affected.

Deductions will be made for oversize knots in knot whorls and knot 

clusters when oversize knots show on one or more faces of the log. 

Use the Knot Deduction Guide when making the deduction. Reduce 

the defect deduction for the actual length and faces affected.
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33.7 - Exhibit 04

Live Oversize Knots in Knot Whorls

Given:

Recorded log length = 20 feet

Small end diameter = 18 inches

Live knot size limit = 3” 

Live oversize knots in whorls affecting 8 feet.

Using the Knot Deduction Guide, a 2-inch diameter deduction 

is indicated. Adjust the deduction to 2” for 8 feet for the length 

affected.

33.8 - Other Defects

33.8a - Burls

1. Burls are dome-shaped growths of various sizes found 

on tree trunks. At times they penetrate into logs as far as their height 

above the log surface. When burls cover about 1/4 the circumference of a log, make a length deduction to cover the volume loss in the

affected portion (one-fourth the length of the burl within the scaling 

cylinder). Usually 1 foot per major burl is sufficient. If the burls 

are so close together as to prevent the manufacture of merchantable 

length lumber between them, apply the pie-cut method for the portion 

of the length affected.
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33.8a - Exhibit 01

Burls - Combination Pie-cut and Length-deduction Method

2. Numerous small burls or pitch scabs may contain 

massed pitch and pitch rings which occur beneath these burls and 

may cause a loss in the outer portions of logs. A diameter deduction 

for this defect equal to the depth and portion affected as for sap rot 

may be equitable but should be checked, and not applied automatically (Exhibit 02 - Figure a). The figure shows areas of defect only. 

Deductions should include all loss of standard-length lumber.

33.8a - Exhibit 02

Numerous Small Burls or Pitch Scabs - 

Diameter-deduction Method
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33.8b - Crotch

A crotch is the point in a tree where it forks into two or more leaders 

or stems. Proper bucking can eliminate much of the defect. Usually 

the loss occurs from a bark seam, split, or cross grain in the end 

of such logs. Loss may occur from flat sides often characteristics 

of a crotch condition. A deduction of 1 or 2 feet in length is often 

made for this type of defect, but the actual deduction depends on 

observation of loss during mill visits. 

33.8b - Exhibit 01

Crotch Log With Characteristic Flat Sides

It may be sufficient merely to square out the bark seam. Amount 

of deduction depends on the point of bucking. See chapter 10, sec. 

17.32 for method of measuring diameters of crotched logs.

33.8b - Exhibit 02

Crotch Log
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33.8c - Foreign Material

Logs that contain foreign material such as insulators, spikes, nails, 

staples, wire, rocks, etc., that may create a safety hazard or may 

damage saw mill equipment when being manufactured, shall be 

treated as follows:

1. The Scaler should identify the log as a safety haza

by marking the log or by using another identifying method. Info

purchaser, equipment operator or other appropriate person so the log 

can be set aside.

2. If the foreign material can be readily removed, remo

the material or have it removed. If the foreign material cannot 

readily removed, make a length deduction in even two foot multiples 

to eliminate the entire length affected. Since foreign material mu

be physically bucked out, the remaining portion of the log must meet 

contract minimum log length after deductions or the log is cull. If t

extent of the material in the log cannot be determined, the log may be

culled.

33.8c - Exhibit 01

Foreign Material Defect

Foreign material is found in two locations on this 20-foot log. Nails 

are located approximately 6 feet from the small end. A deduction 

of 8 feet is necessary to eliminate the length affected by the foreign 
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material and the portion of the log that is less than the contract 

minimum log length, which in this example, is 8 feet. The large end 

has wire embedded in the log 4 feet from the end. A deduction of 4 

feet will eliminate the length affected. Eight feet remains between 

the defected areas. Total deduction for the log is 12 feet.

33.8d - Multiple Defects

More than two types of defect may occur in ends and sides of logs. 

To apply one or more deduction methods to each defect is often 

difficult and time consuming, and may result in erroneous deductions. 

The best method is usually to combine a pie cut with the length of 

defect on such logs. In some cases, the squared-defect method may 

be applicable.

33.8d - Exhibit 01

Multiple Defects - Combination Pie-cut and 

Length of Defect Method

Exhibit 01 illustrates a 16-foot, 24-inch butt log with multiple defects 

in the large end. First estimate what fraction of the scaling cylinder 

is affected. About two-thirds of the tree is affected to some extent. 

Next, estimate the average length of the defects.
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Example: Fire scar 10 feet, rot 6 feet, heart check 8 feet, making an 

average of 8 feet. The deduction then is 2/3 of 8 feet, or a 6-footlength deduction.

33.8e - Spiral Grain

Any grain distortion that exceeds 3” per foot, or 1” in 4”, will require 

a deduction. Measure spiral grain midway through the affected area. 

A 1” diameter deduction shall be taken for each inch by which the 

slope of grain exceeds 3” per foot.

33.8e - Exhibit 01

Spiral Grain

Spiral grain affects the entire log. Grain distortion measures 6” in 

1-foot, which results in a diameter deduction of 3 inches. 

33.8f – Stain

Stain normally affects quality of lumber recovery rather than quantity. 

Generally stains are blue or brown. No deduction is made when 

the stain is firm and light in color, but deduction is made when stain 

is associated with actual rot and there is a breakdown of the wood. 

When to make a deduction for stain in some species is difficult to 

know. Examine dark stain for rot, weather checks, or wormholes. 

Brown spots are generally an indication of actual rot. See Rot, Sap.

Earlier stages of actual breakdown of wood can be determined 

frequently by driving the corner of a sharp hand-axe bit, or Hallin 
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hammer, into the end of a log and twisting. If fibers break across, the 

wood is weakened. Fibers of firm sound wood will cut clean and pull 

straight out rather than tear or break across.

The significance of mineral stain and firm blackheart varies in 

different areas. Become familiar with any local guides concerning 

these indicators.

33.8g - Wormholes

Wormholes are classed as pin size, not over 1/16 inch in diameter; 

small, not over 1/4 inch in diameter; and large, over 1/4 inch in 

diameter. Pin and small wormholes are caused by different kinds of 

beetles; large wormholes by wood borers or grubs. Wormholes are 

common in logs cut from snags and in some down timber. When 

found in sap rot, the deduction for rot will also include any deduction 

for wormholes. When found in connection with catfaces and fire 

and lightning scars, include large wormholes in the measurements of 

those defects.

Make deductions only for large (grub) wormholes when they are 

massed and this condition causes an actual loss of volume. Generally 

use the pie-cut deduction method. The diameter-deduction method 

may occasionally be applied when wormholes are uniformly 

distributed around the log.
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33.8g - Exhibit 01

Grubworm Holes - Pie-cut Method
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Table of Contents

41 - LOGS NOT MEETING UTILIZATION SPECIFICATIONS 2

41.1 - Because of Defect .................................................. 2

41.2 - Chunks, Slabs, and Small Logs.............................. 2

42 - UTILIZATION INSPECTIONS........................................... 3

42.1 - Material to be Removed.......................................... 5

42.1a - Procedure for Determining Diameters............... 5

42.1b - Proper Utilization ............................................... 6

42.2 - Massed Interior Defects.......................................... 9

42.2a - Proper Bucking Point for Logs With 

Massed Interior Defect................................................. 10

42.3 - Massed Defect With Sound Sector....................... 10

42.3a - Proper Bucking Point for Logs With 

Sound Sector............................................................... 12

42.4 - Perimeter Defects................................................. 12

42.4a - Proper Bucking Point for Logs With 

Perimeter Defect.......................................................... 13

42.5 - Exterior Defects .................................................... 14

42.6 - Stump Heights ...................................................... 22

43 - SCALING DEBARKED LOGS........................................ 23

44 - TIMBER TRESPASS ...................................................... 24

44.1 - Stump Scaling....................................................... 24

44.2 - Stump Cruising ..................................................... 26

44.3 - Scaling When Stumps and Other Direct 

Evidence is Lacking ........................................................ 26

45 - SPECIAL SECTIONAL PROBLEMS.............................. 27
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41 - LOGS NOT MEETING UTILIZATION SPECIFICATIONS

41.1 - Because of Defect

Cull logs are logs which do not meet utilization standards for net 

scale as a percent of gross scale under the terms of the contract. Such 

logs may or may not contain some merchantable material. Usually 

the removal of cull logs from the sale area is by the option of the purchaser. If cull logs are removed as a product specified in the contract, 

record the log as a cull and show the gross scale in the defect column 

(sec. 55.63). If cull logs are being removed from the sale area as a 

product not specified in the contract, inform the Contracting Officer. 

In such cases, the product shall be appraised, rates established, and 

instructions to the scaler (ex. 1, sec. 55.5) revised.

41.2 - Chunks, Slabs, and Small Logs

1. A chunk is a piece of wood in log form which measures 

less than the contract minimum length. Chunks may originate from 

long butting, bucking out defects, failure to vary log length, or breakage. When chunks result from purchasers’ carelessness or waste of 

what would have been standard material, as determined by the Forest 

Service representative for the sale, chunks may be scaled. Some 

timber sale contracts provide that products removed which do not 

meet the utilization standards because of size or net scale will be paid 

for at the same rates as standard timber. Therefore, under this type of 

contract if a chunk is not cull because of defect, it will be scaled if it 

is removed from the sale area. Also see section 42.

2. Slabs are portions of logs created when a log splits 

lengthwise. The statements in paragraph 1 about chunks also apply 

to the treatment of slabs.
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3. Scale slabs and chunks in the same manner as other 

logs. When slabs approximate one-half the original log, determine 

the gross volume as one-half the volume of a full log with the same 

dimensions. If pieces are not round, take square or rectangular measurements and determine the volume in the same manner as defect 

volumes are obtained by use of Coconino-scale stick or shortcut 

procedure (sec. 22). Deduct for any remaining defect.

4. Logs with top diameters smaller than the contract minimum must be measured at the top diameter specified in the contract 

when there would be a volume loss if scaled as presented. Also see 

section 17.5. An exception to this would be when a timber sale 

contract provided for the scaling of material with a diameter smaller 

than the contract minimum and needs to be converted to board feet 

measure. In such cases, the Regional Forester must issue special 

instructions and approved volume tables.

5. Except for utilization scaling in the woods (sec. 42), the 

minimum volume that can be recorded for any piece is 10 board feet, 

or 1 decimal C, unless otherwise specified by the timber sale contract.

42 - UTILIZATION INSPECTIONS

Timber sale contracts provide for the greatest practicable utilization of the included timber. Product specifications normally include 

minimum length, diameter, and net scale in percent of gross scale. 

Conduct utilization checks in cut over areas during or as soon after 

logging as practical. When more than incidental amounts of material 

meeting the product specifications have been left in the woods, the 

Timber Sale Administrator should promptly notify the purchaser in 

writing to remove the material.
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 40 - SPECIAL SCALING PROBLEMS

WO Amendment 2409.11-2006-1 Page 40- Effective 10/30/2006

Some examples of improper log manufacturing include:

1. A cull log under the terms of the contract, which would 

have met contract specifications if the end containing the major portion of the defect had been cut off.

2. A log left in the woods because its top diameter is 

smaller than the contract minimum, but it would meet minimum 

specifications if cut shorter.

3. Top material with a diameter larger than the contract 

minimum, which when properly bucked, would have been included 

with the log removed.

4. Excessive sound material showing on one end of a 

defective log or long butt which, if properly bucked, would have been 

included on a log that was removed.

5. Sound material wasted in bucking-out defects, breaks, 

or crooks which could have been utilized if bucking had been done 

correctly.

6. Tree not bucked so as to avoid excessive sweep deduction.

7. Long-butts that are excessive due to attempts to eliminate all the stump rot.

8. A log meeting contract specifications with less than the 

defect percent of the net percent of gross stated in the contract and 

capable of producing 6 foot lumber.

9. Stumps exceeding the contract height specification.
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NATIONAL FOREST LOG SCALING HANDBOOK

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42.1 - Material to be Removed

All logs and pieces which meet the minimum contract specification 

are required to be removed. When determining the proper utilization in the woods, each piece must be considered on its own merits. 

Depending on the characteristics of the log or piece, one or more 

of the following criteria should be used to determine if the required 

merchantability is met.

Use these criteria to estimate proper log manufacturing in the woods 

and to assess merchantable material remaining after yarding:

1. The log end diameter and the diameter dimension of the 

defect.

2. The net scale of a log and the percent of gross scale 

stated in the contract (Normally 33 1/3 percent).

3. Merchantable material meets the net scale in percent of 

gross scale at the point it is severed.

4. The capability of the piece to produce lumber at least 6 

feet in length.

42.1a - Procedure for Determining Diameters

1. Long Butts.

a. If the butt end is defective, estimate the diameter at 

4 feet above the butt end to compare to the defect diameter (large end) to determine if a long butt was 

warranted.
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WO Amendment 2409.11-2006-1 Page 40- Effective 10/30/2006

b. When checking long butts for proper utilization use 

the small end diameter where the piece is or should have 

been long butted for proper utilization. When long butts 

are less than 4 feet in length, measure at the small end, 

ignoring flare.

2. Other Logs.

a. Assess defect at the large end of the defect.

b. Use the small end diameter of the piece for log or 

segment diameter.

c. Check each end of the piece for merchantability 

requirements, such as the merchantability specifications of 33 1/3 percent where the log has been severed, 

and check the minimum top diameter as stated in the 

contract.

42.1b - Proper Utilization

When determining proper utilization in the woods, the piece left must 

be considered on its own merits. When determining the merchantability of a piece and the correct bucking points, 2 foot multiples 

must be considered when determining piece length. Determine all 

log lengths in even lengths in 2 foot multiples plus the specified trim 

allowance. For example, use lengths of 10, 12, and 14 feet, and so 

forth.

Refer to an appropriate utilization table for interior defect (ex. 01 

and 02). The major types of defects are explained in the following 

sections. Examples shown are for a net of 33-1/3 percent sound 

volume.
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NATIONAL FOREST LOG SCALING HANDBOOK

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 42.1b - Exhibit 01

Utilization Table for Internal Defect 

and 33-1/3 Percent Merchantability

 Small End

Diameter

(Inches)

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39 

40

Maximum

Interior Defect

Dianeter

(Inches)

3

3

5

5

6

6

7

8

8

9

10

11

12

12

13

14

14

15

16

17

17

18

19

20

20

21

21

22

23

24

24

25

26
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WO Amendment 2409.11-2006-1 Page 40- Effective 10/30/2006

42.1b - Exhibit 02

Utilization Table for Perimeter Defect 

and 33-1/3 Percent Merchantability

Small End

Diameter

(Inches)

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39 

40

Maximum

Interior Defect

Dianeter

(Inches)

1

2

3

4

4

5

4

5

5

6

7

7

7

7

8

8

8

9

9

9

9

10

11

11

12

12

13

14

14

14

14

15

16

16
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42.2 - Massed Interior Defects

Assess a log or piece which contains interior defect for meeting the 

contract utilization specifications by using a utilization table for interior defect (sec. 42.1b, ex. 01).

42.2 - Exhibit 01

Cull Log End Due to Interior Defect

The log end in exhibit 02 exceeds the maximum interior defect. The 

tree may be long butted to a point where the interior defect is not 

more than the maximum shown on the interior utilization table.

