r10-id_2409.11a-2001-1
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FOREST SERVICE HANDBOOK
ALASKA REGION
(REGION 10)
JUNEAU, ALASKA
FSH 2409.11A – CUBIC SCALING HANDBOOK
CHAPTER 30 – MEASURING METHODS FOR
OTHER PRODUCTS
Interim Directive No.: R10-2409.11a-2001-1
Effective Date: November 13, 2001
Duration: This interim directive expires on 04/15/2003.
Approved: /s/ Steven A. Brink
Acting Regional Forester
Date Approved: 11/13/2001
Posting Instructions: Interim directives are numbered
consecutively by Handbook number and calendar year. Post by
document at the end of the chapter. Retain this transmittal as the first
page(s) of this document.
New Document
Superseded
Document(s) (Interim
Directive Number
and Effective Date)
r10-id_2409.11a-2001-1
Digest:
30 – Provides Region 10 instructions for scaling utility logs.
17 Pages
0 Pages
R-10 INTERIM DIRECTIVE 2409.11a-2001-1
EFFECTIVE DATE: 11/13/2001
DURATION: Expires on 04/15/2003.
r10-id_2409.11a-2001-1
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FSH 2409.11A – CUBIC SCALING HANDBOOK
CHAPTER 30 -–MEASURING METHODS FOR OTHER
PRODUCTS
FIBER SCALING
Fiber scaling is determining wood content that, as a minimum, will be
suitable for the production of usable pulp chips. When scaling fiber
logs, lengths and diameters will be determined the same as for sawlog
or veneer logs and recorded in accordance with the guidelines outlined
in chapter 2, section 21.
1. ASSESSING DEFECT 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.
Deductible fiber defects are:
a. Voids
b. Soft Rots
c. Char
d. Massed Pitch
2. BASIC DEFECT DEDUCTION RULES
Use the following basic defect deduction rules when using any of the
four defect deduction methods described in section number 3:
a. Record any single occurring defect only when that defect
meets a minimum volume of 0.2 cubic feet before rounding.
b. Record defect volume to the nearest 0.1 cubic foot. For
example, 0.23 is recorded as 0.2, 1.78 is recorded as 1.8, and 3.55 as
3.6.
R-10 INTERIM DIRECTIVE 2409.11a-2001-1
EFFECTIVE DATE: 11/13/2001
DURATION: Expires on 04/15/2003.
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CHAPTER 30 -–MEASURING METHODS FOR OTHER
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c. When calculating manually use four decimal places for
unrounded figures. Use computer precision in software applications.
d. A maximum segment length of 20 feet.
e. Consider the extent of defect length in 1 foot multiples.
f. Consider defect shape (cylinder, cone) in determining
average defect length.
g. More than one defect deduction method may be used in
scaling a log.
h. Use actual defect dimensions in determining defect
volume.
i. Make deductions of segment length that are not debarkable
to a minimum of 90 percent.
j. Make deductions of segment length with char penetrating
the wood fiber.
3. DEFECT DEDUCTION METHODS FOR FIBER LOGS
There are four defect deduction methods for scaling fiber logs:

