JIOIT Oi? 1 STUM >D MD
L(
PINE
.0. Donk, C.i. Snattuok
.1). tarsia 11
. , . U 3ul. 1005 Dec. 1921
- Forestry. Main Lihrai
s >, , ysim
H
UNITED STATES DEPARTMENT OP AGRICULTURE
BULLETIN No. 1003
Contribution from the Bureau of Chemistry
W. G. CAMPBELL, Acting Chief
And the University of Idaho, A. H. UPHAM,
Washington, D. C.
December 5, 1921
THE DISTILLATION OF STUMPWOOD
AND LOGGING WASTE OF WESTERN
YELLOW PINE
By
M. G. DONK, Assistant Chemist
Leather and Paper Laboratory, Bureau of Chemistry
C. H. SHATTUCK, Professor of Forestry, and W. D. MARSHALL
Research Fellow, Forestry Department, University of Idaho
CONTENTS
Pag?
Importance of western yellow pine . . 1
Distribution of western yellow pine . . 2
Purpose of investigation 13
Taking samples 15
Distillation of samples 22
Crude products of retort distillation . . 31
Products obtained ih refining crude
turpentine 37
Calculation of yields of refined turpen-
tine and pine oil ., 41
Commercial distillation processes ... 43
Page
Feasibility of distilling western yellow
Pine 46
Relation of wood distillation to land
clearing 51
Small, semi-portable wood-distilling
plants 53
Use of oil for ore flotation 54
Refining crude wood turpentine .... 56
Summary 67
Literature cited 69
WASHINGTON
GOVERNMENT PRINTING OFFICE
1921
UNITED STATES DEPARTMENT OF AGRICULTUR
BULLETIN No. 1003
Contribution from the Bureau of Chemistry
W. G. CAMPBELL, Acting Chief
And the University of Idaho, A. H. UPHAM
President
Washington, D. C.
December 5, 1921
THE DISTILLATION OF STUMPWOOD AND LOGGING
WASTE OF WESTERN YELLOW PINE.
By M. G. DONK, Assistant Chemist, Leather and Paper Laboratory, Bureau of
Chemistry, C. H. SHATTUCK, Professor of Forestry, and W. D. MARSHALL,
Research Fellow, Forestry Department, University of Idaho. 1
CONTENTS.
Importance of western yellow pine
Distribution of western yellow pine-
Purpose of investigation
Taking samples
Distillation of samples
Crude products of retort distillation-
Products obtained in refining crude
turpentine
Calculation of yields of refined tur-
pentine and pine oil
Page.
2
13
15
22
31
37
41
Page.
Commercial distillation processes 43
Feasibility of distilling western yel-
low pine 46
Relation of wood distillation to land
clearing- 51
Small, semi-portable wood-distilling
plantjs 53
Use of oil for ore flotation 54
Refining crude wood turpentine 56
Summary 67
Literature cited 69
IMPORTANCE OF WESTERN YELLOW PINE.
Western yellow pine (Pinus ponderosa) is the most widely dis-
tributed of the western commercial softwoods (4, 10) 2 (fig. 1).
The Forest Service estimates the amount of standing timber of this
species to be approximately 335,000,000,000 board feet, or more than
that of any other species except Douglas fir (6). The reported cut
for this species for 1917 was 1,862,914,815 board feet. This repre-
sents an area of more than 350,000 acres of land annually cleared
and left covered with stumps after logging operations. About one-
third of this is within the national forests and is generally of little
value for agriculture, because of the roughness of the land. Much
of the remaining two-thirds, however, is valuable for crops.
1 The sections on the importance and distribution of the western yellow pine are by
C. H. Shattuck. The report of the investigation is by M. G. Donk.
2 The numbers in parenthesis throughout this bulletin refer to the bibliography on
page 69.
60953 21 1
^96093
2 BULLirirc: ; rv.: m$rA.Kt"rtr.NT or Acuirri/rrnr..
Removing the stumps is arduous Mini costly (8), and so far they
have leen considered to be worthless after removal. Any process
which may serve to reduce the cost of clearing the laud or lead to
the discovery of a profitable use for the stumps is, therefore, worthy
of careful consideration. Observations on the methods of utilizing
the more resinous portions of the yellow 7 pine of the South in the
manufacture of wood-distillation products su^c-ted the possibility
that the western species might serve the same purpose, as these trees,
especially the stumps, are often quite resinous.
It is well known that western yellow pine was used in California as
a profitable source of turpentine during the Civil War (13). In
speaking of turpentine obtained from western yellow pine. Schorger
(7) says: "There is no reason to suppose that both the California
and the Ari/ona oils will not serve the purposes for which ordinary
turpentine is commonly used." According to Betts (2), nearly as
much turpentine and rosin was obtained from western yellow pine
as from the pines of the Southeast. Wenzell (5) states that the odor,
specific gravity, and boiling point of oleoresin from Pinus ponderosa
correspond with those of the common oil of turpentine. It is there-
fore reasonable to suppose that turpentine operations in the large
tracts of virgin pine timber in the West will be undertaken within a
few years, because of the rapid cutting of the yellow pine of the
South.
DISTRIBUTION OF WESTERN YELLOW PINE.
For convenience the chief areas of western yellow pine may be
grouped as follows :
(1) Arizona and New Mexico.
(2) California.
(3) Oregon jind Washington.
(4) Idaho, Montana, and Utah.
(5) Colorado, South Dakota, and Wyoming.
For want of accurate data, no estimates covering the quantities of
this species annually cut for fuel and uses other than for lumber are
given, although this amount is known to be considerable. Neither
is any account taken of the distillation material to be derived from
"fat" limbs and "pitchy" butts.
The estimates of stands, and therefore of stumps, in many of the
States are low because the results of the cruises of much privately
owned timber were not obtainable.
The problem of the better utilization of this species is by no means
confined to Idaho. Tables 2 to 1-J and the map (fig. 1) furnish con-
clusive proof of the enormous quantities of yellow-pine stumps to be
had in several Western States. It will not be profitable to work up
by distillation methods any but the more resinous of the stumps,
" fat " limbs, and " pitchy " butts. A complete field survey of each
DISTILLATION
3
region to determine the stand or number of rich resinous stumps and
the practicability of profitable distillation must be left to those in
FIG. 1. Geographic distribution of Pinus ponderosa.
the various regions who plan to enter the field of wood-distillation
from a commercial standpoint. Such a survey, however, should al-
ways be made before undertaking distillation in any section.
;/
P, PKARTJVfENT OF AGRICULTURE.
ARIZONA AND NEW MEXICO.
Total area in the national forests acres__ * 4, 571, 425
Total stand in the national forests board feet 17,002,000,000
Total annual cut (1917) , do 154, 2J)7, 815
Total area annually cleared (if clear cutting is em-
ployed) acres 38, 574
Total annual volume of stumpwood cords * 77, 148
For average stands the number of trees over 18 inches varies from
85 to 12, and the number of those over 24 inches varies from 7 to 9 ;
heavy stands have from 12 to 30 trees 18 inches and over, and from
11.5 to 20 trees 24 inches and over.
Since 500 board feet is a liberal average volume for a yellow-pine
tree 22 inches in diameter at breast height, or 24 inches on the stump
(3, 13), stands of 5,000 feet an acre would contain 10 trees averaging
24 inches on the stump. The average stand over Arizona and Xew
Mexico being approximately 4,000 board feet for all the area covered
with yellow pine, the average number of 24-inch stumps an acre would
be 8. Many thousands of acres show stands above 5,000 feet, the
actual number of trees 24 inches and over being from 10 to 15 to the
acre.
It is evident, therefore, that this region has future possibilities
from the standpoint of wood by-products, if it is found that a fair
percentage of the stumps are rich in resin. No account has been
taken of the material obtainable from "fat" limbs or "pitchy" butts,
and only the timber on national forests, where accurate cruises
have been made, is here considered. Though no figures are avail-
able for the timber on private holdings, Indian lands, and the pub-
lic domain, it is known that these areas are quite extensive, and many
of the stands are average or better.
CALIFORNIA.
Total area acres 10,000,000
Total stand board feet__ 85,000,000,000
Total annual cut (1917) do 154,297,815
Total area annually cleared ( if rlcar cutting
is employed) acres 38,574
Total annual volume of stumi\vood cords 4 77, 148
California has about 10,500,000 acres of commercial yellow pine,
with from 85,000,000,000 to 90,000,000,000 board feet, or from 8,000
to 12,000 board feet an acre. Trees above 12 inches in diameter, breast
high, have an average diameter of 38 inches, or approximately 41
inches on the stump, for which reason the yellow-pine trees of Cali-
fornia are the largest known. Since the species usually grows in
mixed stands, the number of trees an acre is low. The pitch content,
however, is higher than that in any other section. As the yellow
pine in California is the heaviest known (Table 1), the amount of
"pitchy" wood can safely be takvn as average or better.
National forests only. ' 1 '<>r roducing factors s**' Table d.
DISTILLATION OF STUMPWOOD.
TABLE 1. Stands of western yellow pine in California, Oregon, and Washing-
ton, ivith reduction factors for various volumes and diameters of trees and
stumps*
Diameter.
Average volume
Reduc-
Reduc-
tion
Breast
high.
tion,
breast
height to
Stump
high.*
Of
trees.
Of
stumps.
units for
different
volumes
stump
height.
and di-
ameters.
Inches.
Inches.
Inches.
Bd.ft.
Cords.
22
2
24
500
0.25
1
23
2
25
600
24
2
26
750
.375
1.5
25
2
27
850
26
2
28
950
26.5
2
28.5
1,000
.5
2
27
2
29
1,150
28
2.5
30.5
,250
.625
2.5
29
2 5
31 5
350
30
2 5
32.5
,425
30.5
2.5
33
,500
.75
3
32
2 5
34.5
,600
32 5
2 5
35
,750
3.5
33
2.5
35.5
,850
.875
33 5
2 5
36
,925
34
3
37
2,000
1
4
35
3
38
2,150
36
3"
39
2,250
1.125
4.5
37
3
40
2,400
38
3
41
2,500
1.25
5
39
3.5
42.5
2,600
40
3.5
43.5
2,750
.375
5.5
41
3.5
44.5
3,000
.5
6
41.5
3.5
45
3,250
.625
6.5
42
3.5
45.5
3,500
.75
7
43
3.5
46.5
3,750
.875
7.5
44
3 5
47 5
3 900
45
4
49
4,000
2
8
1 This working table must be adapted by the user to meet the variations from the normal stand as they
are found to occur. The volumes inboard feet represent close approximations of the averages of all
obtainable volume tables for the regions named. The volumes in cords are taken from measurements of
corded stumpwood in various regions, and are as conservative, when the wood is split for the retort, as
those used for volume, B. M.
The height of the stump is here assumed to be 18 inches. For higher stumps the diameter would be
duced according to the scale, as given in columns 5 and 6.
TABLE 2. Sample cruises of California, yellow pine from different parts of the
State, with volume and acre equivalent in number of stumps of various diam-
eters required to produce the given yields (area covered, 6,400 acres, average
xtand, or slightly better). 1
Location.
Volume
per acre.
Number stumps.
Per cent
total
stand.
24-
inch.
28.5-
inch.
37-
inch.
Eldorado T 8 N R 15 E, sec. 35
Bd.ft.
10, 082
10, 501
18,236
12, 253
12, 444
9,503
5,870
10, 518
17,163
12, 276
20.00
21.00
36.40
2450
24.88
19.00
11.74
21.02
34.32
24.55
10.00
10.50
18.20
12.25
12.44
9.50
5 87
10.51
17.16
12.27
5.00
5.25
9.10
6.12
6.22
4.80
3.92
5.25
8.58
6.11
83.6
64.7
46.4
68.5
87.6
26.9
71.6
83.4
72.1
47.4
Lassen, T 25 N, R 14 E, sec. 24
Lassen, T27N, R 10 E sec. 5
Lasen T 32 N R 8 E sec
Modoc, T 46 N, R 15 E, sec. 32.. .
Plumas T 23 N R 9 E, sec. 5
Sequoia, T 13 S, R 19 E, sec. 19
Sierra, T 5 S, R 21 E, sec 18.
Sierra, T 6 S, R 24 E, sec. 27
Stanislaus, T 4 N R 18 E, sec. 17 .
Average for 6,400 acres
11,884
23.75
11.88
5.94
64.5
1 Estimates furnished by T. D. Woodbury, assistant district forester, San Francisco, Calif. If the stump-
high diameters were used instead of those'breast high, a large number of trees would be included in the
24-inch class, as many trees measuring 22 inches and over, breast high, would come within the 24-inch class
if measured on the stump.
BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
TABLE 3. Practical application of Table 1.
Vol-
Trees
24
Aver-
cedt
1
Humps ]
^er acre <
jquivale.
at.
Location.
Area.
per
acre.
inches
and
over.
ameter
stump
high.
24-
inch.
33-
inch.
35-
inch.
43-
inch.
49-
inch.
T 4 N RISE, sec. 19.
Acre*.
7
Ed.it.
:<:> 4<*)
9 1
Inches.
48
70.9
23.6
20.3
12.8
8.8
T 9 S R 24 E sec 2
16
11) 7(K)
i 1'.
34.5
21 4
7.1
6.1
T 9 N. R 24 E, sec. 1. .
16
9 74i
5.5
32.0
19.5
6.5
T 8 N R 23 E sec. 15
16
11 (KM)
4
43.5
22.0
7.3
4.0
T 4 N R 21 E sec 32
16
13 112
4.7
43 5
26 2
8.7
4.7
TlOandllS R25and36E
17, 495
12' 200
33.0
24.4
8 1
T 4 and 5 S, R 20 and 21 E ...
i, ;!.):(
6.710
32.5
13 4
4.5
T 3 and 4 S, R 19 E
3 820
6 770
33.5
13.5
4,5
T 7 S R 22 E
300
8 139
33.0
16 2
5 4
Volume equivalents:
Lumber (board feet)..
500
1 000
1 500
2 000
2 500
3 000
3.500
4.000
.25
50
.75
1.0
1.25
1.50
1.75
2.00
OREGON AND WASHINGTON.
Oregon.
Washington.
Total area
acres 10 000 000
3 400,000
Total stand...
board feet 70, 000, 000, 000
17, 000, 000, 000
Volume per acre
do 7 000
5,000
Total annual cut (1917)
do.... 470,488,000
220,924,000
Total area annually cleared (1917)
acres 67 212
44,185
Total annual volume of stumpwood
cords.. 235,244
110,462
Western yellow pine occurs on about 14,000,000 acres in Oregon,
practically a quarter of the State and half of its timbered land. Of
this area about 10,000,000 acres may be classed as commercial forest,
the estimated stand amounting to 70,000,000,000 board feet, or an
average of 7,000 board feet an acre, interforest waste areas in-
cluded (6).
TABLE 4Rcprcsentatir( irrxtern yelloiv-vim stands in Oregon.
Location.
Area.
Average number of trees.
Per cent
of stand.
12-inch
and over.
18-inch
and over.
24-inch
and over.
Near Austin and Whitney
Acres.
258
44
30
159
25.42
34.57
32.00
25.37
18.97
21.34
21.23
19.85
13.78
15.48
15.10
15. 41
83.2
87.3
1 99.5
75.2
Near Looldngglass Creek
Near Embody
Klamath Lake Section. . .
Table 4 shows average stands of Oregon yellow pine more or less
mixed with other timber. Pure stands contain a proportionately
greater number of trees. In cruises made by the United States
( " "logical Survey, on pure, heavy stands of yellow pine near Kich-
land, the average number of trees above 12 inches on strip acres
ran from o<) to !">. and of those above 22 inches, from 15 to 24.
The timber on tliese strips, ninning about IDjiDii tVet M n acre, will
yield approximately 5 cords of stumpwood an acre.
DISTILLATION OF STUMPWOOD.
Munger (6) states that 42 per cent of all butt logs in Oregon are
fire scarred, and that 25 per cent of them are "pitched." The
average diameter of the " pitchy " area on the basal cross section of
the log is 14.7 inches on a tally of 1,184 butt logs. This means that
25 per cent of the stumps would also be " pitched " as the result
of fire alone (p. 8).