42.2 - Exhibit 02

Merchantable Log End With Interior Defect
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CHAPTER 40 - SPECIAL SCALING PROBLEMS

WO Amendment 2409.11-2006-1 Page 40-10 Effective 10/30/200

The maximum allowable interior defect for a 16” log is 8”. Long 

butting of this log is not necessary.

42.2a - Proper Bucking Point for Logs With Massed Interior 

Defect

Examine logs to determine the extent of defect, make test cuts. 

Check to see that the piece was bucked at the point on the log that 

meets minimum contract requirements such as 33-1/3 net percent of 

gross which is used in this example.

42.2a - Exhibit 01

Proper Bucking Point for Log With Interior Defect

Large end diameter = 12” Small Diameter = 11”

Defect diameter = 9” Defect diameter = 5”

6” is the maximum 5” is the maximum

allowed interior defect. allowed defect for

for a 12” log end division an 11” diameter

(refer to exhibit 01)

42.3 - Massed Defect With Sound Sector

On log ends containing defect which can be confined to a portion of 

the log, use the percentage of end area method.
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NATIONAL FOREST LOG SCALING HANDBOOK

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42.3 - Exhibit 01

Sound Sector - Unmerchantable

Less than 33 1/3 percent

The defective portion is not merchantable as the log end does not 

meet contract specifications.

42.3 - Exhibit 02

Sound Sector - Merchantable

More than 33 1/3 percent

Bucking out the defect is not justified.

Logs with diameters of 6”, 7”, and 8” that do not contain a product 

(4” in width) are culls.
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 40 - SPECIAL SCALING PROBLEMS

WO Amendment 2409.11-2006-1 Page 40-12 Effective 10/30/20

42.3a - Proper Bucking Point for Logs With Sound Sector

Examine logs to determine the extent of defect, test cuts should be 

made. Buck the piece at the point on the log that meets minimum 

contract requirements such as 33-1/3 percent of end area sound.

42.3a - Exhibit 01

Sound End Area

42.4 - Perimeter Defects

A log or piece which contains perimeter defect can be assessed for 

meeting the contract utilization specifications by using the utilization 

table for perimeter defect (sec. 42.1b, ex. 02).

42.4 - Exhibit 01

Cull Log End - Perimeter Defect
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NATIONAL FOREST LOG SCALING HANDBOOK

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The log exceeds the maximum log perimeter defect. The tree may be 

long butted to a point where the perimeter defect is not more than the 

maximum shown on the perimeter utilization table.

42.4 - Exhibit 02

Merchantable Log End - Perimeter Defect

The maximum allowable perimeter defect for a 16” log is 6”. Long 

butting of this log would not be appropriate.

42.4a - Proper Bucking Point for Logs With Perimeter 

Defect

Examine logs to determine the extent of defect, test cuts should be 

made. Buck the piece at the point on the log that meets minimum 

contract requirements.
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 40 - SPECIAL SCALING PROBLEMS

WO Amendment 2409.11-2006-1 Page 40-14 Effective 10/30/200

42.4a - Exhibit 01

Proper Bucking Point for Log With Perimeter Defect

Large end diameter = 16” Small diameter = 15”

Perimeter defect = 8” Perimeter defect = 5”

6” is the maximum 5” is the maximum

allowed interior defect allowed defect for

a 16” log end diameter 15” log end diameter

42.5 - Exterior Defects

These include crooks, sweep, forks and breaks.

1. Determine if long butting is necessary when crook is 

present. If no other internal defect affects the log, determine the 

bucking point by extending the log through the crook. The proper 

bucking point is located where the extended log side emerges.
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42.5 - Exhibit 01

Proper Bucking Point on a Log With Crook

2. The correct location of the bucking point changes for a 

log with crook or sweep that also contains an additional defect, such 

as heart rot. Additional long butting is appropriate in this circumstance. Determine the initial bucking point for the crook. Determine 

the need for additional long butting due to internal defect. The additional defect is used to determine the additional length of the long 

butt.

42.5 - Exhibit 02

Proper Bucking Point on a Crooked Log With Interior Defect
FSH 2409.11 

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CHAPTER 40 - SPECIAL SCALING PROBLEMS

WO Amendment 2409.11-2006-1 Page 40-16 Effective 10/30/20

3. Permit long butting for sweep when the curvature is 

sufficiently severe to create an unmerchantable piece less than the 

contract minimum. These pieces more commonly occur in the top or 

butt end of a tree, but can occasionally occur in the middle if there is 

severe sweep. As with crook, it is essential to check for correct bucking prior to skidding.

a. Long butting is permissible in the following examples because the sweep created an unmerchantable piece 

less than the contract minimum. This is applicable to 

both the butt and the top of the tree.

42.5 - Exhibit 03

Long Butting Permissible

b. Long butting would not be permissible in the following example when proper bucking would create 2 

merchantable pieces or logs. This is also applicable to 

logs in the top of trees.
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42.5 - Exhibit 04

Log With Merchantable Pieces on Each Side of the Crook

4. Consider logs containing multiple crook or sweep to be 

merchantable if they meet the minimum merchantable specification in 

the contract and contain the minimum piece length.

a. The following is an example of a tree which has an 

unmerchantable piece in the top due to multiple sweep. 

The same example could be applicable to the butt end of 

the tree.
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 40 - SPECIAL SCALING PROBLEMS

WO Amendment 2409.11-2006-1 Page 40-18 Effective 10/30/20

42.5 - Exhibit 05

Proper Bucking Point to Eliminate Unmerchantable Piece

b. The following is an example of a tree that has unmerchantable material in the middle but has merchantable material on both ends. For these types of external 

defects, it is essential that the sale administrator check 

bucking prior to removal of the merchantable material.

42.5 - Exhibit 06

Proper Bucking Point to Eliminate Crook

5. Proper bucking of crotched logs can eliminate much of 

the defect. Loss that occurs is from bark seams, splits, cross grain, 

and flat sides. The 2 foot multiple rule also applies to crotched logs. 

Measure lengths from the butt cut in 2 foot multiples, plus trim, to 
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NATIONAL FOREST LOG SCALING HANDBOOK

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determine the bucking point for a crotch. The ideal bucking point 

when the top contains merchantable logs in each fork would be when 

the 2 foot multiple falls exactly at the point where daylight shows 

in the crotch. When this does not occur, move back to the next 2 

foot multiple towards the large end of the log for the correct bucking 

point.

The following exhibit is an example of bucking forked logs:

42.5 - Exhibit 07

Proper Bucking Point of Forked Logs

6. Occasionally, a tree forks near the merchantable top 

diameter. If the fork is less than 4 feet from the merchantable top 

diameter inside bark (DIB), the bucking point must be moved backward towards the large end of the log into the fork in 2 foot multiples 

to create a top log that meets the minimum piece length. See the following exhibit for an example:
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 40 - SPECIAL SCALING PROBLEMS

WO Amendment 2409.11-2006-1 Page 40-20 Effective 10/30/200

42.5 - Exhibit 08

Proper Bucking Point on Forked Logs With a Substandard Fork

7. At times, bucking out forks may be necessary.

a. This occurs when defect, such as rot caused by a 

sucker limb or old dead top, is present in the fork or 

crotch. The first bucking point would be determined by 

measuring the log length from the larger end in 2 foot 

multiples. Determine the second bucking point at the 

upper end using the long butting procedure for crook, 

sweep, or internal defect, whichever is applicable.

42.5 - Exhibit 09

Forked Log With Internal Defect
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NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 40 - SPECIAL SCALING PROBLEMS

8. Breaks must be bucked to a point that meets contract 

specification, such as 33 1/3 net percent of gross as long as merchantable lumber can be manufactured.

a. Breaks commonly occur in the tops of trees during 

felling. To determine if a piece is merchantable and/or 

the proper bucking point, locate the point that represents 

one-half of the surface area of the break on the large 

end and measure the length in 2 foot multiples to the 

minimum contract top diameter.

42.5 - Exhibit 10

Bucking Point on Broken End Log With Length Determination

b. Breaks frequently occur in a tree during felling. Utilization should occur in the bottom log(s) by measuring 

from the butt to the break. The length should be in 2 

foot multiples.

42.5 - Exhibit 11

Log With Break in the Mid Section
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NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 40 - SPECIAL SCALING PROBLEMS

WO Amendment 2409.11-2006-1 Page 40-22 Effective 10/30/20

42.6 - Stump Heights

To determine stump heights, measure from high ground, paralleling 

the vertical axis of the stump, up to the point where a projected right 

angle intercepts the highest mechanical cut on the top of the stump. 

High stumps may be permitted when they are caused by obstructions 

or unsafe conditions. The contract specified maximum allowable 

stump height is 12 inches in the following exhibits.

42.6 - Exhibit 01

Unacceptable High Stumps
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NATIONAL FOREST LOG SCALING HANDBOOK

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42.6 - Exhibit 02

Acceptable High Stumps

43 - SCALING DEBARKED LOGS

In some situations, logs can be presented for scaling after the bark 

has been removed. This may present the following problems:

1. Reduction in the scaling diameter, if any, by mechanical 

debarking and loss of wood fibers. This is generally no problem with 

hydraulic barkers. A volume-adjustment factor might be agreed upon 

if a study showed loss in scaling volume after debarking. Also see 

section 17.5.

2. Destruction of defect side indicators. This is more than 

compensated for by the removal of slime and dirt in the debarking 

process. Also the mill deck cutoff saw provides fresh end cuts.

3. Removal of species indicators, especially where large 

price differentials exist between species. This may be offset by arranging to paint or brand the species on the log ends before debarking 

or by presorting logs by species.

4. Removal of brand indicators. Procedures are similar to 

those outlined above.
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NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 40 - SPECIAL SCALING PROBLEMS

WO Amendment 2409.11-2006-1 Page 40-24 Effective 10/30/200

In summary, there may be problems but also good reasons to accept 

debarked log scaling if proper precautions are taken to identify species and ownership.

44 - TIMBER TRESPASS

Stump scales and stump cruises are made when logs are removed 

from the woods before being scaled and cannot be later scaled, as is 

often the case in timber trespass cases. All measurements must be 

performed by certified scalers and cruisers, and should be coordinated 

with the Law Enforcement staff prior to any field work. Sections 

44.1 through 44.3 contain the suggested procedure for obtaining 

volume.

Use extreme care in scaling trespass timber, especially by a stump 

scale, and keep complete accounts and legible notes of the method 

used. This information may be needed as legal evidence in court.

44.1 - Stump Scaling

If the logs within the tree can be reconstructed, use the following 

procedure:

1. Locate the top of the tree and measure the diameter at 

the point where the last log was bucked.

2. Measure the distance from the stump end to the top and 

convert this distance to the number of logs. Consider trim. Holes in 

the ground often help to locate where the butt rested; sawdust helps to 

show the length of logs.
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3. Measure the stump diameter; stamp and number the 

stump. Establish the diameter breast height (dbh) from this measurement by comparison with adjacent trees or tested tables. Consider 

numbering with an aluminum tag.

4. Obtain diameter inside bark (dib) at the top of the first 

16-foot log by use of d.b.h. and average form class for stand. Volume 

tables based on d.b.h. and number of logs is sometimes used.

5. Use actual taper, or local taper tables, to establish the 

diameter of all logs obtained in step 2.

6. Record length and diameters of these logs, identified by 

the stump number. Consider trim. Make deductions for defect on the 

basis of what you see in the stump, top, or any cull logs left. Record 

lengths according to the common bucking practice for the area.

7. Number and stamp “US” on each stump and top to 

indicate that logs have been scaled.

For example: (20-foot maximum scaling length.) 

Top diameter-8 inches.

Distance from stump end to top-96 feet.

Number of logs from evidence on the ground-four 16-

foot, one 10-foot, and one 8-foot log.

Stump diameter-30 inches; d.b.h. 26 inches. 

Average form class-80; 80 percent of 26 inches 21 

inches d.i.b. at top of first 16-foot log. 
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 40 - SPECIAL SCALING PROBLEMS

WO Amendment 2409.11-2006-1 Page 40-26 Effective 10/30/20

Taper from 8-inch top to 21 inches (diameter of first log) is 13 inches.

This provides the following diameters for all logs: 21, 19, 16, 13, 11, 

and 8 inches.

Record-16’-21”, 16’-19”, 16’-16”, 16’-13”, 10’-11”, and 8’-8”, with 

a total scale of 85.

Merchantable volume left in tops, in high stumps, and in unused logs 

are scaled and recorded separately. Stamp “US” on each stump and 

top, and number each piece for future identification.

44.2 - Stump Cruising

Timber theft cruising instructions are contained in Forest Service 

Handbook (FSH) 2409.12, chapter 80, section 81.

44.3 - Scaling When Stumps and Other Direct Evidence is 

Lacking

If a trespass, or other unauthorized cutting, is discovered after the 

stumps have been disturbed by clearing, site preparation, or similar 

activities, indirect methods must be used to determine actual volume. 

In some cases, cruise or compartment examination data may be available for the area.

If so, it should be used to the extent possible. The situation, however, 

may be that there is no existing data for the area. The approved 

method for determining volume is a cruise on similar timber using 

the most recent aerial photos of the cut timber as a basis for selecting 
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a similar stand. Other stand attributes, such as species distribution, 

elevation, aspect, and site index should be as close as possible to the 

cut timber. The selected stand should then be cruised using approved 

Regional standards for tree-measurement sales.

45 - SPECIAL SECTIONAL PROBLEMS

Special sectional problems such as scaling, sinkers, jackpots, and so 

on, which have minor general significance in the scaling of National 

Forest timber may be addressed in Regional supplements.
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CHAPTER 50 - ner

Table of Contents

51 - SELECTION OF SCALING LOCATIONS......................... 2

52 - SAFETY IN SCALING ...................................................... 2

53 - REQUIREMENTS OF PURCHASER..............................

54 - SCALER QUALIFICATIONS AND PROFICIENC

REQUIREMENTS ............................................................

54.1 - General................................................................... 3

54.2 - Mill Visits to Develop Judgment.............................. 4

55 - SCALING EQUIPMENT...................................................

55.1 - General................................................................... 4

55.2 - Scaler’s Information Form ...................................... 5

55.3 - Accountability.......................................................... 5

55.4 - Recording Log Scale Data and Scale Sheets......... 6

56 - LOG ACCOUNTABILITY.................................................. 

56.1 - Stamping................................................................. 6
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WO Amendment 2409.11-2006-1 Page 50- Effective 10/30/2006

51 - SELECTION OF SCALING LOCATIONS

The Contracting Officer is responsible for selection of scaling locations. Determination of the scaling location shall consider:

(1) the need for proper scale under safe working conditions with minimum expense to the Government and the 

purchaser, and 

(2) adequate provisions for check scaling. 

Practice economy in scaling insofar as possible. Losses from poor 

scaling caused by inadequate tools, training, or log presentation 

quickly exceed apparent savings. Inform the Contracting Officer 

when logs cannot be scaled efficiently and accurately. Purchasers 

are required by the timber sale contract to present logs so they can be 

scaled economically and safely.

52 - SAFETY IN SCALING

The varied hazards present in all types of scaling require the scaler to 

be safety minded at all times. FSH 6709.11, Health and Safety Code 

Handbook, provides information on good safety practices to follow in 

all types of scaling. Each scaler should have a copy of that handbook. 

Follow the safety rules of the Health and Safety Code, as well as 

applicable Occupational Safety and Health Administration (OSHA) 

standards. 
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53 - REQUIREMENTS OF PURCH

Purchasers may be required to present, assemble, or hold logs for 

scaling in the manner prescribed by the Forest Service. Special requirements are usually covered by the timber sale contract. Methods 

of scaling should consider safety, efficiency of scaling, provisions for 

check scales, and the operating needs of the purchaser.

