FOR9
A LANDOWNER'S GUIDE: MEASURING FARM TIMBER
ISSUED: 776
REVISED: 986
D.H. Graves
The volume of timber products in the
farm woodland is often an unknown quantity, yet it is of great importance
for inventory, management plans, investment evaluation and timber sales.
Units of Measure
All products are measured by some unit.
Farm woodland products have many common units of measure, described in
the following paragraphs. A thorough understanding of the unit used in
the sale of any product is extremely important. Such understanding may
help bring a greater financial return and should minimize the chances of
misunderstanding a sale agreement's terms.
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 specifications
for Southern Pine Poles are shown in Appendix A. Specifications for other
piece products may be more or less detailed; however, in general the same
factors are involved.
Tight Cooperage Units
Some variation of methods may be found
in measurement of the tree or bolts which are considered 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 are commonly accepted.
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 inches in length.
Measurement is taken from outer corner of sapwood to the opposite outer
corner of sapwood (B to B). Thus a bolt measuring 12 inches across from
outer corner to the opposite outer corner of sapwood would contain 1 boltfoot.
Smaller bolts would contain proportionately less and larger ones more.
Sample specifications for stave and heading bolts are given in Appendix
B. In general, stave bolts measuring 12 inches across the outside are preferred
with a range of from 6 inches to 16 inches accepted. Bolts must also have
a certain range of radial or heartwood thickness (C to C). Some buyers
set this measurement as ranging from 5 to 8 inches.
Regional practice in measuring by the
boltfoot varies as to whether the measurement is made from outer corner
to sapwood to opposite corner or sapwood (B to B), or from outer corner
of heartwood to the opposite outer corner of heartwood (A to A).
Stave bolts are graded as suitable
for bourbon or oil staves. Bourbongrade bolts must have clear, straightgrained
heartwood. No defects such as worm holes, dote or shake are allowed unless
the defect location is such that it would be removed in the endtrimming,
edging or jointing of the staves. Oilgrade bolts allow a few small defects,
such as 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 24 inches in diameter should be worked up into such bolts. Many stave
companies do not advocate 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 a thousand board foot log or tree scale is assumed to be the
equivalent of 100 boltfeet, or a quantity of staves that would make 10
barrels.
Another variation sometimes found is
the custom of piling stave bolts in a rick 4 ft high and 8 ft long, face
measure. A rick of this size (stave bolts) is estimated the equivalent
of 500 bd ft, tree scale, or 50 bolt feet, or 5 barrels.
Heading bolts are usually measured
by the rick (24" x 4' x 8').
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 permissible
defects.
Weight
Some companies buy mine props, pulpwood
or pallet logs at so much per ton, green weight. Here again, the unit of
measurement is correlated with specifications as to species, diameter limits
and permissible defects.
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 ft
high and 8 ft long is a cord.
The standard cord is set as a unit
equivalent to a pile of wood 4 ft high, 8 ft long and 4 ft deep, having
a displacement of 126 cu ft (Fig. 2).
Fire wood is usually cut in 16 or 18
inch lengths and is sold in pile units of 4 ft high and 8 ft long. This
socalled firewood cord is actually only a third of a standard cord.
Pulpwood and acid wood (chestnut) sticks
are cut 5 ft and 5 1/2 ft long respectively, and the "cord" has the same
face measurement, 4 x 8 ft. Displacement of the pulpwood cord is therefore
4 x 8 x 5 ft or 160 cu ft and the acid wood cord is 4 x 8 x 51/2 ft or
176 cu ft.
The actual solid wood content of any
pile of wood is dependent on care in piling and on surface irregularities
of the individual sticks. The solid cube contents of a standard cord vary
from 60 cu ft for limb wood, tops and small diameter material to 100 cu
ft for large, smooth, straight and regular logs and bolts.
Board Foot
The board foot is the most commonly
used unit of measure for standing trees, logs and lumber. It is a unit
1 inch thick, 12 inches wide and 1 ft long. To determine the number of
board feet in any rectangular piece of wood the formula is:
Board feet = The quantity thickness in inches times width in inches,
divided by 12, times the length in feet.
1" x 8" x 16' would therefore be computed:
Bd ft = 
(1 x 8)
12

x 16 = 
2
3

x 16 = 10 2/3 
In general, rough lumber less than 1
inch thick is computed as an inch. Rough lumber more than 1 inch thick
is computed to the nearest full quarter inch. Thus a board 1 3/8 inches
thick would be computed at 6/4 inch. Widths are usually taken to the nearest
full inch. Some slight variations in thickness and widths by size classes
are allowed in grading but are beyond the scope of this discussion. Likewise,
the finished sizes in thickness 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 combinations of given sizes. Thus a 4 x 6 inch piece is
the same as two 2 x 6's.
The volume of a log in terms of board
feet is determined by a log rule. A log rule is merely a tabulation of
the board foot volume in logs of various diameters and lengths (Table 2).
The log rule seeks to give the volume of sawed lumber that could be cut
from a log after allowing for milling losses in sawdust and slabs and edgings.
Log rules have been based on a mathematical
formula, diagrams and actual mill tallies. Since different people have
different ideas on how the slab and edging and sawdust deduction should
be handled, many different log rules have been constructed and used in
various sections of the country. The International log rule, based on a
1/4 inch saw kerf, is considered to give values consistently closest to
the actual sawed content of sound, straight logs of all sizes. The values
given in Table 2 are based on oneinch lumber.
For a "rule of thumb," the formula
(D1)(D1) x (L/20) will give fairly close results with D equaling the
smallend 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 smallend diameter
of 14 inches and a length of 12 ft would be:
(14  1)(14  1) x 
12
20

= (13)(13) x .6 = 169 x .6 = 101.4 bd ft 
When measuring the smallend diameter
of a log, take the average diameter inside bark to the nearest full inch.
Length is measured in feet and is to the nearest full foot plus about 4
inches for trimming allowance. Thus a 12ft log length must measure at
least 12 ft, 4 inches.
Table 1 .Board Foot Contents of Lumber
Thickness
and width
(inches) 
Board length in feet