Squared area

Circular area

Length deduction

Diameter deduction
R-10 INTERIM DIRECTIVE 2409.11a-2001-1
EFFECTIVE DATE: 11/13/2001
DURATION: Expires on 04/15/2003.
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FSH 2409.11A – CUBIC SCALING HANDBOOK
CHAPTER 30 -–MEASURING METHODS FOR OTHER
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Each of these deduction methods may be used in combination with
percent.
a. Squared Area Deduction. Square or rectangular shaped
defects showing in one or both log ends will be deducted for by using
the squared area deduction method. When multiple squared area
defects occur on the log end(s), it is not required to take secondary
defect dimensions at right angles to the primary (largest) defect. For
irregular shaped defects, the dimensions of the square or rectangle
should balance unsound wood with usable fiber. This is known as the
give and take procedure.
Calculate defect volume treated as squares or rectangles as shown in
chapter 2, section 22.31:
defect area (square inches) x defect length (feet)
144
W xH xL
=
144
Defect volume ( ft 3 ) =
Where:
ft3
W
H*
L
= cubic feet
= actual width of defect (inches)
= actual height of defect (inches)
= length of defect (feet)
*
For defects on the surface of a segment, 'height' refers to 'depth' of the
defect.
b. Circular Area Deduction. Defect that is determined to be
circular in shape will be deducted for by using the circular area
deduction method. The give and take procedure will be used when
determining defect dimensions. The Smalian Formula is used to
calculate defect volume.
R-10 INTERIM DIRECTIVE 2409.11a-2001-1
EFFECTIVE DATE: 11/13/2001
DURATION: Expires on 04/15/2003.
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FSH 2409.11A – CUBIC SCALING HANDBOOK
CHAPTER 30 -–MEASURING METHODS FOR OTHER
PRODUCTS
Give and take.
14”
RL 13’
3b Figure 1--Calculating circular defect
Given:
D = Defect diameter large end = 14 inches
d = Defect diameter small end = 10 inches
L = Defect length
Defect volume ( ft3 ) = 0.002727 (D2 + d2) L
= 0.002727 (142 + 102) 13
= 0.002727 (196 + 100) 13
= 0.002727 x 296 x 13
= 0.002727 x 3848
= 10.5 ft3
(or from Table II: 10 inches with 4 inches taper, 13 feet long)
10”
R-10 INTERIM DIRECTIVE 2409.11a-2001-1
EFFECTIVE DATE: 11/13/2001
DURATION: Expires on 04/15/2003.
r10-id_2409.11a-2001-1
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FSH 2409.11A – CUBIC SCALING HANDBOOK
CHAPTER 30 -–MEASURING METHODS FOR OTHER
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When the defect is circular and judged to be blunt in shape, the defect
volume can be calculated using the Smalian Formula.
8”
RL 16’
9’
Figure 3b Figure 2--Calculating circular defect
Defect volume ( ft3 ) = 0.002727 (D2 + d2) L
= 0.002727 (82 + 82) 9
= 0.002727 (64 + 64) 9
= 0.002727 x 128 x 9
= 0.002727 x 1152
= 3.1 ft3
(or from Table II: 8 inches with no taper, 9 feet long)
For ring rot defect, the defect volume would be the difference between
the volume of the outer core defect and the volume of the inner
chipable core.
R-10 INTERIM DIRECTIVE 2409.11a-2001-1
EFFECTIVE DATE: 11/13/2001
DURATION: Expires on 04/15/2003.
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FSH 2409.11A – CUBIC SCALING HANDBOOK
CHAPTER 30 -–MEASURING METHODS FOR OTHER
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13”
RL 14’
7”
15”
9”
Figure 3b Figure 3--Calculating ring rot defect
Given:
Recorded length = 14 feet
Rot diameters
Outer:
Large end = 15 inches
Small end = 13 inches
Inner:
Large end = 9 inches
Small end = 7 inches
Defect and core volumes:
Outer (13" with 2" taper, 14' long) = 15.0 ft3
Inner (7" with 2" taper, 14' long) = 5.0 ft 3
Defect volume( ft3 ) = outer core volume - inner core volume
= 15.0 - 5.0
= 10.0 ft3
c. Length Deduction. Use the length deduction method when
unsound wood affects a portion of segment length. See chapter 2,
section 22.32.
In this example the deduction is for unsound wood in the heart and
sapwood areas due to soft rot.
R-10 INTERIM DIRECTIVE 2409.11a-2001-1
EFFECTIVE DATE: 11/13/2001
DURATION: Expires on 04/15/2003.
r10-id_2409.11a-2001-1
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FSH 2409.11A – CUBIC SCALING HANDBOOK
CHAPTER 30 -–MEASURING METHODS FOR OTHER
PRODUCTS
Sap Rot
Heart Rot
RL 14’
5’
3c Figure 1--Calculating defect using length deduction
Given:
Recorded length = 14 feet
Gross segment volume = 27.6 ft3
Length cut = 5 feet
defect length
x gross segment volume
segment length
5

