xt7f1v5bdt9h https://exploreuk.uky.edu/dips/xt7f1v5bdt9h/data/mets.xml   Kentucky Agricultural Experiment Station.  journals kaes_circulars_004_533 English Lexington : The Service, 1913-1958. Contact the Special Collections Research Center for information regarding rights and use of this collection. Kentucky Agricultural Experiment Station Circular (Kentucky Agricultural Experiment Station) n. 533 text Circular (Kentucky Agricultural Experiment Station) n. 533  2014 true xt7f1v5bdt9h section xt7f1v5bdt9h · _   CIRCULAR 533
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  i  MEAsumNG
University of Kentucky . . . College of Agriculture ¤nd Home Eco-
ngmiqg, Extgnsiqn Service , , , FRANK J. WELCH, Dean and Director

 C O N T E N T S
Page
Units of Measure ................ 3
Measurement of Log or Tree Dimensions and
Equipment Used
Logs .................. 24
Standing Trees - Diameter Measurement. . . 25
Height Measurement . . . Z'?
Estimating Board—£oot Content of a Standing Tree
By Volume Table ............. 33
By Use of Log Rule ............ 36
Estimating Board-foot Volume in a Tract of Timber 38 i
Evaluating Timber Volume on a Tract by Species
Groups and Sizes ............... 46
Appendix A — Specifications for Southern Pine Poles
Material Requirements .......... 46
Limitations of Knot Size .......... 49
Dimensions ................ 51
Manufacturing Requirements ........ 52.
_ Storage and Handling ........... 52
Definition of Terms ............ 53
Appendix B — Grading Stave and Heading Bolts
Requirements ............... 57 A
Rules for Inspection ............ 57

 MEASURING FARM TIMBER
By O. M. Davenport
The volume of timber products in the farmwood-
land is often an unknown quantity, yet it is of great
importance for purposes of inventory, management
plans, investment evaluation, and timber sales.
I. — UNITS OF MEASURE
All products are measured by some unit, For
fa rm woodland products there are many common
units of measure. These are described in the fol-
lowing paragraphs. A thorough understanding of
i the unit to be used in the sale of any product is of
extr eme importance. It may mean a greater fi-
nancial return as well as minimizing the chances of
a misunderstanding of the terms of a s ale agree-
ment.
A. — Piece
The piece is the simplest unit of measure, yet
there are usually certain specifications involved
which should be thoroughly understood before any
timber cutting is started. Such specifications
cover acceptable diameters, lengths, species,
- defects, and other variables which may set up
several grades of a product. Poles, piling, fence
posts, railroad ties, and in many cases, mine
props, are sold by the piece. Sample specifica-
A tions for Southern Pine Poles are shown in Ap-
, pendix A. Specifications for other piece products
may be more or less detailed; however,in gen-
eral the same factors are involved.
B. — Tight Cooperage Units
Some variation of methods maybe found in meas-
» 3

 urement of the tree or bolts which are consider-
ed for cooperage products. Only trees of the white
oak group are suitable for this use. White oak is
preferred; however, bur oak, swamp white oak,
swamp chestnut oak, overcup oak, and chinkapin
oak &I‘€ CO1'1"1IT1OI`1lY &CC€PlZ€d.
/ 
/&  
\ . Heurtwoo .
f \\ g / u
  Q   .
    \ SODWOOC
A §;$?5?i’?§  ' Bm f
*’ ·’4;./ I?
FM; \- The sum Bolt
The stave bolt (Fig. 1) is usually the basic rough
product. The bolt is split from a section of the
tree trunk which has been cut approximately 39 n i
inches in length. Measurement is taken from
outer corner of sapwood to the opposite outer
corner of sapwood (B-B). Thus a bolt measur-
ing 12 inches across from outer corner to the
opposite outer corner of sapwood would containl ` A
bolt foot. Smaller bolts would contain proportion-
ately less and larger ones more. Sample specifi-
cations for stave and heading bolts are givenin
Appendix B. In general, stave bolts measuring
12 inches across the outside are preferredwith
4