8 
10 
12 
14 
16 
18 
20 
Board foot content

1 x 2 
1 1/3 
1 2/3 
2 
2 1/3 
2 2/3 
3 
3 1/3 
1 x 3 
2 
2 1/2 
3 
3 1/2 
4 
4 1/2 
5 
1 x 4 
2 2/3 
3 1/2 
4 
4 2/3 
5 1/3 
6 
6 2/3 
1 x 5 
3 1/3 
4 1/6 
5 
5 5/6 
5 2/3 
7 1/2 
8 1/3 
1 x 6 
4 
5 
6 
7 
8 
9 
10 
1 x 7 
4 2/3 
5 5/6 
7 
8 1/6 
9 1/3 
10 1/2 
11 2/3 
1 x 8 
5 1/3 
6 2/3 
8 
9 1/3 
10 2/3 
12 
13 1/3 
1 x 10 
6 2/3 
8 1/3 
10 
11 2/3 
13 1/3 
15 
16 2/3 
1 x 12 
8 
10 
12 
14 
16 
18 
20 
1 1/4 x 4 
3 1/3 
4 1/6 
5 
5 5/6 
6 2/3 
7 1/2 
8 1/3 
1 1/4 x 6 
5 
6 1/4 
71/2 
8 3/4 
10 
11 1/4 
12 1/2 
1 1/4 x 8 
6 2/3 
8 1/3 
10 
11 2/3 
13 1/3 
15 
16 2/3 
1 1/2 x 4 
4 
5 
6 
7 
8 
9 
10 
1 1/2 x 6 
6 
7 1/2 
9 
10 1/2 
12 
13 1/2 
15 
1 1/2 x 8 
8 
10 
12 
14 
16 
18 
20 
2 x 4 
5 1/3 
6 2/3 
8 
9 1/3 
10 2/3 
12 
13 1/3 
2 x 6 
8 
10 
12 
14 
16 
18 
20 
2 x 8 
10 2/3 
11 1/3 
16 
18 2/3 
21 1/3 
24 
26 2/3 
2 x 10 
13 1/3 
16 2/3 
20 
23 1/3 
26 2/3 
30 
33 1/3 
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 
4 x 4 
10 2/3 
13 1/3 
16 
18 2/3 
21 1/3 
24 
26 2/3 
6 x 6 
24 
30 
36 
42 
48 
54 
60 
Table 2.International Log Rules. 1/4" Saw Kerf.
Log diameter
at small end
(inches) 
Log lengths in feet

8 
10 
12 
14 
16 
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 
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 
Defects
Any condition that will cause a reduction
in the quantity of lumber that might otherwise be cut 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 grade only, such as stain,
are not considered defects in logscaling practice.
To warrant a deduction, the defect
must penetrate into the central cylinder as determined by the smallend
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
•end and surface
•center
•crook and sweep
•uniform surface
•cracks and splits
•shake
The method most commonly used, and described
in textbooks treating with timber measurements, boxes in the defective
area and determines its volume in board feet by use of the formula:
Deduction = (D x W x L)/15
In this formula, D equals the depth or thickness in inches, W equals
the width in inches, and L equals the length in feet of the defect.
An alternate method of computing deduction
for defects has been outlined by L.R. Grosenbaugh of the U.S. Forest Service
(Southern Forest Experiment Station Occasional Paper #126, pp. 1415) 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 computed
by the formula D x W x L divided by 15. Since this formula admittedly imposes
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 crosssection
in an ellipse.
2. Measure the short and long
dimension of the ellipse. Add 1 inch to each.
3.Determine the ratio of each increased
dimension to the log diameter less 1 inch. Round off to the nearest tenth
(Table 3).
4.Estimate the length of the defect
and determine the ratio of defect length to the log length. Round off to
the nearest tenth (Table 3).
5.Multiply the three ratios together.
The result is the proportion to be deducted from the gross scale for the
defect.
Table 3.Ratio of Defect Dimension to Log Dimension
Log
Dimension 
Defect Dimension