54 - SCALER QUALIFICATIONS AND PROFICIENC

REQUIREME

54.1 - General

The scaler makes the final determination of volume of National Forest products removed from sale areas. The scaler must be equipped 

with good tools, and have the ability and skill to measure length and 

diameters systematically and accurately. The scaler must properly 

identify species, detect defect, and use skill and good judgment in 

making deductions and in performing other phases of the job.

Team scaling can be less accurate than individual scaling and therefore must not be used. A scaler’s accuracy is determined by check 

scales. Specific standards for satisfactory scaling are established. 

These are listed in chapter 60 of this handbook. Any check scale 

showing unsatisfactory scaling by a scaler, contract scaling organization, or third-party scaling organization (TPSO) indicates the need 

for corrective action. This is the responsibility of the Contracting 

Officer. 
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The ability of a scaler to identify logs by species is extremely important. Wide differences in value result in variations in merchantability 

specifications by species. Species identity should be determined by 

bark characteristics, color and amount of sapwood and heartwood, 

presence of pitch, and the size and distribution of knots.

54.2 - Mill Visits to Develop Judgmen

A proficient scaler must know how defects extend into logs and must 

keep that knowledge current. The best way to acquire skill and judgment in making defect deductions is to see defective logs opened on 

the saw carriage and note the losses caused by various defects.

In a mill visit the scaler should be concerned primarily with peculiarities of defects in timber from certain localities, and not quality, just 

as the scaler avoids scaling to include certain grades of lumber to the 

exclusion of other grades. 

Defect in timber changes with localities, sites, and species. The 

scaler should make scheduled, periodic mill visits to observe sawing 

of logs similar to the ones being scaled. By this means the scaler can 

correctly maintain his judgment and proficiency.

Mill visits should be considered part of the routine of the scaler’s 

initial and followup training.

55 - SCALING EQUIPM

55.1 - General

All scaling equipment must be kept serviceable and safe to use. For 

accurate length measurements and for checking trim allowances, a 

50-foot steel tape with end hook should be carried and a steel hand-
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tape makes accurate diameter measurements possible and should 

always be carried. Scalers should use a spud, or an equivalent device 

to locate and identify defect in the ends and sides of logs. 

In most types of scaling, a hand held data recorder has become the 

best way for recording log length, diameter, net scale, and defect as 

standard equipment, however, a scalebook or scale sheets may be 

used.

55.2 - Scaler’s Information Form

Each Region shall provide a standard form for informing scalers of 

scaling requirements, sampling information, applicable National 

Forest Log Scaling Handbook (FSH 2409.11) supplements, and any 

other pertinent scaling information such as abnormal delay.

The Contracting Officer is responsible for the completion and distribution of these scaler information forms to scalers and check scalers 

(and scaling organizations, when necessary) prior to hauling. Scalers 

shall have them available for references at the scaling site. 

55.3 - Accountability

Regional Foresters issue instructions for scale data accountability, 

and for the place and system of storage for completed scale tickets 

and volume reports (electronic and hardcopy) or books and series 

numbered scale sheets. Keep these records for the required number 

of years after the sale is closed.
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55.4 - Recording Log Scale Data and Scale Sheets

Use approved scale sheets or field data recorders to record log scale 

data. The minimum data include:

HEADER LOG DATA

Sale Name Log Number

Contract Number Species

Date/Time Scaled Length

Receipt Number Diameters

Scaler I.D. Defect

Scaling Location

Stratum I.D. (Sample Scale)

Make corrections on the paper copy by drawing a single line through 

the incorrect entry and writing the correct figure beside it.

Regional Office Forest Management staff must verify that field data 

recorder programs identify changes or corrections to the original 

scale data after the load has been scaled and closed out on the field 

data recorder.

56 - LOG ACCOUNTABILIT

56.1 - Stamping

Forest Service scalers normally stamp logs which they have scaled 

with the symbol “US” as evidence that the logs have been scaled 

and to assist in accountability control. Specific requirements may be 

established by the Regional Forester.
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Table of Contents

61 - PURPOSE......................................................................... 2

62 - FREQUENCY.................................................................... 2

63 - PROCEDURE ................................................................... 3

64 - STANDARDS.................................................................... 5

65 - RECORDS AND REPORTS ............................................. 5
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61 - PURPOSE

Systematic check scaling is a necessary part of timber sale 

administration. The purpose of check scaling is to make and keep 

accurate and uniform the scale of all National Forest timber. This is 

done by checking the scaler’s work and determining sources of errors.

The check scaler should always keep in mind the need for additional 

training of the scaler and note their weaknesses if any. 

62 - FREQUENCY

Standards for check scale frequency are difficult to set. However, the 

more frequent the check scales, the simpler it is to solve a situation 

that might result when they are unsatisfactory. A satisfactory check 

scale usually establishes as final the volume scaled to that date.

Minimum standards for check scaling are established by the Regional 

Forester with approval by the Chief. The following factors deserve 

consideration:

1. New scalers.

2. Volume scaled.

3. Result of last check.

4. Amount of defect. The more defective the timber, the 

more difficult the scaling job. Chances of error and variation in scale 

are more common. Make check scales more frequently in heavily 

defective timber.
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5. Change in defect. Normally fewer checks are needed 

where sound timber is scaled. But if conditions vary and units of 

defective timber are presented, visit such scaling locations more 

frequently.

6. Variation in scaling load. The frequency of check scales 

should be increased when a scaler moves from a light-load station to 

a heavy-load station.

7. Changes in species. These may require more frequent 

training and checking until the scaler becomes familiar with appearances of defects and their effect in the new species.

63 - PROCEDURE

1. Check scaling should be done by the most experienced 

scalers. Regions should establish more than one check scaling position where the check scaling load is heavy. This provides a good 

opportunity for training scalers for Regional check scaler positions.

2. Most Forest Service Regions recognize two primary 

check scaler positions, (a) Forest and (b) Regional. More experienced scalers on a Ranger District often need to conduct check scales 

to meet the frequency standards.

a. Forest Check Scaler. This person is selected by the 

Forest Supervisor for assisting Rangers in training and 

checking all scalers scaling on the forest.
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b. Regional Check Scaler. This person is selected by 

the Regional Forester and is responsible for technical 

control for all scaling within a Region. They should 

conduct Regional scaler-training sessions, check scale 

to settle controversies, and check area and forest check 

scalers.

3. Check scale as far as practicable under conditions 

similar to those under which the original scale was made. Wherever 

possible, check soon after the original scale and without the scaler’s 

knowledge. In mill deck scaling and often in truck scaling, it may 

be necessary to check scale at the time logs are scaled. Note any 

effort by the scaler to change his way of scaling. Usually any serious 

change can be detected.

4. Normally, a check scale includes at least 200 short logs 

(16 to 20 feet and under) or at least 100 long logs. Sample the species and defect situation as fairly as possible. Individually analyze 

more complex scaling situations and increase the number of logs 

check scaled if necessary.

5. If possible, make check scales independent of the scaler, 

but when check scales are made with the scaler’s knowledge, first put 

him at ease. Explain that Forest Service check scales are required to 

keep the scale of all logs accurate and uniform. When the comparison of figures shows the need, training should follow. 

6. When check scaling inexperienced scalers, be sure and 

share the results before leaving the area. Attempt to eliminate any 

weaknesses found. Note all important variances in measurements, 

defect deductions, and defect missed. Where logs checked are still 

available, return with the scaler and point out these variances. Be 

sure they are using proper methods of measurement and deduction.
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64 - STANDARDS

Use the following standards to determine the proficiency of 

individual scalers.

1. Gross Scale. A variance of 1 percent in gross scale 

is the satisfactory standard, unless otherwise justified by abnormal 

amounts of pieces with sloughed sap rot, fire damage, or chunks.

2. Net Scale. The allowable variance is as follows:

Check scaler’s % 

defect in logs

Scaler’s allowable variance

0 - 10% 2%

Over 10% .2 x % defect to a maximum of 5%

Regional Foresters may supplement these standards to allow for 

difficult scaling situations such as very small timber or highly 

defective timber (defect exceeding 60%).

65 - RECORDS AND REPORTS

1. Check scale reports and summaries are primarily computer generated, however, hand generated forms are also acceptable 

and may be unique from Region to Region.

2. Each check scale record must contain the following 

information as a minimum:

a. Log number

b. Species
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c. Length

d. Diameter (small and large end when applicable)

e. Product code if applicable

f. Space for comments

g. Defect and defect type

h. Gross volume

i. Net volume

j. Grade if applicable

k. Sale name and contract number

l. Log brand

m. Load receipt number

n. Scaler name

o. Check Scaler name

p. Date and time of check scale

q. Region, Forest, District

r. Location of scaling
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3. Each summary must compare the following by product 

or grade as a minimum:

a. Piece count (number of logs or segments)

b. Species

c. Sum of KPIs (3P) if applicable

d. Sum of Ratios (3P) if applicable

e. Gross volume

f. Net volume

g. Percent defect

h. Allowable variances for gross and net volumes

i. Gross variance

j. Net Variance

l. Remote or non-remote check scale

m. Summary rating

4. Regions are encouraged to develop their own summary 

reports to fit local needs.
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Table of Contents

70.1 - Authority.................................................................. 2

70.3 - Policy ...................................................................... 2

71 - SCALING CYLINDER IN INTERNATIONAL RULE ......... 

72 - MILL OVERRUN............................................................... 

73 - LOG LENGTHS ................................................................ 4

74 - DEFECT DEDUCTIONS ................................................... 
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70.1 - Authority

Title 36 of the Code of Federal Regulations, part 223, section 

223.36(b) (36 CFR 223.36(b)) sets out the authority for using the 

International 1/4-inch log rule or the International 1/4-inch Decimal 

Rule in log scaling.

70.3 - Policy

1. Use of International 1/4-inch log rule to obtain log scale 

more nearly equal to the lumber tally.

2. Use the Forest Service International 1/4-inch Decimal 

rule whenever necessary. This rule is applied the same as the International 1/4-inch log rule. The principal difference is that volumes 

are rounded to the nearest 10 board feet. Regional Foresters may 

authorize the use of either of these rules on any saw timber sale.

3. Use the same general scaling practices with these rules 

including defect deductions, as with the Scribner Decimal C rule. 

Differences in detail are explained in sections 71 through 74 below.

Appendix X in the appendix chapter gives the board foot contents 

of logs 4 to 20 feet long based on the International 1/4-inch log rule. 

Appendix XI in the appendix chapter gives those based on the Forest 

Service International 1/4-Inch Decimal rule.

71 - SCALING CYLINDER IN INTERNATIONAL RUL

The International 1/4-inch log rule is based on a formula applied 

to each 4-foot section of the log and an assumed taper of 1/2 inch 

in each 4 feet (2 inches in 16 feet). Thus the International scaling 

cylinder differs from that used with the Scribner Decimal C rule. For 
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practical purposes, assume that the scaling cylinder becomes a frustum of a cone with a taper of 2 inches in 16 feet. See sec. 71-exhibits 

01, 02, and 03 and compare them with chapter 10, sec. 18-exhibits 

01, 02, and 03.

The International 1/4-inch log rule considers a 1-inch collar for slab, 

as does Forest service practice with the Scribner Decimal C rule. For 

sap rot and similar side defects, use of the tapered scaling cylinder results in larger deductions in comparison to deductions by the Scribner 

rule with its non-tapered scaling cylinder.

71 - Exhibit 01

Scaling Cylinder for International Rule

71 - Exhibit 02

Defect Both Inside and Outside the Scale Cylinder
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71 - Exhibit 03

Defect Outside the Scaling Cylinder

72 - MILL OVERRU

Normally where the International 1/4-inch log rule is used, log scale 

closely corresponds to lumber tally. The rule considers a minimum 

board of 2 board feet. Inch lumber is considered if 3 inches wide by 

8 feet long or any other combinations of dimensions making 2 board 

feet, down to 12 inches wide by 2 feet long. If a mill does not practice such good utilization, an underrun could result.

73 - LOG LENGTHS

1. In Forest Service scaling, logs as long as 20 feet are 

scaled as one log by the International 1/4-inch log rule and the Forest Service International 1/4-Inch Decimal rule; that is, if studies 

show that local timber does not greatly exceed the assumed taper of 

2 inches in 16 feet. Where logs from 16 to 20 feet long average 3 

inches or more taper in 16 feet, use the maximum scaling length of 

16 feet. Where this condition exists, the timber sale contract should 

stipulate the maximum scaling length.
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a. Example: With the International 1/4-Inch rule, a 

16-inch log, 20 feet long, scales 235 board feet. If this 

log has the taper assumed in the log rule, the large-end 

diameter is 18 1/2 inches. But if this log were typical 

and had a large-end diameter of 19 3/4 inches, there 

would be 3-inch taper in 16 feet.

2. To scale railroad ties cut 8 1/2 feet long, scale an 8 1/2-

foot log as an 8-foot log unless the difference between the scale of an 

8- and a 9-foot log is 10 board feet. If so, add 5 feet to the scale of 

the 8-foot log.

3. If the difference is 15 feet or more, add half the difference. But use the next lower 5 feet where half the difference does not 

fall on a 5-foot interval. (Half of 15 is 7 1/2 use 5.)

a. Example: Scale a 10-inch, 8 1/2-foot log as an 8-foot 

log, with 30 board feet.

b. Example: Scale a 15-inch, 8 1/2-foot log as an 

8-foot log with 75 board feet, plus 5 feet (half the difference between the scale of an 8- and a 9-foot log), or 80 

board feet.

c. Example: Scale a 17-inch, 8 1/2-foot log as an 8-foot 

log with 95 board feet plus 5 feet (half the difference 

between the scale of an 8- and a 9-foot log (15 feet) 

rounded down to the nearest 5 feet) or 100 board feet.
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74 - DEFECT DEDUCTION

The International 1/4-inch log rule and the Forest Service International 1/4-Inch Decimal rule allow 1/16 inch for shrinkage in addition 

to the 1/4 inch for saw kerf. The net effect is to give a squared-defect 

deduction formula almost identical to the “shortcut” one used with 

the Scribner rule. The basic formula is:

Height in inches x width in inches x length in feet

16

However, with the International 1/4-inch log rule, round the product 

of height by width to the nearest 5; with the Forest Service International 1/4-Inch Decimal Rule, round to the nearest 10, above or 

below.

When defects extend all the way through a log, use their average 

dimensions. Do this because the International 1/4-inch log rule is 

based on the use of short and narrow material.

For sap-rot and side-defect deductions, see discussion in section 71.