 a range of from 6 inches to 16 inches accepted.
Bolts must also have a certain range of radial or
heartwood thickness (C—C). Some buyers set this
measurement as ranging from 5 to 8 inches.
There appears to be some variation in regional
practice in measuring by the bolt—foot as to wheth-
er the measurement is made from outer corner
of sapwood to opposite outer corner of sapwood
(B-B),_ or from outer corner of heartwood to the
opposite outer corner of heartwood (A—A).
Stave bolts are graded as suitable for bourbon or
oil staves. Bourbon—grade bolts must have clear,
straight—grained heartwood. No defects such as
worm holes, dote, or shake are allowed unless
the location of the defect is such that it would be
removed in the end—trimming, edging, orjoint—
ing of the staves. Oil—grade bolts allow a few
small defects, suchas one or·two tight pin knots,
a slight waviness of the grain, and more sapwood.
A minimum heartwood thickness of 4 to 5 inches
is usually allowable in this grade.
Heading bolts follow the same pattern in grades
and sizes except that the bolt length is 24 inches.
Trees larger than Z4 inches in diameter should
be worked up into such bolts. Many stave com-
panies do not advocate cutting trees less than 12
inches in diameter for either stave or heading
bolts.
· A variation from using the bolt—foot measure as
previously described is found in the practice of
estimating the board foot contents of the portion
of the tree suitable for stave bolts. In this case
athousandboard—foot log or tree scale is assum-
ed the equivalent of 100 bolt feet, ora quantity of
staves that would make l0 barrels.
5

 Another variation sometimes found is the custom
of piling stave bolts in a rick 4 feet high and8
feetlong, face measure. A rick of this size (stave
bolts) is estimated the equivalent of 500 board
feet, tree scale, or 50 bolt feet, or 5 barrels.
Heading bolts are usually measured by the rick ~
(Z4" x 4‘ x 8‘).
C. - Lineal Foot
Piling, poles, (and sometimes mine props in tree
lengths) are sold locally by lineal measure. As
in piece products, there are usually specifications
as to species, diameter limits, and permissable
defects.
D. - Weight _
Some companies buy mine props at so much per
ton, green weight. Here again, the unit of meas-
urement is correlated with specifications as to ‘
species, diameter limits, and permissable defects.
4I /
L "
l—-————·- a
.  
Fig. 2 - Siondord Cord
6

 E. - Cord Measure

This unit is useful in determining the measure of
a stack or pile of wood, particularly when the
value of the individual piece is not large enough
to justify measurement of it. By custom, when
this form of measurement is used, all sticks in
the pile are cut to approximately the same length,
and a face measurement of 4 feet in height and 8
feet in length of the pile is a cord.

The standard cord is set as a unit equivalent to a
pile of wood 4 feet in height, 8 feet in length and
4feetin depth, havinga displacement of 128 cubic
feet (Fig. 2).

- Fire wood is usually cut in 16 or 18 inch lengths
and is sold in pile units of 4 feet in heightand 8
feet in length. This so—called firewood cord is

' actually only a third of a standard cord.
Pulpwood and acid wood (chestnut) sticks are cut
5 feet and 5 1/2 feet respectively in length, and
the ”cord" has the same face measurement, 4 x
8 feet. Displacement of the pulpwood cord is
therefore 4 x 8 x 5 feet or 160 cubic feet,and the
acid wood cord is 4 x 8 x 5 1/2 feet or 176 cubic
feet.

The actual solid wood content of any pile of wood

is dependent on care in piling and surface irreg-

ularities of the individual sticks. The solid cubic
' contents of a standard cord vary from 60 cubic

feet for limb wood, tops, and small diameter

material to 100 cubic feet for large, smooth,

straight, and regular logs and bolts.