1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
13 
14 
15 
16 
8 
.1 
.25 
.4 
.5 
9 
.1 
.2 
.3 
.4 
.6 
10 
1 
.2 
.3 
.4 
.5 
11 
.1 
.2 
.3 
.4 
.5 
.5 
12 
.1 
.2 
.25 
.3 
.4 
.5 
13 
.1 
.2 
.2 
.3 
.4 
.5 
14 
.1 
.1 
.2 
.3 
.4 
.4 
.5 
.6 
15 
.1 
.1 
.2 
.3 
.3 
.4 
.5 
.6 
16 
.1 
.1 
.2 
.25 
.3 
.4 
.4 
.5 
.6 
17 
.1 
.1 
.2 
.3 
.3 
.4 
.4 
.5 
.5 
18 
.1 
.1 
.2 
.2 
.3 
.3 
.4 
.4 
.5 
.6 
19 
.1 
.2 
.2 
.3 
.3 
.4 
.4 
.5 
.5 
.6 
20 
.1 
.15 
.2 
.25 
.3 
.35 
.4 
.45 
.5 
.55 
21 
.1 
.1 
.2 
.2 
.3 
.3 
.4 
.4 
.5 
.5 
.6 
22 
.1 
.1 
.2 
.2 
.3 
.3 
.4 
.4 
.5 
.5 
.5 
23 
.1 
.1 
.2 
.2 
.3 
.3 
.3 
.4 
.4 
.5 
.5 
.6 
24 
.1 
.1 
.2 
.2 
.25 
.3 
.3 
.4 
.4 
.5 
.5 
.5 
25 
.1 
.1 
.2 
.2 
.2 
.3 
.3 
.4 
.4 
.4 
.5 
.5 
.6 
26 
.1 
.1 
.2 
.2 
.2 
.3 
.3 
.3 
.4 
.4 
.5 
.5 
.5 
27 
.1 
.1 
.1 
.2 
.2 
.3 
.3 
.3 
.4 
.4 
.4 
.5 
.5 
.6 
28 
.1 
.1 
.1 
.2 
.2 
.25 
.3 
.3 
.4 
.4 
.4 
.5 
.5 
.5 
29 
.1 
.1 
.1 
.2 
.2 
.2 
.3 
.3 
.3 
.4 
.4 
.4 
.5 
.5 
.6 
30 
.1 
.1 
.1 
.2 
.2 
.2 
.3 
.3 
.3 
.4 
.4 
.4 
.5 
.5 
.5 
Examples of the various kinds of defects
together with sample calculations are shown in the following cases.
Case l.Butt rot in a log 18 inches in diameter
and 16 ft long.
Formula Method
The dimension of the defect as shown
are 5 inches thick by 9 inches wide by 4 ft long. In all cases involving
a rotten area, 1 inch is added to the thickness and width measurement to
make sure the defective area is enclosed. Use of the formula would then
give:
Deduction =
((5+ l) x (9+ l) x 4)/15 = (6 x 10 x 4)/15 = 16 bd ft
With a gross scale of 230 bd ft as found in Table 2, the net scale of
the log is 230  16 or 214 bd ft.
Grosenbaugh Method
As Step 1, the crosssection of the
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)/(18  1) = 6/17 = .3
(9 + 1)/18  1) = 10/17 = .6
In Step 4, we note that the length of
the defect is 4 ft. This expressed as a ratio of the length is 4/16 or
.25. 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.Surface defect in a log 18 inches in
diameter at the small end, 24 inches in diameter at the large end and 16
ft long.
Formula Method
Again, the defect thickness, width
and length can be determined. In this case, the defect is in the butt end
of the log and only that portion of the defect which is in a central cylinder
of the log's smallend diameter less 1 inch is subject to deduction. The
total depth of the defect as given in the sketch is 8 inches, of which
5 inches lie in the central cylinder. The width is given as 7 inches. Length
is estimated at 3 ft.
Use of the formula would give:
Deduction =
((4+ l) x (7+ l) x 3)/15 = (5 x 8 x 3)/15 = 8 bd ft
With a gross scale of 230 bd ft, the net scale is 230  8 or 222 bd
ft.
Case 2a.Surface defect in a log 18 inches in
diameter at the small end, 23 inches in diameter at the large end and 16
ft long.
Grosenbaugh Method
Again the defect crosssection and
length can be estimated. In this case the defect is at the butt of the
log and all of the defective area is deductible except that occurring in
the peripheral halfinch which is the slab collar. Depth of the defect
as illustrated in Fig. 5 is 8 inches, width is 7 inches and the length
is 3 ft.
Computations would then be:
(7 1/2 + 1)/17 = .5; (7 + 1)/17 = .5; and 3/16 = .2
Proportionate deduction for the defect would then be .5 x .5 x .2 or
.05. Five percent of 230 is 11.5 or 12 ft. The net scale of the log would
then be 230  12 or 218 bd ft.
Case 3.Center or heart rot in a log 18 inches
in diameter and 16 ft long.
Formula Method
With a defect of this type the procedure
involves averaging the defect dimensions of small and large ends of the
log to get an average defect crosssection. Since the defective area showing
at both ends is roughly circular, thickness and width in this case are
the same. Adapted to the basic formula, the computation is given as follows:
((5 + 1) + (8 + 1))/2 = 15/2 = 7.5" average diameter of defect
Deduction = (7.5 x 7.5 x 16)/15 = 60
bd ft 15
The net scale of this log would be 230  60 or 170 bd ft.
Grosenbaugh Method
Procedure in this case is slightly
different, but involves the same principles as in cases 1 and 2a. The rot
in this case is almost circular in crosssection. Long and short dimensions
are thus the same. The deduction percentage is computed for each half length
of the log to compensate for change in dimension of the defect. For the
butt half of the log, the crosssection dimensions of the defect are 8
inches and 8 inches. These, in terms of a percentage of the smallend diameter
less one inch, are 9/17 and 9/17 or .5 and .5. The length of 8 ft is 50%
of the log length, or .5.
Deduction for defect in the butt half
of the log is thus .5 x .5 x .5 or 13%. Procedure for the other half of
the log is the same except that the defect crosssection is 5 inches. Computations
for this half of the log (.4 x .4 x .5) give 8% as the deduction. Adding
the two deductions gives 21% as the total deduction from the gross scale;
.21 x 230 = 48.3 bd ft. The gross scale would then be 230  48, or 182
bd ft.
A short cut in the computations involved
would be:
1. square and defect crosssection
percentages for large and small ends of the log;
2. add results; and
3.divide by 2.
Thus:
1..5 x .5 = .25 and .4 x .4 =.16;
2..25 and .16, added together, equals
.41;
3..41/2 = .21 or 21%.
This short cut follows the same procedure as does the more detailed
computation.
Case 4.Shake.
Shake is a condition where one or more
growth rings are loose from adjacent wood. It may extend entirely around
the ring or only for a few inches. Areas having only a limited amount of
shake can be considered as having a center defect and standard procedure
followed. In some cases, however, where the shake extends completely around
the ring, and where a sizeable core of wood 6 inches or more in diameter
remains in the center as illustrated in sketch, the procedure is modified
to allow salvage of the sound center.
Figure 7 shows an 18 inch diameter
log, 16 ft long with a shake zone extending completely around the annual
rings and about 1 inch thick. The outside dimensions 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 (small end).
Formula Method
Computations would be as follows:
((9 + 1 ) + ( 12 + 1 ))/2 = 23/2 = 11.5 average diameter of shake
Deduction = (11.5 x 11.5 x 16)/15 = 2116/15 = 141 bd ft
if the entire center were shakey. In this case, however, a 7 inch sound
core is equivalent to a 7 inch log, 16 ft long. The scale of such a log,
using the rule of thumb, is
(D  1)(D  1) x L/20, is (6)(6) x 16/20, or 29 bd ft.
Thus, the deduction for Case 4 would be 141  29 or 112 bd ft. The
net scale would then be 230  112 or 118 bd ft. Except for the log of a
valuable species, such a deduction of approximately 50% would cause the
log to be a cull.
Grosenbaugh Method
Computations would be as follows:
10/17 = .6, .6 x .6 = .36
13/17 = .8, .8 x .8 = .64
(.36 + .64)/2 = .50 or 50% initial deduction
If the gross scale of the log is 230 bd ft, the initial deduction would
be .50 x 230, or 115 bd ft. This however is less the scale of the sound
core. A 7 inch by 16 ft log will scale out approximately 29 bd ft. Thus,
115 bd ft less 29 bd ft is 86 bd ft, which is the deduction for this defect.
Case 5.Rotten sapwood or any condition which
is surface in nature and can be confined to a collar or uniform thickness.
In Figure 8 the log's defective portion
is estimated to be 2 inches thick. The log is 18 inches in diameter at
the small end. Procedure in this case is to reduce the diameter by twice
the average thickness of the defective sheath and scale as a 14inch diameter
log. The net scale would thus be 135 bd ft.
Case 6.Crack or Splits.
If the log is straightgrained, the
defect can be enclosed in an area having thickness, width and length, and
the standard procedure followed. If, however, the log has spiral grain,
the defect is best enclosed in a sector of the log.
In Figure 9 a crack spirals along the
log's length and extends in approximately to the log center. The sector
which enclosed the defect is equivalent to 1/4 of the log volume, or a
25% deduction from the gross scale.
Case 7.Sweep in a log 18 inches in diameter
and 16 ft long.
Sweep is a curve in the log. When the
sweep occurs in one place, the actual deviation of the log center from
a line connecting the center point at each end is considered the measurement
of the sweep(s). Deduction percentage for sweep is obtained by use of the
formula:
Proportion deducted = S  2/(Scaling diameter of log)
In case of a sweep of 6 inches in the log diagrammed above, the deduction
percentage would be computed as (6  2)/18 or 4/18 or 22%. In terms of
board feet this would be .22 x 230 or 51, and the net scale 230  51 or
179 bd ft.
Case 8.Crook in a log 18 inches in diameter
and 16 ft long.
Crook is a sharp bend in a log while
sweep has a rather uniform curvature along the log length. Measurements
of the magnitude of the crook are taken as indicated in Figure 11. The
deduction is then computed by the rule:
Proportion deducted =
(sideways measurement of crook)/(scaling diameter of log) x (length
of log affected)/(log length)
Computation of deduction in Case 8 would be:
Proportion deducted = (9)/18 x (4)/16 = .50 x .25 = 12 1/2%
12.5 % of 230 is 29 bd ft. The net scale for this case is then 230
 29 or 201 bd ft.
Measurement of Log or Tree Dimensions and Equipment Used
Logs
Measurements are taken of the average
smallend diameter (inside bark) and of the length. A common yardstick
or any scale graduated in inches can be used. When measuring the diameter,
be careful to get the average measurement, 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).
Standing TreesDiameter Measurements
Measurement is customarily made of
tree diameter (outside bark) at D.B.H. (Diameter at Breast Height). This
point is standardized at 4 1/2 ft above ground level.
Perhaps the simplest and most consistently
accurate method of measuring the diameter of a standing tree is to measure
the circumference by stretching a tape measure around the tree, and then
divide the reading by 3. To be strictly accurate, the reading should be
divided by 3.1416; however, the approximate diameter obtained by dividing
by 3 is within the standards of accuracy usually required.
Calipers and the Biltmore scale can
also be used if available. The principle of the Biltmore scale follows:
(Figure 12)
The lines AB' and AE represent diverging lines of sight when a person
looks at the side of a tree. B'C' or D/2 is a radius of the circle (tree
diameter). CD is the proportionate measurement that would be included on
a stick held horizontally against the tree. AB or a would represent 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/AB = C'B'/AB'
Simplifying this proportion in terms of a and D (reach and diameter)
we can derive the following formula:
S = a(D)(D)/(a + D)
In the above formula, a equals the reach, which for the average person
will be 25 inches, and D represents a particular diameter. S is then the
scale measurement (line CD) for the particular diameter used.
For example, the graduation, (S) for
a 10 inch diameter and a 25 inch reach (a) would be computed as follows:
S = (25 x (10)(10))/(25 + 10) = 2500/35 = 71.43+(square root) = 8.45+"
Graduations for other diameters can
be computed 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
to whatever is considered a normal reach. A table of graduations for a
25 inch reach is given in Table 4.
Table 4.Biltmore Scale Graduations (25 inch reach.)
Diameter 
Scale gradation
to the nearest
1/10 of an inch 