Also refer to appendices XII and XIII in the appendix chapter, showing defect allowances under the International 1/4-Inch log rule and 

the Forest Service International 1/4-inch Decimal log rule.
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Table of Contents

81 - CORD MEASURE............................................................. 2

81.05 - Definitions.......................................................... 2

81.1 - Measuring Methods ................................................ 3

81.2 - Measuring Stacked Wood....................................... 4

81.3 - Stamping or Painting and Numbering..................... 5

81.4 - Check Measurements............................................. 5

82 - CUBIC FOOT MEASUREMENT....................................... 5

83 - LINEAR MEASUREMENTS ............................................. 5

83.1 - Measurement Method............................................. 6

83.2 - Numbering and Stamping or Painting..................... 7

83.3 - Check Measurements............................................. 7

83.4 - Combined Linear and Diameter 

Measurements .................................................................. 7

84 - COUNTING ....................................................................... 8

84.1 - Procedure ............................................................... 8

84.2 - Numbering and Stamping or Painting..................... 8

84.3 - Check Measurement............................................... 8

85 - SAMPLE SCALING .......................................................... 9

86 - WEIGHING PRODUCTS OTHER THAN SAW LOGS...... 9

86.1 - Scaling by Weight................................................... 9

87 - FIBER SCALING ............................................................ 10

87.1 - Defects in Fiber Logs............................................ 10

87.2 - Basic Defect Deduction Procedures..................... 10

87.3 - Defect Deduction Methods for Fiber Logs .............11

87.31 - Squared Area Deduction Method .................... 12

87.32 - Circular Area Deduction Method...................... 12

87.33 - Length Deduction Method ............................... 14

87.34 - Diameter Deduction Method............................ 16

87.4 - Debarkability......................................................... 17

87.41 - Shatter............................................................. 17

87.42 - Severe Crook................................................... 18
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81 - CORD MEASURE

81.05 - Definitions

Cord. A unit of measure that expresses the volume of stacked wood. 

It differs from the board foot and cubic foot units because it is not 

a measure of the individual bolt or piece in terms of solid-wood 

content.

1. A standard cord is a pile of stacked wood measuring 8 

feet long, 4 feet high, and 4 feet wide. The standard cord contains 

128 cubic feet. The actual solid wood content is generally 100 cubic 

feet or less. Forest Service scalers measure in terms of 128 cubic feet 

of stacked wood. Reduce the total cubic feet occupied to cords by 

dividing by 128.

2. A long cord contains a greater volume of wood than the 

standard cord. This unit measures 8 feet long and 4 feet high with 

a width greater than 4 feet. A long cord may consist of pieces that 

exceed 4 feet in length. Often a long cord is 8 feet by 4 feet by 5 feet. 

Pulpwood is often sold by this unit.

3. A short cord is a unit smaller than the standard cord and 

is usually used for fuelwood less than 4 feet long. For fuelwood, a 

rick is a pile 8 feet long, 4 feet high, and 1 foot wide, or 4 ricks per 

cord. Fuelwood cut to a 16-inch length will stack three ricks per 

cord.

4. A sound cord contains only the merchantable pieces 

or bolts of a standard stacked cord. Merchantable pieces or bolts 

are defined in each timber sale permit or contract. Gross cubic foot 

measurement is reduced to net cubic measurement usually by applying the percentages of unmerchantable material. Since sound and net 
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standard cord are synonymous use of the term “sound cord” is largely 

obsolete. A cord of shingle bolts usually measures 8 feet by 

4 feet by 4 1/3 feet.

Rough wood. The term used to designate wood with bark in contrast 

to smooth or peeled wood, which is wood with the bark removed. 

Sales contracts are normally on a rough wood basis, and if measurements of peeled wood must be made, volume must be increased by an 

amount determined to be equitable for the material involved.

81.1 - Measuring Methods

1. The volume in cords may be calculated by measuring 

length, height, and width in feet and tenths, calculating the cubic 

volume and dividing by 128. The scale of 48-inch wood can be 

converted to any other length by applying converting factors listed 

below.

 

Length

(inches)

36

38

40

42

44

46

50

52

54

56

58

60

Percent of 

48-inch 

scale

75

79

83

87

92

96

104

108

112

117

121

125
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Example: Find the contents of a stack of wood 38 feet long, average 

height of 52 inches, and 40 inches wide which would be 5.11 cords 

if it were 48-inch wood. Multiply 5.11 by 0.83, the converting factor 

for 40-inch wood. Answer: 4.24 standard cords.

2. Regional Foresters may specify the use of other methods of cordwood measurement if better adapted to local conditions. 

In lieu of measuring of stacked wood, tree or sample tree measurement, weight, or other measurement may result in lower scaling cost 

without sacrifice in accuracy.

81.2 - Measuring Stacked Wood

1. Measure stacks of wood accurately. Record length 

to the nearest foot, height to the nearest inch or tenth of foot. It is 

permissible to allow up to a maximum of 1 inch per foot of height to 

compensate for settling where long transportation to consumer is involved. The equitable settlement factor, if any, should be determined 

on the basis of documented tests, and not merely assumed.

2. If stacks are standing on slopes, measure the length 

parallel to the slope and the height at right angles to this plane. If 

end stakes are used here, obtain the length by measuring at a point 

half the distance between the top and bottom. Otherwise, measure at 

enough places to obtain a fair average. Measure the height at several 

places to obtain the true average.

3. Check piece lengths sufficiently to make sure they do 

not regularly overrun those specified in the sale contract. If they do, 

follow the procedure outlined under section 42.
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81.3 - Stamping or Painting and Numbering

Regional Foresters may issue special instructions for stamping, painting, and numbering. Straight lines made with a paint gun are most 

effective. Household bluing in a paint gun produces a good mark 

that does not interfere with pulp production. Otherwise stamp or 

paint both ends and top of each stack. Number each stack. Enter the 

measurements and contents of each stack opposite its number in the 

scalebook or field data recorder. Indicate whether roughwood, hand 

peeled, or machine peeled.

81.4 - Check Measurements

Minimum standards for check measurements are established by the 

Regional Forester with approval by the Washington Office. In the 

absence of specific Regional standards, make check measurements as 

instructed in chapter 60, Check Scaling. Follow the same procedure 

as to frequency of checks, methods, reports, and action.

82 - CUBIC FOOT MEASUREMENT

See National Forest Cubic Scaling Handbook (FSH 2409.11a) for 

direction on cubic foot measurement.

83 - LINEAR MEASUREMENTS

Linear measurement involves the measurement of length only.

Posts, piling, fence poles, converter poles, telephone and power 

poles, hop poles, stulls, mine timbers, and lagging may be sold by 

the linear foot. Length and strength are often more important than 

the volume they contain. Timber sale contracts should specify the 

minimum length and diameter(s) of sticks classed as merchantable 
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for each product. Contracts under which higher prices are charged 

for products cut from larger materials should set maximum lengths 

and diameters. For cedar poles and other products, the dimensions of 

material planned for each product should be specified.

Wherever necessary, similar specifications should cover the amount 

and kinds of defect admissible in products sold by the linear foot; 

also the character of the material considered merchantable for the 

purpose. This is especially important for valuable products like telephone and power poles, which often require the best grades of timber. 

Use Forest Service specifications when available. Otherwise, use 

current commercial specifications of associations of local pole dealers 

or other associations.

83.1 - Measurement Method

Where pieces are cut in uniform standard lengths, make periodic 

measurements to check the bucker’s work. When several products are cut in the same sale, make a similar current check of the 

diameter(s) of linear-foot material. Also, check periodically when 

prices depend upon both diameter(s) and length.

The standard trim allowance for telephone poles is 1 inch for each 5 

feet of length. Regional Foresters may authorize greater allowances 

for specific products if local conditions require such action. Make 

utilization measurements for lengths with excessive trim as outlined 

in section 17.2. Sale contracts should specify trimming allowances 

for other classes of material where advisable. Sale contracts also may 

specify the equivalent in board feet versus linear feet. This facilitates 

the use of a flat stumpage rate per board foot. As standard practice, 

however, it is preferable to require payment on a linear foot or piece 

basis.
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83.2 - Numbering and Stamping or Painting

Regional Foresters may establish procedures for numbering, and 

stamping or painting. In the absence of Regional instructions, number each pile of material measured. Do this with posts, fence poles, 

hop poles, converter poles, lagging, and other material which is small 

and of low value. Enter the number of pieces in each pile and their 

linear-foot contents opposite the pile number in the scalebook or the 

field data recorder. Number and stamp or paint large pieces equivalent in value to saw logs, such as telephone and power poles, piling, 

and stulls. Enter the length of each piece opposite its number in the 

scalebook or field data recorder.

83.3 - Check Measurements

See section 81.4 for direction on check measurements.

83.4 - Combined Linear and Diameter Measurements

Top diameters as well as lengths may affect the market value of products like telephone and power poles and stulls. Where this happens, 

use a schedule of stumpage rates for the various lengths and sizes. In 

such sales, accurately measure the diameter(s) of each piece. Average 

diameters to the nearest inch unless otherwise agreed upon. Number 

every piece and record it in a scalebook or field data recorder as with 

saw logs.
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84 - COUNTING

84.1 - Procedure

Standard practice of the Forest Service is to count ties sold by the 

piece. Ties are also counted in sales where their board foot contents 

are specified in the sale contract. Where ties are scaled, follow the 

instructions under scaling. Count poles, posts, lagging, Christmas 

trees, and so on, when sold by the piece.

Contract requirements should conform to the local market specifications of products concerned. Designate clearly by special contract 

clauses the maximum and minimum piece sizes to be counted rather 

than scaled. Include specifications as to defect or class of material 

necessary to establish precisely what timber is merchantable for those 

products.

84.2 - Numbering and Stamping or Painting

Stamp or paint each piece of mine timbers, ties, posts, or poles 

counted. Painting helps identify the pieces counted. Christmas trees 

are usually counted and recorded by size classes.

Number each pile of material with crayon even though immediate removal is planned. Record the number of pieces opposite the number 

of the pile in the scalebook or field data recorder.

84.3 - Check Measurement

See section 81.4 for direction on check measurement.
WO Amendment 2409.11-2006-1 Page 80- Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 80 - OTHER FORMS OF MEASUREMENT

85 - SAMPLE SCALING

Direction on sample scaling is located in Forest Service Handbook 

2409.11a, National Forest Cubic Scaling Handbook in chapter 50. 

Procedures found in chapter 50 apply to both Cubic and Scribner 

scaling methods.

86 - WEIGHING PRODUCTS OTHER THAN SAW LOGS

Bark, stumps, limbs, or other material not readily measured otherwise 

may be sold by weight, normally with the ton as the unit. Obtain 

records of the actual weights whenever possible, for example, when 

the products are weighed by common carrier agents. Truck scales 

must be reliable. If the long ton of 2,240 pounds is used instead of 

the standard ton, specify this in the sale agreement.

86.1 - Scaling by Weight

Weight scaling is used to sell forest products by weighing every 

load. Weight sales should be sold using pounds/tons as the unit of 

measure. Weight scaling is a technically sound and an efficient way 

to sell and measure forest products. Variations in weight occur from 

environmental and biological factors. Some variables to consider are: 

species, uniformity in size, seasonal conditions, and defects. When 

selecting a weight ratio, it is very important to ensure it is accurate 

and has been validated. There are several ways to achieve an accurate weight ratio (see FSH 2409.12, ch. 80). 
WO Amendment 2409.11-2006-1 Page 80-10 Effective 10/30/200

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 80 - OTHER FORMS OF MEASUREMENT

87 - FIBER SCALING

Fiber scaling determines the wood content that, as a minimum, is 

suitable for the production of usable pulp chips. When scaling fiber 

logs, determine lengths and diameters using the same method as for 

sawlogs and record the results in accordance with the guidelines 

outlined in section 17.

87.1 - Defects in Fiber Logs

Fiber defect is any unsound wood that is stringy, crumbles, or crushes 

when rolled in the hand, or lacks the fibrous element that is basic in 

the development of specific items manufactured from wood chips. 

Other deductible defects in fiber logs are:

1. Voids - when there is an absence of wood fiber. Gouges, 

slabs, stump pull and open catface are examples of void.

2. Soft Rots - resulting from advanced decay such as conk 

rot, heart rot, sap rot, stump (butt) rot, and rot associated with rotten 

knots. 

3. Char - when wood fiber has been charred.

4. Massed Pitch - when the wood fiber is saturated with 

accumulated pitch and considered unusable.

87.2 - Basic Defect Deduction Procedures

Use the following basic defect deduction procedures for scaling fiber 

logs when using any of the defect deduction methods described in 

section 87.3:
WO Amendment 2409.11-2006-1 Page 80-11 Effective 10/30/20

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 80 - OTHER FORMS OF MEASUREMENT

1. When a log or segment contains multiple defects, use a 

combination of any or all of the acceptable defect deduction methods 

for fiber scaling.

2. Make deductions for defects only when present in the 

scaling cylinder.

3. Consider the extent of the defect length in 1-foot multiples.

4. Consider the defect shape (cylinder, cone) in determining average defect length.

5. Use actual defect dimensions when determining loss. 

(Do not add an inch for waste.)

6. Apply the give and take procedure when measuring 

irregular shaped square, rectangular or circular defects. Dimensions 

should balance the unsound wood with usable fiber (sec. 87.32, ex. 

01).

87.3 - Defect Deduction Methods for Fiber Logs

Each of the following deduction methods may be used in combination with a percentage for scaling fiber logs:

1. Squared area (sec. 87.31);

2. Circular area (sec. 87.32);

3. Length deduction (sec. 87.33); and

4. Diameter deduction (sec. 87.34).
WO Amendment 2409.11-2006-1 Page 80-12 Effective 10/30/20

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 80 - OTHER FORMS OF MEASUREMENT

87.31 - Squared Area Deduction Method

1. Square or rectangular shaped defects occurring in one or 

both log ends may be deducted by using the squared area deduction 

method (sec. 22.4 and 22.5).

2. When defect occurs in one log end, use actual defect 

dimensions for the length affected. When defect occurs in both log 

ends, average the end defect dimensions for the length affected.

3. When multiple squared area defects occur on log end(s), 

it is not required to take secondary defect dimensions at right angles 

to the primary (largest) defect.

4. See section 22 for further direction on using this deduction method. 

87.32 - Circular Area Deduction Method

1. A defect that is determined to be circular in shape may 

be deducted by using the circular area deduction method.

2. Defect volume is calculated as core volume (do not 

square). 

3. When defect occurs in one log end, use actual defect 

diameter for the length affected. When defect occurs in both log ends, 

average the end defect diameters for the length affected.
WO Amendment 2409.11-2006-1 Page 80-13 Effective 10/30/20

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 80 - OTHER FORMS OF MEASUREMENT

87.32 - Exhibit 01

Circular Area Defect

Given:

Average defect diameter = 12 inches

Defect length = 13 feet

Circular area deduction 12” x 13’ = 6 Dec C

87.32 - Exhibit 02

 Circular Area Defect

Given:

Defect diameter = 8 inches

Defect length = 9 feet

Circular area deduction 8” x 9’ = 1 Dec C
WO Amendment 2409.11-2006-1 Page 80-14 Effective 10/30/20

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 80 - OTHER FORMS OF MEASUREMENT

87.33 - Length Deduction Method

1. Use the length deduction method when unsound wood 

affects a portion of the segment length.

2. Make segment length deductions to eliminate char that 

penetrates the wood fiber (sec. 87.33, ex. 01 and 02).

3. Make segment length deductions when logs are not 90 

percent debarkable (sec. 87.4).

4. See section 24 for further direction on using this deduction method.

Any char present in the wood fiber of a log causes the entire length 

affected to be unusable. Deduct 100% of the length affected. The 

remaining portion must meet contract minimum specifications for 

length, or the segment is cull. 