TABLE 5. Cruises on the Whitman National Forest, 1912-1916.
Number of stumps per acre.
Volume.
Location.
Area.
Total
Vol-
ume per
acre.
24-inch.
28.5-
inch.
33.5-
inch.
37-inch.
Per
acre.
Ter
area.
Acres.
Bd.ft.
Bd.ft.
Cords.
Cords.
T10S, R34E,sec.l9. ..
640
8, 511, 000
13, 299
26.59
13.29
8.86
6.649
6.649
4,255
T10S, R34E,sec.33. ..
640
6, 220, 000
9,718
19.43
9.72
6.48
4.859
4.859
3,109
T10S, R34E,sec.34. ..
640
7, 440, 000
11,006
22.00
11.00
7.34
5.503
5.503
3.521
T11S, R34E,sec. 1.. ..
640
5, 128, 000
8,012
16.02
8.01
5.34
4.006
4.006
2,564
T11S, R34E, sec. 2.. ..
640
5, 716, 000
8,931
17.86
8.93
5.95
4.465
4.465
2,857
T11S, R34E,sec. 11. ..
640
6,992.000
10, 925
21.85
10.92
7.28
5.462
5.462
3,495
T11S, R23E,sec.23. ..
640
6, 260, 000
9,781
19.56
9.78
6.52
4.890
4.890
3,130
T12S, R34E, sec. 3.. ..
640
5,900,000
9,287
18.57
9.28
6.19
4.643
4.643
2,971
T12S, R34E, sec. 10. ..
640
4, 776, 000
7,448
14.89
7.44
4.96
3.724
3.724
2,383
T 12S, R 34E, sec. 21 ...
640
3, 153, 000
4,926
9.85
4.92
3.28
2.463
2.463
1,576
T 12S, R 34E, sec. 28. . .
640
8,110,000
12, 672
25.36
12.68
8.45
6.336
6.336
4,056
Total
7,040
67,701 000
33, 916
Average
9,474
18. 95
9.47
6.32
4.737
4. 737
Stand on 56 forties
2,240
30, 821, 000
13, 759
27.52
13.76
9.17
6.879
6.879
15,409
Stand on 27 sections
17,280
153, 565, 000
8,886
17.77
8.88
5.92
4.443
4.443
76, 775
The total stand of western yellow pine for Washington is 12,500,-
000,000 feet in private and State ownership, and 4,500,000,000 feet in
Government ownership, or a total of 17,000,000,000 board feet.
Allowing a stand of 5,000 feet an acre, which is thought to be low,
since Oregon and Washington are similar, the Washington area will
be approximately 3,400,000 acres.
The area of the yellow-pine land in the two States is approxi-
mately 13,400,000 acres, carrying a commercial stand of from 5,000
to 7,000 feet an acre, or the equivalent of from 10 to 14 trees 24 inches
on the stump, which will yield from 2 to 6| cords of yellow-pine
stumpwood an acre.
IDAHO, MONTANA, AND UTAH.
Idaho.
Montana.
Utah.
Total area
acres
10 000 000
3 500 GOO
(i)
Total stand..
board feet
5S 050 000 000
14 OOO'OOO'OOO
m
Volume per acre
do
5 800
4 000
4 000
Total annual cut (1917)
do
315 009 000
150 905 000
4 676 000
Total area annually cleared (1917)
Total annual volume of stumpwood . . .
acres..
cords..
54', 311
157,504
' 37^726
75, 452
1,169
2,338
i No reliable figures obtainable.
Many large areas of yellow-pine timber in Idaho are as good as
the best of that in California and Oregon, but as a whole the stand
8
BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
will probably average close to 6,000 feet an acre. Conservative
estimates for the area would be 10,000,000 acres, and for the total
stand, 50,000,000,000 feet.
There is much wastage in butt logs, due to " pitchiness " resulting
from fire scars and natural causes. Fires tend to make the stumps
more resinous and to increase the number of those sufficiently " fat "
to serve for purposes of distillation. It has been the experience of
an Idaho lumber company that some of these " pitchy " butts occur
in all the western yellow-pine timber. They state that these pitchy
butts are more prevalent in the northern section of Idaho, but that
this territory and the Baker, Oregon (Blue Mountain), territory pro-
/.O ./ .2 .3 4 .J .6 .7.3.3 20J.2J4-.J.0 .7.3 .3 &?./.'.(? .4 .30 .7.0' WM.
/* ' /VtfS -2.3 4- .J~.0 7.8 .& to./ ?.3 4- tf.C 7.8.9 Z'Corfs
FIG. 2. Yellow-pine stumpage in 6 western States. A, volume of tree (thousand board
feet) ; B, volume of stumpage (cords) ; C, difference between diameter breast high and
diameter stump high (inches).
duce less " pitchy " lumber than any other yellow-pine section that
has come under their observation.
From this it would seem that the question of " pitchy " butts is
important, and should not be ignored by those who attempt to de-
termine the amount of resinous wood to be obtained from any lo-
cality. Since 25 per cent of the butt logs from the Blue Mountain
region bear more or less pitch, and a wastage in " pitchy " butts
trimmed off of from 4 to 5 cords a day is reported by one company,
this constitutes a very important source of valuable wood for dis-
tillation purposes. Samples sent to the University of Idaho com-
pared favorably with the best stumpwood in yield of products. The
DISTILLATION OF STUMPWOOD.
9
mill which submitted the samples was compelled to sell more than
a million board feet of yellow-pine lumber at a loss, because of the
amount of " pitchy " lumber in the butt logs. Inspection by one of the
writers showed a large amount of this wood to be suitable for distil-
lation.
TABLE 6. Average volume of loestern yellow pine and reduction factors for
various volumes and diameters of trees and stumps (Idaho and Montana).
Diameter.
Average volume.
Reduc-
Reduc-
for
different
Breast
high.
breast
height
to stump
height.
Stump
high.i
Of tree.
Of stump.
volumes
and
diame-
ters.
Inches.
Inches.
Inches.
Bd.ft.
Cords.
22
2.0
24.0
500
0.25
1.0
23
2.0
25.0
550
24
2.0
26.0
600
25
2.0
27.0
675
26
2.0
28.0
750
0.375
1.5
27
2.0
29.0
850
28
2.0
30.0
,000
0.50
2.0
29
2.5
31.5
,150
30
2.5
32.5
,250
0.625
2.5
31
2.5
33.5
375
32
2.5
34.5
^500
0.75
3.0
33
2.5
35.5
.625
34
3.0
37.5
1,750
0.875
3.5
35
3.0
38.5
1,875
36
3.0
39.0
2,000
1.00
4.0.
37
3.0
40.0
2,250
1.125
4.5
38
3.0
41.0
2,400
38.5
3.5
42.0
2.500
1.25
5.0
39
3.5
42.5
2,600
40
3.5
43.5
2,700
40.5
3.5
44.0
2 850
42
3.5
45.5
3,000
1.50
6.0
1 See also Figure 2.
TABLE 7. Cruise of 160 acres of western yellow pine in Boise County, Idaho (all
trees calipered).
Average diame-
ter.
Num-
ber
Ptumpwood.
Num-
stumps
Aver-
ber
per acre
Eauiv-
age
24-inch
equiva-
alent
Location.
stand
stumps
lent,
used in
per
acre.
Breast
high.
Stump
high.i
per acre
eauiva-
lent.
based
on aver-
age
Per
acre.
Per
section.
reduc-
tion.
diame-
ter.
Bd.ft.
Inches.
Inches.
Cords.
Cords.
Bd.ft.
T 6N, R 5E. sec. 8 NW NW
14 693
25 5
27 5
29 38
20 55
7 34
293 6
715
T 7N. R 4E, sec. 35 SE NE . . .
15,144
27.4
29.4
30.29
16.83
7.' 57
302.8
900
T 7N, R 4E, sec. 35 NE NE.
13,866
25.5
27.5
27 73
19 40
6 93
277 2
715
T 7N, R 4E, sec. 35 NE SE .
15 783
26.7
28 7
31 57
18 70
7 89
315 6
800
Average, 4 forties
14,896
26.27
28.27
29.74
19.12
7.681
2189.2
782.5
1 From Table 6.
2 Total number of cords of stumpwood for entire area.
10 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
TABLE 8. Cruises of 478.85 acres of western yellow pine in Latah County, Idalw.
Average diame-
ter.
Num-
ber
Stumpwood.
Num-
stumps
Aver-
age
ber
21-inch
per acre
equiva-
Equiv-
alent
Location.
stand
stumps
lent,
used in
per
acre.
Breast
high.
Stump
high.i
per acre
equiva-
Fent.
based
on aver-
age
Per
acre.
Per
area.
red uc-
tion.
diame-
ter.
Bd.ft.
Inches.
Inches.
Cords.
Cords.
Bd.ft.
T 39N R 1W sec 2 lot 7
R 7.10
29
31.5
17.50
7.60
4.18
162. 39
1,150
T39N, R lW,scc. 9 SE NW 10,625
34
37.5
21.25
6.07
5.12
204.80
1,750
T39N. R IW.sec. 23 NE SW... ' 8750
34 37. 5
17.50
5.00
4.19
167.60
1,750
T 40N R IW.sec. 23 NE SW i 7500
28 30-0
13.00
7.50
3.75
150.00
1,000
T40N, R IW.soc. 24NENE... .10,500
26
28.0
21.00
14.00
5.25
210.00
750
T40N, R IW.sec. 24 NESE.. 8925
26
28.0
17.86
11.89
4.46
17v in
750
T40N,R2W,sec. 14SENW.... n.x7:>
28.0
23.75
15.83
5.93
237.20
750
T 42N R 3W sec 36 NE NW 17 500
29 31.5
35.00
15.30
8.75
350.00
,150
T 41N, R 4W,sec. 29 SE SE... 9,625
34 37. 5
19.25
5.50
4.81
192.40
,750
T 41N, R 4W, sec. 31 SE NW 10.000
32 34. 5
20.00
6.67
5.00
200.00
,500
T 42N, R 4W, sec. 33 SE N W . . .
11,500
30 32. 5
23.00
9.20
5.57
222.80
.-'.-(>
T 42N, R 5W, sec. 36 SW SE ..
11,000
29. 5 32.
22.00
9.17
5.50
220.00
,200
Average, per forty
10,545
29.8
32.38
21.09
9.48
5.21
207.97
1,229
1 From Table 6.
TABLE 9. Recapitulation of cruixes.
Location.
Area
cruised.
Total stand-
Volume
per acre.
Number
24-inch
trees per
acre
equiva-
lent.
Stumpwood.
Per acre.
Per area.
T 39N, R 1W, B M...
Acres.
4,840
10,291
7,380
4,733
6,147
4,240
Bd.ft.
24.967,000
52,218,000
69, 125, 000
36, 894, 000
37, 525, 000
25,680,000
Bd.ft.
5,158
5,074
9,366
7,729
6,098
6,056
10.32
10.15
18.73
15.46
12.21
12.06
Cards.
2.57
2.53
4.68
3.86
3.04
3.02
Cords.
12,438
26,136
34,538
18,423
18,686
12,804
T 40N, R 1W, B M
T 40N, R 2W B M
T 42N, R 3W.B M...
T 41N, R 4W, B M
T 42N, R 4W B M
Total
37,671
246,409,000
123, 025
Average
6,580
13.15
3.28
1 The estimates include only yellow pine, which constituted but 53.34 per cent of the entire stand. A
pure stand would be heavier.
In all tables a slight discrepancy will be noticed between the total
number of cords of stumpwood, when added and when computed.
This is due to the dropping of decimals and the using of even numbers
only in cruise tables.
The average stand over large areas of yellow pine in Idaho is from
5,000 to 15,000 board feet an acre, or from 10 to 30 trees, '24 inches in
diameter on the stump, the volume of stumpwood running from *2\ to
8 cords an acre. For more open stands the number of Mumps will
be less, but such stumps are generally larger and consequently more
resinous. Therefore the volume of " pitchy" wood will be consider-
able, but can be determined only by a field survey of each region.
DISTILLATION OF STUMPWOOD.
11
TABLE 10. Cruises of 3,200 acres of western yellow pine in Boise County,
Idaho. 1
Location.
Av-
erage
per acre
for sec-
tion.
Average diam-
eter.
No. 24-
inch
stumps
per acre
equiv-
alent.
No.
stumps
per acre
equiv-
alent,
based
on av-
erage
diam-
eter.
Stump wood.
Diam-
eter
equiv-
alent,
used in
r^duc-
tion.
Breast
high.
Stump
high.
Per
acre.
Per sec-
tion.
T 7 N R 5 E, sec. 12
Bd.ft.
9,945
10,960
15, 336
18, 814
10, 453
Inches.
29.2
25.5
28.5
31.0
22.3
Inches.
31.7
27.5
30.5
35.5
25.3
19.90
21.92
30.66
37.63
20.90
8.50
15.10
14.60
13.68
18.66
Cords.
4.97
5.19
7.66
9.40
5.22
Cords.
3, 180. 8
3,321.6
4,902.4
6,016.0
3,340.8
Bd.ft.
1,170
715
1,050
1,375
560
T 7 N. R 4 E. see. 35
T 14 N R 5 E, sec. 30
T 14 N. R 3 E, sec. 12
T 13 N, R 5 E, sec. 7
Average
13, 101
27.3
29.7
26.20
14.11
6.51
220,761.2
974
1 Only yellow pine which is practically all over 22 inches diameter, breast high, or 24 inches diameter,
stump high, is included.
2 Total number of cords of stumpwood for the entire area.
TABLE 11. Recapitulation of cruises of 509,670 acres of pure western yellow
pine.
Location.
Area.
Diam-
eter,
stump
high.
No. trees.
Av-
erage
diam-
eter,
stump
high.
Av-
erage
No.
bd.ft.
per
tree.
No.
bd.ft.
per
acre.
Av-
erage
no. 24-
inch
stumps
per acre
equiv-
alent.
No.
stumps
per
acre
of av-
erage
diam-
eter.
Av-
erage
no.
cords
stump-
wood
per
acre.
Total.
Av-
erage
per
acre.
Kaibab National For-
est
Acres.
300,000
Inches.
13-16
18-22
24+
3,258,000
2,400,000
2,220,000
11.76
8.00
6.74
Inches.
15.00
20.18
28.70
145
330
820
1,705
2,600
5,527
Total
11.05
6.74
4.0
8,148,000
298, 908
167,808
403, 788
25.50
9,838
South Payette River,
Payette National
Forest
___-!' _'-
52, 440
13-16
18-22
24 +
5.7
3.2
7.7
14.8
21.1
28.2
140
410
770
798
1,312
5,929
Total
11.86
7.50
3.62
870,504
16.6
8,039
Middle Fork, Payette
National Forest
Total
58,690
13-16
Ir22
24+
297,558
190,742
434,306
5.07
3.25
7.40
15.38
20.50
29.50
165
355
900
786
1,154
6,660
=
=
-. -.
13.32
7.40
3.9
922,606
15.72
8,600
Weiser National For-
est
98,540
13-16
18-22
24+
451,367
274,926
675,984
4.68
2.79
6.86
14.29
20.04
29.00
120
325
850
562
907
5,831
^^
Total
11.66
6.86
3.36
1,402,277
14.33
7,300
All commercial stands of yellow pine in Montana are confined to
the western part of the State. Much of the timber is of about the
same grade as that found in Idaho, but the stand usually is lighter
and the timber a little shorter, and as a rule it contains a slightly
smaller percentage of " pitchy " stumps. Many large areas in the
12
nr 1. 1. 1. TIX loon, r. s. DKPAKT.MKXT OF AGRICULTURE.
State carry heavy stands of from 5,000 to 7,000 board feet, and in
time the resinous wood may lv handled to commercial advantage.
The working tables for Idaho can readily be applied in efforts to
determine the volume of stumpwood on any area. The average stand
to the acre for the entire commercial yellow-pine region of the State
may be taken to be 4,000 board feet.