inches 
8 
7.0 
10 
8.5 
12 
9.8 
14 
11.2 
16 
12.5 
18 
13.7 
20 
14.9 
22 
16.1 
24 
17.1 
26 
18.2 
28 
19.2 
30 
20.2 
32 
21.2 
34 
22.1 
36 
23.0 
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 indicated 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 graduation of
the Biltmore scale. Repeat for other diameters.
To use the stick, hold it horizontally
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 your head, swivel your line of sight to the right side of
the tree trunk and read treediameter on the Biltmore scale. Remember that
the scale was graduated on the basis of a specified reach. Accuracy in
use of the scale depends on how closely the correct reach (a) is maintained.
Also, be sure to take an average of the largest reading and the smallest
reading, since many trees are oval in crosssection.
Standing TreesHeights
Measuring the height of the point on
the tree trunk where the last cut will normally be made requires some training;
however, the procedure and equipment can be relatively simple. The length
of the usable section of the tree trunk is influenced by (1) the
taper of the tree trunk, and (2) the breaking up of the central
trunk into large branches. In the latter case, the top limit of usable
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 minimum
usable diameter (usually 8 inches inside bark) is estimated to occur. If
bark is estimated to be about onehalf inch thick at the 8inch diameter
point, the outside dimension would thus be 9 inches. Determining the point
on the tree trunk at which it would measure 9 inches outside the bark is
at best an approximation. If the D.B.H. is known, it can be used as a comparative
measure.
Method l.Formula
Some estimators use the formula:
(Circumference in inches at D.B.H. x .28)  2" equals diameter inside
bark at the top of the first 16 foot log. For each 16 ft additional length,
deduct 2 inches to secure the diameter inside bark at the top end of the
log in question.
Thus a 20 inch D.B.H. tree would give the following:
(63" x .28)  2 = 17.6  2 = 15.6" diameter inside bark at the top
of the first 16 ft log length. At 32 the diameter (i.b.) would be 13.6
inches, and at 48 ft, 11.6 inches.
The above example assumes that the
tree tapers gradually and extends up at least 48 ft before any large branches
occur. For thickbarked trees, use the factor .27 instead of .28.
Having estimated the point on the tree
trunk that is the limit of usable trunk length of logs, one still must
determine how high that point is above stump height. Stump height can usually
be standardized at about 1 ft above ground for this purpose.
Many methods of measuring height require
special and sometimes expensive equipment; however, Method 2 is just as
accurate and employs quite simple equipment.
Method 2.The Merritt Hypsometer (Similar Triangles)
Based on a known distance (for example
66 ft) from a known height unit, and holding a stick in a vertical position
a known distance from the eye (25 inches) one can calibrate that stick
so that tree heights can be read from it when standing 66 ft from the tree
and holding the stick 25 inches from the eye. For example, in Fig.
13, AB is equal to the reach, or 25 inches; AB' is equivalent to the
set distance that one must stand away from the tree (66 ft); C'B' is a
set height unit (16 ft), and BC is the interval or scale graduation that
the lines of sight would cover on the measure stick. The following relationship
of sides can now be set down:
BC/AB = C'B'/AB'
Substituting values as used in above explanation:
BC/25" = 16'/66'
BC = (25" / 12" x 16')/66' = 33.33'/66' = .51' or 6.06"
A scale unit of 6.06 inches on the stick
will cover 16 ft on the tree with the 25 inch reach and 66 ft distance
factor. Multiples of this unit can be marked on the stick. Thus when one
is 66 ft from a tree with the stick held 25 inches from the eye, and the
lower lines of sight to the stump height cuts the bottom of the stick,
the upper line of sight to the point of heightmeasurement can be read
on the scale in terms of 16 ft units. A slight error is involved; however,
results are within limits of accuracy of this type of measurement.
Method 3.Similar Units
In this approach a pole of known length,
say 10 ft, is leaned against the tree and used as an ocular yard stick
in estimating the number of 10ft units in the usable part of the tree
bole.
Estimating the BoardFoot Content of a Standing Tree
By Use of a Volume Table
A volume table (Tables 5 and 6) shows
the average volume in trees by D.B.H. and height classes. Thus, all that
is needed to determine the volume in any tree of normal form is a measurement
of the D.B.H. (outside bark) and a measurement of the usable length of
the tree. The methods of obtaining these measurements are explained in
the previous section. A tree that is determined to be 14 inches at D.B.H.,
and to have 1 1/216 ft units (from 2027 ft) of usable trunk length, will
contain 112 bd ft (International 1/4" Rule). This is found in Table 6 by
reading at the intersection of the 14inch D.B.H. and the 1 1/2 log columns.
The volume for any normal tree of a size within the D.B.H. and height range
of the volume table can be determined in a similar fashion.
Since volume tables are necessarily
based on average volumes of a large number of trees, and the height is
treated by halflog or 8ft units, the volume given for any individual
tree may be slightly greater or less than the actual volume in the tree,
depending on how closely the tree approximates the average of that particular
size class. In general, volume tables are most usable for trees with a
central bole or stem that ( 1 ) tapers gradually to the inside bark diameter
that is determined to be the limit of merchantability, and (2) does not
have any very large limbs or forks within this usable bole length. Tables
are based on an 8inch (inside bark) top diameter. Volume tables are also
based on Form Class, which is the relationship of the diameter (inside
bark) at the top of the first 16ft log to the D.B.H. (outside bark). Tables
are based on a Form Class of 80, which is about right for trees on average
sites in Kentucky.
The volume table is useful because
it requires only two measurements (D.B.H. and usable height). When used
with large numbers of trees, the individual errors tend to balance out
and the end estimate is within the limits of error permissible for this
type of work.
Deduction for defect may be handled
in the manner previously described for logs and the defect calculated and
noted for each tree. An alternate method is to estimate the percentage
of the gross scale that may be defective and make deductions on a percentage
basis. Either method is at best a guess when dealing with standing timber,
and considerable experience is required to become proficient.
Table 5.TREE SCALEDoyle Rule
D.b.h.*
(inches) 
BOARD FEET CONTENTS OF TREES
Compiled for Hardwoods