The log in exhibit 01 has two areas of charred wood fiber. A length 

deduction of 8 feet is made to eliminate the affected areas.
WO Amendment 2409.11-2006-1 Page 80-15 Effective 10/30/20

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 80 - OTHER FORMS OF MEASUREMENT

87.33 - Exhibit 01

Length Deduction for Char

Given:

Recorded length = 20 feet

Defect length = 4 feet 

Length deduction = 8 feet

87.33 - Exhibit 02

Cull Log Due to Char

Char affects the full length of this log; therefore, the entire log is not 

usable for utility pulp chips and is cull.
WO Amendment 2409.11-2006-1 Page 80-16 Effective 10/30/20

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 80 - OTHER FORMS OF MEASUREMENT

87.33 - Exhibit 03

Pie-Cut Deduction

Given:

Recorded length = 17 feet

Recorded diameter = 19 inches

Gross segment volume = 25 Dec C

Void affects 50% of 7 feet.

7-foot length deduction = 10 Dec C

50% Pie-cut deduction = 10 x .50 = 5 Dec C 

87.34 - Diameter Deduction Method

1. Use the diameter deduction method for perimeter defects such as sap rot.

2. Reduce the original diameter of the segment according 

to the extent of defect to obtain net volume. The defect volume is the 

difference between the gross and net volume.

3. See section 25 for further direction on using this deduction method.
WO Amendment 2409.11-2006-1 Page 80-17 Effective 10/30/20

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 80 - OTHER FORMS OF MEASUREMENT

87.4 - Debarkability

A log segment shall be considered debarkable if it would not create a 

safety hazard, would not fall apart when subjected to the mechanical 

debarking process, and is 90 percent debarkable. The portion of a 

segment that cannot be mechanically debarked will have a length deduction made to eliminate 100% of the affected length. The remaining portion must meet contract minimum specifications for length, or 

the segment is cull. 

87.41 - Shatter

Depending on the extent of defect, shatter can be considered a nondebarkable defect. In exhibit 01, shatter affects 7 feet on the large 

end segment that would fall apart, and may be a safety hazard when 

subjected to the debarking process. Use the length deduction method 

to deduct for the defect.

87.41 - Exhibit 01

Log With Shatter

Given:

Recorded length = 32 feet

Segment length = 16 feet

Shatter affects 7 feet

Length deduction = 7 feet
WO Amendment 2409.11-2006-1 Page 80-18 Effective 10/30/200

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

CHAPTER 80 - OTHER FORMS OF MEASUREMENT

87.42 - Severe Crook

Exhibit 01 illustrates how to calculate defect volume for severe crook 

defects. Due to severe crook, this log would be considered less than 

90% debarkable and should be culled. In addition, this log would be 

considered a safety hazard if debarked. 

87.42 - Exhibit 01

Log With Severe Crook

Given:

Recorded length = 16 feet

Defect length = 16 feet

Log is cull
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A- Effective 10/30/2006

Table of Contents

Appendix 1 -Standard Division of Long Logs 

for Scaling - 20-foot Maximum Scaling Length.............2

Appendix 2 - Scribner Decimal C Log Rule -

4- to 20-foot Logs ............................................................3

Appendix 3 - Long Logs, Volume According to Taper,

Maximum Scaling Length 20 Feet..................................8

Appendix 4 - Deductions for Squared Defects From Solid

Board-foot Contents, Based on Formula1 ...................15

Appendix 5 - Deductions for Rectangular Defects, From

Solid Board-foot Contents............................................17

Appendix 6 - Deductions for Pitch and Shake Rings 

Showing on Both Ends of Logs, With Various 

Amounts of Ring Taper1 ................................................30

Appendix 7 - Twelve Common Rots and

Fungi in Saw Logs.........................................................32

Appendix 8 - International 1/4-inch Log Rule1 ...................48

Appendix 9 - Forest Service International

1/4-inch Decimal Rule....................................................51

Appendix 10 - Defect Allowance Chart—International

1/4-inch Log Rule...........................................................54

Appendix 11 - Defect Allowances - For Optional Use .......56

Appendix 12 - Standard Converting Factors .....................58

Appendix 13 - Board-foot Contents of Standard Lumber

and Timber Sizes ...........................................................60

Appendix 14 - Board-foot Contents of Railroad Ties........63

Appendix 15 - Factors for Computing Scribner 

Decimal C Log Volumes................................................64

Appendix 16 - Scribner Decimal C Recorded

Lengths and Segment Lengths ....................................65
WO Amendment 2409.11-2006-1 Page A- Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 1 - Standard Division of Long Logs for 

Scaling - 20-foot Maximum Scaling Length
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A- Effective 10/30/2006

Appendix 2 - Scribner Decimal C Log Rule - 

4- to 20-foot Logs 
WO Amendment 2409.11-2006-1 Page A- Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 2 (continued) - Scribner Decimal C Log Rule - 

4- to 20-foot Logs 
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A- Effective 10/30/2006

Appendix 2 (continued) - Scribner Decimal C Log Rule - 

4- to 20-foot Logs 
WO Amendment 2409.11-2006-1 Page A- Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 2 (continued) - Scribner Decimal C Log Rule - 

4- to 20-foot Logs
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A- Effective 10/30/2006

Appendix 2 (continued) - Scribner Decimal C Log Rule - 

4- to 20-foot Logs
WO Amendment 2409.11-2006-1 Page A- Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 3 - Long Logs, Volume According to Taper, 

Maximum Scaling Length 20 Feet
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A- Effective 10/30/2006

Appendix 3 (continued) - Long Logs, Volume According to 

Taper, Maximum Scaling Length 20 Feet

1-2 3-4 5-6 7-8 9-10 11-12 13-14 15-16 1-2 3-4 5-6 7-8 9-10 11-12 13-14 15-16

6 ---------- 3 3 4 5 6 8 9 11 3 3 4 5 6 8 9 11

7 ---------- 4 5 6 7 9 10 12 14 4 5 6 7 9 10 12 14

8 ---------- 5 6 7 9 10 12 14 16 5 6 7 9 10 12 14 16

9 ---------- 7 8 10 11 13 15 17 19 7 8 10 11 13 15 17 19

10 ---------- 8 10 11 13 15 17 19 22 9 11 12 14 16 18 20 23

11 ---------- 11 12 14 16 18 20 23 25 12 13 15 17 19 21 24 26

12 ---------- 14 16 18 20 22 25 27 30 15 17 19 21 23 26 28 31

13 ---------- 17 19 21 23 26 28 31 34 18 20 22 24 27 29 32 35

14 ---------- 21 23 25 28 30 33 36 38 22 24 26 29 31 34 37 39

15 ---------- 25 27 30 32 35 38 40 44 26 28 31 33 36 39 41 45

16 ---------- 28 31 33 36 39 41 45 47 30 33 35 38 41 43 47 49

17 ---------- 33 35 38 41 43 47 49 54 35 37 40 43 45 49 51 56

18 ---------- 37 40 43 45 49 51 56 60 40 43 46 48 52 54 59 63

19 ---------- 42 45 47 51 53 58 62 66 45 48 50 54 56 61 65 69

20 ---------- 48 50 54 56 61 65 69 72 51 53 57 59 64 68 72 75

21 ---------- 52 56 58 63 67 71 74 76 56 60 62 67 71 75 78 80

22 ---------- 58 60 65 69 73 76 78 82 62 64 69 73 77 80 82 86

23 ---------- 63 68 72 76 79 81 85 90 68 73 77 81 84 86 90 95

24 ---------- 70 74 78 81 83 87 92 94 75 79 83 86 88 92 97 99

25 ---------- 78 82 85 87 91 96 98 103 84 88 91 93 97 102 104 109

26 ---------- 85 88 90 94 99 101 106 107 92 95 97 101 106 108 113 114

27 ---------- 92 94 98 103 105 110 111 118 99 101 105 110 112 117 118 125

28 ---------- 97 101 106 108 113 114 121 125 104 108 113 115 120 121 128 132

29 ---------- 103 108 110 115 116 123 127 136 110 115 117 122 123 130 134 143

30 ---------- 111 113 118 119 126 130 139 142 119 121 126 127 134 138 147 150

31 ---------- 117 122 123 130 134 143 146 151 126 131 132 139 143 152 155 160

32 ---------- 124 125 132 136 145 148 153 160 133 134 141 145 154 157 162 169

33 ---------- 129 136 140 149 152 157 164 170 139 146 150 159 162 167 174 180

34 ---------- 137 141 150 153 158 165 171 177 147 151 160 163 168 175 181 187

35 ---------- 147 156 159 164 171 177 183 188 158 167 170 175 182 188 194 199

36 ---------- 159 162 167 174 180 186 191 198 171 174 179 186 192 198 203 210

37 ---------- 170 175 182 188 194 199 206 210 183 188 195 201 207 212 219 223

38 ---------- 178 185 191 197 202 209 213 219 191 198 204 210 215 222 226 232

39 ---------- 189 195 201 206 213 217 223 229 203 209 215 220 227 231 237 243

40 ---------- 201 207 212 219 223 229 235 241 216 222 227 234 238 244 250 256

41 ---------- 212 217 224 228 234 240 246 252 228 233 240 244 250 256 262 268

42 ---------- 223 230 234 240 246 252 258 265 239 246 250 256 262 268 274 281

43 ---------- 234 238 244 250 256 262 269 275 251 255 261 267 273 279 286 292

44 ---------- 244 250 256 262 268 275 281 288 262 268 274 280 286 293 299 306

45 ---------- 253 259 265 271 278 284 291 298 272 278 284 290 297 303 310 317

46 ---------- 264 270 276 283 289 296 303 310 284 290 296 303 309 316 323 330

47 ---------- 275 281 288 294 301 308 315 322 296 302 309 315 322 329 336 343

48 ---------- 287 294 300 307 314 321 328 336 308 315 321 328 335 342 349 357

49 ---------- 299 305 312 319 326 333 341 348 321 327 334 341 348 355 363 370

50 ---------- 310 317 324 331 338 346 353 361 334 341 348 355 362 370 377 385

Refer to code 17.33 for scaling of butt logs.

Taper in inches (difference between diameters of 2 ends)

26- foot logs (1 12- and 1 14-foot 

segment)

28-foot logs (2 14-foot segments)

[Scribner Decimal C rule—board feet in tens]

Top

diam.

(in.)
WO Amendment 2409.11-2006-1 Page A-10 Effective 10/30/200

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 3 (continued) - Long Logs, Volume According to 

Taper, Maximum Scaling Length 20 Feet

1-2 3-4 5-6 7-8 9-10 11-12 13-14 15-16 1-2 3-4 5-6 7-8 9-10 11-12 13-14 15-16

6 ---------- 4 4 5 7 8 9 11 12 5 5 6 8 9 10 12 13

7 ---------- 5 6 8 9 10 12 13 16 6 7 9 10 11 13 14 17

8 ---------- 6 8 9 10 12 13 16 18 7 9 10 11 13 14 17 19

9 ---------- 9 10 11 13 14 17 19 21 10 11 12 14 15 18 20 22

10 ---------- 11 12 14 15 18 20 22 25 13 14 16 17 20 22 24 27

11 ---------- 13 15 16 19 21 23 26 29 15 17 18 21 23 25 28 31

12 ---------- 17 18 21 23 25 28 31 35 18 19 22 24 26 29 32 36

13 ---------- 19 22 24 26 29 32 36 38 21 24 26 28 31 34 38 40

14 ---------- 24 26 28 31 34 38 40 43 25 27 29 32 35 39 41 44

15 ---------- 28 30 33 36 40 42 45 50 30 32 35 38 42 44 47 52

16 ---------- 32 35 38 42 44 47 52 54 34 37 40 44 46 49 54 56

17 ---------- 37 40 44 46 49 54 56 62 39 42 46 48 51 56 58 64

18 ---------- 43 47 49 52 57 59 65 69 45 49 51 54 59 61 67 71

19 ---------- 49 51 54 59 61 67 71 76 52 54 57 62 64 70 74 79

20 ---------- 54 57 62 64 70 74 79 82 58 61 66 68 74 78 83 86

21 ---------- 60 65 67 73 77 82 85 88 63 68 70 76 80 85 88 91

22 ---------- 67 69 75 79 84 87 90 95 71 73 79 83 88 91 94 99

23 ---------- 73 79 83 88 91 94 99 104 78 84 88 93 96 99 104 109

24 ---------- 81 85 90 93 96 101 106 109 86 90 95 98 101 106 111 114

25 ---------- 90 95 98 101 106 111 114 118 96 101 104 107 112 117 120 124

26 ---------- 99 102 105 110 115 118 122 124 105 108 111 116 121 124 128 130

27 ---------- 106 109 114 119 122 126 128 136 113 116 121 126 129 133 135 143

28 ---------- 112 117 122 125 129 131 139 143 119 124 129 132 136 138 146 150

29 ---------- 119 124 127 131 133 141 145 156 127 132 135 139 141 149 153 164

30 ---------- 128 131 135 137 145 149 160 164 137 140 144 146 154 158 169 173

31 ---------- 136 140 142 150 154 165 169 174 145 149 151 159 163 174 178 183

32 ---------- 142 144 152 156 167 171 176 184 152 154 162 166 177 181 186 194

33 ---------- 149 157 161 172 176 181 189 196 158 166 170 181 185 190 198 205

34 ---------- 158 162 173 177 182 190 197 204 168 172 183 187 192 200 207 214

35 ---------- 169 180 184 189 197 204 211 217 180 191 195 200 208 215 222 228

36 ---------- 184 188 193 201 208 215 221 229 195 199 204 212 219 226 232 240

37 ---------- 197 202 210 217 224 230 238 242 210 215 223 230 237 243 251 255

38 ---------- 205 213 220 227 233 241 245 252 219 227 234 241 247 255 259 266

39 ---------- 218 225 232 238 246 250 257 264 232 239 246 252 260 264 271 278

40 ---------- 232 239 245 253 257 264 271 278 247 254 260 268 272 279 286 293

41 ---------- 245 251 259 263 270 277 284 291 261 267 275 279 286 293 300 307

42 ---------- 257 265 269 276 283 290 297 304 274 282 286 293 300 307 314 321

43 ---------- 270 274 281 288 295 302 309 317 288 292 299 306 313 320 327 335

44 ---------- 281 288 295 302 309 316 324 331 300 307 314 321 328 335 343 350

45 ---------- 292 299 306 313 320 328 335 343 311 318 325 332 339 347 354 362

46 ---------- 305 312 319 326 334 341 349 357 325 332 339 346 354 361 369 377

47 ---------- 318 325 332 340 347 355 363 372 339 346 353 361 368 376 384 393

48 ---------- 331 338 346 353 361 369 378 386 353 360 368 375 383 391 400 408

49 ---------- 344 352 359 367 375 384 392 401 367 375 382 390 398 407 415 424

50 ---------- 359 366 374 382 391 399 408 416 382 389 397 405 414 422 431 439

Refer to code 17.33 for scaling of butt logs.

[Scribner Decimal C rule—board feet in tens]

Top

diam.

(in.)