F. — Board Foot
The board foot is the most commonly used unit
7

 of measure for standing trees, logs and lumber.
It is a unit 1 inch thick, 12 inches wide and l
foot in length. For purposes of determining the
number of board feet in any rectangular pi ece
of wood the formula is:
, Board feet = The quantity thickness in inche s
times width in inches, divided by
l2, times the length in feet.
1" x 8" - l6‘ would therefore be figured:
Bd.ft.:1x8xl6:2x16:1()2_/3
12 3
In general, rough lumber less than l inch thick
is figured as an inch. Rough lumber more than
l inch thickis figured to the nearest full quarter
inch. Thus a board 1 3/8 inches thick wouldbe ‘
figured as 5/4 inch. Widths are usually taken
Table 1. · Board Foot Contents of Lurnber .
Thickness Board length ln feet
¤¤=¤ wldih mI1!HdK 14 1111 Z9
Inches Board loot content
1x2 11/3 12/3 2 21/3 22/3 3 31/3
1x3 2 21/2 3 31/2 4 41/2 5
1144 22/3 31/2 4 42/3 51/3 6 62/3
1x5 31/3 41/6 5 55/6 52/3 71/2 81/3
lx 6 4 5 6 7 8 9 10
1x7 42/3 55/6 7 81/6 91/3 101/2 112/3
1xs 51/3 62/3 0 91/3 10 2/3 12 131/3 ‘
1x10 62/3 81/3 10 112/3 131/3 15 162/3
lx 12 8 10 12 14 16 18 20
11/4x4 31/3 41/6 5 55/6 62/3 71/2 81/3
11/4 x6 5 61/4 71/2 83/4 10 111/4 121/Z
1 1/4xB 62/3 81/3 10 112/3 131/3 15 162/3
1 1/2 x4 4 5 6 7 8 9 10
1 1/2x6 6 71/Z 9 101/Z 12 131/2. 15
1 1/2x8 8 10 12 14 16 18 20
2x4 31/3 62/3 8 91/3 10 2/3 12 131/3
2 x 6 8 10 12 14 16 18 20 1
zxa 10 2/3 ll 1/3 16 18 2/3 211/3 24 Z6 2/3
2xlO 131/3 162/3 20 231/3_ 262/3 30 331/3
2 x 12 16 20 24 28 32 36 40
2 1/2 x 12 20 25 30 35 40 45 50
3 x 6 12 15 18 21 24 27 30
3 x 8 16 20 24 28 32 36 40
3 x 10 20 25 30 35 40 45 50
3 x 12 24 30 36 42 48 54 60
4x4 10 2/3 131/3 16 182/3 21 1/3 24 262/3
6x6 Z4 30 36 42 48 54 60
8

 to the nearest {ull inch. Some slight variations
in thickness and widths by size classes are al-
lowed in grading butare beyond the scope of this
discussion. Likewise, the finished sizes in thick-
ness and width are not covered. The board foot
content in various common sizes of lumber is
given in Table 1. For sizes not listed, use com-
binations of given sizes. Thus a 4x6 inchpiece
is the same as two 2x6's.
The volume of a log in terms of board feet is de-
termined by a log rule. A log rule is merely a
tabulation of the board foot volume in logs of var-
Table 2. — International Log Rule. 1/4" Saw Keri.
Log diameter Lo  len ths in feet
. at small me mj 12 14 16
inches Volume in board feet
8 15 20 25 35 40
9 20 30 35 45 50
_ 10 30 35 45 55 65
11 35 45 55 70 80
12 45 55 70 85 95
13 55 70 85 100 115
14 65 80 100 115 135
15 75 95 115 135 160
16 85 110 130 155 180
17 95 125 150 180 205
18 110 140 170 200 230
19 125 155 190 225 260
20 135 175 210 250 290
21 155 195 235 280 320
22 170 215 260 305 355
23 185 235 285 335 390
24 205 255 310 370 425
25 220 280 340 400 460
26 240 305 370 435 500
27 260 330 400 470 540
28 280 355 430 510 585
I 29 305 385 465 545 630
30 325 410 495 585 675
32 375 470 570 670 770
34 425 535 645 760 875
36 475 600 725 855 980
38 535 670 810 955 1095
40 595 750 900 1060 1220
(Values rounded off to the nearest 5)
9

 ious diameters and lengths (Table Z). The log rule
seeks to give the volume of sawed lurnber that
could be cut from a. log after allowing for milling
losses in sawdust and slabs and edgings. Log
rules have been based on use of a mathematical
formula, diagrams, and by a c tual mill tallies.
Since different people have different ideas on how
the slab and edging and sawdust deduction should p
be handled, there have been many differentlog
rules constructed and used in various sections of
the country. The International log rule, based on
a l/4—inch saw kerf is considered as the one that
gives values consistently close st to the actual saw-
ed contents of the sound, straight logs of all sizes.
The values given in Table 2 are based on one-inch
lumber.
For a "rule of thumb, " the formula (D-l)2‘ x L _
26
will give fairly close results with D equaling
the small—end diameter of the log in inches and
L equaling the length of the log in feet. Thus
the board foot volume of a log with a small—end
diameter of 14 inches and a length of 12 feet
would be:
(14~l)2xE = 1321;.6: 169 x .6 Z 101.4 bd. ft.
2.0 ‘
When measuring the small—end diameter of a
log, the average diameter inside bark Should be
taken to the nearest full inch. Length is meas-
ured in feet and is to the nearest full foot plus
about 4 inches for trixnming allowance. Thus a
12—foot log length must measure at least 12. feet,
4 inches, and so forth for other lengths.
Defects
Any condition that will cause a reduction in the
quantity of lumber that might otherwise be cut
10