Number of 16Foot Logs

1 
1 1/2 
2 
2 1/2 
3 
10 
16 
20 
23 


12 
31 
39 
47 


14 
52 
67 
82 
93 
104 
16 
77 
101 
125 
143 
161 
18 
110 
140 
180 
210 
230 
20 
140 
190 
240 
280 
320 
22 
190 
250 
310 
370 
420 
24 
230 
310 
400 
470 
540 
26 
280 
390 
490 
580 
660 
28 
340 
470 
590 
700 
810 
30 
400 
550 
700 
830 
960 
32 
470 
650 
820 
980 
1140 
34 
540 
750 
950 
1140 
1320 
*Diameter at 4 1/2 feet above ground.
Several forms of tally sheets may be
used for tallying the number of trees of different sizes and species. A
sample sheet that will fulfill most requirements is shown in Fig. 14. Changes
can be made in size ranges and species group to fit conditions at hand.
Individual trees are tallied in the appropriate space by making a short
line or a dot. If care is taken, a large number of any onesize trees can
be tallied in the space provided. Also, if the stand is composed of predominantly
smallertree sizes, the spaces allocated for these sizes can be tailored
to fit the need.
Additional tally sheets can always
be used if more space is required. After the field work has been completed,
a count of the lines or dots in each space will indicate the number of
trees in each D.B.H. and heightclass by species group. By consulting the
volume table, one can find the volume of an average tree for each D.B.H.
and heightclass. Multiplying each averagevolume by the number of trees
tallied in its sizeclass will give the volume in board feet for the individual
size classes. Total volume for all the trees tallied is then a simple matter
of adding up all of the volumes determined for the various size classes.
Table 6.TREE SCALEInternational 1/4 inch Rule
D.b.h.*
(inches) 
BOARD FEET CONTENTS OF TREES

Number of 16Foot Logs

1 
1 1/2 
2 
2 1/2 
3 
10 
39 
51 
63 


12 
59 
78 
98 


14 
83 
112 
141 
164 
186 
16 
112 
151 
190 
223 
256 
18 
140 
200 
250 
290 
340 
20 
180 
250 
310 
370 
430 
22 
220 
300 
390 
460 
530 
24 
270 
370 
470 
560 
640 
26 
310 
440 
560 
660 
770 
28 
370 
510 
650 
780 
900 
30 
420 
590 
760 
900 
1050 
32 
480 
680 
870 
1040 
1210 
34 
550 
770 
990 
1190 
1380 
*Diameter at 4 1/2 feet above ground.
By Use of a Log Rule
As noted in an earlier section, a log
rule is a tabulation of the estimated volume in logs of various smallend
diameters and length classes. Thus, if the sizes of the logs that could
be cut from a standing tree could be determined or estimated, the volume
of each log could be found by the log rule and the sum of the volumes of
the logs in a tree would represent the boardfoot content of the tree.
This method requires more work than the "Volume Table Method" and a little
more skill; however, it is more accurate in the case of short, thickboled
trees, and for any one individual tree since the actual log sizes that
could be cut from the tree are computed exactly as they would be if the
tree were felled and bucked into logs. The difficulty lies in estimating
the correct smallend diameters and lengths of the logs as they appear
in a standing tree. Any standard of comparison, such as a 10 or 12ft
pole with a yardstick fastened across its top and leaned against the tree,
is a great help to the beginner.
A form of tally sheet that can be modified
to suit local requirements is shown in Fig. 15. Spaces have been provided
for identifying the individual tree by a number and by species, for noting
the diameter and length of as many as 4 separate logs, and for the tree
volume after it has been computed.
Figure 14.  Field Tally Sheet

Location 
Sheet No. 
Owner 
D.B.H. 
Pine

Yellowpoplar

1/2 
1 
1 1/2 
2 
2 1/2 
3 
1/2 
1 
1 1/2 
2 
2 1/2 
3 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 
21 
22 
Figure 15.Field Tally Sheet for Individual Tree Measurements