Taper in inches (difference between diameters of 2 ends)

30- foot logs (1 14- and 1 16-foot

segment)

32-foot logs (2 16-foot segments)
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A-11 Effective 10/30/20

Appendix 3 (continued) - Long Logs, Volume According to 

Taper, Maximum Scaling Length 20 Feet

1-2 3-4 5-6 7-8 9-10 11-12 13-14 15-16 1-2 3-4 5-6 7-8 9-10 11-12 13-14 15-16

6 ---------- 5 5 6 8 10 11 1.3 15 5 5 6 8 10 11 1.3 15

7 ---------- 6 7 9 11 12 14 16 19 6 7 9 11 12 14 16 19

8 ---------- 7 9 11 12 14 16 19 21 7 9 11 12 14 16 19 21

9 ---------- 10 12 13 15 17 20 22 25 10 12 13 15 17 20 22 25

10 ---------- 14 15 17 19 22 24 27 30 14 15 17 19 22 24 27 30

11 ---------- 16 18 20 23 25 28 31 34 17 19 21 24 26 29 32 35

12 ---------- 19 21 24 26 29 32 35 39 20 22 25 27 30 33 36 40

13 ---------- 23 26 28 31 34 37 41 44 24 27 29 32 35 38 42 45

14 ---------- 27 29 32 35 38 42 45 49 29 31 34 37 40 44 47 51

15 ---------- 32 35 38 41 45 48 52 56 34 37 40 43 47 50 54 58

16 ---------- 37 40 43 47 50 54 58 61 39 42 45 49 52 56 60 63

17 ---------- 42 45 49 52 56 60 63 70 45 48 52 55 59 63 66 73

18 ---------- 48 52 55 59 63 66 73 77 51 55 58 62 66 69 76 80

19 ---------- 55 58 62 66 69 76 80 86 58 61 65 69 72 79 83 89

20 ---------- 62 66 70 73 80 84 90 93 65 69 73 76 83 87 93 96

21 ---------- 68 72 75 82 86 92 95 98 72 76 79 86 90 96 99 102

22 ---------- 75 78 85 89 95 98 101 107 80 83 90 94 100 103 106 112

23 ---------- 83 90 94 100 103 106 112 118 87 94 98 104 107 110 116 122

24 ---------- 92 96 102 105 108 114 120 123 97 101 107 110 113 119 125 128

25 ---------- 102 108 111 114 120 126 129 134 108 114 117 120 126 132 135 140

26 ---------- 112 115 118 124 130 133 138 140 118 121 124 130 136 139 144 146

27 ---------- 120 123 129 135 138 143 145 153 127 130 136 142 145 150 152 160

28 ---------- 126 132 138 141 146 148 156 162 133 139 145 148 153 155 163 169

29 ---------- 135 141 144 149 151 159 165 177 142 148 151 156 158 166 172 184

30 ---------- 146 149 154 156 164 170 182 186 154 157 162 164 172 178 190 194

31 ---------- 154 159 161 169 175 187 191 197 163 168 170 178 184 196 200 206

32 ---------- 162 164 172 178 190 194 200 209 171 173 181 187 199 203 209 218

33 ---------- 168 176 182 194 198 204 213 221 178 186 192 204 208 214 223 231

34 ---------- 178 184 196 200 206 215 223 231 188 194 206 210 216 225 233 241

35 ---------- 192 204 208 214 223 231 239 245 202 214 218 224 233 241 249 255

36 ---------- 208 212 218 227 235 243 249 258 220 224 230 239 247 255 261 270

37 ---------- 223 229 238 246 254 260 269 274 236 242 251 259 267 273 282 287

38 ---------- 233 242 250 258 264 273 278 285 246 255 263 271 277 286 291 298

39 ---------- 247 255 263 269 278 283 290 298 261 269 277 283 292 297 304 312

40 ---------- 263 271 277 286 291 298 306 314 278 286 292 301 306 313 321 329

41 ---------- 278 284 293 298 305 313 321 329 294 300 309 314 321 329 337 345

42 ---------- 291 300 305 312 320 328 336 345 308 317 322 329 337 345 353 362

43 ---------- 306 311 318 326 334 342 351 359 323 328 335 343 351 359 368 376

44 ---------- 319 326 334 342 350 359 367 376 337 344 352 360 368 377 385 394

45 ---------- 330 338 346 354 363 371 380 389 349 357 365 373 382 390 399 408

46 ---------- 345 353 361 370 378 387 396 405 364 372 380 389 397 406 415 424

47 ---------- 360 368 377 385 394 403 412 421 380 388 397 405 414 423 432 441

48 ---------- 375 384 392 401 410 419 428 437 396 405 413 422 431 440 449 458

49 ---------- 391 399 408 417 426 435 444 454 413 421 430 439 448 457 466 476

50 ---------- 406 415 424 433 442 451 461 471 430 439 448 457 466 475 485 495

Refer to code 17.33 for scaling of butt logs.

[Scribner Decimal C rule—board feet in tens]

Top

diam.

(in.)

Taper in inches (difference between diameters of 2 ends)

34- foot logs (1 16- and 1 18-foot

segment)

35-foot logs (2 18-foot segments)
WO Amendment 2409.11-2006-1 Page A-12 Effective 10/30/20

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 3 (continued) - Long Logs, Volume According to 

Taper, Maximum Scaling Length 20 Feet

1-2 3-4 5-6 7-8 9-10 11-12 13-14 15-16 1-2 3-4 5-6 7-8 9-10 11-12 13-14 15-16

6 ---------- 5 5 6 9 10 12 14 16 5 5 6 9 10 12 14 16

7 ---------- 6 7 10 11 13 15 17 21 6 7 10 11 13 15 17 21

8 ---------- 7 10 11 13 15 17 21 23 7 10 11 13 15 17 21 23

9 ---------- 11 12 14 16 18 22 24 27 11 12 14 16 18 22 24 27

10 ---------- 14 16 18 20 24 26 29 33 15 17 19 21 25 27 30 34

11 ---------- 18 20 22 26 28 31 35 38 18 20 22 26 28 31 35 38

12 ---------- 21 23 27 29 32 36 39 44 22 24 28 30 33 37 40 45

13 ---------- 25 29 31 34 38 41 46 49 26 30 32 35 39 42 47 50

14 ---------- 31 33 36 40 43 48 51 55 32 34 37 41 44 49 52 56

15 ---------- 36 39 43 46 51 54 58 63 38 41 45 48 53 56 60 65

16 ---------- 41 45 48 53 56 60 65 68 43 47 50 55 58 62 67 70

17 ---------- 48 51 56 59 63 68 71 78 50 53 58 61 65 70 73 80

18 ---------- 54 59 62 66 71 74 81 86 57 62 65 69 74 77 84 89

19 ---------- 62 65 69 74 77 84 89 95 65 68 72 77 80 87 92 98

20 ---------- 69 73 78 81 88 93 99 104 73 77 82 85 92 97 103 108

21 ---------- 76 81 84 91 96 102 107 110 80 85 88 95 100 106 111 114

22 ---------- 85 88 95 100 106 111 114 120 89 92 99 104 110 115 118 124

23 ---------- 92 99 104 110 115 118 124 131 97 104 109 115 120 123 129 136

24 ---------- 102 107 113 118 121 127 134 137 107 112 118 123 126 132 139 142

25 ---------- 114 120 125 128 134 141 144 150 119 125 130 133 139 146 149 155

26 ---------- 124 129 132 138 145 148 154 156 130 135 138 144 151 154 160 162

27 ---------- 135 138 144 151 154 160 162 171 141 144 150 157 160 166 168 177

28 ---------- 141 147 154 157 163 165 174 180 149 155 162 165 171 173 182 188

29 ---------- 150 157 160 166 168 177 183 197 158 165 168 174 176 185 191 205

30 ---------- 163 166 172 174 183 189 203 207 171 174 180 182 191 197 211 215

31 ---------- 172 178 180 189 195 209 213 220 181 187 189 198 204 218 222 229

32 ---------- 181 183 192 198 212 216 223 233 190 192 201 207 221 225 232 242

33 ---------- 188 197 203 217 221 228 238 247 198 207 213 227 231 238 248 257

34 ---------- 199 205 219 223 230 240 249 258 209 215 229 233 240 250 259 268

35 ---------- 213 227 231 238 248 257 266 272 224 238 242 249 259 268 277 283

36 ---------- 233 237 244 254 263 272 278 289 244 248 255 265 274 283 289 300

37 ---------- 249 256 266 275 284 290 301 306 262 269 279 288 297 303 314 319

38 ---------- 260 270 279 288 294 305 310 318 273 283 292 301 307 318 323 331

39 ---------- 276 285 294 300 311 316 324 333 290 299 308 314 325 330 338 347

40 ---------- 294 303 309 320 325 333 342 351 309 318 324 335 340 348 357 366

41 ---------- 311 317 328 333 341 350 359 368 327 333 344 349 357 366 375 384

42 ---------- 325 336 341 349 358 367 376 385 342 353 358 366 375 384 393 402

43 ---------- 342 347 355 364 373 382 391 400 359 364 372 381 390 399 408 417

44 ---------- 356 364 373 382 391 400 409 419 375 383 392 401 410 419 428 438

45 ---------- 369 378 387 396 405 414 424 434 388 397 406 415 424 433 443 453

46 ---------- 385 394 403 412 421 431 441 451 405 414 423 432 441 451 461 471

47 ---------- 402 411 420 429 439 449 459 469 423 432 441 450 460 470 480 490

48 ---------- 419 428 437 447 457 467 477 488 441 450 459 469 479 489 499 510

49 ---------- 436 445 455 465 475 485 496 506 459 468 478 488 498 508 519 529

50 ---------- 454 464 474 484 494 505 515 526 477 487 497 507 517 528 538 549

Refer to code 17.33 for scaling of butt logs.

Taper in inches (difference between diameters of 2 ends)

38- foot logs (1 18- and 1 20-foot

segment)

40-foot logs (2 20-foot segments)

[Scribner Decimal C rule—board feet in tens]

Top

diam.

(in.)
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A-13 Effective 10/30/20

Appendix 3 (continued) - Long Logs, Volume According to 

Taper, Maximum Scaling Length 20 Feet

Top

diam.

(in,)

12-345-678-91011-121314-1512-345-678-91011-121314-15

6 5 5 6 7 9 11 13 15 18 20 6 6 7 9 11 12 15 16 20 22

7 6 7 9 10 13 14 17 19 23 25 7 8 11 12 14 16 18 21 25 27

8 8 9 11 13 15 17 21 23 26 29 9 11 13 14 17 18 23 25 28 31

9 11 12 15 16 20 22 25 27 32 34 13 14 16 18 21 24 27 29 34 37

10 14 16 19 21 24 26 30 33 37 40 16 17 21 22 26 28 32 35 40 44

11 19 20 23 25 29 31 36 38 43 46 20 22 24 27 31 33 38 41 47 49

12 23 25 29 31 35 38 42 45 50 52 25 26 31 33 37 40 45 49 53 56

13 28 30 34 36 41 43 48 51 55 60 29 32 36 38 43 46 52 54 60 65

14 34 36 40 43 47 50 56 58 64 66 36 38 42 45 50 54 59 62 69 71

15 40 42 47 49 55 58 62 66 71 76 42 44 49 52 59 61 66 71 76 82

16 46 49 54 57 62 64 71 73 81 85 48 51 57 61 65 68 76 78 87 91

17 54 56 61 64 69 73 78 83 89 93 56 59 65 67 73 78 83 89 95 100

18 61 64 70 72 79 81 88 92 100 103 64 68 73 76 84 86 94 98 107 110

19 69 72 77 81 85 90 98 102 107 109 73 75 81 86 90 96 104 109 114 117

20 78 80 86 88 97 101 107 110 117 121 81 84 91 93 103 107 114 117 125 130

21 85 89 95 100 106 110 118 120 128 133 89 94 100 106 112 117 125 128 137 142

22 95 97 104 108 117 120 126 130 139 141 100 102 110 114 124 127 134 139 148 151

23 103 108 117 121 128 130 138 143 148 153 108 114 123 128 135 138 147 152 158 162

24 115 119 127 130 136 140 148 150 157 158 121 125 134 137 144 149 157 160 166 168

25 128 132 139 141 148 153 157 162 167 174 134 139 146 149 157 162 167 171 177 185

26 140 143 148 152 159 161 170 171 183 187 147 150 156 161 168 171 179 181 194 198

27 150 152 158 163 169 174 180 187 193 202 157 160 167 172 179 183 190 198 204 215

28 157 161 170 172 182 183 192 196 210 213 165 170 179 182 191 193 203 207 223 227

29 167 172 179 184 187 194 203 212 216 221 176 181 189 193 197 205 214 225 230 235

30 181 183 190 191 203 207 217 220 232 239 190 193 199 201 214 218 230 234 246 254

31 190 195 201 208 213 222 232 237 248 254 200 204 211 219 224 235 246 251 263 270

32 202 203 211 215 231 234 243 250 265 271 211 213 222 226 244 248 257 265 281 288

33 209 216 227 236 243 248 264 270 279 284 219 227 238 249 257 262 279 286 296 302

34 224 228 241 244 258 265 274 280 290 297 235 239 254 258 272 280 290 297 308 316

35 239 248 260 265 275 281 292 297 311 315 250 261 274 279 290 297 309 315 330 334

36 261 264 272 279 290 296 308 315 325 331 274 278 286 294 306 313 326 334 344 351

37 276 281 293 299 312 317 330 334 346 352 290 295 308 315 329 335 349 353 366 373

38 289 296 309 315 326 333 343 349 360 366 303 311 325 332 344 352 362 369 381 388

39 308 314 326 331 344 348 359 365 378 384 323 330 343 349 363 367 379 386 400 407

40 327 333 344 351 360 366 379 385 395 402 343 350 362 370 379 386 400 407 418 425

41 345 350 362 366 379 385 395 401 414 420 362 368 381 385 399 406 417 424 437 445

42 361 368 379 385 395 401 413 420 432 439 379 387 398 405 416 423 436 443 457 464

43 380 384 394 400 412 418 431 437 450 457 399 403 414 421 434 441 454 462 475 483

44 395 401 413 419 431 438 450 457 470 477 414 421 434 441 454 461 475 482 496 504

45 411 417 429 435 448 454 467 474 488 495 431 438 451 458 471 479 492 500 515 524

46 429 435 447 454 466 473 487 494 507 515 450 457 470 477 491 498 513 521 536 544

47 447 453 466 472 486 493 506 513 528 535 469 476 489 497 511 519 533 542 557 566

48 465 472 485 492 505 512 526 534 548 556 488 495 510 517 531 539 555 563 579 587

49 485 491 504 511 525 532 547 554 569 577 508 516 529 537 552 561 576 585 600 609

50 504 511 525 532 546 554 568 576 591 599 529 536 551 559 575 583 599 607 623 632

 Refer to code 17.33 for scaling of butt logs.