 out of a log is considered a defect. Thus rot,
cracks, or splits, crook or sweep, and similar
conditions which cause an actual reduction in the
scaled contents of a tree or log, are defects.
Conditions that cause a lowering of g1‘3·d€ OHIY.
such as stain, are not considered defects in log-
1 scaling practice.
To warrant a deduction, the defect must pen-
etrate into the central cylinder as determined
' by the small—end diameter (inside bark) less
one inch, extended the length of the log. Thus a
surface defect at the butt or large end of the log
must be deep enough to penetrate into the central
cylinder, and only the depth of penetration into
_ the cylinder is considered as the depth of the
defect. Defects can be classified as (1) end and
surface, (2.) center, (3) crook and sweep, (4)
uniform surface, (5) cracks and splits, and( 6)
shake.
The method most commonly used, and describ-
ed in textbooks treating with timber measure-
ments, boxes in the defective area and deter-
_ mines its volume in board feet by use of the
formula:
Deduction = DxWxL
15
In this formula, D equals the depth or thickness
in inches, W equals the width in inches, and 1..
equals the length in feet of the defect.
Examples of the various kinds of defects togeth-
er with sample calculations are shown in the
following cases:
Case 1. - Butt rotinalog 18inches in diameter
and 16 feet long.
ll

 T _ T ‘
IB"  ,··
-- 4
J. —>1s"l+
H.- 4* 1-4
}•—;?·—*‘ 1s`  
Case I
The dimensions of the defect as shown are 5
inches in thicknessbyc) inches in width by 4 feet
in length. In all cases involving a rotten area,
1 inchis added to the thickness and width meas-
urement to make sure the defective area is en-
closed. Use of the formula would then give:
Deduction = ·
(5+1)x(9+1)x4:6xl0x4=,16bd, ft. _
_"“‘E‘ ‘ 15
With a gross scale of 230 board feet asfound in “ ,
Table 2, the net scale of the log is 230-16 or
214 board feet.
Case 2.. - Surface defect in a log 18 inches in T
diameter at the small end, 23 inches in diame-
ter at the large end and 16 feet in length. I
-•t7" 1* L JL
T — _ _ _ _____ T- _ -`?JY·;?;i1g% ll 81
IB" Canlrcl CyInndar"—"’ ly" T 23
}•—— a' -14
}<—————-—·‘ 1s'  
Case 2
12

 (5+l)+(8+ l) = l__5 : 7. 5" average diameter of
2 2
defect -
Deduction : 7.5 x 7. 5 x 16 = 60 bd. ft.
15 ‘
The net scale of this log wouldbe 230-60 or 170
board feet.
Case 4. — Sweep in a log 18 inches in diameter
and 16 feet in length. (See solution given for
Case 4-a on page 22.)
Case 4' — Crook in a log of the same size as
Case 4. (See Case 4-b, Page 22.)
Case 5. - Rotten sapwood or any condition which
is surface in nature and can be confined to a '
collar of uniform thickness.
l f
I8" “‘H
l i '
R/ 16" ’/’l
Case 5
In the above example, the defective portion of
the log is estimated to be 2 inches thick. The p
log is 18 inches in diameter at the small end.
Procedure inthis case is to reduce the diameter
by twice the average thickness of the defective ‘
sheath and scale as a 14—inch diameter log. The
net scale would thus be 135 board feet.
Case 6. - Crack or Splits.
If the log is straight-grained, the defect can be
14