x 27.6
14
 0.3571 x 27.6
Defect volume (ft 3 ) 
 9.9 ft 3
This example uses a length deduction with percent. Estimate the
percentage of log end affected in whole percents and the extent of
defect in one foot multiples. See chapter 2, section 22.33.
R-10 INTERIM DIRECTIVE 2409.11a-2001-1
EFFECTIVE DATE: 11/13/2001
DURATION: Expires on 04/15/2003.
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FSH 2409.11A – CUBIC SCALING HANDBOOK
CHAPTER 30 -–MEASURING METHODS FOR OTHER
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7’
50% Void
RL 17’
3c Figure 2--Calculating defect, using length with
percent deduction
Given:
Recorded length = 17 feet
Gross segment volume = 33.6 ft3
Defect affecting one-half of 7 feet
defect length
x percent end area affected x gross seg ment volume
segment length
7

x 0.5 x 33.6
17
 0.4118 x 0.5 x 33.6
 0.2059 x 33.6
Defect volume (ft3 ) 
 6.9 ft 3
d. Diameter Deduction. Use this method for perimeter defects such as
sap rot. 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. See chapter 2, section
22.34.
R-10 INTERIM DIRECTIVE 2409.11a-2001-1
EFFECTIVE DATE: 11/13/2001
DURATION: Expires on 04/15/2003.
r10-id_2409.11a-2001-1
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FSH 2409.11A – CUBIC SCALING HANDBOOK
CHAPTER 30 -–MEASURING METHODS FOR OTHER
PRODUCTS
RL 16’
30” 24”
22” 28”
11’
3d Figure 1--Calculating defect using diameter deduction
Given:
Recorded length = 16 feet
Small end diameter = 28 inches
Large end diameter = 30 inches
Average thickness of rot = 3 inches
To find the deduction:
Reduce both end diameters by 6 inches ( 3 inches x 2)
Reduced small end diameter = 22 inches
Reduced large end diameter = 24 inches
Gross segment volume = 73.5 ft3
Adjusted segment volume = 46.2 ft3
defect length
3
Defect volum e(ft ) 
x (gross segm entvolum e adjusted segm entvolum e)
segm entlength

11
x (73.5  46.2)
16
 0.6875x 27.3
 18.8 ft
3
R-10 INTERIM DIRECTIVE 2409.11a-2001-1
EFFECTIVE DATE: 11/13/2001
DURATION: Expires on 04/15/2003.
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CHAPTER 30 -–MEASURING METHODS FOR OTHER
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e. Deduction Methods for Common Types of Defects. Use the following guidelines as applicable
defect deduction methods for common types of fiber defects.
(1) Voids. When wood fiber is missing or absent within a
log, the defect is called void. Gouges, slabs, stump pull,
open catface, and bark seams are examples of void.
3e(1) Figure 1--Calculating defect volume for voids
Defect volume:
Stump pull =
W x H x L 4 x 12 x 3 144