Taper in inches (difference between diameters of 2 ends)

[Scribner Decimal C rule—board feet in tens]

42-foot logs (three 14-foot 

segments)

44-foot logs (two 14- and one 

16-foot segments)
WO Amendment 2409.11-2006-1 Page A-14 Effective 10/30/20

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 3 (continued) - Long Logs, Volume According to 

Taper, Maximum Scaling Length 20 Feet

12-345-678-91011-121314-1512-345-678-91011-121314-15

6 ---------- 7 7 8 10 12 13 17 18 22 24 8 8 9 11 13 14 18 19 23 25

7 ---------- 8 9 12 13 16 18 20 23 26 28 9 10 13 14 17 19 21 24 27 29

8 ---------- 10 12 15 16 19 20 24 26 30 33 11 13 16 17 20 21 25 27 31 34

9 ---------- 15 16 18 20 22 25 29 31 35 38 16 17 19 21 23 26 30 32 36 39

10 ---------- 18 19 22 23 28 30 33 36 43 46 20 21 24 25 30 32 35 38 44 48

11 ---------- 21 23 26 29 32 34 40 43 49 51 23 25 28 31 34 36 42 45 51 53

12 ---------- 27 28 32 34 39 42 47 51 55 58 28 29 33 35 40 43 48 52 56 59

13 ---------- 30 33 38 40 45 48 54 56 62 67 32 35 40 42 47 50 56 58 64 69

14 ---------- 38 40 44 47 52 56 61 64 72 74 39 41 45 48 53 57 62 65 73 75

15 ---------- 44 46 51 54 61 63 69 74 80 86 46 48 53 56 63 65 71 76 82 88

16 ---------- 50 53 59 63 68 71 80 82 90 94 52 55 61 65 70 73 82 84 92 96

17 ---------- 58 61 68 70 77 82 86 92 99 104 60 63 70 72 79 84 88 94 101 106

18 ---------- 67 71 77 80 87 89 98 102 112 115 69 73 79 82 89 91 100 104 114 117

19 ---------- 77 79 84 89 94 100 109 114 119 122 80 82 87 92 97 103 112 117 122 125

20 ---------- 84 87 95 97 108 112 119 122 131 136 88 91 99 101 112 116 123 126 135 140

21 ---------- 93 98 105 111 117 122 131 134 143 148 96 101 108 114 120 125 134 137 146 151

22 ---------- 105 107 115 119 130 133 140 145 155 158 109 111 119 123 134 137 144 149 159 162

23 ---------- 113 119 129 134 141 144 154 159 165 169 118 124 134 139 146 149 159 164 170 174

24 ---------- 127 131 140 143 151 156 164 167 174 176 132 136 145 148 156 161 169 172 179 181

25 ---------- 140 145 153 156 164 169 175 179 186 194 146 151 159 162 170 175 181 185 192 200

26 ---------- 154 157 163 168 176 179 188 190 203 207 160 163 169 174 182 185 194 196 209 213

27 ---------- 164 167 175 180 188 192 199 207 214 225 171 174 182 187 195 199 206 214 221 232

28 ---------- 173 178 188 191 200 202 213 217 232 236 180 185 195 198 207 209 220 224 239 243

29 ---------- 185 190 198 202 207 215 223 234 240 245 193 198 206 210 215 223 231 242 248 253

30 ---------- 199 202 209 211 223 227 240 244 257 265 208 211 218 220 232 236 249 253 266 274

31 ---------- 210 214 220 228 234 245 257 262 274 281 219 223 229 237 243 254 266 271 283 290

32 ---------- 220 222 232 236 255 259 268 276 294 301 230 232 242 246 265 269 278 286 304 311

33 ---------- 229 237 249 260 268 273 292 299 310 316 238 246 258 269 277 282 301 308 319 325

34 ---------- 246 250 265 269 285 293 304 311 322 330 256 260 275 279 295 303 314 321 332 340

35 ---------- 261 272 287 292 304 311 323 329 345 349 272 283 298 303 315 322 334 340 356 360

36 ---------- 287 291 300 308 320 327 341 349 360 367 298 302 311 319 331 338 352 360 371 378

37 ---------- 304 309 322 329 344 350 365 369 383 390 317 322 335 342 357 363 378 382 396 403

38 ---------- 317 325 340 347 360 368 379 386 399 406 331 339 354 361 374 382 393 400 413 420

39 ---------- 338 345 359 365 380 384 397 404 419 426 352 359 373 379 394 398 411 418 433 440

40 ---------- 359 366 379 387 397 404 419 426 437 444 374 381 394 402 412 419 434 441 452 459

41 ---------- 379 385 399 403 418 425 436 443 457 465 395 401 415 419 434 441 452 459 473 481

42 ---------- 397 405 417 424 435 442 456 463 478 485 414 422 434 441 452 459 473 480 495 502

43 ---------- 418 422 433 440 454 461 475 483 497 505 436 440 451 458 472 479 493 501 515 523

44 ---------- 433 440 454 461 475 482 497 504 519 527 452 459 473 480 494 501 516 523 538 546

45 ---------- 451 458 472 479 493 501 515 523 538 547 470 477 491 498 512 520 534 542 557 566

46 ---------- 471 478 492 499 514 521 536 544 561 569 491 498 512 519 534 541 556 564 581 589

47 ---------- 491 498 512 520 534 542 558 567 582 591 512 519 533 541 555 563 579 588 603 612

48 ---------- 511 518 533 540 556 564 580 588 605 613 533 540 555 562 578 586 602 610 627 635

49 ---------- 531 539 554 562 577 586 602 611 627 636 554 562 577 585 600 609 625 634 650 659

50 ---------- 554 561 576 584 601 609 626 634 652 661 577 584 599 607 624 632 649 657 675 684

 Refer to code 17.33 for scaling of butt logs.

Taper in inches (difference between diameters of 2 ends)

[Scribner Decimal C rule—board feet in tens]

46-foot logs (1 14-foot and 2 16-foot 

segments) 48-foot logs (3 16-foot segments)

Top

diam.

(in.)
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A-15 Effective 10/30/20

Appendix 4 - Deductions for Squared Defects From Solid 

Board-foot Contents, Based on Formula1
WO Amendment 2409.11-2006-1 Page A-16 Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 4 (continued) - Deductions for Squared Defects 

From Solid Board-foot Contents, Based on Formula1
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A-17 Effective 10/30/2006

Appendix 5 - Deductions for Rectangular Defects, 

From Solid Board-foot Contents
WO Amendment 2409.11-2006-1 Page A-18 Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 5 (continued) - Deductions for Rectangular 

Defects, From Solid Board-foot Contents
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A-19 Effective 10/30/2006

Appendix 5 (continued) - Deductions for Rectangular 

Defects, From Solid Board-foot Contents
WO Amendment 2409.11-2006-1 Page A-20 Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 5 - Deductions for Rectangular Defects, 

From Solid Board-foot Contents
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A-21 Effective 10/30/2006

Appendix 5 (continued) - Deductions for Rectangular 

Defects, From Solid Board-foot Contents
WO Amendment 2409.11-2006-1 Page A-22 Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 5 (continued) - Deductions for Rectangular 

Defects, From Solid Board-foot Contents
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A-23 Effective 10/30/2006

Appendix 5 (continued) - Deductions for Rectangular 

Defects, From Solid Board-foot Contents
WO Amendment 2409.11-2006-1 Page A-24 Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 5 (continued) - Deductions for Rectangular 

Defects, From Solid Board-foot Contents
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A-25 Effective 10/30/2006

Appendix 5 (continued) - Deductions for Rectangular 

Defects, From Solid Board-foot Contents
WO Amendment 2409.11-2006-1 Page A-26 Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 5 (continued) - Deductions for Rectangular 

Defects, From Solid Board-foot Contents
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A-27 Effective 10/30/2006

Appendix 5 (continued) - Deductions for Rectangular 

Defects, From Solid Board-foot Contents
WO Amendment 2409.11-2006-1 Page A-28 Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 5 (continued) - Deductions for Rectangular 

Defects, From Solid Board-foot Contents
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A-29 Effective 10/30/2006

Appendix 5 (continued) - Deductions for Rectangular 

Defects, From Solid Board-foot Contents
WO Amendment 2409.11-2006-1 Page A-30 Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 6 - Deductions for Pitch and Shake 

Rings Showing on Both Ends of Logs, 

With Various Amounts of Ring Taper1
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A-31 Effective 10/30/2006

Appendix 6 (continued) - Deductions for Pitch and Shake 

Rings Showing on Both Ends of Logs, With Various 

Amounts of Ring Taper1

Instructions for Use of Appendix 6 Pitch and Shake Ring 

Deduction Table.

1. Measure rings at both ends to obtain taper.

2. Refer to table. Use small end ring and proper taper 

column for deduction.

3. When 2 full rings are over 2 1/2 inches apart, measure 

diameter of both rings, refer to the proper columns for deductions. 

Add deductions together.

Supplementary Instructions

For rings showing on one end only, use squared-defect method and 

replace volume of core.

For logs shorter than 16 feet, use the large end ring and the Coconino 

scale stick.

When 2 full rings are not more than 2 1/2 inches apart, measure diameter of the outside ring. Add 1 inch. Apply squared-defect method 

for gross deduction. Reduce this by the scale of a log with a diameter 

of the inner ring.

When multiple rings occur with no recovery between them, square 

the overall defect and allow for the scale of any inside log surrounded 

by rings.

For a full or partial ring 2 1/2 inches or less from the outside at the 

top end (perimeter ring), deduct as for sap rot.
WO Amendment 2409.11-2006-1 Page A-32 Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 7 - Twelve Common Rots and 

Fungi in Saw Logs

1. Fomes pini

Common name.—Conk rot, red ring rot; sometimes called honeycomb rot, particularly in pine and larch.

Hosts.—Western white, ponderosa lodgepole, white bark, limber 

pine; Engelmann spruce; western hemlock; sugar pine; mountain 

hemlock; white, alpine, Shasta red fir; Douglas-fir; western redcedar; 

western larch.

General form.—Trunk rot rarely acting as butt rot. Generally patchy. 

Enters through dead branch stubs, rarely through wounds. The rot 

column is roughly conical in both directions from area of greatest 

decay in trunk. Often as patchy ring- or crescent-shaped areas not 

uniformly attacking the heartwood except in very advanced stages.

The rot column may extend from a few feet to entire tree length.

Characteristics.—Heart rot In resinous trees, heart rot or sap rot in 

trees with little or no resin. Rot In early stages reddish color In split 

section with small white patches mingled with pitted areas and In 

advanced stages ring-scaled. Delignifying rot, converting wood to 

cellulose; white pocket rot.

External signs.—Typical fruiting bodies or conks of fungus on log. 

Indications at old branch whorls, either by swells or by brownish 

punky substance, that fruiting bodies have dropped off. Soundings 

made on trunk to detect punkiness Indicating decay. Punk knots or 

blind conks.
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A-33 Effective 10/30/2006

Appendix 7 (continued) - Twelve Common Rots 

and Fungi in Saw Logs

Fruiting body.—Sometimes called ring-scale fungus, brown shell 

fungus. Fruiting body Is hoof or shell shape, perennial, hard, woody, 

upper surface dark brown, rough, hairy when young, with concentric 

raised zones, substance brown, pores usually large and round, pore 

layer stratified.

2. Polyporus schweinitzii

Common name.—Red-brown butt rot. Stump or ground rot.

Hosts.—Western white, ponderosa, lodgepole, whitebark, limber 

pine; Douglas-fir; grand, white, alpine, Shasta red fir; western redcedar; Engelmann spruce.

General form.—A uniform circular butt rot; a wound fungus. The 

rot column Is generally conical from base of tree upward. Uniform, 

usually not advancing beyond first log. The rot column may extend 

from roots to 8 to 12 feet up Into first log. Usually not more than 5 or 

6 feet upward.

Characteristics.—Uniform heart rot of butt of tree, also enters roots. 

Rot in the early stage is light reddish brown; typical stage is reddish 

brown, pronounced cubical, crumbly, brittle when dry; occasionally 

with thin resinous crusts of white felt like material (mycelium), odor 

of turpentine. Carbonizing rot.

External signs.—Typical fruiting bodies of the fungus on the ground 

near the tree (often partly covered by debris), sometimes found as 

bracket fungus issuing from injuries at base of the tree (never high up 
WO Amendment 2409.11-2006-1 Page A-34 Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 7 (continued) -Twelve Common Rots 

and Fungi in Saw Logs

on the trunk). Indications of brown rot in the exposed roots. Soundings on the basal portion of the tree and exposed roots. Indications of 

typical rot.

Fruiting body.—Sometimes called velvet-top or cowdung fungus. 

Fruiting body annual, stem short, dark brown, covered with stiff 

hairs, flesh brown, soft and spongy when fresh, brittle when dry, 

pores large when young, becoming torn with age. Attached to the 

roots near the base of the tree or directly on the base of the tree.

3. Echinodontium tinctorium

Common name.—Brown stringy rot; rust-red stringy rot.

Hosts.—Alpine, white, grand fir; western, mountain hemlock. Of 

economic Importance only on true firs and hemlocks. Shasta red fir; 

Engelmann spruce.

General form.—A uniform circular trunk rot, entering through branch 

stubs and wounds. The rot column is roughly conical in both directions from area of greatest decay. Very uniform in occupying most or 

all of the heartwood. The rot column may extend from a few feet to 

entire tree length, depending upon the degree of infection.

Characteristics.—Uniform heart rot, confined to given trees almost 

entirely. Rot in early stages: wood spongy yellow stained; typical 

stage: soft stringy, often separating along the annual rings, brownish
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A-35 Effective 10/30/2006

Appendix 7 (continued) -Twelve Common Rots and 

Fungi in Saw Logs

to rusty red in color, knots show deep rusty red color. Sawed surface 

of cross section pitted, broken, stringy with reddish brown discolorations, often hollow rotted, carbonizing rot; viz, reducing cellulose, 

producing dark-colored decay.

External signs.—Typical fruiting bodies of the fungus on the tree. 

Indications at branch whorls either by swells or by deep rust red punk 

knots that fruiting bodies had dropped off. Large number of dead 

branch stubs accompanied by pronounced swells of whorls. Deep 

rusty red color in old branch stubs. Soundings made on trunk.

Many injuries, such as logging scars, fire scars, frost cracks, blazes, 

etc., are indications of typical rot.

Fruiting body.—Sometimes called Indian paint fungus, fruiting body 

perennial, hard and woody, gray or black above with concentric 

growth zones, substance brick red, lower surface covered with hard 

sharp spines when mature.

4. Fomes pinicola

Common name.—Brown crumbling rot.

Hosts.—Attacks all the imports conifers, but principally western 

larch; western, mountain hemlock; alpine, grand fir; Douglas-fir 

(dead); Shasta red, white fir; especially Sitka spruce and hemlock In 

Alaska.
WO Amendment 2409.11-2006-1 Page A-36 Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 7 (continued) - Twelve Common Rots and 

Fungi in Saw Logs

General form.—A uniform circular trunk rot; a wound fungus. The 

rot column is generally uniform and conical. The rot column usually 

occupies entire heartwood of tree on the portion of the tree infected. 

Rarely extending beyond the first log length.

Characteristics.—Uniform heart rot found principally in dead, 

standing, and down timber, occasionally acting as heart rot in living 

trees by gaining entrance through injuries. In early stages rot is light 

brown; typical stage, reddish brown, cubical, crumbly and brittle 

when dry, white feltlike layers of mycelium between cubical patches. 

Felt patches larger, thicker, and nonresinous as compared to those of 

velvet-top fungus. Carbonizing rot.

External signs.—Typical “red belt” fruiting bodies of the fungus 

on the tree. Typical rot at old branch stubs. Soundings made on the 

trunk. Indications of typical rot.

Fruiting body.—Sometimes called red-margin Fomes; red belt 

Fomes. Fruiting body, perennial, hard, woody, flat or hoof-shaped, 

surface smooth, furrowed gray or black with resinous crust, margin 

white or reddish, substance whitish or wood colored, pores In layers.

5. Polyporus sulphureus

Common name.—Brown cubical rot; reddish-brown heart rot.

Hosts.—Attacks most all of the important conifers but principally 

ponderosa, western white pine; Douglas-fir; western larch

Shasta red fir; Engelmann spruce; white fir.
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A-37 Effective 10/30/2006

Appendix 7 (continued) - Twelve Common 

Rots and Fungi in Saw Logs

General form.—This is a uniform circular butt and trunk rot. A 

wound fungus.

The rot column is generally uniform and conical.