 enclosed in anarea having thickness, width, and
length, and the standard procedure followed. If,
l however, the log has spiral grain, the defect is
best enclosed in a sector of the log.
Case 6
In the above sketch, a crack spirals along the
_ length of the log, and extends in approximately
to the log center. The sector which encloses
the defect is equivalent to one—fourth of the log
volume, or aZ5-percent deduction from the gross
scale.
T T J‘ ,*'f:‘;:\`. /1  T
na" 9H 7.. l\ZU,'r,' ,` _ 1_`.\ /7 1* nz"
i i T .;;//I     i
k-—————-———-———————- m" ———-—————————————4
Case 7
Case 7. - Shake
» Shake is a term used to identify a condition
where one or more growth rings are loose fmm
adjacent wood. It may extend entirely around
the ring or extend only for a fewinches. Areas
having only a limited amount of shake can be con-
sidered as a. center defect, and standard proce-
15

 dure followed. In some cases, however,where
the shake extends completely around the ring,
and where there is still a sizeable core of wood
in the center of 6 inches or more in diameter as
illustrated in sketch, the procedure is modified
to allow salvage of the sound center.
The above example shows an 18 inch diameter
log of 16 feet in length, with a shake zone_ ex- .
tending completely around the annual rings and
about 1 inch in thickness. The outside dimen-
sions of the shake zone average 9 inches at the
small end of the log, and 12 inches at the butt end.
There is a sound core of 7 inches in diameter
(smallend). Computations wouldbe as follows:
(9+ 1) + (12+ 1) = 23 :.11. 5 average diameter
2 T
of shake
Deduction :11. 5 x 11.5 x 16 = 2116 = 141
15 15
bd. ft. , if the entire center were shaky. ln this
case, however, there is a 7 inch sound core which
is equivalent to a 7 inch log, 16 feet long. The
scale of such a log, using the rule of thumb,
(D-l)Z L , is 62 x 16, or 29 board feet. Thus,
E6 Eli
the deduction for the case in question would be
141-29 or 112 board feet. The net scale would
then be 230-112 or 118 board feet. Except for
the log of a valuable species, a deduction such
as this ofapproximately 50—percentwould cause
the log to be a cull.
An alternate method of computing deduction for
defects has been recently outlined by L. R. Gros- '
enbaugh of the U.S. Forest Service (Southern
Forest Experiment Station Occasional Paper
16

 #126, pp. 14-15) in which a percent deduction
from the gross scale is computed. In general,
the deductions by this method are less than those
in similar cases as computed by the formula
D x W x L. Since this formula admittedly im-
15
poses a heavy penalty for defective portions, the
alternate method should have merit in localities
where a high standard of utilization of the log
· contents is possible.
Procedure for calculating deduction for end or
surface defects is given as follows:
1. Enclose the defect cross-section in an ellipse.
Z. Measure the short and long dimension of the
ellipse. Add l inch to each.
3. Determine the ratio of each increased dimen-
_ sion to the log diameter less 1 inch. Round
off to the nearest tenth. (Table 3 p. 18.)
4. Estimate the length of the defect and deter-
mine the ratio of defect length to theloglength.
Round off to the nearest tenth. (Table 3).
5. Multiply the three ratios together. The re-
sult is the proportion to be deducted from
the gross scale for the defect.
Examples of the various kinds of defects to-
T
" · T
IB ®9»
—` T
JL ·1s"I»
, R; o' me
l* m ns'  
Case Ic
17

 Table 3. — Ratio 0[ Defect Dirnension to Log Dixnension
 
Defect Dimension
Log
Dimension 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
2 -E -2 E-----------
2 HE -2 I-----------
22 --2 -2 -2 EIIII------
22 - -2 -2 lElIII------ `
22 -2 -2   I--------
22 --2 -2 -2 IIIII------
22 -- -2 -2 EIEE------- -
22  -2 -2 -2 -2 IEE-------
22 -2  -2   -2 IEE------
22 -I -2  -2 IIEE------
22  -2 -2 -2 -2  -2 EE-----
22  -2  -2 -2  -2 IEE----
22      IEEE---- 1
22 -I-  -2 -2 -2  -2 H----
22 -I-I  -2 -2  -2 -2 E----
22 -I-   -2 -2 -2 I------
22 -I-  -2   -2 I-- -2 E--
22 -I-I   -2 -2  -2 EEE-
22   -2 -2 -2 -2 -2 I-----
22  -2 -2 -2 -2 -2 -2 -2 I----- 1
22  -2  -2 -2  -2 -2 I-----
_ 30   .2 .2 .2 .3 .3 .3 .4   ,5 .5
18