The yellow-pine region of Utah is scattered over an extensive area,
and until a more detailed survey is made it will be impossible to
state the value of the stumpwood for distillation purposes. As a
rule, it is far from transportation facilities and markets, so that for
the present it may be considered as having but a slight bearing on
the distillation problem. It has been assumed that the average stand
from which the 1917 lumber cut was obtained carried 3,000 board
feet an acre. In all probability it was decidedly higher, as the best
stands are generally being cut first. This would reduce the number
of acres a'nnually cleared, but would not affect the volume of stump-
wood.
COLORADO, SOUTH DAKOTA, AND WYOMING.
Colorado.
South Dakota.
Wyoming.
Total area J
acres
916,415
707,000
8,000
Total stand >
board feet
1 618 614 000
2 873,000 000
23 500 000
Volume per acre
do....
1,766
4,063
2,937
Total annual cut (1917)
do
35,328 000
29,045,000
3 678 000
Total area annually cleared (1917)
Total annual volume of stumpwood
acres..
. t cords..
20,004
17,664
7,149
14,522
1,252
1,839
i From Forest Service records.
The commercial stands of yellow pine in Colorado are confined
in a large measure to the national forests. They are scattered over
nearly a million acres, but the volume to the acre is lower than
that in any other State. It is not probable that any value may be
derived from this stumpland in the way of distillation products.
The chief yellow-pine area in South Dakota is located in the
Black Hills region. The average stand for the 707,000 acres is
4,063 board feet an acre, making the volume of stumpwood about
two cords an acre, which is thought to be low for distillation pur-
poses, as the wood is not especially resinous.
The stand in Wyoming is so small as to be entirely negligible for
the purposes of distillation.
SUMMARY.
This brief survey shows that the quantity of stumpwood is enor-
mous and that the problem of handling the cut-over areas is of first
importance. It is known, however, that not all of these stumps
arc sufficiently resinous for profitable distillation, under present
conditions.
DISTILLATION OF STUMPWOOD. 13
TABLE 12. Annual lumber cut of western yellow pine in the United States (9).
Volume.
State.
1914
1915
1916
19171
Stumpwood 2
California
Bd.ft.
409 953 000
Bd.ft.
389 991 000
Bd.ft.
494 973 000
Bd.ft.
478 565 000
Cords.
239 282
Oregon ...
210. 438. 000
189, 203, 000
399, 102, 000
470, 488, 000
235,244
Washington
175. 426. 000
148,789 000
188 215,000
220,924 000
110 462
Idaho
159, 839, 000
201, 858, 000
240, 160, 000
315,009,000
157,504
Montana
134, 568, 000
118, 920, 000
138, 206, 000
150, 905, 000
75, 452
Arizona
78.667 000
75, 843, 000
92 133 000
78 147 022
39, 074
New Mexico
54, 728, 000
61,466,000
72,004,000
76, 149, 793
38,074
Colorado. . .
65,117,000
37, 241, 000
27, 848, 000
35, 328, 000
17,664
South Dakota
18,744 000
22 457 000
25 466 000
29 045 000
14, 522
All other
19, 885, 000
6,476,000
6,880,000
8,354,000
4,177
Total
1 327 366 000
1 252 244 000
1 684 987 000
1 862 914 815
931 455
1 From records of the district foresters.
2 For 1917 only.
SUMMARY OF TABLE 12.
Total volume, 1914-1917, inclusive (board feet). . 6, 127, 511, 815
Total area equivalent cleared, 1914-1917, inclusive, assuming 5,000 feet
as average per acre .' (acres) . . 1, 225, 502
Total stumpwood, 1914-1917, inclusive , (cords) . . 3, 063, 755
If the areas are not agricultural in character, they should be
allowed to reforest. In this case the land-clearing problem is not
so important, although the stumps should be utilized, if it is economi-
cally possible to do so. Table 12 shows that for the entire area of
western yellow-pine land the average volume of stumpwood is 2.5
cords an acre, or 100 cords for every 40-acre tract. Probably half
of this land carries double this amount of stumpwood. Be that as it
may, it is certain that many thousands of cords of stumpwood must
be removed before those who desire to make homes on the splendid
yellow-pine lands, some of which are known to be among the best
remaining lands obtainable for agriculture, can bring them into the
proper state of cultivation and production.
PURPOSE OF INVESTIGATION.
In January, 1914, the Bureau of Chemistry, United States Depart-
ment of Agriculture, in cooperation with the Department of For-
estry of the University of Idaho, at Moscow, Idaho, began a study
of the destructive distillation of logging and land-clearing waste in
the State of Idaho, particularly of the yellow-pine stumps of that
region. These investigations were instituted with the twofold pur-
pose of ascertaining the feasibility of more effectively utilizing the
timber resources of the Northwest and of reducing the net cost of
clearing cut-over lands for agricultural purposes by the recovery of
commercially valuable products from the stumps. The work resolved
itself into determining (a) the nature, amount, and probable value
of certain by-products obtained in clearing the land of stumps by
14 BTLLKTIX 1003, U. S. DEPARTMENT OP A< iIM( TLTURE.
burning and the practicability of recovering these products by this
method, and (b) the yield and value of products obtainable from
yellow-pine stumpwood throughout the State when subjected to re-
tort distillation.
The chief aim of the cooperative work was to determine the value
for distillation purposes of western yellow-pine stumps and such
other logging or land-clearing waste in the State of Icttiho as might
lend itself to the treatment. The abundance of yellow-pine waste
is readily inferred from the volume of such lumber sent to market
from mills throughout the State, and the relative abundance of yel-
low-pine stumps in any section can be ascertained from timber-cruise
records, supplemented by the proper volume tables. The quality of
the stumps with respect to their resin content, on which depends
their value for distillation purposes, however, can not be determined
from such field or timber-cruise data. The results of careful field
inspections have led to the conclusion that much of the western yel-
low pine is of the relatively nonresinous or "bull pine" variety.
Even the more resinous yellow-pine stumps varied so widely in their
resin content that it soon became apparent that field investigations
were indispensable to a proper knowledge of the proportion in which
the various grades of stumps occur in the regions from which samples
were collected. A knowledge of the conditions in the yellow-pine
belt of the Atlantic and Gulf States made this all the more impera-
tive, for the reason that the apparent preponderance of the lower
grade of stumps clearly indicated that the profitable utilization by
distillation of all yellow-pine stumps would be found impracticable,
and that success in utilizing any of them would depend on a proper
selection of material to be treated.
From an agricultural standpoint the object of the work was to
determine the practicability of reducing cut-over land clearing costs
through recovery of by-products from the stumps. The extent to
which distillation products from the stumps can be made to defray
the cost of clearing such land obviously depends, among other things,
on the total number of stumps to the acre, the number of these stumps
suited to distillation purposes, the yield and value of the by-products,
and, finally, the cost of recovering these by-products from the stumps
to be treated. The first of these probably can be fairly well estab-
lished from timber-cruise records for regions in which such data are
available; the second is a combined field and laboratory problem; the
third a laboratory and trade inquiry problem ; and the fourth a field
and chemical engineering problem. The work accordingly resolved
itself into an investigation involving each of these closely related
problems.
DISTILLATION OF STUMPWOOD. 15
TAKING SAMPLES.
In the spring of 1914, samples, with the attendant field data, were
obtained from four acres in different parts of the State typical of
the regions they were selected to represent, namely: (a) Cut-over
land of a lumber company in Latah County, hereafter referred to as
the Potlatch-Deary region; (l>) the Coeur d'Alene and Hay den Lake
region; (c) the South Idaho or Boise-Payette region; and (d) the
Craig Mountain or Winchester region.
In these field-sampling operations a rapid reconnaissance trip was
made to get a general idea as to the abundance and apparent quality
of the stumps in a region. On the basis of such knowledge an area
considered representative of the district was selected, from which
samples representing the different qualities of stumps, together with
data for an estimate of their relative abundance and number per
acre, w r ere taken.
In the beginning the stumps were arbitrarily classed as " rich "
when the top showed a marked resinous exudation, or, if burned over,
revealed decidedly resinous wood when cut into with an axe, as
"medium" when it showed but little of such exudation, and as
"poor" when, although apparently sound, it was devoid of any
resinous exudation. All stumps containing little if any resinous
wood are classed as " bull pine," despite the fact that this term is
usually limited to the western yellow pine less than 24 inches across
the stump.
Selected stumps of each class were removed by blasting, and only
enough of their heartwood was taken to make, with wood from other
stumps of the same quality, a cord sample of that class. This cord,
or a smaller sample selected from this measured cord, was then
shipped to Moscow for the experimental work.
In all cases the sapwood was split off and rejected; hence the re-
sults obtained in this investigation do not show what can be ob-
tained from the whole stump of each quality, but only from the
resinous heartwood. Because the western yellow-pine stumps ordi-
narily contained so little heartwood (on an average about 50 per
cent), stumps under 24 inches were considered only when they con-
tained larger proportions of the resinous heartwood. Such stumps,
in later years, should the sapwood rot off while the heartwood re-
mained sound and resinous, would then be practically 100 per cent
resinous, but, of course, would yield a much smaller quantity of
total wood.
Distinction between " yellow pine " and " bull pine" The term
" yellow pine " is here used to designate such members of the Pinus
ponderosa group as contain an appreciable portion of relatively resin-
16 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
ous, dark-colored heartwood, compared to the sap wood layer. " Bull
pine," although often large, has relatively no such high proportion
of the richer resinous heartwood. Botanically, the "bull pine' 1 is
considered to belong also to the Pinus ponderosa, or western yellow-
pine group, appearing to differ from the "yellow pine" only in
being a less mature or more rapidly developed tree. Whatever may
be the cause, the important fact remains that " bull-pine " stumps,
aside from their content of what appears to be sapwood, are all but
devoid of resinous matter and are utterly worthless for the recovery
of turpentine or other distillation products (Table 14). " Bull-pine "
stumps, irrespective of their size, therefore, are not included in the
number of yellow-pine stumps to the acre in a given area or section,
which makes it highly important to remember that no such distinc-
tion between these classes of stumpage is made by timber cruisers.
POTLATCH-DEARY REGION.
The southwest quarter of the southeast quarter of section 15, town-
ship 40 north, range 2 west, readily accessible and fairly represen-
tative of the number, size, and quality of stumps to the acre of
yellow-pine land in the Potlatch- Deary section of the State, had had a
yellow-pine stand of 395,000 board feet a " forty," averaging 500
feet a tree. The average yellow-pine stand for the township was
234,000 board feet to 40 acres.
The stumps were taken from a south slope, a ridge, and its adjacent
lowland. The trees had been felled six or seven years before, and
the stumps were generally found with all the bark. A few burnt-
over stumps, of which the bark and sapwood had been destroyed,
from trees said to have been dead when cut and in some cases felled
for fuel wood 13 years earlier, were included. Ten stumps of each
class were blown out and enough of the heartwood from each stump
taken to make up a cord sample of each class. The stumps were re-
moved by blasting with both 40 per cent and 20 per cent dynamite.
Few of the stumps were removed entirely by the blast, most of them
being either split through the middle, with only part of the stump
thrown out, or left standing in a shattered condition. It was neces-
sary, therefore, to employ a team of horses to remove enough of such
shattered stumps to obtain a sufficient portion of each for the samples.
All of the heartwood of the first few stumps shot out was removed
and split to approximately cordwood size, and a sample taken from
each stump thus entirely reduced. The labor cost, estimated at from
$4 to $5 a cord, made it so expensive, however, that only a portion
of each stump sufficient to obtain enough for a sample was reduced.
The diameters of the ten " rich " stumps varied from 24 to 40 inches,
with an average of 32 inches: those of "medium" quality, from 26
to 36 inches, with an average of 30 inches; and the "poor" stumps,
DISTILLATION OF STUMPWOOD. 17
from 24 to 36 inches with an average of 28 inches. The cost of
shooting the 30 stumps was as follows (spring, 1914) :
Two men, 2^ days, at $2.50 a day of 10 hours $12. 50
50 pounds of 20 per cent dynamite 7.50
165 pounds of 40 per cent dynamite 28. 05
Fuses and caps 2. 75
Total 50. 80
Splitting the 30 stumps so as to obtain from each a sufficient por-
tion for the sample required the work of 3 men for 3 days, which,
at $2.50 a 10-hour day, amounted to $22.50. The cost of gathering
and hauling the 3 cords of wood, requiring the services of 2 men and
a 2-horse team for three-fourths of a day at $7.50 a day, was $5.62.
If special stumping powder, selling for $12.50 a 100 pounds at that
time, had been used, the powder cost could perhaps have been reduced
by 20 per cent, or to $30 for the 30 stumps. The labor cost of plac-
ing the shot holes and shooting the stumps could probably be reduced
on a steady job. Against this it should be said that to have removed
all the stumps completely would have required the time of a man
and a team of horses for an additional day, as well as extra powder,
fuses, and caps. The labor cost of shooting the 30 stumps should
accordingly be left at $12.50. To have split the stumps completely
so as to recover all the heartwood and permit the handling of the
pieces by 2 men would have taken the 3 men 3 days more, making
the cost of splitting the 30 stumps $45. On a steady job with men
accustomed to the work, provided with tools or equipment that
experience would suggest, this item possibly could be reduced by
at least 50 per cent, or, in this case, to $22.50. On the basis of an
average of 50 per cent heartwood in the stumps, it is estimated that
at least 3 stumps are required to make a cord of wood, or about 10
cords from the 30 stumps. To gather up, haul, and load this on the
car would cost 10/3 times $5.62, or $18.73. Summing up on this
basis, the cost of these 10 cords of wood loaded on the car after a
1-mile haul is :
Powder, fuse, and caps $30. 00
Shooting 12. 50
Splitting 22. 50
Gathering and hauling 18. 73
Total 83. 73
Cost u cord . 8. 37
Liberal allowances have been made in the items on which the cost
of this yellow-pine stumpwood depends, and the cost a cord is con-
fidently believed to be a minimum one. A material reduction of this
figure need be expected only from the use of hitherto undeveloped
60953 21 2
18 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
land-clearing methods, from a failure on the part of the farmer to
charge the value of his time and equipment in shooting, reducing,
and hauling the stumps against the cost of the wood so delivered, or
from a decided reduction in the selling price of explosives or in
labor.
The conclusions based on this method of sampling were subse-
quently checked by removing all the yellow-pine stumps on a typical
acre, taken to represent a good stand of large yellow pine in the
Potlatch- Deary yellow-pine region, in the southwest quarter of the
southeast quarter of section 36, township 42 north, range 5 west.
The yellow-pine stand on this " forty " was 540,000 board feet, of
which 240,000 board feet were from trees averaging TOO feet a tree,
and 300,000 board feet from trees averaging 2,500 feet a tree. This
figures out to a stand of 9 of the smaller trees containing a total of
6,000 feet and 3 large trees containing a total of 7,500 feet, or a
total of 13,500 feet an acre. Of the 12 yellow-pine stumps on this
chosen acre, 9 averaged 30 inches and 3 averaged 45 inches in di-
ameter. The proportion and quality of the heartwood were so
markedly different in the large stumps, as compared with that in the
small stumps, that the woods from the large and small stumps were
collected separately as two samples, and are hereafter referred to
as " large " and " small " yellow-pine stumps, Potlatch, Idaho.
A sample taken from so-called " rich butts," " tops," etc., was
collected throughout the area from which the stumps at Deary were
obtained, where a large amount of this material is available in the
form of dead standing trees and windfalls. Judged by its appear-
ance, little, if any, of it is rich in resinous matter. Hence one sample
only, designated in the tables as " dead, down wood," was selected
from the richer material of this class.
COEUR D'ALENE AND HAYDEN LAKE REGION.
The Coeur d'Alene and Hayden Lake region, taken as being rep-
resentative of cut-over yellow-pine lands in northern Idaho, proved
to be an unwise selection, as a larger proportion of " bull pine " or
nonresinous material was found there than in the Pend d'Oreille
River country farther to the north. It should be considered typical
rather of the yellow pine in the territory within a 50-mile radius of
Spokane. Two yellow-pine samples were taken, one on a ranch some
2 miles northwest of Hayden Lake towards Garwood, the other from
the Mica Bay section of Coeur d'Alene Lake. The first was repre-
sentative of the average quality of yellow-pine stumps proper in the
Hayden Lake region, few, if any, of which showed resinous exuda-
tion, and approximated 20 to 35 an acre in the closest yellow-pine
stand of this region, which had been cut over a few years before.