 1.0 ft 3
144
144
144
Bark seam # 1=
W x H x L 2 x 9 x 7 126


 0.9 ft 3
144
144
144
Bark seam # 2=
W x H x L 3 x 8 x 6 144


 1.0 ft 3
144
144
144
Total defect volume( ft3 ) = 1.0 + .9 + 1.0 = 2.9 ft3
R-10 INTERIM DIRECTIVE 2409.11a-2001-1
EFFECTIVE DATE: 11/13/2001
DURATION: Expires on 04/15/2003.
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CHAPTER 30 -–MEASURING METHODS FOR OTHER
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NOTE: For logs having multiple squared area defects, squaring at right
angles is not required.
(2) Soft Rots. There are various forms of rot such as conk
rot, heart rot, sap rot, stump (butt) rot, and rot associated
with rotten knots. Use the appropriate deduction method,
or combination of methods, depending on the defect(s).
30” 24”
RL 16’
8”
5’
3e(2) Figure 1--Calculating defect volume for soft rots
Given:
Recorded length = 16 feet
Small end diameter = 28 inches
Large end diameter = 30 inches
Defect deduction:
Heart rot:
Defect volume ( ft3 ) = 0.002727 (D2 + d2) L
= 0.002727 (82 + 82) 5
= 0.002727 (64 + 64) 5
= 0.002727 x 128 x 5
= 0.002727 x 640
= 1.7 ft3
(or from Table II: 8 inches with no taper, 5 feet long)
22” 28”
R-10 INTERIM DIRECTIVE 2409.11a-2001-1
EFFECTIVE DATE: 11/13/2001
DURATION: Expires on 04/15/2003.
r10-id_2409.11a-2001-1
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FSH 2409.11A – CUBIC SCALING HANDBOOK
CHAPTER 30 -–MEASURING METHODS FOR OTHER
PRODUCTS
Sap rot:
Reduce both end diameters by 6 inches (3 inches x 2), or
measure sound core.
Reduced small end diameter = 22 inches
Reduced large end diameter = 24 inches
Gross segment volume = 73.5 ft3
Adjusted segment volume = 46.2 ft3
Defect volume( ft3 ) = gross segment volume - adjusted segment volume
= 73.5 - 46.2 = 27.3 ft3
Total defect volume( ft3 ) = 1.7 + 27.3 = 29.0 ft3
(3) Char. Any char present in the wood fiber causes the
entire length affected to be unusable. The remaining
portion must meet contract minimum specifications for
length, or the segment is cull.
4’
12’
4’
RL 20’
Charred wood fiber
3e(3) Figure 1--Log with char
Given:
Gross log volume = 48.2 ft3
Defect length = 8 feet
A portion of this log is unusable due to charred wood fiber. Use the
R-10 INTERIM DIRECTIVE 2409.11a-2001-1
EFFECTIVE DATE: 11/13/2001
DURATION: Expires on 04/15/2003.
r10-id_2409.11a-2001-1
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FSH 2409.11A – CUBIC SCALING HANDBOOK
CHAPTER 30 -–MEASURING METHODS FOR OTHER
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length deduction method to determine the defect volume.
defect length
x segment volume
segment length
8
=
x 48.2
20
= 0.4 x 48.2
Defect volume ( ft 3 ) =
= 19.3 ft 3
(4) Massed Pitch. Consider massed pitch as a defect the same as a
void and deduct for the length affected.
3e(4) Figure 1--Calculating defect volume for massed pitch
Defect volume ( ft3 ) =
W x H x L 6 x 10 x 3 180


 1.25 or 1.3 ft 3 (rounded)
144
144
144
R-10 INTERIM DIRECTIVE 2409.11a-2001-1
EFFECTIVE DATE: 11/13/2001
DURATION: Expires on 04/15/2003.
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CHAPTER 30 -–MEASURING METHODS FOR OTHER
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(5) Multiple Defects. When a log or segment contains
multiple defects, use a combination of any or all of the
acceptable defect deduction methods for fiber scaling.
(6) Debarkability. A log segment shall be considered
debarkable if it will not create a safety hazard, will not
fall apart when subjected to the mechanical debarking
process, and is 90% debarkable. The remaining section of
length must contain a length that meets contract minimum
specifications or the entire segment is cull.
7’
RL 32’
3e(6) Figure 1--Log with shatter
Given:
Large end segment gross volume = 48.4 ft3
Defect length = 7 feet
Due to shatter, seven feet of the large end segment will fall apart, and
may be a safety hazard when subjected to the debarking process. Use
the length deduction method to determine the defect volume.
R-10 INTERIM DIRECTIVE 2409.11a-2001-1
EFFECTIVE DATE: 11/13/2001
DURATION: Expires on 04/15/2003.
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defect length
x segment volume
segment length
7
=
x 48.4
16
= 0.4375 x 48.4
Defect volume ( ft 3 ) =
= 21.2 ft 3
RL 16’
3e(6) Figure 2--Log with severe crook
Given:
Gross log volume = 25.3 ft3
Defect length = 16 feet
Due to severe crook this log is considered to be less than 90 percent
debarkable, and in addition a safety hazard if debarked. This log is
considered a cull.
R-10 INTERIM DIRECTIVE 2409.11a-2001-1
EFFECTIVE DATE: 11/13/2001
DURATION: Expires on 04/15/2003.
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defect length
x gross segment volume
segment length
16

x 25.3
16
 1.0 x 25.3
Defect volume (ft 3 ) 
 25.3 ft 3