 gether with sample computations are shown
in the following;
Case 1-a. — Butt rot ina log 18 inches in diameter
and 16 feet long.
As Step 1, the cross section ofthe defect can be
enclosed in an ellipse. Following through with
Step 2, the short and long dimensions are 5
. inches and 9 inches respectively; adding 1 inch
to each, and dividing by the log diameter — 1
(Step 3) we get:
5 + 1 = 6 = .3
18-1 17
9 + l I 10 : . 6
_ 18-1 T7
In Step 4, we note that the length of the defect
is 4 inches. This expressed as a ratio of the
length is 4 or .25.
16
Step 5 consists of multiplying the three ratios
together  3 x . 6 x . 25), giving .045, which to
the nearest unit percent is 5,
This is the proportionate deduction for the defect
from the gross scale of the log, or .05 x 230 =
11. 5 or 12 bd. ft. The net scale thus is 230-12
or 218 bd. ft.
Case 2-a. —Surface defect in a log 18 inches in
diameter at the small end, 23 inches in diame-
ter at the large end, and 16 feet in length.
Again the defect cross—section and length can be
estimated. Tn this case the defect is at the butt
of the log and all of the defective area is deduc-
table except that occurring in the peripheral
ha1f—inchwhichis the s1ab—collar. Depth of the
19

 h-1"·»1 A
—  1]
r O 1
18"
}_ ua" mn
collar
»<——-·-s'-——·•
|<—41*‘"*” na` -j————j""l _
Cuse 2u
defect as illustrated in the sketch is 8 inches,
width is 7 inches, and the length is 3 feet.
Computations would then be:
(7-1/2+ 1) - .5; 7 +1 = .5; and_3_= .2
17 17 16
Proportionate deduction for the defect would
thenbe.5x.5x .2or.O5. Five percent of 320 4
is 16 board feet. The net scale of the log would
then be 320-16 or 304 board feet.
Case 3-a. - Center or heart rot inalog 18inches
in diameter and 16 feet in length.
Tg ,;\____....-.-------··" ‘  T
.. .·   ; 8**
I-E.? "/·"····-—-————--.-..-.... k
  IG"  
Case 30 1
Procedure in this case is slightly different, lzut
involves the same principles as in cases 1-a and
2-a. The rot in this case is almost circular in
20

 l

1 cross section. Long and short dimensions are
thus the same. The deduction percentage is com—
puted for each half length of the log to compen-
sate for change in dimension of the defect. For

- the butt half of the log, the cross section di-

‘ mensions of the defect are 8 inches and 8 inches.
These, in terms of a percentage of the small—
end diameter less one inch, are 9 and 9 or .5

17 T7
and .5. The length of 8 feet is 50-percent of
the log length, or .5.
Deduction for defect in the butt half of the log is
thus . 5 x . 5 x . 5 or l3-percent. Procedurefor
the other half of the log is the same except that
the defect cross section is 5 inches. Computa—

’ tions for this half of the log (.4 x . 4 x .5) give

. " 8-percent as the deduction. Adding the two de—
ductions gives 21—percent as the total deduction
from the gross scale; .21 x230348. 3 bd. ft.
The gross scale would then be 230—48, or 182

, board feet.

A short cut in the computations involved would
be to (1) square the defect cross sectionpercent-
ages for large and small ends of the log, (2)

a add results, and (3) divid Say 2. Thus (1) .5 x

1 ‘ .5:.25and.4x,.4:.16&.ZSand.16 add-
ed together equals .41 (3) .41 = .21 or Zl-per-

—Z'

3 cent. In effect, this is following the same pro-
cedure as given in the more detailed computa-
tion.

~ ; Case 4-a. — Sweep in a log 18 inches in diam-

, eter and 16 feet in length.