DISTILLATION OF STUMP WOOD. 19
The sample collected at Coeur d'Alene Lake was from " rich " stumps
on a 20 to 30 acre tract near Mica Bay, not yet brought under culti-
vation. Stumps of the quality represented by the sample do not
occur in commercial quantities in the Coeur d'Alene Lake region.
SOUTH IDAHO REGION.
The wooded country throughout the South Idaho region is prac-
tically undeveloped and without railroads. The forests remain un-
touched, except in a few places where small-scale logging operations
have been carried on to supply local mills. The timber resources are
now being opened up for extensive logging operations to supply a
mill of about 200,000 feet daily capacity at Barber, some 6 miles
out from Boise.
Working out from this company's logging camp, about 35 miles
northeast of Boise, a hasty survey was made of an area which had
been cut over in places 7 or 8 years before the company had taken
over the land or timber rights. Although the timber throughout this
region is largely yellow pine, few of the stumps appeared pitchy
enough to be considered " rich." Fully 50 per cent were unsound
and therefore worthless for distillation purposes. The stand of yel-
low-pine trees or stumps 24 inches or more in diameter is estimated
as not exceeding an average of 10 an acre. The actual count for
several 1-acre plots, taken to represent a close stand, was 20, 22, and
18 trees, respectively. Three 1-acre plots taken to represent a stand
of medium density ran 10, 6, and 9 trees an acre. Toward the other
extreme the stand diminished to where, on the higher ridges, no yel-
low pine was encountered.
According to one of the company's cruisers, the whole of the Boise-
Payette pine belt is very much like the land traversed, and an esti-
mate of 10 yellow-pine trees, over 24 inches in diameter, an acre is
liberal.
Of the total number of yellow-pine stumps on a given area in the
old cuttings perhaps 1 out of 25, or not to exceed 5 per cent, may be
considered as belonging to the " rich " or " pitchy " class, probably
40 to 50 per cent are of " medium " quality, and the remainder of a
quality from which it was not considered worth while to take a
sample. Four samples were taken: (a) One from old cuttings to
represent the "rich." or "pitchy," stumps; (b) one of "medium"
quality, from the old cuttings; (c) one from green stumps from
which the tree had been felled within a month of the time the stumps
were shot ; and (d) one of green " bull-pine " stumps. Samples c and
d, included because they were the stumps and logs from freshly
fallen trees, though containing no well-defined heartwood, had an
abundant exudation of what appeared to be gum on the freshly cut
20 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
surface. There was a little dead, down wood, and, as the tops of
freshly fallen trees did not appear to be essentially different from
those seen elsewhere and were obtainable nearer Moscow, a sample
of this wood was not taken. It was difficult to judge the relative
quality of the green stumps other than by the proportion of heart-
wood to sapwood, the apparent resin content of the heartwood being
quite uniform. The proportion of truly resinous heartwood to sap-
wood varies greatly, however, a matter of importance in considering
the value of the stumps, owing to the dearth of resin in the sapwood.
Probably 50 per cent of the green yellow-pine stumps are of the
quality represented by sample, and the remainder of inferior quality,
in so far as the proportion of heartwood to sapwood is concerned.
It would be very difficult to remove these stumps unless they were
taken out with the logging operations, because of the fact that the
mountainous topography and limited rainfall preclude an extensive
agricultural development in the wake of the logging operations. The
surface of the land presents an irregular series of steep ridges be-
tween which wind deep, narrow valleys, where spur tracks are laid
for the logs which are skidded down the hillsides to be loaded on
tracks, moved as fast as the logs are taken away. The stumps,
therefore, become inaccessible as soon as the tracks are taken up.
CRAIG MOUNTAIN REGION.
The yellow pine of the Craig Mountain region is a practically
pure stand over an area some 10 miles long by 5 miles wide on an
elevated, fairly level plateau. Receding from this central area the
timber opens abruptly on Mission Canyon and the prairie country
toward the north and west, and less abruptly toward the east,
while toward the south it soon becomes mixed with fir and tamarack
in the Salmon River country. A lumber mill with a daily capacity
of about 125,000 feet operates in Winchester, which is centrally lo-
cated in this yellow-pine belt. Comparatively little of the timber
had been cut.
In the central pine area the stand of yellow pine varied from
400,000 to 800,000 board feet a "forty," with an average of approxi-
mately 20 stumps over 30 inches in diameter an acre where the
stand was closest. The mill men and cruisers consulted agreed that
probably 25 per cent of the total stand throughout this region is
"bull pine."
Seven samples were taken from this region, as follows: (a)
Green yellow-pine stumpwood from several stumps blown out of
the roadbed in extending spur tracks for logging purposes; (b)
medium to rich stumpwood from stumps blown out in highway
construction; (c) medium to poor stumpwood from the same locality
in which the medium to rich samples were obtained; (d) medium to
DISTILLATION OF STUMPWOOD. 21
rich stumpwood shot on land that had been cut over 4 or 5 years
before; (e) dead, down yellow-pine wood collected from the better
quality of knots, limbs, and trunks of trees lying throughout the
woods; (/) rich, dead tops from trees felled in logging operations,
the tops of which were dead from advanced maturity, and dead
standing trees that had died from the same cause; (g) the better
quality of tops and limbs from freshly felled trees. In addition,
certain other samples were included in the investigation. The sam-
ple designated "rich stumpwood, Viola" was from western yellow-
pine stumpwood, from a ranch located near Viola. These stumps,
the last of those remaining scattered through the field, had been
shot out with dynamite, and the best snaked to the house for fuel.
It was from this lot, the weight a cord of which was estimated to
be 3,500 pounds, that a sample was taken. Trees cut from these
stumps were said to have been felled 35 or more years before. The
wood was very resinous, and to all appearances the same as the
better grades of pitch pine of North Carolina or other southern
States.
The sample 30-inch stump from Priest River, obtained from a
single large yellow-pine stump sent in from Priest River, Idaho,
was selected as representing the best of the rich, or pitchy, stumps
in that region. It had been blown out with dynamite, and the whole
stump, roots and body, split into several pieces by the blast, was
weighed, split, and reduced to stove-wood size. It was then mixed
by being thrown together in a heap and repiled five or six times,
after which it was neatly stacked under a shed. Dimensions of
the pile of wood thus stacked were 8x7x1.5 feet, equal to a volume
of 84 cubic feet. The stump weighed 2,190 pounds, so that as piled
o 1 9Q v" 1 28
this wood weighed -~r > or 3,330 pounds a cord, in round
numbers. The tree cut from this stump had been felled about
seven years, not long enough for the sapwood to have rotted away
or become detached from the lightwood within. This sapwood con-
tained absolutely no turpentine and impoverished the wood to that
extent. It is estimated to have constituted 20 per cent of the total
volume of wood in the stump.
The samples identified in Table 14 as "dead, down limbs" and
"fire-scarred butts, Viola" were from yellow pine taken near
Viola. Both samples were very resinous for these classes of wood.
There was not a sufficient quantity of either to determine closely the
weight of a measured cord. Nevertheless, if these facts are borne
in mind and these samples are considered with other samples of the
same classes of wood, they furnish an indication of the products to
be recovered from these materials, which are quite plentiful in some
sections. In some regions as much as 20 per cent of the butt logs
22 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
are fire scarred. The values on these samples given in Table 14 are,
therefore, only estimates.
SUMMARY.
Northern Idaho:
Rich stninpwood, Priest River.
PotlatHi I>e:iry Region:
Rich stumpwood, Viola.
I -. a<l. down limbs, Viola.
Fire-srimvd butt, Viola.
I'oor stumpwnoil, Deary.
Rich stumpwood, Deary.
Medium stumpwood, Deary.
Dead, down limbs, Deary.
Rich stumpwood, Potlatch (three large stumps).
Medium to rich stumpwood, Potlatch (from stumps other than the three
large, rich stumps).
Coeur d'Alene Region:
Rich stumpwood, Coeur d'Alene Lake.
Medium stumpwood, Hayden Lake.
Somh Idaho, Boise Region:
Bull-pine stumpwood, Boise.
Medium stumpwood, Boise.
Rich stumpwood, Boise.
Green selected stumpwood, Boise.
Craig Mountain Region:
Selected green stumpwood, Craig Mountain.
Rich roadside stumpwood, Craig Mountain.
Medium stumpwood, Craig Mountain.
Rich, cut-over stumpwood, Craig Mountain.
Dead, down limbs, etc., Craig Mountain.
Dead tops, limbs, etc., Craig Mountain.
Green tops, limbs, etc., Craig Mountain.
Moscow :
Tamarack stumpwood.
DISTILLATION OF SAMPLES.
PREPARATION.
The wood as delivered was sawed in lengths that would fit into
a pile of cord dimensions and split into pieces approximately 2
to 4 inches in diameter. It was then thrown into a heap, replied
a sufficient number of times to render it uniform in quality, corded,
taking care to pack closely, and left standing, protected from the
weather, until run. The entire sample thus prepared was weighed
on a portable platform scale immediately before the distillation,
and the weight calculated from its measured dimensions. In mak-
ing these weighings 3 separate portions, usually of 175 pounds each,
were taken from throughout the entire pile in such manner as to
make sure that each sample was truly representative of the original
field sample.
When a cord of wood is split into smaller pieces and again corded
its volume is increased because of the greater proportion of voids
DISTILLATION OF STUMPWOOD. 23
or air spaces, the weight decreasing as the cubical content increases.
An increase of about 10 per cent is said to result from reducing
average cordwood to the size in which the wood making up the
samples used in this work was piled and measured, from which
it would appear that the weights per cord on which the yields are
computed should be increased by 10 per cent. Owing, however, to
the irregular shape of the pieces of stump cordwood and the care
observed in piling the reduced wood closely, it is believed that the
observed weights are not essentially lower than the average weight
of a commercial cord of western yellow-pine stumpwood of corre-
sponding quality. In support of this it was found that of the 3
cords of stumpwood from near Deary, Idaho, piled and measured
in the field, when corded again after having been reduced to the
size in which they were used in the retort, one measured an even
cord, one 19 per cent less than a cord, and the third 10 per cent
more than a cord. It seems unnecessary, therefore, to use other
than the observed weights in calculating results.
The retort distillations were made on charges of known weights,
varying from 150 to 200 pounds, depending on the nature of the
wood. The distillation products were measured in liters per charge
and the yields reported in gallons per cord. This basis of state-
ment was selected in preference to the more exact unit-of-weight
basis, the ton, for example, because of the difficulty of estimating
the quantity of the several classes of wood on a given acre and
applying the results to the problems in hand on other than the
cord basis. The yields can be quickly figured to the ton basis from
the data given in Table 14.
APPARATUS.
In principle, the apparatus (figs. 3 and 4) is essentially an oil-
jacketed retort (a) in which high-flash cylinder oil, heated to the
desired temperature, is circulated through closely spaced heating
coils (&, <?, and d) within the retort. The coil system of jacketing
is preferable to a double shell in that it insures a positive flow of
the heated oil, and, by dividing the coils into sections, prevents an
excessive drop in temperature between the incoming and outgoing
oil. A 3-inch layer of asbestos lagging and pipe covering of the
same material protects the retort and exterior piping against ex-
cessive radiation. A coarse wire-gauze screen placed on the jacket
coils facilitates removal of the charcoal.
The motor-driven oil pump (/) takes oil from the overflow tank
(g) and discharges it through the gas-fired oil heater (e) into the
jacket coils (b and c), from the other end of which it flows back
into the tank (g). This circulation is maintained with the jacket oil
as it comes from the heater and is held at 260 C. as registered on
24 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
thermometer 1 until the turpentine has been recovered. The tem-
perature is then raised to 343 C., and the bottom coil (d) made to
join in the circulation of the oil by opening valve o until destructive
distillation of the charge has been effected. Valves m, n, and o are
adjusted (ordinarily unnecessary) so that thermometers 2, 3, and 4,
registering the temperature of the return oil from coils &, tf, and e?,
respectively, read essentially alike, indicating thereby that the oil
flows equally through the three coils.
PROCEDURE.
Turpentine is present in resinous wood, along with rosin, as an
oleoresin. Subjected to the designated retort temperature this oleo-
resin is partially sweated out and escapes from the pores of the wood,
losing the turpentine by vaporization, while the resin accumulates
FIG. 3. Plan of retort used for distillation of samples.
with certain decomposition products, as pitch, in the bottom of the
retort. The distillation is therefore conducted in two stages.
During the first stage the turpentine is recovered, and the result-
ing rosin liberated from the wood is collected in the bottom of the
retort. The oil-bath temperatures during this stage are between ap-
proximately 220 and 265 C. The valve to the bottom coil (d) that
lies embedded in the molten rosin is then opened, and the tempera-
ture of the circulating oil raised to 343 C. This brings about de-
structive distillation of the wood and the rosin, with the production
of pyroligneous acid and the formation of rosin oils containing also
creosote and other constituents derived from the wood, which distil
from the retort in two stages as light oil and heavy oil.
The light and heavy oils come over with the aqueous distillate
(pyroligneous acid) resulting from the clicniK-al transformation of
the wood and rosin during the destructive stage of the distillation,
DISTILLATION OF STUMPWOOD.
25
the light oil between 260 and 330 C., and the heavy oil above
330 C. A strong evolution of wood gas, which burns with a bright
luminous flame, takes place while the heavy oil comes over. Char-
coal and pitch are the end products of the distillation. The pitch is
drawn off through a plug cock in the bottom of the retort at the end
of a run. There is no sharp line of demarcation between the stages
in which the distillation is conducted, because decomposition of the
wood takes place long before all the turpentine has distilled over,
and to effect a maximum recovery of it this stage of the distillation
FIG. 4. Elevation of retort.
a, Retort shell.
& and c, Main heating coils.
d, Bottom heating coil.
v, Oil heater.
f, Oil circulating pump.
a, Overflow tank.
h, Worm condenser.
;', Trapped vent pipe.
k, Oil tank.
I, Overflow catch.
m, n, o, Valves.
1, 2, 3, 4, Thermometers.
must be continued to the point at which the wood is converted into
a brown friable substance approaching charcoal in its nature. This
decomposition sets in when most of the hygroscopically held moisture
has been expelled from the wood (about 260 C.), and is made appar-
ent by the sharp odor of the distillate and development of a reddish
color in the hitherto colorless aqueous layer. This incipient decom-
position is soon attended by a perceptibly acid taste of the distillate,
turbidity of the turpentine layer, and the escape of noncondensable
gases (mostly carbon dioxid) from the vent pipe (j). This point in
26 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
the distillation can be distinguished by an experienced person within
fairly close limits by means of the changes indicated.
Contamination with decomposition products and the proportion of
heavier oils, that subsequently must be removed, increase rapidly be-
yond this point. This comparatively pure fraction, therefore, is not
allowed to mingle with that coming over beyond this point, but is
collected separately as "first crude turpentine," while the remainder
constitutes u second crude turpentine." The aqueous distillate com-
ing over with the first crude turpentine, being practically free from
alcohol and acid, is discarded, but that from the second turpentine is
collected and saved with the pyroligneous acid obtained throughout
the remainder of the run. The temperature being held fairly con-
stant, the second turpentine fraction is continued to the point where
the flow of distillate from the condenser drops below a practical
limit, equivalent to about a gallon a half hour in these experiments,
and the oil passing over no longer contains turpentine, as shown
when it is dry distilled.
Along with the drop in speed of condenser discharge, the distillate
suddenly takes on a true consistency and undergoes such a char-
acteristic change of odor that there is no mistaking the point at
which all turpentine has passed over. By the time combustible
gases that burn with a pale blue flame begin to escape from the
vent pipe. The bottom coil is then opened and the temperature
of the jacket oil run up to approximately 345 C., where it is main-
tained until the end of the distillation. The oil becomes heavier as
the temperature rises, until presently it separates from the aqueous
portion of the distillate only after standing for some time. This
marks the end of the " light-oil " period. The greater viscosity of
the heavy oil and its characteristic odor are further relied on in
cutting the light and heavy oil fractions. The discharge of non-
condensable gases now reaches a maximum, and these suddenly burn
with a bright luminous flame in place of the one hitherto blue.