Location 
Sheet No. 
Owner 
Tree No. 
Species 
Log Dimensions

Tree
Volume 
Diam 
Lgth 
Diam 
Lgth 
Diam 
Lgth 
Diam 
Lgth 
















Estimating the BoardFoot Volume in a Tract of Timber
The two previous sections have indicated
how tree diameters and heights can be determined, and how these measurements
can be used to determine the volume in a tree.
In small tracts of timber up to 10
or 15 acres in extent, it is best to measure diameter and height of every
tree that is above minimum size for the inventory of sale. When only large,
mature trees are being considered, then only the trees in this category
are measured and tallied.
In larger tracts, the same procedure
can be followed with considerable expenditure of time and effort; however,
it is more practical to limit the work to sample areas in the form of parallel
strips or lines of plots running across the area. The strips or lines of
plots should be aligned so as to obtain a proportionate coverage of variations
in size and density of the timber. When there are ridges and valleys involved,
the strips or lines of plots should cross the main ridges and valley at
approximately right angles so that sparser ridge timber is obtained as
well as the larger and denser timber on the lower slopes and in the valleys.
One side of the tract can be used as
a baseline and the spacing of the strips or lines of plots laid off along
it. A staff or pocket compass can be used to maintain strip alignment.
A tape or chain should be used to determine distances.
The strips can be of any set width;
however, a narrow strip of onehalf chain width (33 ft) is easier to stay
within, as are small circular plots of 1/5 acre (52 ft radius) or 1/10acre
plots of 37 ft radius. The distance traveled along the strips must be measured
so that the area cruised can be determined. Thus, a strip of 1/2 chain
(33 ft) wide and 20 chains ( 1,320 ft) long covers 10 square chains, or
1 acre. Likewise, in lines of 1/5acre plots spaced at a set distance from
center to center, the number of plots taken divided by 5 gives the acreage
of the sample. In order to eliminate personal choice of sample areas, the
spacing of the strip or lineofplotsintervals should be mechanical, and
carried out according to a predetermined pattern.
The number of strips or lines of plots
to be run should be determined by the percentage of estimate that will
satisfy the requirements of accuracy. Usually the smaller the tract, the
larger the sample should be. Thus, for tracts of 20 to 100 acres, a 20%
estimate should give a fair standard of accuracy. If the timber is fairly
uniform, a 10% estimate may do. On larger tracts, a 10% estimate is usually
satisfactory, or even a 5% may do in some timber.
With the percentage of estimate determined
that will be satisfactory, the spacing between strips or lines of plots
can be computed. If 1/2chainwidth strips are used, a spacing of 5 chains
between strip centers will give an approximate 10% coverage of the tract.
In the case of 1/5acre plots, a spacing of plots in the line at 4chain
center distance and 5 chains between lines of plots will also give an approximately
10% estimate. Strips or lines of plots should be one half of the strip
or line of plots spacing interval inside of the timber edge. Figure
16 and Figure 17 illustrate most of the details
explained in this section.
When using the strip method, use one
tally sheet for each 5 or 10 chains of strip covered. Individual tally
sheets may be numbered or otherwise identified by strip number and distance
interval such as "Strip #1, Distance 010 chains." Likewise, separate tally
sheets for each circular plot help to keep the records straight and each
should be identified as to line and plot number.
When the field work is completed, the
volume of the trees on the strips or lines of plots can be computed as
given in the section dealing with "Estimating the Board Foot Content in
a Standing Tree." The area of the strips or plots can also be determined.
The relationship of the measured sample area and its volume to the tract
area and tract volume can be expressed by the proportion:
V/v = A/a or V = (vA)/a
In the above proportion, V equals the
volume of timber on the tract, v equals the volume of timber in the sample
area; A equals the area of the tract in acres, and a equals the area in
acres of the sample area.
Evaluating Timber Volume on a Tract by Species Groups and Sizes
Knowing the total volume of timber
on a tract is extremely valuable for inventory or sale. An average value
per 1,000 bd ft can be set and total value thus easily computed. It is
better business, however, to be able to compute volume and value by species
groups and sizes when such variation in the timber occurs. This can be
done easily if species groups are separated in making the tally during
the estimating procedure as advocated in Section III. The sample tally
sheets proposed in this section are likewise designed to allow such separation.
Thus, the estimated value of the species groups, such as White Oak, Red
Oak, Beech, and Hickory or Yellow Poplar, are their diameter ranges (for
example: 8"12", 13"16"', 17'20', etc.) can be determined and computed
separately. This separation is more satisfactory than attempting to set
an average for all species and all sizes.
Appendix A: Specifications for Southern Pine Poles
(From American Standard Specifications and Dimensions for Southern
Pine Poles. American Standards Association, (05.11979)
This standard consists of specifications
and dimensions for southern pine poles that are to be given preservative
treatment as specified by the purchaser. The poles described here are considered
as simple cantilever members subject to transverse loads only. Modification
of the requirements may be necessary if the poles are to be used for other
types of construction.
Requirements for the preservative treatment
of poles are not included in the standard. These requirements are detailed
in other standards (for example those of the American WoodPreservers'
Association and American Society for Testing Materials) and in customer
specifications. However, exceptions are made to this exclusion of those
cases where conditioning the wood for treatment or where the actual process
of preservation could reduce the fiber stresses below standard specifications
(8,000 PSI) and as a consequence necessitate a change in the minimum 6
ft from the butt dimension given.
The species, the length and class of
poles, the type of treatment (including seasoning details, if seasoning
is desired), and complete details for roofing, gaining, boring and branding,
not included in this standard, must be given in purchase orders.
Complete detailed instructions must
be given to the supplier whenever the requirements of this standard are
modified to meet special conditions.
Material Requirements
Species
All poles must be cut from live southern
pine timber: Longleaf Pine (Pinus palustris), Shortleaf Pine (Pinus echinata),
Loblolly Pine (Pinus taeda) and Slash Pine (Pinus elliottii).
Prohibited Defects
•Cross breaks (cracks).
•Decay  except as permitted
for firm red heart, defective butts and decayed knots.
•Dead streaks.
•Holes  open or plugged, except
holes for test purposes, which shall be plugged.
•Hollow butts or tops  except
as permitted under hollow pith centers and defective butts.
•Marine borer damage.
•Nails, spikes and other metal
not specifically authorized by the purchaser.
Permitted Defects
•Firm Red Heart. Firm red heart
not accompanied by softening or other disintegration (decay) of the wood
is permitted.
•Hollow Pith Centers. Hollow
pith centers in tops or butts and in knots are permitted in poles that
are to be given fulllength treatment.
•Sap Stain. Sap stain not accompanied
by softening or other disintegration (decay) of the wood is permitted.
•Scars. Turpentine acid face
scars are permitted anywhere on the pole surface.
Limited Defects
•Bark Inclusions. Depressions
containing bark inclusions must be no more than 2 inches deep, measured
from the surface of the pole.
•Compression Wood. The outer
1 inch of all poles shall be free from compression wood visible on either
end.
•Defective Butts. Hollowing
in the butt caused by "splinter pulling" in felling the tree is permitted,
provided that the area of such a hollow is less than 10% of the butt area.
•Insect Damage. Insect damage,
consisting of holes 1/16 inch or less in diameter, or surface scoring or
channeling is permitted. All other forms of insect damage are prohibited.
•Knots. The diameter of any
single knot and the sum of knot diameters in any lft section shall not
exceed the limits of Table 7. Type II "decayed knots" are permitted.
•Scars (Cat face). No pole shall
have a scar or turpentine cat face located within 2 ft of the ground line.
Turpentine scars need be trimmed only to the extent necessary for examination
for evidence of fungus infection and insect damage. Other sound scars are
permitted elsewhere on the pole surface, provided they are smoothly trimmed
and do not interfere with the cutting of any gain, and provided that:
(A) The circumference at any
point on trimmed surfaces located between the butt and 2 ft below the ground
line is not less than the minimum circumference specified at 6 ft from
the butt for the class and length of the of pole; and
(B) The depth of the trimmed
scar is not more than 2 inches, if the diameter is 10 inches or less or
1/5 the pole diameter at the location of the scar if the diameter is more
than 10 inches.
•Shakes. Shakes in the butt
surface which are not closer than 2 inches to the side surface of the pole
are permitted, provided they do not extend to the ground line. Shakes or
a combination of connected shakes which are closer than 2 inches to the
side surface of the pole are permitted, provided they do not extend farther
than 2 ft from the butt surface and do not have an opening wider than ,/8
inch. Shakes in the top surface are permitted in poles that are to be given
fulllength preservative treatment, provided that the diameter of the shake
is not greater than 1/2 the diameter of the top of the pole.
•Shape. Poles shall be free
from short crooks. A pole may have sweep subject to the following limitations.
(A) Where sweep is in one plane
and one direction only
1.For poles 50 ft and shorter, a straight
line joining the surface of the pole at the ground line and the edge
of the pole at the top, in 90% or more of an inspection lot, shall
not be distant from the surface of the pole at any point more than 1 inch
for each 10 ft of length between these points. In the remainder of the
inspection lot (10%) the poles may have a deviation of 1 inch for each
6 ft of length when measured as above.
2.Poles 55 ft and longer shall meet
the 1 inch in 10 ft requirements in 75% or more of an inspection lot. In
the remainder of the lot (25%) the poles may have a deviation of 1 inch
for each 6 ft of length when measured as above.
(B) Where sweep is in two planes
(double sweep), or in two directions in one plane (reverse sweep) a straight
line connecting the midpoint at the ground line with the midpoint at
the top shall not at any intermediate point pass through the surface of
the pole.
•Spiral Grain. Spiral grain
(twist grain) is permitted as follows:
Length of Pole (ft) 
Maximum Twist of Grain Permitted 
30 and shorter 
1 complete twist in any 10 ft 
3545, inclusive 
1 complete twist in any 16 ft 
50 and longer 
1 complete twist in any 20 ft 
•Splits and Checks.
(A) In the top. A split or a
combination of two single checks (each check terminating at the pith center
and separated by not less than 1/6 of the circumference) having one or
both portions located in a vertical plane within 30 degrees of the top
bolt hole shall not extend downward along the pole more than 6 inches.
All other combinations of check or split shall not extend downward along
the pole more than 12 inches.
(B) In the butt. A split or
a combination of two single checks, as defined above, shall not extend
upward along the pole more than 2 ft.
Table 7.Limits of Knot Size