The rot column usually occupies the entire heartwood of the tree at 

point of greatest infection. Usually a butt rot, rarely extending beyond 

the first log length.

Characteristics.—Uniform heart rot. Rot in early stages light brown, 

typical stage, dark reddish brown, brittle dry, crumbly, not pronounced cubical, with thick felty mycelial masses In clefts, arranged 

star-shaped in cross section. Carbonizing rot.

External signs.—Typical fruiting bodies of the fungus on the tree. 

Soundings made on the trunk. Indications of typical rot.

Fruiting body.—Sometimes called sulfur fungus. Fruiting structure 

annual, broad, with several parts one above another, smooth, zoned, 

lemon yellow to orange, white when old, flesh white, crumbly when 

dry, pores small, sulfur yellow.

6. Fomes officinalis

Common name.—Reddish-brown heart rot; brown trunk rot.

Hosts.—Attacks all important conifers but principally western larch; 

ponderosa, sugar pine; white, Shasta red fir; Douglas-fir; Engelmann 

spruce.
WO Amendment 2409.11-2006-1 Page A-38 Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 7 (continued) - Twelve Common 

Rots and Fungi in Saw Logs

General form.—Trunk rot. Wound fungus.

The rot column to generally uniform and conical.

The rot column usually occupies the entire heartwood of the tree in 

advanced stages. Most commonly occupies upper portion of merchantable timber; rarely a typical butt rot.

Characteristics.—Uniform heart rot. Rot in early stages light brown; 

typical stage, dark reddish brown, brittle dry, crumbly with thin felty 

mycelial masses in clefts. Carbonizing rot.

External signs.—Typical fruiting bodies of the fungus on the tree, the 

principal means of distinction between rots of this species and that of 

sulfur fungus. Soundings made on the trunk. Indications of typical 

rot.

Fruiting body.—Also known as Fomes laricis (chalky quinine 

fungus). Perennial hoof-shaped, sometimes cylindrical, snow white, 

substance white soft, bitter to the taste, pores small, white arranged 

in layers.

7. Poria weirii

Common name.—Yellow laminated rot.

Hosts.—Western redcedar and eastern arborvitae. Douglas-fir.

General form.—Butt rot. Uniform circular rot. Wound fungus.
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A-39 Effective 10/30/2006

Appendix 7 (continued) - Twelve Common 

Rots and Fungi in Saw Logs

The rot column is generally uniform and conical.

The rot column may extend from roots to 5 to 8 feet up into first log, 

often causing hollow butts. Rarely throughout entire pole length in 

old trees.

Characteristics.—Uniform heart rot. Rot yellow color, decays 

springwood, separating annual rings. In advanced stages brown, 

felty, mycelium between layers. Carbonizing rot.

External signs—Typical fruiting bodies of the fungus on the tree (in 

the root crotches, often cementing the forest debris about the roots 

into a punky mass). Soundings at base of tree and exposed root 

spurs.

Fruiting body.—Sometimes called brown cedar Poria. Fruiting 

structure flat growing, inconspicuous, perennial, stratified, substance 

brown. Grows in root crotches and underside of down trees and logs.

8. Fomes annosus

Common name.—White spongy rot.

Hosts.--Western white, ponderosa, lodgepole, whitebark, limber pine; 

Engelmann spruce; western, mountain hemlock; Shasta red, alpine, 

grand, white fir; Douglas-fir; western redcedar; western larch.
WO Amendment 2409.11-2006-1 Page A-40 Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 7 (continued) - Twelve Common 

Rots and Fungi in Saw Logs

General form.--Butt rot. Uniform circular. Pathogenic: can attack the 

cambium layer.

The rot column is generally conical and uniform, filling heartwood 

and part or all sapwood.

The rot column may extend from roots to 6 or 8 feet into first log; 

sometimes much higher in hemlock. Soon producing hollow butts.

Characteristics.--Uniform sap rot and heart rot of butt. Rot in early 

stages, ranging from lilac to reddish color; typical stage in whitish 

areas separated by smaller areas of sound wood, not prominently 

pitted, occasionally with black dots in center of white areas, in last 

stages annual rings separated; finally wet spongy. Fine felty masses 

(mycelium) under bark scales. Delignifying rot.

External signs.—Typical fruiting bodies of the fungus in root 

crotches usually covered by litter or duff. Resin flow at base of tree 

and exposed roots. Soundings at base of tree and exposed roots.

Fruiting body.—Sometimes called root Fomes. Fruiting body woody, 

usually thin and irregular, with a smooth brown crust, perennial; 

substance white or pale yellowish, pores small stratified and white. 

Found in the root crotches or under litter, not easily seen.
FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

WO Amendment 2409.11-2006-1 Page A-41 Effective 10/30/2006

Appendix 7 (continued) - Example of Local Chart Guide

 for Conk Rot for One Species

9. Pholiota adiposa

Common name.—Mottled rot; yellow heart rot.

Hosts.—Alpine, grand, white, Shasta red fir; western, mountain 

hemlock; Engelmann spruce; western white pine. Usually of most 

importance on the true firs.

General form.—Trunk rot. Uniform circular.

The rot column is generally conical in heartwood.

The rot column may extend from stumps to entire merchantable tree 

length. Usually confined to the first two log lengths. Sometimes 

localized in a single log.

Characteristics.—Uniform. Heart rot, principally of trees with little 

or no resin. Rot in early stages a light yellow stain; typical stage, yellow or honey color, brownish streaks, yellowish to light tan or white 

felty masses. Running across grain, breaking up in the last stages and 

separating annual rings, finally becoming hollow rotted. Carbonizing 

rot.

External signs.—Typical fruiting bodies of the fungus on the tree. 

Soundings made on the trunk. Indications of typical rot.

Fruiting body.—Sometimes called scaly Pholiota or yellow cap 

fungus. Fruiting body annual, mushroom type, appearing in clusters, 

yellow on upper surface, sticky when wet, stem yellow, gills yellowish to brown.
WO Amendment 2409.11-2006-1 Page A-42 Effective 10/30/2006

FSH 2409.11 

NATIONAL FOREST LOG SCALING HANDBOOK

APPENDIX

Appendix 7 (continued) - Twelve Common 

Rots and Fungi in Saw Logs

10. Ceratostomella species

Common name.—Blue stain.

Hosts.—Especially ponderosa, southern yellow, lodgepole, whitebark, limber pine; Engelmann spruce; western hemlock; but all soft 

and hard woods are affected.

General form.—Sap stain. Since the bluing fungus does not attack 

the cell walls except to a negligible extent and feeds only upon the 

cell contents, blued wood is not weakened. This has been determined 

by comparative mechanical tests on stained and unstained wood. But 

high moisture content and warm weather, which promote the development of the bluing fungus, are highly favorable to the development of true wood-destroying fungi. The fact that blued wood may 

soon show evidences of decay when put in service is due to the true 

wood-destroying fungi and not to the bluing fungus. Although the 

strength of blued wood is not impaired by the color, the wood may be 

objectionable in places where color is a factor.

NOTE: Certain other discolorations of sapwood are produced by 

fungi belonging to the molds, of which the green mold on fruits or in 

certain cheeses is an example. Such stains are usually superficial and 

may be planed off. They are difficult to distinguish by visual inspection from the true blue stain.
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WO Amendment 2409.11-2006-1 Page A-43 Effective 10/30/2006

Appendix 7 (continued) - Twelve Common 

Rots and Fungi in Saw Logs

Characteristics.—Blue or bluish gray or black color of the sapwood, 

rarely in the heartwood, color usually most intense in the rays, causing it to appear in streaks in early stages. Due to the character of the 

wood, conifers are more susceptible than hardwoods. Fruiting body 

of the bluing fungus not readily seen. When the color Is so dense that 

it is almost black, small bristles with a bulbous base may be seen with 

a hand lens. The color, depending upon the weather conditions, usually appears very rapidly In trees killed by bark beetles or fire, or in 

piled logs cut from green trees. Lumber in yards may blue very rapidly if not properly piled or treated. Blue color is due to the reflection 

to the surface of the wood of the colored mycelium in the wood cells. 

The wood itself is not stained by the true bluing fungus.

External signs.—”Blued” sapwood. Blued streaks extending from 

the sap into the heartwood of some logs. Dead and dying trees, killed 

by bark beetles, fire, or various other agents, are very susceptible to 

blue stain.

Fruiting body.—Sometimes called Bluing fungus. Fruiting body 

small, black, with long appendages, can best be seen with hand lens, 

appears on surface of boards or on wood of logs beneath bark.

11. Polyporus amarus

Comon name.—Pocket dry rot.

Hosts.—Incense-cedar.
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Appendix 7 (continued) - Twelve Common 

Rots and Fungi in Saw Logs

General form.—Trunk rot. The rot column usually occupies entire 

heartwood, not common In butt portion.

Characteristics.—In early stage, pocket dry rot appears as a faint 

yellowish-brown discoloration of the heartwood. Later elongated 

pockets with pointed ends develop, longer than broad, from 1/2 inch 

to 12 inches. Wood broken down into a dark brown friable residue. 

Pockets confined to the heartwood of the main trunk or bases of large 

limbs. Pockets seldom form in exposed heartwood, are sparse near 

large open wounds.

External signs.—Typical fruiting bodies on the tree, rare. 

Open borings or shot-hole cups replace conks. Large open fire 

wounds are indicators of this rot in most locations.

Fruiting body.—Half bell-shaped or somewhat hoof-shaped, 4 to 

8 inches wide, buff to tan on top, bright sulfur-yellow underneath, 

darkens In age to chalky tan, soft and moist when fresh, firm and dry 

when old.

12. Polyporus anceps

Common name.—Western red rot; red ray rot.

Host.—Ponderosa pine.

General form.—Heart rot. Fungus does not require conspicuous 

entrance courts such as wounds, fire scars, or dead tops. Enters only 

through recently dead, bark-covered branches. Requires moisture to 

sustain attack. The rot column extending to heartwood is invaded 
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WO Amendment 2409.11-2006-1 Page A-45 Effective 10/30/2006

Appendix 7 (continued) - Twelve Common 

Rots and Fungi in Saw Logs

longitudinally by a localized infection in the form of a decay column 

from a knot. Radial and tangential spread is initially slow; may 

spread through entire tree length but affects mostly logs from middle 

portion.

Characteristics.—Wood decayed in irregular streaks or pockets. In 

early stage of decay, heartwood reddish to dark brown. Discolored 

areas, often fan-shaped, radiate out from the log center, resemble 

spokes of a wheel or may be isolated anywhere in heartwood. In advanced stage, heartwood is whitish or grayish in color. Rotted wood 

consists of soft white strands of cellulose Intermixed with less rotted 

wood particles, often wet and soggy, usually in log center, often 

surrounded by the fanlike areas of an early stage. In longitudinal section, Incipient decay often appears as several separate discolored areas. In advanced stage, appears continuous. Decay entering through 

knots may be concentrated in the pith cavity.

External signs.—Limited. Fruiting bodies rarely formed on trees and 

then only on dead bark-covered branches. No swollen knots.

Fruiting body.—Fruiting bodies found mostly on decaying dead 

material in contact with the ground.
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Appendix 7 (continued) - Example of Local Chart Guide

 for Conk Rot for One Species
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WO Amendment 2409.11-2006-1 Page A-47 Effective 10/30/2006

Appendix 7 (continued) - Example of Local Chart Guide 

for Conk Rot for One Species
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Appendix 8 - International 1/4-inch Log Rule1
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WO Amendment 2409.11-2006-1 Page A-49 Effective 10/30/2006

Appendix 8 (continued) - International 1/4-inch Log Rule1
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Appendix 8 (continued) - International 1/4-inch Log Rule1
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WO Amendment 2409.11-2006-1 Page A-51 Effective 10/30/2006

Appendix 9 - Forest Service International 

1/4-inch Decimal Rule
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Appendix 9 (continued) - Forest Service International 

1/4-inch Decimal Rule
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WO Amendment 2409.11-2006-1 Page A-53 Effective 10/30/2006

Appendix 9 (continued) - Forest Service International 

1/4-inch Decimal Rule
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APPENDIX

Appendix 10 - Defect Allowance Chart—International 

1/4-inch Log Rule
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WO Amendment 2409.11-2006-1 Page A-55 Effective 10/30/2006

Appendix 10 (continued) - Instructions for 

Use of Defect Allowance Chart

1. Measure width and height of defect in inches. Add 1 

inch to each to allow for waste.

2. Multiply width by height.

3. Measure or estimate length of defect.

4. Place straightedge through product of W X H (left line) 

and length (right line).

5. Read deduction, to nearest 5 board feet, on center line.

For example, if a defect measured 7” by 8” by 10’, the deduction 

would be determined by holding the straightedge through 72 on the 

left line (7 + 1) X (8 + 1) and 10 on the right line. The deduction, 

center line intersection, is 45 board feet.

Shortcut method: Width of defect In inches X height in inches = 

deduction if defect extends through a 16-foot log. Otherwise take 

proper proportion, round to nearest 5 bd. ft. (or 10 bd. ft. if scaling by 

Forest Service International 1/4-Inch Decimal rule).
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Appendix 11 - Defect Allowances - For Optional Use 
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WO Amendment 2409.11-2006-1 Page A-57 Effective 10/30/2006

Appendix 11 (continued) - Instructions for 

Use of Defect Allowance Chart

1. Measure width and height of defect in inches. Add 1 inch to each 

to allow for waste.

2. Multiply width by height.

3. Measure or estimate length of defect.

4. Place straightedge through product of W X H (left line) 

and length (right line).

5. Read deduction, to nearest 5 board feet, on center line.

For example, if a defect measured 7” by 8” by 10’, the deduction 

would be determined by holding the straightedge through 72 on the 

left line (7 + 1) X (8 + 1) and 10 on the right line. The deduction, 

center line intersection, is 45 board feet.

Shortcut method: Width of defect In inches X height in inches = 

deduction if defect extends through a 16-foot log. Otherwise take 

proper proportion, round to nearest 5 bd. ft. (or 10 bd. ft. if scaling by 

Forest Service International 1/4-Inch Decimal rule).
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Appendix 12 - Standard Converting Factors
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WO Amendment 2409.11-2006-1 Page A-59 Effective 10/30/2006

Appendix 12 (continued) - Standard Converting Factors
WO Amendment 2409.11-2006-1 Page A-60 Effective 10/30/2006

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Appendix 13 - Board-foot Contents of 

Standard Lumber and Timber Sizes
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WO Amendment 2409.11-2006-1 Page A-61 Effective 10/30/2006

Appendix 13 (continued) - Board-foot Contents 

of Standard Lumber and Timber Sizes
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Appendix 13 (continued) - Board-foot Contents 

of Standard Lumber and Timber Sizes
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WO Amendment 2409.11-2006-1 Page A-63 Effective 10/30/2006

Appendix 14 - Board-foot Contents of Railroad Ties
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SPECIAL NOTE: Log diameters 6” - 11” have separate factors for 

log lengths 1’ - 15’, and 16’ - 20”.

Appendix 15 - Factors for Computing 

Scribner Decimal C Log Volumes

For logs 1’ through 20’ in length

Revised 7/1/72
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WO Amendment 2409.11-2006-1 Page A-65 Effective 10/30/2006

Appendix 16 - Scribner Decimal C Recorded 

Lengths and Segment Lengths
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Appendix 16 (continued) - Scribner Decimal C Recorded 

Lengths and Segment Lengths