RESULT OF DISTILLATION.
The products obtained by this method of destructive distillation
;iiv. therefore, seven in number: Crude first turpentine, crude second
turpentine, light oil, heavy oil, pyroligneous acid, pitch, and char-
coal. The temperatures and the volumes of oil and acid distillate.
collected were entered every half hour in a log kept of each charge
(Table 13). The distillates were collected in large graduated cylin-
i-rs and the oil removed from the aqueous layer in separatory fun-
nels. The sum of the half-hour oil readings tends to be a little high
because of the imperfect separation of the water and the volume
of the oil accumulated by the end of the period a little low because
DISTILLATION OF STUMPWOOD.
27
of unavoidable transfer losses. The mean of the two, therefore,
is used in calculating gallons a cord.
TABLE 13. Specimen log of a run of 150 pounds of Boise medium yellows-pine
stumptvood.
Time.
Temper-
ature of
oil bath.
Products obtained.
Com-
bined oil
and wa-
ter.
Remarks.
Oil.
Water.
A. M.
8.25
10.00
10.30
11.00
11.30
12.00
12.30
P.M.
1.00
1.30
2.00
2.30
3.00
3.30
4.00
4.30
5.00
5.30
6.00
6.10
6.30
7.00
7.30
8.00
8.30
9.00
9.30
10.00
C.
Cc.
Cc.
Cc.
Lighted gas, started pump, closed bottom coil.
Distillate started.
Took sample acid liquor for analysis.
Noncondensable white vapors first appeared; last
of first turpentine.
First of second turpentine; began saving acid liquor.
Gas from vent-pipe burns.
Last of second turpentine; ran up temperature;
opened bottom coil.
First of light oil.
Last light oil.
Heavy oil started.
Shut down, drew pitch; drip 150 cc. heavy oil by
next morning.
223
238
250
260
261
256
261
261
261
260
260
263
258
281
298
310
319
322
327
336
340
344
346
342
342
342
410
540
500
495
430
360
385
370
300
235
180
160
135
165
170
380
230
790
1,100
940
800
640
485
530
570
590
590
570
560
490
560
830
1,550
740
3,050
4,050
2,050
1,550
1,100
600
240
90
CHARACTER OF CHANGES OCCURRING DURING DISTILLATION.
Wood tissue is made up primarily of cellulose, which, built up
into cells and tissue, constitutes the structural element of plants,
and lignin, which occurs as an incrusting matter or coating on the
cell walls. In resinous wood there is a further deposit in the wood
tissue of oleoresin from which the turpentine and pine oils are ob-
tained when the wood is subjected to distillation at a relatively low
temperature.
As previously explained, the nonvolatile substance remaining
when the volatile oils are distilled from the oleoresin is rosin, a sub-
stance largely composed of abietic acid. Toward the end of the tur-
pentine stage of the distillation the contents of the retort may be
considered as made up principally of abietic acid, cellulose, and
ligninlike substances, all of which are composed of the elements
carbon, oxygen, and hydrogen. The molecules of these substances,
being comparatively large and complex, are readily broken down
by the application of heat into a series of simpler compounds, some
of which, reacting the one on the other, may form still other com-
28 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
pounds. Of them all, water is the compound formed in the greatest
quantity, because of the fact that oxygen and hydrogen constitute
55 per cent of cellulose, the principal wood constituent. This water,
holding in solution numerous other compounds, produced simtdtane-
ously with its formation, is referred to in this bulletin as the " acid
liquor," an exceedingly complex liquid of a wine-red color, having
a sharp, tarry odor and strong acid reaction. In addition to water.
it is largely made up of acetic acid, methyl or wood alcohol, tar acids,
oils, esters and acetone aldehyde bodies, together with small propor-
tions of numerous other compounds of an unknown nature.
It is not meant to convey the idea that these changes occur in
clear-cut stages. Neither is it strictly true that the charge in the
retort is in reality made up of cellulose, lignin, and abietic acid or
rosin at any time during the distillation, for these compounds, owing
to their instability toward heat when dry, undergo progressive
changes as the moisture is more and more completely driven out
of the wood, before the recovery of turpentine is complete. Though
the period during which the distillation products do not result from
decomposition of the wood substances and the destructive stages of
the distillation merge into each other or overlap, the nature of the
changes taking place is essentially as set forth.
DISTILLATION OF WOOD (EXOTHERMAL) AND OF ROSIN (ENDOTHERMAL).
The chemical reactions brought about during the destructive dis-
tillation of cellulose are exothermal, that is, heat is given off during
the changes taking place once the action, for which a temperature of
270 C. is necessary, has been started. The amount of heat thus lib-
erated was found by Klason, Heidenstam, and Norlin 5 to be equiva-
lent to 4.6 per cent of the calorific or fuel value of the wood (pine).
The reactions involved in the decomposition of rosin by destructive
distillation, in the course of which rosin oils are formed, however,
cease unless an adequate supply of heat is maintained throughout the
distillation. This is due to the fact that the changes taking place,
instead of liberating, take up heat, being " endothermic " reactions.
These facts are of significance in view of the difference in behavior
observed when the more highly resinous wood and that containing
but little resinous matter, such as " bull pines," are distilled. In the
case of the more highly resinous wood a decided exothermic effect
was observed while the destructive stage of the distillation was in
progress, continuance of the high temperature (343 C.) being neces-
sary to carry the distillation to completion. In the distillation of
"bull pine" in the same state of dryness, however, the reaction be-
. Kemi. Min. C.-ol., Hand :',. N.I. in, H,.ft 1>. Published ly th- Royal Academy of
Science* at Stockholm.
DISTILLATION OF STUMPWOOD. 29
came so violent when a temperature of about 300 C. was reached that
the distillation could practically be completed without further heat-
ing, and in less time than the richer wood with continued heating.
It was necessary, therefore, in distilling the " bull pine " to watch
the oil-bath thermometer carefully in running up the temperature
for destructive distillation and turn off the heater flame when this
period was reached. The reaction progresses so rapidly that the dis-
charge of gas and vapors may exceed the otherwise ample condenser
capacity, and loss of distillate result from imperfect condensation.
The difference in behavior is due to the fact that the richer wood con-
tains a much greater ratio of rosin to " cellulose. The heat set free
during decomposition of the wood substance is more than offset by
that required to effect decomposition of the rosin in such wood, and
additional heat must be supplied to insure the decomposition of rosin
and the distillation of the products.
The fact that in the destructive distillation of nonresinous woods
enough heat above a certain temperature is developed to complete the
distillation without the application of heat from outside sources,
necessitates the installation of larger condensers in the distillation
of nonresinous woods than are needed in the distillation of resinous
woods. When the exothermal reaction begins, it proceeds so rapidly
that the condensers, which in the earlier stages were large enough to
condense all condensable material, can no longer do so, and a loss of
valuable products occurs if the condensers are too small to meet all
the requirements that may be placed upon them during the exother-
mal period.
YIELDS.
The yields of crude products obtained in the retort distillation, and
of the refined turpentine and pine oil for each sample, are given in
Table 14. A summary of these tabulations, giving the average re-
covery from the various grades of wood distilled, is given in Table 19.
30
BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
l mer-
table
ucts.
.S
I
eupuedjnj,
5: 8 ! -apaio pnooeg
d turp
from
epruo puooes
epruo isayj
epruo puooeg
epruo isiij
.-4 00 CO 1 04 O t~ 00 00
^ OCO
04 co 04 to <N oo
S* 2' 2* S * ^
jf CO CO * ^ 0>0 00 CO
3^
<-l 04 O <O >0
c4 <N -4
;-H-H^
^4 ^ rH
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DISTILLATION OF STUMPWOOD. 31
CRUDE PRODUCTS OF RETORT DISTILLATION.
CRUDE WOOD TURPENTINE.
The crude wood turpentine is distilled from the wood during the
first stage of the destructive distillation. During this first stage of
distillation the turpentine passes over for the most part unchanged,
as it probably exists in the wood tissue. The crude first turpentine,
therefore, is nearly free from pyroligneous bodies. It is often light
in color, and usually possesses an agreeable odor. It has a specific
gravity of about 0.875 at 20 C., a refractive index of about 1.4768
at the same temperature, and an initial boiling point of about 164 C.
The crude second turpentine necessarily contains more of the pyro-
ligneous or heat-decomposition products and of the heavier pine oils,
since the retort operator cuts the distillate at the first signs of de-
composition of the wood, indicated by the appearance of noncon-
densable gases, and collects the remainder of the turpentine as " sec-
onds." The heat-decomposition products of the rosin and wood
constituents consist of acids, alcohols, ketones, phenols, aldehydes,
etc., the nature and quantity of which depend on the temperature
and rate at which the turpentine stage of the distillation is conducted.
This crude second turpentine is darker than the crude first, and its
color is sharper and more suggestive of wood decomposition. It has
a specific gravity of about 0.910 at 20 C., a refractive index of about
1.4850 at the same temperature, and an initial boiling point of about
130 C. (due to the presence of decomposition products).
The difference between these two crude turpentines is well set forth
in Table 15.
TABLE 15. Products of dry distillation of crude turpentine at 760 mm. pressure.
Temperature of distillation ( C.).
First
turpen-
tine.
Second
turpen-
tine.
Below 170
Per cent.
9 3
Per cent.
7 5
Between 170 and 175. .
52 8
9 06
Between 175 and 180. .
16
18 05
Between 180 and 185. .
18 02
Residue
21 9
47 37
The details of refining the crude turpentine are discussed on
page 56.
LIGHT OIL.
The crude light oil is brownish black, has a sharp, penetrating,
empyreumatic odor, an average specific gravity of about 0.995, a
refractive index of 1.514, each at 20 C., and an acid value of about
29. Its average viscosity at 25 C. is 2.58 Engler. The yield is
about 4^ gallons a cord of rich wood. Distilled in the ordinary
manner at atmospheric pressure, using a fractionating column, it
has an uncertain initial boiling point, around 70 C., due to the pres-
32 BULLETIN KHia, r. s. I'KI'AKTMKXT OF AGRICULTURE.
ence of water and other low-boiling constituents, which rises rapidly
to 160 C. The complex nature of this material is indicated by its
wide temperature range when subjected to distillation. Typical
results are shown in Table 16.
TAP.I.K Hi. - -IH.xtilliitinn data of ennifinsite entile lifilif dl.
Material distilling between
Amount.
Material distilling between
Amount.
55 and 120 C .
Per cent.
3.5
230 and 350 C. .
Per cent.
54.3
120 and 180 C
13 6
Watery layer
1.8
1 80 and 230 C...
21.1
Residue soft pitch
5.7
On subjecting the various samples of crude light oil to dry dis-
tillation at atmospheric pressure, using a fractionating column, an
average of 34.5 per cent was found to distil below 225 C. Of the
total distillate an average of 1.8 per cent was aqueous. This aque-
ous portion, as well as the lighter portions of the oily distillate, con-
tains quantities of acetic acid, methyl alcohol, and acetone. The
difficulty of their recovery in a state pure enough for quantitative
estimation is such, however, that it is as yet possible only to esti-
mate the quantities of these bodies present.
On treating the distillate obtained below 225 C. with an excess
of 20 per cent alkali solution, a marked contraction in volume of the
oil and decided heating were observed. When the oil thus treated
was steam distilled to exhaustion, 87 per cent (1.3 gallons a cord)
of total distillate was recovered as a rather sharp-smelling, light-
yellow oil having an uncertain initial boiling point of about 125 C.
On dry distilling this steam-distilled oil, 60 per cent passed over
below 175 C., and the remainder distilled up to 250 C. In its
behavior on distillation it shows a close resemblance to rosin spirits.
By treating the crude light oil with alkali and distilling with
steam as in the refining of the crude turpentine, 10 per cent (0.4
gallon a cord) of the oil is recovered as refined rosin spirits dis-
tilling at from 130 to 200 C. and 20 per cent as a pine-oil fraction
distilling at from 175 to 275 C. The pine-oil fraction distilling
at from 175 to 275 C. has a lemon-yellow color like refined pine
oil, but an unpleasant, altogether different odor, and can not be con-
sidered as pine oil, except perhaps in certain of its constituents.
Fifty per cent of it distils below 200 C.
The residue from this steam distillation of the crude light oil
forms a heavy emulsion with the alkali present. On the addition of
acid about 10 per cent of the original oil separates out as a heavy tar
that settles to the bottom. The remaining oil has about the density of
water, slowly floating to the top, is dark, and has a mild odor.
Distilled in a vannim of from 10 to 20 mm., 80 to 85 per cent
(3.2 to 3.4 gallons a cord) of the crude light oil is recovered as a
DISTILLATION OF STUMP WOOD. 33
clear, brownish-red oil that darkens on standing and has a creosote
odor. The residuum from this distillation is a hard pitch. Ke-
peated rectification of this light oil has given a series of fractions
ranging from 166 to 176. The fraction from 174 to 176 gives
an oily bromin addition product. Apparently it adds hydrochloric
acid gas to form needlelike crystals after standing a number of days,
but all attempts to make a nitrosyl chlorid were fruitless.
The yield of crude light oil, compared to that of heavy oil, is
small. Since the light oil differs but little from the heavy oil,
it probably will be found expedient to collect and market or work
it up along with the heavy oil in the operation of a commercial
plant. One application to which this crude oil may be put is as a
vehicle for cheap paints and shingle stains, and other such pur-
poses for which certain of the creosote oils are now used.
HEAVY OIL.
The properties of the heavy oil which results chiefly from the
destructive distillation of rosin resemble strongly those of rosin oil.
The crude oil also contains decomposition products of the wood tis-
sue, to which extent it is like wood creosote and rosin oil. The
crude heavy oil is slightly heavier than water (average density
of 1.048 at 20 C.), is brownish black, and has a penetrating, creosote-
like odor. The average viscosity at 25 C. is 11.9 Engler. Like
the light oil, it is comparatively unknown and untried, and there-
fore lacks a well-established market value.
Heavy oil is one of the important products obtained in the dis-
tillation of resinous woods. The yield is exceedingly variable, run-
ning from about 75 gallons a measured cord of very rich stump-
wood to as little as 16 gallons from dead, down wood. Making up
a large proportion of the total volume of oil recovered, its disposal
to the best advantage possible is essential to the profitable operation
of a commercial plant where the process is similar to that employed
in this investigation. Consequently, certain experiments, looking to
the most probable means by which an enhancement in the value of
the crude oil may be expected, were conducted.
From the results of laboratory work it was found that in sepa-
rating its low-boiling fraction by distilling at atmospheric pressure
from a flask fitted with a Hempel column, distillation begins at an
uncertain initial temperature of about 85 or 90 C., with an average
recovery of 25 per cent (8.7 gallons a cord) below 225 C. This
fraction is quite similar to the corresponding fraction obtained from
the crude light oil.
The crude heavy oil can be used with some success for flotation
purposes. In other fields of industry it must be sold largely in com-
petition with products commonly obtained from coal tars such as
60953 21 3
34 BULLETIN 1003, U. S. DEPARTMENT OF AGEICULTURE.
are used in the manufacture of roofing cement and shingle stains,
and as. a softener and binder in treating heavy cotton cloths with
metallic resinates, for water and mildew proofing purposes. In Rus-
sia a similar pine product is used extensively as a leather dressing for
harnesses, boots, etc. Either by itself or mixed with tar it might
be successfully employed in the preparation of cordage, tar soap,
moth-proof paper bags, leather dressings, etc. Bacteriological tests
have shown it to possess a phenol coefficient equal to one-half that
of carbolic acid.
Both the light and heavy crude oils, as well as some of the other
products of this investigation, were examined to determine their
adaptability to flotation purposes by the United States Bureau of
Mines at Salt Lake City, Utah (page 54), and also by several mining
companies operating in the western States. One company reported
that while all the pine oils were generally satisfactory for zinc ores,
the crude light oil and a partially refined pine oil were particularly
good. Another stated that the results differed only slightly from
those obtained with oil from the southeastern pines, this being one of
the most effective oils for flotation purposes. Probably all would be
good for copper ores if used in conjunction with kerosene sludge acid.