Maximum Sizes Permitted, inches

Diameter of Any Single
Knot (inches)

Sum of Diameters of All
Knots Greater than 0.5 inch
in Any 1ft Section (inches) 
Length of Pole 
classes
13 
classes
410 
classes
110 
45 ft and shorter 
lower half of length 

2 
8 
upper half of length 
5 
4 
8 
50 ft and longer 
lower half of length 
4 
4 
10 
upper half of length 
6 
6 
10 
Dimensions
Length
Poles less than 50 ft long shall not
be more than 3 inches shorter or 6 inches longer than nominal length. Poles
50 ft long or more shall be not more than 6 inches shorter or 12 inches
longer than nominal length.
Length shall be measured between the
extreme ends of the pole.
Circumference
The minimum circumference at 6 ft from
the butt and at the top, for each length and class of pole are listed in
Table 8. The circumference at 6 ft from the butt of the pole shall be not
more than 7 inches or 20% larger than the specified minimum, whichever
is greater.
The top dimensional requirement shall
apply at a point corresponding to the minimum length permitted for the
pole.
Classification
The true circumference class shall
be determined as follows: measure the circumference at 6 ft from the butt.
This dimension will determine the tree class of the pole, provided that
its top (measured at the minimum length point) is large enough. Otherwise,
the circumference at the top will determine the true class provided that
the circumference at 6 ft from the butt does not exceed the specified minimum
by more than 7 inches or 20%, whichever is greater.
Table 8.Circumference Specifications for the Various Classes of
Creosoted Southern Pine Poles
Length
of pole
(Feet) 
Distance of
ground line
from butt*
(Feet) 
Pole Class

1 
2 
3 
4 
5 
6 
7 
9 
10 
Minimum top circumference (inches)

27 
25 
23 
21 
19 
17 
15 
15 
12 
Minimum circumference six foot from butt (inches)

20 
4 
31.0 
29.0 
27.0 
25.0 
23.0 
21.0 
19.5 
17.5 
14.0 
25 
5 
33.5 
31.5 
29.5 
27.5 
25.5 
23.0 
21.5 
19.5 
15.0 
30 
5.5 
36.5 
34.0 
32.0 
29.5 
27.5 
25.0 
23.5 
20.5 
35 
6 
39.0 
36.5 
34.0 
31.5 
29.0 
27.0 
25.0 
40 
6 
41.0 
38.5 
36.0 
33.5 
31.0 
28.5 
26.5 
45 
6.5 
43.0 
40.5 
37.5 
35.0 
32.5 
30.0 
28.0 
50 
7 
45.0 
42.0 
39.0 
36.5 
34.0 
31.5 
29.0 
55 
7.5 
46.5 
43.5 
40.5 
38.0 
35.0 
32.5 
60 
8 
48.0 
45.0 
42.0 
39.0 
36.0 
33.5 
65 
8.5 
49.5 
46.5 
43.5 
40.5 
37.5 
70 
9 
51.0 
48.0 
45.0 
41.5 
38.5 
75 
9.5 
52.5 
49.0 
46.0 
43.0 
80 
10 
54.0 
50.5 
47.0 
44.0 
85 
10.5 
55.0 
51.5 
48.0 
90 
11 
56.0 
53.0 
49.0 
95 
11 
57.0 
54.0 
50.0 
100 
11 
58.5 
55.0 
51.0 
105 
12 
59.5 
56.0 
52.0 
110 
12 
60.5 
57.0 
53.0 
115 
12 
61.5 
58.0 
120 
12 
62.5 
59.0 
125 
12 
63.5 
59.5 
*For use in applying specifications which require a definition of "ground
line."
Table 9.Diameter Specifications for the Various Classes of Creosoted
Southern Pine Poles*
Length of
pole (Feet) 
Pole Class

1 
2 
3 
4 
5 
6 
7 
Minimum top diameter (inches)

8.8 
8.1 
7.5 
6.9 
6.2 
5.6 
5.0 
Minimum diameter six feet from butt (inches)

16 
 
 
 
 
 
7.2 
6.8 
18 
 
 
 
 
 
7.7 
7.2 
20 
 
 
 
 
 
8.0 
7.5 
25 
 
 
 
10.8 
10.0 
9.0 
8.2 
30 
 
 
 