. When the sweep occurs in one plane, the actual

' deviation of the log center from a line connect-

21

 *~
  ns' ..————j——*{
T l//Log Comer
,8·· _ _; _ sus") {
I
Lma Between End Camus
Case 4u
ing the center point at each end is considered the
measurement ofthe sweep(s). Deduction per-
centage for sweep is obtained by use of the for- .
I mula:
Proportion deducted ; s - 2
Scaling diameter of log  
In case ofa sweep of 6 inches in the log diagramed \
above, the deduction percentage would be com- _
puted as 6-2 orior 22—percent. In terms of
18 18
board feetthis would be .22 x 230 or 51, and the I
net scale 230-51 or 179 bd. ft. .
IB"
1
- .. .... J.
k-- ¤' ———->|
y—»——m; IS`  I A
4b ·
•
Case 4-b. - Crook in a log l8 inches in diame— .
ter and l6 feet in length.
22

 * Crook is a sharp bend in a log as differentiated
from the rather uniform curvature of sweep a-
long the log length. Measurements of the mag-
nitude of the crook are taken as indicated inthe
J above sketch. The deduction is then computed
by the rule:
Proportion deducted =
sideways measurement of crook x
* scaling diameter of log
` Length of log effected
  log length
Computation of deduction in Case 4-b would be
. I Proportion deducted =(9 )x( 4) I 1/2 x 1/4 =
y 18 16
` 1/8 or 12-l/2 percent.
l2. 5-percent of 230 is 29 bd. ft. The net scale
for this case is then 230-29 or 201 bd. ft.
` Case 5-a. - Shake
Shake is a term used to identifya condition where
one or more growth rings are loose from adja-
a cent wood. It may extend entirely around the
l ring or extend only for a few inches. Areas
having only a limited amount of shake canbe con-
’ sidered as a center defect and standard proce-
dure followed. In some cases, however, where
t the shake extends completely around the ring
and where there is still a sizeable core ofwood
inthe center of 6 inches or more in diameter as
I illustrated in sketch, the procedure is modified
to allow salvage of the sound center.
23

 T T 1 T A
ns" 9" 7" nz"
l i T 1 .
  1G' —-——-m·"l
5c
The above example shows an 18 inch diameter
log 16 feet in length, with a shake zone extend- `
ing completely around the annual rings and about
1 inch in thickness. The outside dimensions of j
the shake-zone average 9 inches at the small end  
of the log and 12 inches at the butt end. There
is a sound core of 7 inches in diameter ( small 1
end).
Computations would be as follows:  
L0:.6 .6x.6:.36 I
17
Ef.8 .8x.8:.64
17 A
. 36 + . 64 : . 50 or 50—percent initial deduction
2
If the gross scale of the log is 230 bd. ft., the  
initial deduction would be . 50 x 230, or 115bd.
ft. This however is less the scale of the sound
core. A 7 inch by 16 foot log will scale out ap- ‘
proximately 29 board feet. Thus, 115 board feet ,
less 29 board feet is 86 board feet, whichis the
deduction for this defect.
I1. - MEASUREMENT OF LOG OR TREE DIMEN-
SIONS AND EQUIPMENT USED.
A. - Logs. - Measurements are taken of the average I
24

 small—end diameter (inside bark) and of the
length. A common yardstick or any scale grad—
. uated in inches can be used. When measuring
the diameter, care should be exercised that the
average measurement is obtained, since many

' logs are not exactly round. Length is measured
in feet to the nearest full foot plus about 4 inches
for trimming allowance. With a diameter and a
length measurement, the volume of the log in

. board feet can be obtained by consulting a log

. rule. (Table 2, p. 8.)

1 B. Standing Trees — Diameter Measurements.

l , , .
Measurement 15 customarily made of tree diam-
eter ( outside bark) at D. B. H. (Diameter at

. Breast Height). This point is standardized at
4-1/2 feet above ground level.
Perhaps the simplest and most consistently ac—
curate method of measuring the diameter of a
standing tree is to measure the circumference
by stretching a tape measure around the tree,

l and then divide the reading by 3. To be strictly
accurate, the reading should be divided by
3. 1416, however, the approximate diameter ob—
tained by dividing by 3 is within the standards of
accuracy usually required.

I

7 Calipers and the Biltmore scale can also be used
if available. The principle of the Biltmore scale
is shown as follows:

The lines AB' and AE represent diverging lines
of sight when a person looks at the side of a
tree. B'C; or D is a radius of the circle (tree
7
diameter). CD is the proportionate measure—
ment that would be included on a stick held hor-
25