PITCH.
The average yields of pitch from all classes of wood are not widely
different except those from dead, down wood, which are much smaller
than those from richer woods. No tests, either physical or chemical,
have been developed with which to compare the qualities of the
different samples of resinous-wood pitch found in commerce, other
than the presence or absence of foreign matter, and no specifications
on the basis of which to make such comparisons have been estab-
lished. For this reason, and because its most important application
is for impregnating fibers in the manufacture of oakum and cordage,
and for closing seams in the decks of vessels, when it is combined in
various proportions with tar and turpentine to secure the consistency
desired, a systematic examination of individual samples of this ma-
terial has not been made. These differ so little, the only apparent
distinction that could be drawn between samples being a slight varia-
tion in their relative hardness, that a general description will suffice.
The pitch is a black, brittle to slightly pliant solid, having a
specific gravity of 1.144 to 1.148 and in hardness varying from that
of common rosin, in the more brittle, to that holding a finger print
and possessing slight tackiness in the softer samples at ordinary tem-
peratures. So susceptible is it to temperature changes that samples
which were found to be tough or pliant through the day Inviunc quite
brittle during the night. Its melting point is consequently very in-
definite. It behaves like a viscous fluid at 75 to 100 C,, is sirupy
DISTILLATION OF STUMPWOOD. 35
at 100 to 125 C., and free flowing at about 125 to 150 C. It is
practically devoid of taste or odor, and dissolves readily in turpen-
tine, but only very sparingly in either cold or hot alcohol, differing in
this respect from common or black rosin. Its acid value was found
to be 2, extracted with alcohol, against 150 to 180 for black rosin.
It differs from what is purchased under Government contracts for
" North Carolina pitch " in being, on the whole, blacker, and some-
what softer, and in having, therefore, a generally lower melting
point. It is believed, however, that this will not detract from its
value in the uses previously enumerated, but rather that its somewhat
greater pliability may be found to be advantageous.
CHARCOAL.
The charcoal obtained in these experiments from western yellow
pine, especially that from the richer or more resinous samples of
wood, is very soft and friable It retains an appreciable amount of
bituminous matter, due undoubtedly to incomplete distillation, which
causes it to burn with a long, smoky flame. Its possible application is
suggested in industries where powdered fuel is used, or in metallurgi-
cal operations in which the crushing strength is not a prime requisite.
The charcoal from " bull " pine was in every respect superior to
that obtained from yellow pine proper, and, in general, the quality
of the charcoal fell off as the rosin content of the wood increased.
Compared to that from hardwood, the western yellow-pine char-
coal must be considered of inferior quality, especially as to hardness.
Tamarack charcoal has a much denser structure and is not so
friable as that obtained from yellow pine. Moreover, it is clean or
free from bituminous matter, and appears to be quite similar to hard-
wood charcoal.
ACID LIQUOR (PYROLIGNEOUS ACID).
The specimen log of a run (page 27) shows that an aqueous dis-
tillate which is nearly pure water comes over with the turpentine at
the beginning of a distillation and is rejected. As the heating is
continued, the wood tissue begins to decompose and the aqueous
liquor takes on a straw color. From this point it contains acids and
alcohol in varying quantities, and constitutes a true acid liquor,
which in these experiments was retained and examined.
The acid liquor results from chemical transformations of bodies
making up the wood tissue and rosin contained in the wood, brought
about by heating the wood to a sufficiently high temperature. This
reaction is a true chemical process, none of the compounds found
in the liquor occurring in the untreated wood. The action is alto-
gether different, therefore, from the recovery of turpentine and pine
oils, the separation of which is effected by a physical change of
36
BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
state. In other words, the heat serves only to convert these oils
into vapors, which, after being cooled in the condenser, are col-
lected essentially as originally present in the wood.
The three important constituents of acid liquor are acetic acid,
methyl (wood) alcohol, and acetone. Up to the present time these
products have been obtained almost exclusively from hardwood.
Owing to the greater amount of tarry substances present, softwood
acid liquor is extremely difficult to free from this constituent, and
the calcium acetate made therefrom is inferior in quality to that
from hardwood acid liquor. The yield, consisting of methyl alcohol
and acetone, is also substantially lower than that from hardwoods.
The proportions of acid, alcohol, and acetone as found in these
western yellow-pine acid liquors (Table 17) were obtained by
analyzing a composite sample of acid liquor from each set of
charges run on the various kinds of wood. 6
TABLE 17. Composition of add liquor*.
Grade and source.
Acid
liquor,
per
cord.
Acetic acid.
80 per
cent
acetate
of
lime
(calc.
from
acetic
acid),
per
cord.
Methyl alco-
hol.
Acetone.
Dissolved oils
and tars.
Per
liter.
Per
cord.
Per
liter.
Per
cord.
Per
liter.
Per
cord.
Per
liter.
Per
cord.
Poor stump wood, Deary
Rich stumpwood, Deary
Medium stumpwood, Deary. .
Dead, down wood, Deary
Rich stumpwood, Coeur
d'Alene
Galls.
59.4
55.9
54.3
53.4
60.9
61.4
64.3
63.9
59.5
63.6
69.2
62.4
63.6
74.0
75.8
63.2
80.8
66.6
65.7
Gms.
67.76
64.67
67.82
64.49
64.37
65.44
77.55
64.67
68.12
71.05
70.40
73.41
65.12
41.95
48.35
57.90
49.67
58.21
59.72
Lbs.
33.6
30.2
30.7
28.7
32.7
33.5
41.6
34.5
33.8
37.7
40.7
38.2
34.6
25.9
30.6
30.5
33.5
32.4
32.7
Lbs.
55.3
49.7
50.5
47.2
53.8
55.1
68.5
56.8
55.6
62.0
67.0
62.9
56.9
42.6
50.4
50.2
55.1
53.3
53.8
Galls.
27.82
25.45
26.11
25.98
23.19
27.35
29.37
25.21
25.34
27.64
26.18
30.17
29.27
13.88
24.32
27.71
28.09
28.21
18.26
Goto.
2.10
1.80
1.79
1.76
1.79
2.13
2.40
2.04
1.91
2.23
2.29
2.38
2.36
1.30
2.34
2.22
2.S7
2.38
1.54
Gms.
2.24
2.77
2.44
2.33
2.00
1.92
2.21
2.12
2.16
2.42
2.26
1.81
2.07
1.49
1.75
2.09
1.73
2.10
1.69
Galk.
0.20
.16
.16
.15
.15
.15
.18
.17
.16
.19
.19
.14
.16
.14
.17
.16
.17
.17
.14
Gms.
Lbs.
120.08
L84.68
156.86
122.34
136. 11
172. 12
133.90
128.54
161. 16
159.29
152.37
143.31
66.15
11'.'. 71
117. M
78, '.'s
114
I JO. 83
56.0
60.9
69.9
62.2
69.7
92.3
71.4
63.8
85.5
92.0
79.3
76.0
40.8
75.7
62.1
53.2
63.6
66.1
Medium stumpwood, Hayden
Lake
Bull-pine stumpwood, Boise..
Medium stumpwood, Boise...
Rich stumpwood, Boise
Green selected stumpwood,
Boise
Green selected stumpwood,
Craig Mountain
Rich cut-over stumpwood,
Craig Mountain ...
Rich ^cut-over stumpwood,
roadside, Craig Mountain...
Tamarack stumpwood, Mos-
cow Mountain
Selected dead, down wood,
Craig Mountain
Selected dead tops, Craig
Mountain
Selected green tops and limbs,
Craig Mountain
Medium stumpwood, road-
side, Craig Mountain
Rich stumpwood, near Pot-
latch
"Tin- analyses of tin- arid liquors w.-iv made by V. E. (Jrotlis. h :iml C. <'. Sponcer,
I'.uivaii <>f riimiistry, I'nit.d States Department of
DISTILLATION OF STUMPWOOD. 37
The yield of calcium acetate is approximately but one-fourth of
that generally obtained in distilling the best hardwoods. Probably
on a commercial scale the yields would be somewhat less than those
shown by the analyses. The yield of wood alcohol also is but one-
fourth of that generally obtained in hardwood distillation.
PRODUCTS OBTAINED IN REFINING CRUDE TURPENTINE.
REFINED TURPENTINE.
In order to separate the valuable turpentine constituents of the
crude turpentines from the pyroligneous and resinous heat-decompo-
sition products of the wood, the crude turpentines are first treated with
caustic soda, which combines with acids and resinifies the aldehydes
and phenols, forming nonvolatile compounds. By a subsequent steam
distillation the turpentine and pine oil are recovered. Just as in the
case of the original retort distillation of the wood, the oily products
of the steam distillation are separated into several fractions. The
first product is called " first grade " or " first-quality refined turpen-
tine." The receivers are changed at a certain point (page 58), and
the distillate which then comes over is called " refined second-
quality turpentine." This has distilling temperature limits somewhat
higher than those accepted for true commercial wood turpentine.
Finally, the receivers are changed again, the last of the distillate be-
ing called " pine-oil fraction."
On refining crude first turpentine a yield of approximately 80 per
cent of refined first-grade turpentine is obtained, most of which dis-
tils between 170 and 175 C. From crude second turpentine the
yield of refined first-quality turpentine lies in the neighborhood of
43 per cent. The other distillates from the crude turpentines are as
follows: From crude first turpentine, 5J per cent refined second-
quality turpentine fraction and 7| per cent pine-oil fraction; from
crude second turpentine, 13 per cent refined second turpentine and
12 per cent pine-oil fraction.
38 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
1?
388
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DISTILLATION OF STUMPWOOD.
39
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8 $
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s
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oi
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i;1
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40 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
PINE OIL.
Pine woods contain oils other than those entering into the composi-
tion of commercial spirits of turpentine. These oils, collectively
spoken of as pine oil, are liberated more or less completely from
the wood in their original form, along with the turpentine con-
stituents proper. This pine oil is a complex substance made up to
a large extent of oxygenated derivatives of the terpenes (turpentine
constituents), and has a comparatively high boiling point and spe-
cific gravity. The characteristic odor of pine wood is due chiefly
to the presence of this oil, in conjunction with turpentine. The
characteristic odor of wood turpentine is also due to small quan-
tities of pine oil present. The quantity of this oil recovered is
always relatively small, varying from a total of 3 gallons from a
cord of very rich stumpwood to less than 1 gallon from a cord of
dead, down wood and poor stumps. It is necessary to remove or
separate this oil as completely as possible from the turpentine, be-
cause it does not evaporate readily, and a turpentine containing even
a small percentage of it will remain sticky or "tacky" after drying.
Its value as a thinner in the paint and varnish industry would be
affected accordingly.
The sum of the total refined turpentine and pine oil recovered
from the crude first turpentine amounts, on an average, to 92 per
cent, and that from the crude second turpentines to TO per cent. On
the basis of the average yields from rich and medium stumpwood,
this would amount to 13.5 and 7.8 gallons a cord for the first crude
turpentine, and 8.3 and 5.7 gallons for the second crude turpentine.
These are the results obtained when the steam distillation is con-
tinued to the point where the oil layer makes up 5 per cent of the
total distillate coming over at the time. By continuing the distil-
lation to exhaustion, or until no more oil is carried over by the
steam, an additional 5 or 8 per cent of pine oil may be recovered.
Considerations for economy of operation did not warrant the carry-
ing of the distillation to this state of completion. The composition
of the pine oil progressively changes, so that the portion coming over
at the close of the distillation is heavier than that passing over
at the earlier stau
ALKALI RESIDUUM.
On prolonged standing the black, alkaline liquid remaining from
the distillation separates into an aqueous layer and a thick, oleagi-
nous, soaplike mass which floats on top of the water. This mass
will be designated " alkali residuum." Dissolved in the aqueous layer
is a small proportion of what appears to be creosote bodies. The
alkali residuum, which is essentially an impure rosin soap, dissolves
in wait -i- to form a colloidal solution of great stability that exhibits
DISTILLATION OF STUMPWOOD. 41
an alkaline reaction. This solution possesses germicidal properties,
the undiluted material having a phenol coefficient of 0.5. When the
alkali residuum is decomposed by the addition of acid in excess, a
heavy oil separates, about 75 per cent of which distils over between
180 and 340 C. Most of this distils between 200 and 300 C. The
higher-boiling portion has the general appearance and odor of rosin
oil. When the alkali residuum is distilled without previous treat-
ment with acid, about 3 per cent of its volume is recovered as pine
oil, along with 30 per cent of water, after which the residue remain-
ing in the flask solidifies to a hard, soaplike mass soluble in water,
forming a colloidal solution similar to that from the original alkali
residuum.
CALCULATION OF YIELDS OF REFINED TURPENTINE AND
PINE OIL.
A composite sample of the refined second-grade turpentine when
dry distilled through a fractionating column yielded 83 per cent of
turpentine distilling between 170 and 185 C., having a density of
0.8622 and a refractive index of 1.4736. The residue from this dis-
tillation was a true pine oil, the density of which was 0.9423, with
a refractive index of 1.4937. A composite sample of the pine-oil
fractions obtained in refining first and second crude turpentines, dis-
tilled in a like manner, gave 40 per cent of turpentine distilling be-
tween 175 and 185 C., the density and refractive index of which were
0.8655 and 1.4755, respectively. . The residuum was also true pine
oil similar to that remaining from the distillation of the second-
quality turpentine.
The properties of the turpentine fractions thus obtained from the
refined second turpentine and the pine-oil fractions do not differ
markedly from those of the refined first turpentine. Moreover, the
volume being but small compared to that of the refined first turpen-
tine, it is believed that these may be combined without materially
lowering the quality of the product. The total merchantable tur-
pentine, therefore, will be figured on the basis of the first refined
turpentine plus 83 per cent of the corresponding second refined tur-
pentine and 40 per cent of the pine-oil fraction, respectively. The
sum of the three is entered in the " merchantable turpentine " column
of Table 14.
On the same basis, the volume of true pine oil will be 17 per cent
of the refined second turpentine plus 60 per cent of the pine-oil
fractions obtained in refining the crude turpentines. The yield of
pine oil given in the " merchantable pine oil " column of Table 14
is thus obtained. The sum of the refined first and second turpentine
and pine-oil fraction is not equal to the sum of the first and second
crude turpentine. The portion thus unaccounted for is retained dur-
42
BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
ing the refining process, partly in the alkali residuum and partly in
the aqueous distillate.
A summary of yields a cord of both crude and refined products
obtained from each class of wood is given in Table 19.
TABLE 19. Yields per cord of crude and refined products from each class of
wood distilled.
Product.
Rich stump-
wood (8
samples).
Medium stump-
wood (6
samples).
Green stump-
wood (2
samples).
Dead, down
wood (4 '
samples).
i
s^
S*
l_
6.9
6.8
1 Green tops and limbs
g 2 | (1 sample).
j
I
I
'e
>
i
j
Average.
Maximum.
1
Average.
j
Minimum.
5
Crude first turpentine
(A) gallons..
Crude second turpentine
(B) gallons..
Total do....
Crude light oil do....
Crude heavy oil do
17.1
17.8
13.3
7.6
14.9
11.1
12.1
10.5
6.8
6.4
9.0
8.1
9.9
7.4
8.7
5.0
9.3
6.2
17.8
13.5
4.5
2.8
8.6
6.3
34.9
8.3
70.5
74.4
13.3
7.9
21.0
2.7
29.5
55.9
=====
10.0
3.1
26.0
=====
4.6
46.0
64.4
==
11.8
5.0
22.6
4.9
31.7
74.4
==:
9.7
6.1
13.5 17.1
2. 8 3. 6
24.4 26.5
54.31 64.1
5.1 7.1
1.5 3.6
16.1
3.2
32.1
69.2
===
8.1
3.8
14.9
~2^5
30.1
63.6
=====
7.2
2.5
15.5
"
2.9
31.1
66.4
-
7.6
3.2
31.3
4.9
47.0
75.8
13.6
2.9
7.3
2.8
19.5
53.4
"
14.9
3.6
28.6
63.6
6.4
1.8
13.7 5.9
2.9i 3.3
23.6 in. 1
59.4' 80.8
5.7 2.0
2.8 1.1
Acid liquor do
Refined first turpentine
from A gallons..