11.4 
10.6 
9.7 
9.0 
35 
 
 
13.0 
12.1 
11.3 
10.4 
9.6 
40 
15.6 
14.6 
13.6 
12.8 
11.9 
11.0 
 
45 
16.4 
15.3 
14.2 
13.4 
12.4 
11.5 
 
50 
17.1 
16.0 
14.8 
14.0 
12.9 
 
 
55 
17.7 
16.6 
15.4 
14.5 
13.5 
 
 
60 
18.2 
17.2 
16.0 
15.0 
13.9 
 
 
*Diameters to the nearest onetenth inch obtained by converting circumference
specifications, assuming all poles to be round.
Manufacturing Requirements
Bark Removal
Outer bark shall be completely removed
from all poles. On all poles, no patch of inner bark more than 1 inch wide
shall be left on the pole surface between the butt and 2 ft below the ground
line. On poles that are to be given fulllength treatment, no patch of
inner bark larger than 1 inch wide and 6 inches long shall be left on the
pole surface between the top and 2 ft below the ground line. On poles that
are to be butt treated, no patch of inner bark larger than 1 inch wide
and 6 ft long shall be left on the pole surface between point 1 ft above
and 2 ft below ground line.
Sawing
All poles shall be neatly sawed at
the top and the butt along a plane which shall not be out of square with
the axis of the pole by more than 2 inches per foot of diameter of the
sawed surface. Beveling at the edge of the sawed butt surface not more
than 1/12 the butt diameter in width or an equivalent area unsymmetrically
located is permitted.
Trimming
Completely overgrown knots, rising
more than 1 inch above the pole surface, branch stubs, and partially overgrown
knots shall be trimmed close. Completely overgrown knots less than 1 inch
high need not be trimmed. Trimming may be done by shaving machine or by
hand.
Shaving
If shaving is used, the depth of cut
shall not be more than necessary to remove inner bark and to trim smoothly
and closely all branch stubs and overgrown knots. There shall be no abrupt
change in the contour of the pole surface between the ground line and the
above ground sections. The lower 2 ft of poles may be trimmed to remove
wood fibers causing butt flare, provided sufficient sapwood remains to
obtain the customer's minimum penetration requirement.
Marking and Code Letters
The following information shall be
burnbranded legibly and permanently on the face and the butt of each pole
or included on a metal tag affixed thereto.
1.The supplier's code or trademark.
2.The plant location and year of treatment.
3.Code letters denoting the pole species
and preservative used.
4.The true circumferenceclass numeral
and numerals showing the length of the pole.
Metal tags (noncorrosive) attached to
the butt of the pole shall be securely affixed to serve the intended purpose.
Storage and Handling
Storage
When it is necessary to hold poles
in storage, they shall be stacked on treated or other nondecaying skids
of such dimensions, and so arranged as to support the poles without producing
noticeable distortion of any of them. The height of the piles shall be
limited to avoid damage to poles on the bottom layers.
Poles shall be piled and supported
in such a manner that all poles are at least 1 ft above the general ground
level and any vegetation growing on it. No decayed or decaying wood shall
be permitted to remain underneath stored piles.
Handling
Poles shall not be dragged along the
ground. Cant hooks, pole tongs or other pointed tools shall not be applied
to the ground line section of any pole.
Mechanical Damage
Poles are not acceptable if they contain
indentations attributed to loading or handling slings that are 1/4 inch
or more deep over 20% or more of the pole circumference, or more than 1/2
inch deep at any point. Other indentations or abrasions, for example, fork
lift damage, chainsaw damage, etc. shall not be more than 1/10 the pole
diameter at the point of damage up to a maximum of 1 inch. Such damage
is permitted in an oversized section, where the excess of wood shall be
taken into consideration in evaluating the effects of the damage. In any
case, the circumference for a given class is still required to be not less
than specification minimum.
Definitions of Terms
The following definitions shall apply
to the terms used in this standard.
Check. The lengthwise separation of the wood that usually extends
across the rings of annual growth and commonly results from stresses set
up in wood during seasoning.
Compression Wood. Abnormal wood formed on the lower side of
branches and inclined trunks of softwood trees. Compression wood is identified
by (1) its relatively wide annual rings, usually eccentric; (2)
relatively large amount of summerwood, sometimes more than 50% of the width
of the annual rings in which it occurs; and (3) its lack of demarcation
between springwood and summerwood in the same annual rings. Compression
wood, compared with normal wood, shrinks excessively lengthwise.
Cross Break. A separation of the wood cells across the grain.
Such breaks may be due to internal strains resulting from unequal longitudinal
shrinkage or to external forces.
Dead Streak. An area, devoid of bark, resulting from progressive
destruction of the growth cells of wood and bark at the edges of the streak.
On a pole, a dead streak is characterized by a discolored weathered appearance
and by lack of evidence of overgrowth along the edges of the deadened surface.
Decay. The decomposition of wood substance by fungi.
Decay, advanced (or typical). The older stage of decay in which
the destruction is readily recognized because the wood has become punky,
soft and spongy, stringy, ringshaked, pitted, crumbly or, in poles not
stored or rafted in water, is in a soggy condition. Decided discoloration
or bleaching of the rotted wood is often apparent.
Decay, incipient. The early state of decay that has not proceeded
far enough to soften or otherwise perceptibly impair the hardness of the
wood. It is usually accompanied by a slight discoloration or bleaching
of the wood.
Decayed Knot. A knot containing decay. Two types of decayed
knot are recognized.
Type IKnots containing soft
or loose fibers (decay) which may extend the full length of the knot into
the pole and which are associated with heart rot.
Type IIKnots containing soft
or loose fibers (decay) which are not associated with heart rot.
Face of Pole. The concave side of greatest curvature in poles
with sweep in one plane and one direction, or the side of greatest curvature
between ground line and top in poles having reverse or double sweep.
Groundline Section. That portion of a pole between 1 ft above
and 2 ft below the ground line, as defined in the pole dimension tables.
Hollow Heart. A void in the heartwood caused by decay or insect
attack.
Hollow Pith Center. A small hole at the pith center of the trunk
or of a knot caused by disintegration of the pith (small soft core occurring
in the structural center of a tree or branch).
Insect Damage. Damage resulting from the boring into the pole
by insects or insect larvae. Scoring or channeling of the pole surface
is not classed as insect damage.
Kiln Drying. Drying by the use of heated air in batch or progressivetype
kilns.
Knot Diameter. The diameter of a knot on the surface of the
pole measured in a direction at right angles to the lengthwise axis of
the pole. The sapwood as well as the heartwood portion of a knot shall
be included in the measurement.
Red Heart. A condition caused by a fungus, Fomes pini, that
occurs in the living tree. It is characterized in the early stages of infection
by a reddish or brownish color in the heartwood (known as "firm red heart").
Later the wood of the living tree disintegrates (decays) in small, usually
distinct, areas that develop into whitelined pockets.
Sap Stain. A discoloration of the sapwood, caused by the action
of certain molds and fungi, that is not accompanied by softening or other
disintegration of the wood.
Scar. A depression in the pole's surface resulting from a wound
where healing has not reestablished the pole's normal cross section.
Scar, Turpentine Acid Face. An area in the lower portion of
a southern pine pole where bark hack removal with acid applied has caused
resin to flow. No removal of sapwood has occurred.
Scar, Turpentine Cat Face. A depression in the surface of a
southern pine pole resulting from a wood hack into the sapwood, where healing
has not reestablished the pole's normal cross section.
Shake. A separation along the grain, the greater part of which
occurs between the rings of annual growth.
Short Crook. A localized deviation from straightness which,
within any section 5 ft long or less, is more than 1/2 the mean diameter
of the crooked section.
Spiralgrained (twistgrained) Wood. Wood in which the fibers
take a spiral course about the trunk of a tree instead of a vertical course.
The spiral may extend in a righthanded or lefthanded direction around
the tree trunk. Spiral grain is a form of cross grain.
Split. A lengthwise separation of the wood due to the tearing
apart of the wood cells.
Steam Conditioning. Subjecting poles in a closed vessel to steam
prior to treatment.
Sweep. Deviation of a pole from straightness.
Appendix B
Grading Bourbon Stave and Heading Bolts
All bolts must be split from live,
sound, straightgrained White Oak timber (preferably 16 to 20 inches in
diameter) and must be free of all defects, such as knots, heart checks,
bird pecks, streaks, shake, cat faces, worm holes, water soak, bows or
crooks.
(Figure 18)
Requirements for Stave Bolts
No. 1 stave bolts must square up 5
inches of heartwood and measure 39 inches long.
No. 2 stave bolts include all bolts
not squaring 5 inches of redwood and with a minimum of 5 1/2 inches of
redwood from sap to apex.
(Figure 19)
(Figure 20)
Requirements for Heading Bolts
No. 1 heading bolts must be 15 to 18
inches from corner to comer, and 8 inches deep from heart to sap.
No. 2 heading bolts must be 11 to 15
inches from corner to corner, and a minimum of 6 1/2 inches from heart
to sap.
Rules for Inspections of Bourbon Stave Bolts
Bolts must be split from sound straightgrained
White Oak timber and must be free from all defects, such as knots, heart
checks, bird pecks, streaks, shake, cat faces, worm holes, water soak,
bows or crooks.
Green bolts must have the following
dimensions: 39 inches long, 5 inches to 8 inches wide from heart to sap.
Bolts must average 6 inches deep and
can be 5 inches to 8 inches deep clear of sap.
Bolts will be measured in ricks 4 ft
high and 8 ft long.
Rules for Inspection of Bourbon Heading Bolts
Bolts must be split from sound, straightgrained
White Oak timber 20 inches and up, and must be free from all defects, such
as knots, heart checks, bird pecks, streaks, shake, cat faces, worm holes,
water soak, bows or crooks.
Green bolts must have the following
dimensions: 23 inches long, 6 inches and wider from heart to sap.
Bolts must average 8 inches deep, and
can be 6 inches and deeper clear of sap.
Bolts will be measured in ricks 4 ft
high and 8 ft long.
(Figure 21)
(Figure 22)
(Figure 23)