  W
‘ *`
D 
a
Bmmore Scale
izgntally against the tree. AB or a would rep-
resent the distance the stick was held from the  
eye. Angles ABC and AB'C' are right angles ‘
and thus triangles ABC and AB'C' are similar.
From this relationship, an initial proportion
can be set up —
CB Z C'B'
AB AB' _
Simplifying this proportion in terms of aand D ,
(reach and diameter) we can derive the follow —
ing formula: i
S =I 8. D
a D V
In the above formula, aequals the reach, which
for the average persoiiwill be Z5 inches, and D
represents a particular diameter. Eis then the
scale measurement (line CD) for the particular
diameter used. V
For example, the graduation, (2) for a lOinch
diameter and a25 inch reach (a) would be com-
puted as follows:
s =25x10 -2500 :I7l.46+: 8.74+"
25 + 10 35
26

 Graduations for other diameters can be compu-
ted in a similar fashion. In case of a longer or
shorter reach than the standard 25 inches, the
value of a in the formula can be changed towhat-
ever is c—onsidered a normal reach. A table of
graduations for a 25 inch reach is given on fol-
lowing page:
To make a Biltmore stick, take a piece of lath,
‘ lattice, or a yard stick and plane or sand one
face clean and smooth. Next measure the indi—
cated scale for the smallest diameter reading
(for example 8 inches) from the left end of the

, stick, and mark it on the face of the stick in a
suitable manner. This then is the 8 inch grad—
uation of the Biltmore scale. Repeat for other

‘ diameters.

' To use the stick, hold ithorizontally against the
tree at D. B. H. ; line up the left upper corner of
the stick with your line of sight, cutting the left
side of the tree trunk. Then without moving the
head. swivel your line of sight to the right side
of the tree trunk and read tree-diameter on the
Biltmore scale. Remember that the scale was
graduated on the basis ofa specified reach. Ac-
curacy in use of the scale depends on how closely

: the correct reach (a) is maintained. Also, be

, sure that an average of the largest reading and
the smallest reading is obtained, since many
trees are oval in cross section.

C. Standing Trees - Heights.
Measurement of the height of the point on the
tree trunk where the last out will normally be
made requires some training; however, the
procedure and equipment can be relatively 8 im-
‘ ple. The length of the useable section of the
2.7

 Table 4. - Biltrnore Scale Graduations
(2.5 inch reach.)
 
Diameter Scale graduation to the
nearestlof an inch
10
 
inches
8 ...................... . ']_ O
10 ...................... . 8_ 5 -
12 ....................... g_ 3 l
14 ....................... ]_]_ Z _
16 ....................... 1g_ 5 4
18 ....................... ]3_ 7
Z0 ....... , ................ 14_ 9
22 ....................... ]_6_ 1
Z4 ....................... ]’]_1
26 ....................... ]_8_ Z `
Z8 ....................... ]_9_ 2 .
30 .............. . ........ Z()_ Z
32 ........... . ........... ZL 2
34 ....................... ZZU1
36 ....................... g3_ O
Z8

 tree trunk is influenced by (1) the taper of the
tree trunk, and (2) the breaking up of the cen-
tral trunk into large branches. In the latter
case, the top limit of useable trunk length is
just below the fork, and is easy to determine.
However, in the first case, a point on the tree
trunk must be chosen where the tninimum use-
able diameter (usually 8—inches inside bark) is
estimated to occur. If bark is estimated to be
about one —half inch thick at the 8-inch diame-
ter point, the outside dimension would thus be
9—inches. Determining the point on the tree
trunk at which it would measure 9—inches out-
T side the bark is at best an approximation. If
_ the DBH is known, it can be used as a com-
parative measure.
q Some estimators use the formula:
(Circumference in inches at DBH x . 28) —2"
equals diameter inside bark at the top of the
first 16 foot—log. For each 16—foot additional
. length, deduct 2 inches to secure the diameter
inside bark at the top end of the log in ques-
tion.
Thus a 20-inch DBH tree would give the follow-
. . ing:
(63" x .28) -2 = 17.6 -2 : 15.6" diameter
inside bark at the top of the first 16—foot log
length. At 32 feet the diameter (i.b.) would
be 13. 6 inches, and at 48 feet, ll. 6 inches.
The above example assumes that the tree
trunk tapers gradually and extends up at least
48 feet before any large branches occur. For
thick-barked trees, use the factor .27 in-
stead of .28.
29

 Having estimated the point on the tree trunk that '
is the limit of useable trunk length for logs, (
there remains the problem of determining how
high that point is above stump height. Stump
height can usually be standardized at about 1
foot above ground for this purpose.
There are many methods of measu