Refined, first turpentine
from B. .. gallons
Total do
21.2
=====
1.3
13.4
==
.6
16.8
-
.8
15.8
g
JU,
4
10.7
g
11.0
==
7
10.6
-
4
10.8
~
16. 5J 3.4
"T"
13 3
8.2
7
8.5
4
3.1
3
Refined second turpentine
from A gallons..
Refined second turpentine
from B gallons..
Total do....
Pine oil fraction from
A gallons..
Pine oil fraction from
B gallons..
Total do....
Merchantable turpentine
gallons..
Merchantable pine oil
2.3
.9
1.5
1.5
.9
1.1
1.0
.5
.8
1.9| .3
.8
.7
.3
3.0
==
1.7
2.6
1.7
==
.9
1.1
2.3
==
1.2
1.5
1.9
==
1.1
1.2
1.3
.3
.9
1.7
- "
. .7
1.0
1.4
=====
.5
.5
1.2
.3
.4
1.3
^
.4
3.2
-^- '
1.6
2.8
.6
.3
.3
1.5
.7
1.1
1.1
.3
.6
.6
.2
.3
4.3
===
25.7
3.1
237
988
3,500
2.2
-'""
16.2
1.6
110
670
2,500
2.7
19.8
2.0
188
789
2,812
2.1
18.0
1.6
188
800
3,000
1.2
=====
8.9
1.0
102
651
2,200
1.7
12.7
1.3
131
711
2,417
.9
"
12.5
.s
144
823
2,500
.8
*_""
11.8
.8
143
768
2,400
.9
.-._.^
12.2
.8
143
795
2,450
4.4
21.0
3.1
104
863
3,000
.6
4.6
.4
42
671
2,000
1.8
10.2
1.3
84
790
2,400
.9
9.7
.8
83
714
2,100
.5
3.8
.4
22
764
2,400
Pitch pounds. .
Charcoal do
Cord weights do....
The average weight a cord of the rich stumpwood is 2,612 pounds,
as against 2,450 pounds for selected stumpwood, and 2,412, 2,400,
2,100, and 2,400 pounds for medium stumpwood, dead, down knots
and limbs, poor stumpwood, and green tops and limbs, respec-
tively. The corresponding yields of refined first turpentine are 16.8,
10.8, 10.7, 8.2, 8.5, and 3.1 gallons a cord; and the yields of total
merchantable turpentine are 19.8, 12.2, 12.7, 10.2, 9.7, and 3.8 gallons
a cord, respectively. With the exception of that from the green tops
:in.l limbs, the yield of turpentine a cord follows the weight a cord.
The yields of pine oil and crude light oil, while not varying greatly,
DISTILLATION OF STUMPWOOD. 43
show the same tendency to follow the weight a cord and field classi-
fication of the wood. This tendency is shown also by the yield
of heavy crude oil and of pitch. The acid liquor and charcoal, how-
ever, are not subject to any such general deductions, although the
highest yields of acid liquor are generally given by the green woods,
followed by the richer stumpwood. In all probability this is due
to the fact that acetic acid is one of the decomposition products of
rosin.
An experienced person can classify stumps in the field into several
grades from which the average yields of valuable products differ to
such an extent as to necessitate a proper selection of the material
before collection.
COMMERCIAL DISTILLATION PROCESSES.
There are four general processes for the recovery of products from
resinous wood. Two of these are destructive distillation processes
and two are nondestructive extraction processes. They are : (a) The
common or ordinary destructive distillation process; (b) the con-
trolled temperature destructive process ; (c) the steam distillation or
extraction process; and (d) the solvent extraction process. Of these
the ordinary destructive distillation process is the only one which
seems to be well adapted to the stump-disposal project in the North-
west.
ORDINARY DISTILLATION PROCESS.
The wood-distilling oven now in general use for the destructive
distillation of wood is an outgrowth of the old charcoal heap. By-
product charcoal kilns, round iron retorts, and rectangular iron or
concrete ovens are in use, the rectangular oven being preferred in
the best practice. Experience with these different forms has taught
that there is a mean temperature which gives the most satisfactory
yields. This temperature is necessarily more difficult to maintain
in direct-heated retorts, the smaller of which have the further dis-
advantage that the charcoal must be removed by hand, necessitating
a loss in time required for cooling as well as a fuel loss in reheating
the retort for the next charge.
The uneconomical working of the round retort has led to the de-
velopment of the rectangular oven. Such ovens are of steel or con-
crete construction and are heated either directly by fires under them,
in the case of the steel ovens, or by means of internal-heating flues
in the concrete ovens. The second method is said to be better
adapted to softwood distillation. The height and width of the ovens
are uniform, being in general 8 feet 4 inches and 6 feet 3 inches, re-
spectively, and the length ranges from 26 to 54 feet or more, accord-
44 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
ing t<> the desired capacity. An oven 52 feet long, G feet 3 inches
wide, and 8 feet 4 inches high holds 10 cords of wood.
The charge of wood, of regular con 1 wood size, is loaded onto
steel tramcurs of special construction and hauled into the retort or
oven, which is, of course, tightly closed during the distillation. At
the end of this operation, the train of cars bearing the still hot
charcoal is hauled out into the cooling shed of sheet iron, where the
charcoal cools down without loss of fire. Simultaneously, another
trainload of wood enters the oven, and the new distillation proceeds
with a minimum heat loss.
In addition to the ovens, coolers, cars, and necessary brickwork or
the setting of the ovens, condensers, which should be of ample ca-
pacity to handle the distillate under the most unfavorable operating
conditions, will be required, as well as stills, steel tanks to hold the
product, wooden tanks, pumps, generators, steam boilers and engine,
yard tracks, piping, etc., and the necessary buildings for housing the
plant.
A conservative estimate of the cost of such a plant is between
$4,000 and $5,000 a cord capacity. Before the war these plants could
be built for from $1,500 to $3,000 a cord capacity, or at a total cost,
including working capital, of approximately $20,000 for a 10-cord
.plant. The cost of construction and of operation and the design and
character of the equipment "will vary, and quite widely, with the pro-
posed location of the plant and the work it is to do, and with the
experience and practice of the designing and constructing engineers.
For these reasons, no details of equipment or specifications are given.
This information can best be secured from wood-distillation engi-
neers and from builders of the equipment, whose advertisements ap-
pear in the various industrial journals. The Bureau of Chemistry
can furnish a list of engineers and builders of wood-distilling plants.
CONTROLLED TEMPERATURE PROCESS.
The controlled temperature or circulating oil process and retort
have been fully described in the preceding pages. Even on a com-
mercial scale a prerequisite of this process is that the pieces of wood
be relatively smaller in diameter than those used in the ordinary de-
structive process, to insure rapid distillation. When properly car-
ried out, better separation of the several products of distillation is
obtained, with the result that the turpentine ordinarily obtained com-
mands a slightly higher price (3 to 5 cents a gallon) for paint or
varnish purposes than the turpentine produced by the regular de-
strnctive process, in which the temperature is not definitely con-
trolled. While tliis process yields a better grade of wood turpentine,
the equipment and upkeep are more expensive, and greater skill and
DISTILLATION OF STUMPWOOD. 45
a larger force are required in operating than for the uncontrolled
process. For this reason it is rarely used for distilling resinous
wood.
STEAM DISTILLATION PROCESS.
The steam distillation process requires that the wood to be ex-
tracted shall be finely divided by chipping or shredding before treat-
ment ; the finer the chips, the more rapid and complete the extraction.
For this reason the steam process has been installed by several saw-
mills for the recovery of turpentine from sawdust. The best results
are not obtained with all dust, however, as it packs so tightly that
the steam is kept from penetrating throughout the entire mass to be
extracted. Chips of a size passing an inch and retained by a quarter-
inch screen are desirable, and a limited amount of sawdust can be
mixed with such chips.
Few plants, other than lumber mills where the production of wood
turpentine and pine oil is only a side issue, have continued to operate
on the steam process alone, and have invariably closed when turpen-
tine sold at less than 50 cents a gallon. The turpentine produced by
this method is of high quality, approaching that made by the regular
distillation from gum. The practicability of maintaining a steam
distillation plant depends entirely on market conditions ; if the price
of turpentine is sufficiently high the steam method will be a paying
proposition. The steam distillation outfit is now usually installed in
conjunction with a solvent plant that can extract the residual wood
chips for the recovery of rosin and certain of the heavier pine oils.
SOLVENT EXTRACTION PROCESS.
In the solvent process also the wood must be finely divided. This
process is one where the wood is extracted in large, tight digesters
at a relatively high temperature by means of suitable volatile sol-
vents, the choice of which is determined mainly by price. Gasoline,
coal tar, naphtha, or turpentine can be used, gasoline being the one
in common use. When the solvent is added in the beginning of the
operation, that is, with no previous steam distillation, all of the solu-
ble pine products are removed altogether, and the resulting mixture
is fractionated to recover the naphtha or other solvent and to sepa-
rate the turpentine and pine oils from the rosin. The rosin obtained
in this way is not so free from tackiness as pure gum rosin, and has
a rather darker color, but is quite clear when properly made. Fur-
thermore, it is very difficult to remove the solvent completely from
the turpentine. It has been found advantageous, therefore, to com-
bine the steam and solvent processes, the only objection' to this being
that the steam leaves the chips in a moist condition, in which state
the extraction does not take place as readily as if they were abso-
lutely dry.
46 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
BATH PROCESS.
An advantage of the bath process, another method which has been
used to a limited extent, is that the wood does not require previous
shredding. The wood is run into the retort on cars, and the retort
is flooded with a high-boiling material, 'such as molten rosin, pitch,
or tar, heated to a sufficiently high temperature. Most of the ex-
tracted turpentine and pine oils are volatilized at the temperature
of the bath, and the rest is blown out of the bath with steam. The
remaining wood, which is saturated with the rosin or other material
of the bath, may be destructively distilled to recover the light and
heavy crude oils, tar, charcoal, and pitch.
FEASIBILITY OF DISTILLING WESTERN YELLOW PINE.
Yellow-pine stumps of a quality such as to yield more than 12J
gallons a cord, the average yield from medium-grade stumpwood,
of merchantable wood turpentine, of the properties shown in Table
18, and other products in corresponding proportion, are compara-
tively scarce. " Fat " or " pitchy " stumps, averaging 20 gallons of
merchantable turpentine a cord, are not sufficiently numerous to be
considered in a class by themselves as an impediment to land-clearing
operations, and would need to be hauled for long distances in supply-
ing wood to distilling plants.
The daily yield from a 10-cord plant and the market value of the
products from the rich portion of medium-grade stumps, based on
the yields obtained in these experiments and on the prevailing eastern
prices June, 1918, using the ordinary ovens in general use, would be
approximately as follows:
Merchantable turpentine 127 gallons @ $0. 50 $63. 50
Pine oil 13 do. @ .40 5.20
Light oil (at tar oil prices) 35 do. @ .20 7.00
Heavy oil (at tar prices) 275 do. (6 barrels) @ $0.15 41.25
Pitch 7 barrels ( 1,400 pounds ) @ $3.50_. 24.50
Charcoal 350 bushels (7,110 pounds) @ $0.12_ 42.00
183. 45
Total value of products a cord of selected medium-grade resinous
wood or heartwood .$18. 36
The average yield and market value of the products recovered
from a cord of rich stumpwood on the same basis are estimated to be :
Merchantable turpentine 19.8 gallons @ $0.50 $9.90
Pine oil 2.0 do. @ .40 .80
Light oil 4.5 do. @ .20 .90
Heavy oil 46. do. @ 15 0. 90
Pitch . 138. pounds @ 3. 50 a barrel 2. 41
Charcoal 38. bushels (790.0 pounds) @ $0.12. 4.56
< Total value of products a cord 25. 47
DISTILLATION OF STUMPWOOD.
47,
These yields and values are comparable to those obtained in dis-
tilling longleaf-pine lightwood in the South Atlantic States, as shown
by the following figures, taken from Bureau of Chemistry Bulle-
tin 144 :
Products from 1 cord (4,000 pounds) of longleaf yellow-pine lightwood (destruc-
tive process).
Total crude oil - gallons__ 36 to 120
Refined wood turpentine do 5 to 20
Pine oils do 2 to 5
Rosin oil do 20 to 65
Light and heavy oils :
Creosote gallons 8 tQ 20
Rosin spirits do 2 to 10
Charcoal bushels__ 30 to 50
Cost of operating per day and per cord (1915 figures).
10 cords of wood, at $8.37 a cord, delivered $83. 70
Fuel wood, in addition to gases and fine charcoal, 10 cords, at $2.50 a
cord, delivered 25. 00
Labor, 8 men (3 shifts), at $2.50 a day (average wage) 20. 00
Technically trained works manager, at $125 a month 4. 15
Depreciation, at 15 per cent of investment in plant ($20,000) 8. 20
Upkeep, at 8 per cent of investment in plant ($20,000) 4.40
Insurance, at 3 per cent of investment in plant ($20,000) (average) 1. 65
Chemicals for still house, etc 1. 00
Barrels or other containers for making deliveries 15. 00
Interest on total investment ($25,000), at 6 per cent 4. 11
167. 21
Total daily production cost, exclusive of sales or marketing ex-
penses, a cord 16. 72
Marketing expenses, although an important item, are not included,
because they depend largely on the business policy of the manage-
ment and upon competition.
The cost of operating a plant in the South Atlantic States is
but little more than half this estimate, because of the much lower
cost of wood and of labor in the South. If the medium-grade wood
could be distilled at the usual southern cost, it would yield a fair
return. The approximate cost of operating a destructive distil-
lation plant in the South Atlantic States is as follows :
Cost of wood for distilling, a cord $1. 50 to $3. 00
Management, labor, fuel, packing, a cord 2. 50 to 6. 00
Interest and depreciation, a cord . 60 to 1. 60
Total 4.60 to 10.60
The values assigned to the several products are representative of
those prevailing on the eastern coast shortly after the European
war started. To this must be added the cost of transportation to
48 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
the West and western dealers' profits, which were not included for
the reason that they vary greatly, and also because local freight
rates to interior points would, in many instances, be nearly as great
from western points to consuming points as the through rates from
the South to the same consuming points. Since, in any event, sin -h
competitive freight charges would vary greatly with the locality,
they are not included in the estimation of values here given, but
they must receive very careful consideration before the erection
of a plant for the recovery of products from wood.
On the basis of the foregoing carefully considered and conserva-
tive estimates of cost of production and of the value of products, it
must be concluded that stumps of medium quality, giving the aver-
age yields stated, can not be profitably utilized generally by the
destructive distillation methods. Needless to state, if, because of
exceptionally favorable local conditions, the cost of wood at the
plant can be materially reduced, wood of medium richness could be
profitably distilled. Such localities should be given very thoughtful
and systematic consideration by experienced and practical distilla-
tion experts before undertaking their exploitation.
Since poor stumps and dead, down wood contain even less resin-
ous matter than the medium stumps, they could not be profitably
distilled.
On the other hand, the rich or pitchy stumps contain enough
resins to make their distillation profitable in those localities where
they are sufficiently numerous. With wood containing enough resin-
ous matter to average the yields given for rich stumpwood, obtain-
able at even $10 a cord, a wide margin of profit is possible by the
process outlined, provided all the products can be marketed at prices
not materially lower than those used in the foregoing estimate. To
maintain an adequate wood supply of this quality, sufficient for a
plant to operate a number of years, it will be necessary to resort to
a long-distance railroad haul and long-distance wagon transporta-
tion to railroad sidings. For this reason, a cost of something like
$10 a cord should be allowed in estimates for such wood, the cost of
getting out the stumps alone exceeding $6. The possibility of ob-
taining at reasonable prices sufficient quantities of rich stumps which
are thinly distributed over the land, entailing a high cost of collect-
ing, is the vital point in considering the practicability of wood dis-
tillation in the Pacific Northwest.
The impression that more material than that obtained from the
rich stumps might be drawn on, because, the margin of profit for
this material appearing quite large, an appreciable proportion of
wood intermediate in quality between that from rich and that from
medium-grade stumps combined with the rich grade would give a
material worth working up. would in general be misleading.
DISTILLATION OF STUMPWOOD. 49
When stumps of the different grades (p. 15) were dynamited
but little difference was found between the poor and medium-quality
stumps. Furthermore, unless the exudation of rosin is exception-
ally abundant, it can not be taken as an indication that the stumps
are rich or pitchy. So disappointing was this superficial indication
of quality, used before its true value was established from dyna-
miting a number of stumps, that, to avoid shipping a lot of what
was plainly worthless material, the poor stumps were taken from
those that had been classified as medium, leaving only a few spe-
cially selected stumps from which the rich wood proper was ob-
tained.
In view of these facts, poor and medium-quality stumps, as the
terms are used in this bulletin, are those in which the sound heart-
wood approximately equals in resinous .appearance that found in
the heartwood of an average yellow-pine log, except that it is richer
toward the spreading of the roots. The resinous material in such
wood comes largely from this portion of the stump. Medium
stumps differ from poor stumps only in that there is a somewhat
larger proportion of the very resinous wood at the spreading of the
roots, the main volume of heartwood in these two classes of stumps
appearing to be essentially alike. Rich or pitchy stumps differ from
the medium in that the heartwood is more uniformly resinous
throughout the whole of the stump and constitutes perhaps from
60 to 80 per cent, or more, of the whole stump, while in the poor
and medium stumps the resinous portion constitutes less than half
of the entire stump.
To verify the conclusion that the rich or pitchy stumps average
not more than a cord an acre of wood suitable for distillation, all
the stumps on a typical area were removed, representative samples
selected, and an estimate made of the total quantity of such wood
on the area from which stumps were taken. This selected represen-
tative acre contained 12 stumps, 9 of which were classed as medium
to poor, and 3 as resinous or rich. The 9 nonresinous stumps con-
tained between 3 and 4 cords of wood, of which but 1,500 pounds, or
one-half cord, was sound heartwood, the remainder being doaty,
nonresinous sapwood, which was separated from the heartwood in
the field, only the heartwood being taken to the laboratory. At
least 80 per cent of worthless nonresinous material was split out
of these stumps in obtaining the half cord of heartwood. In the
large resinous stumps there were 1J cords of resinous wood, all of
the quality represented by the sample. The nonresinous stumps,
though quite large (36 to 40 inches), were smaller than the resinous
stumps.
60953 21 4
50 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
The wood selected from that classed as the less resinous stumps
was richer than that from the 3 rich stumps. Weight for weight
of material in the selected samples this is true. However, of the
wood running 18 gallons of turpentine a 3,000-pound cord, only
about 1,500 pounds, or one-half cord, in the entire lot of 9 stumps
contained an estimated volume of 3 or 4 cords of w r ood. To run all
of this wood would eliminate the cost of splitting out the resinous
wood from the sapwood. It would, however, quadruple the cost
of rail and wagon haul and the time and cost of distilling, and, at
the same time, would cut down the yield to about 5 gallons a cord
of very inferior turpentine, with a proportional reduction in other
products.
The half cord of resinous wood from the 9 stumps, combined with
that from the 3 more resinous stumps, gave about 2 cords of wood,
running 17 gallons of turpentine a cord. Had all the wood on the
acre plot been used, there would have been 6 cords, yielding not
more than 6 or 7 gallons of turpentine a cord, with the other prod-
ucts in like proportions. Neither the results of these experiments
nor the wood-distillation practices in the South warrant the belief
that wood of this quality can be profitably distilled. It is better to
split out and reject the low-grade wood.
While a large proportion of the yellow-pine stumps in Idaho con-
tain a certain amount of resinous wood which is as rich as the truly
pitchy stump, such wood forms so small a proportion of the entire
stump that its removal from the nonresinous wood is prohibitively
expensive. The case is similar to that of many ore-bearing forma-
tions in which the valuable mineral is disseminated through so large
a proportion of worthless material as to make its concentration in a
form rich enough for treatment commercially impracticable.
At the 1915 prices for raw material and for products, wood from
60 to 80 per cent of which must be split off and rejected, or wood
which will yield but 6 gallons of turpentine or a total of 30 gallons
of resinous products a cord, could not be profitably distilled. When
the nonresinous portion of the stumps has rotted away, leaving only
the resinous heart, this material, which then would be similar to the
rich stumps, could, of course, be profitably used, provided the ratio
of cost to selling value remained essentially the same.
Future careful studies of the uses to which the heavy crude oil
may be put probably will result in a revision of the price here as-
signed to it. That of 15 cents a gallon is based on its probable value
for uses to which certain of the creosote oils are being put. Undoubt-
edly its value can bo enhanced by suitable refining methods, or by
working it up into special products. These would necessitate addi-
tional equipment and labor, thus increasing the manufacturing cost,
the probable expediency of which can not be foretold. The same con-
DISTILLATION OF STUMPWOOD. 51
sideration applies to the light-oil fraction. From the prevailing price
of articles with which such refined or special products must compete,
it is doubtful if the balance between production cost and market value
of the output of a plant would be materially affected thereby.
The acetone, wood alcohol, and acetic acid content of the aqueous
distillate is, roughly, one- fourth that obtained in the crude distillate
from hardwood plants. The value a cord of the alcohol and acetic
acid recovered as acetate of lime, based on 1915 prices, is approxi-
mately $1 and $1.50, respectively. The crude liquor as obtained from
the retorts is so heavily charged with tarry bodies that the acetate if
obtained therefrom by the ordinary method is of a low grade and
at best usually commands too low a figure to make its recovery profit-
able. Even by some improved processes, the recovery of these three
products, which would increase the gross income by about $2.50 a cord,
could be accomplished at best only on a narrow margin of profit,
and the earning power of a plant thus equipped would not be ma-
terially increased by so doing. A company in the Northwest, oper-
ating a wood- distilling plant on selected Douglas fir mill- waste, in-
cluding the recovery of these products in their margin of profits,
found the enterprise, as then carried out, unprofitable.
One other possibility needs to be mentioned. It has been stated
that lean and also medium resinous stumps contain small propor-
tions of heartwood nearly if not quite as rich in resin as the resinous
portions of rich stumps, but the proportion of such wood is so small
that the cost of splitting it out would be prohibitive. Should the
nonresinous portion rot off the lean and medium stumps in the
course of a few years, as happens in the longleaf yellow-pine cut-
over lands, the remainder or heart of the stump would then be prac-
tically 100 per cent resinous and suitable for distillation. Unfortu-
nately, few such rotted stumps showing only the sound, rich heart
were observed in any of the districts visited. The rotting off of the
sapwood would unquestionably proceed more rapidly farther south.
RELATION OF WOOD DISTILLATION TO LAND CLEARING.
One of the purposes of this investigation was to secure informa-
tion on what part of the cost of clearing land for farm purposes
might be paid for by distilling the wood or by selling the wood for
distillation.
The cost of clearing land for farming in the Pacific Northwest
varies widely, depending on the size, number, and age of the stumps,
the lay, nature, and water content of the soil, cost of labor and ma-
terials, and other factors. The United States Department of Agri-
culture, in cooperation with the State agricultural experiment sta-
tions of Washington, Wisconsin, and Minnesota (11), and the Uni-
52 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
versity of Idaho (8), have done much actual work on land clearing
in this section, and have found the cost of clearing for farm purposes
to vary from $50 for the lightest clearing ground to $150 an acre for
heavily wooded hardwood land.
In the sections from which samples were collected 20 yellow-pine
stumps to the acre is a high average on land where the stand is
mostly or entirely yellow pine ; under more commonly occurring con-
ditions in which there is more of a mixed stand, such as in the Pot-
latch-Deary district, 10 to 12 yellow-pine stumps to the acre is more
nearly correct.
If, as indicated by these investigations, 10 per cent of the yellow-
pine stumps are of the rich, resinous type, yielding 20 gallons of
turpentine and other products in proportion a cord, or 15,4 gallons a
ton, the 12 stumps an acre would yield 1 cord, and 20 stumps about
2 cords of wood an acre.
If the wood could be disposed of for $10 a cord, the return for the
extra labor, time, and expense required to split and sort out the
resinous wood and haul it to a shipping point would be from $10 to
$20. Experiments in clearing 1 acre carrying 12 yellow-pine stumps.
varying from 2 to 5 feet in diameter (page 18), have shown that
this return will a little more than pay for the powder needed to
blast out all the yellow-pine stumps. In other words, provided a
market for the wood at $10 a cord is available, the net cost of land
may be reduced from (>J to 40 per cent, less the cost of sorting and
hauling to a shipping point.
The chief question is whether a farmer can afford to shoot all the
yellow pine clear of the ground, or crack with explosives and pull
the pieces with a puller, then sort the wood and haul it to the rail-
road, or whether he can get his land cleared more cheaply by using
some of the methods of burning described in Idaho Agricultural Ex-
periment Station Bulletin 91, or United States Department of Agri-
culture Farmers' Bulletin 974. If the returns from the fat stumps
on a tract are sufficient to justify the more expensive methods of
clearing, and it is some advantage to have all the roots out of the
ground, blasting is the method which will be most used.
About 100 pounds of explosive would be required to shoot clear of
the ground all the yellow-pine stumps on an acre, while 25 pounds
would crack them enough so that they could be bunted. In the first
case, the cost of explosive (1914-15) would be about $15 and in the
second case $4. The explosive could be placed with a little loss work
if the stumps were to be burned. Possibly it would require about the
same amount of labor to burn the stumps in the ground as it would
to sort over the pieces, burn those unfit for distillation purposes, and
haul the rest to the railroad. On the assumption that it would, it
DISTILLATION OF STUMPWOOD. 53
will be seen that the farmer would just about break even if he could
sell the rich wood for $11 an acre.
A wood- distilling plant of any size can not operate profitably with-
out an ample and steady supply of rich wood extending over a num-
ber of years. For this reason a wood-distilling plant should be built
and conducted as an independent business rather than primarily as
a means of meeting the cost of land clearing. Naturally, it would
be located with reference to available material ; that is, where there
was land ready to be cleared. Such wood as the settlers could supply
would be simply an addition to the stock, though in some instances
the bulk of the wood might be obtained from this source.
In the Winchester and Craig Mountain country, where the condi-
tions are quite different from those observed in the other sections,
there is a close almost pure stand of yellow pine. As there are no
heavy underbrush or slashings, clearing such cut-over lands consists
practically entirely in burning the tops of the cut trees and removing
about 20 large yellow-pine stumps.
The comparative absence of younger growth between the trees,
fairly even surface of the country, and uniform stands, of which per-
haps 40 per cent of the stumps are quite rich or resinous, make such
sections possible localities in which the cost of land clearing may be
met, in a large part at least, if not entirely, by distilling the stumps.
SMALL, SEMIPORTABLE WOOD-DISTILLING PLANTS.
Wood-distilling plants as usually constructed where the daily
capacity varies from 10 to 100 <3ords of wood, are permanent,
especially when a number of products are made and refined for mar-
ket. Furthermore, such plants require capital for financing and
technical skill and experience for profitable operation. Therefore,
wood-distilling plants would be comparatively few, and small plants
of about 1-cord capacity that can be set up, torn down, and re-
located at will would be useful, particularly in sections removed from
railroads and where transportation is difficult. Especially would
this be true if the mixed crude oil and tar obtained could be profitably
disposed of to refiners or directly to users.
Since the work described in this publication was completed, private
companies have built and operated such small plants. Plants of
this kind, of 1-cord capacity, can be built for from $3,500 to $4,500.
They might be bought and operated by a community, the crude oil
being sold direct to the zinc, lead, and copper miners, who use it
for the concentration of ores by the flotation process. The cheap,
semiportable 1-cord retort is probably better adapted to Northwest
conditions than are the large, more permanent, and more expensive
plants making and refining a number of products.
54 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
USE OF OIL FOR ORE FLOTATION.
Of the many oils that have come into use for ore flotation, oil
of eucalyptus, costing about $1.50 a gallon, is prized most highly.
Next in the order of merit come the pine oils, selling for from 40
to 60 cents a gallon. In the effort to discover cheaper oils, most of
the wood creosotes, as well as many coal-tar creosotes, have been
found to be acceptable. They range in price from 15 to 30 cents a
gallon. Producers of petroleum have also entered the flotation field,
though with but limited success when petroleum alone is used.
Better results are obtained by mixing a small amount of pine or
creosote oil with the crude petroleum. "Kerosene sludge acid"
from California oils, obtained by treating the crude oil with sul-
phuric acid in the refining process, is also being sold for flotation.
The sludge acid from coal tar is said to have a flotation value as
good as or better than that from petroleum, and even coal tar itself
is extensively used because of its low price.
These different products entering into ore flotation may be divided,
in a general way, into two classes, known as " frothing agents,"
which promote foaming, and "collecting agents," the function of
which is to coat with a film of oil the mineral particles only, so
that, adhering to the air bubbles in the foam, they are thus sepa-
rated from the gangue. While all oils possess both frothing and
oiling or collecting properties in some degree, eucalyptus oil, the
pine oils, pine-tar oils (the "light" and "heavy" oils of this pub-
lication), and crude turpentine are primarily used as frothing agents.
Coal tar, pine tar, together with hardwood tar, and " sludge acid "
are used as collecting agents. Success in ore flotation demands a
proper adjustment of these two physical properties to the particu-
lar requirements of the ore to be treated. While all of the products
mentioned can be used in proper combination, with some measure of
success, the pine oils occupy a commanding position in the field of
ore flotation.
Samples of pine oil and of the crude distillates obtained in the
retort work were submitted for flotation tests to the Bureau of
Mines Metallurgical Experiment Station, Salt Lake City, Utah, to
ore mills in the Coeur d'Alene district, and to the testing department
of a large copper mining company. The results from their tests
showed that the crude turpentine was virtually as effective a flota-
tion agent as the pine oil, and even the light and heavy oils were
applicable, though requiring a greater proportion a ton of slime,
especially in the case of the heavy oil. Even the acid liquor was
found useful on certain pyrite ores.
Where, therefore, the efforts of the producers were formerly di-
rected toward refining the crude distillate to recover a maximum
DISTILLATION OF STUMPWOOD.
55
quantity of turpentine, the change in market conditions makes it
desirable to throw as much of it into the pine-oil fraction as is
possible, or to go a step farther and market the entire crude dis-
tillate as flotation oil. If this were done it would, of course, re-
duce decidedly the cost of running the plant, and simplify opera-
tion. The consequent reduction in cost of production would prob-
ably amount to $2 or $3 a cord.
As to future flotation-oil values it is difficult to conjecture. The
Bureau of Mines, which experimented with the various oils obtained
in the course of this work, commenting on the conditions that will
probably have to be met in the flotation-oils market during the
coming years, points out that :
Pine oil at 50 to 60 cents per gallon has cost too much. Crude petroleum
and coal tar containing small additions of pine oil can be made to do almost
the same grade of work and are hence cheapening the cost of flotation oils.
Pine cresote, pine tar oils, and various hardwood fractions, together with
hardwood tar, are finding acceptance in place of the more expensive products.
There will always be a market for pine products, however, as long as they
do not cost too much; 30 to 40 cents per gallon, f. o. b. the West, will probably
be the price paid for such material and when the price goes much above that,
the material will merely be eliminated from consideration.
Some idea of the quantities of these pine products used in the flota-
tion of ores may be obtained from Table 20.
TABLE 20. Monthly consumption of flotation oils in the United States (1916).
[Compiled from a report of the Bureau of Mines.]
Type of ore.
Monthly tonnage of ore.
Wood products.
Beginning
of 1916.
End of
1916 (esti-
mated).
Pine
oil.i
Pine-
tar oil.2
Oil of
eucalyp-
tus.
Wood
creosote. 3
Crude
turpen-
tine.
Copper
Tons.
1,248,000
248,000
115,000
45, 700
Tons.
1,942,000
350,000
136,000
123,000
Galls.
7,800
8,000
515
1,300
GaTls.
95
85
Galls.
Galls.
47,600
30,000
13,800
4 600
Galls.
205
450
Zinc and complex .
Lead
28
Gold and silver...
95
Total
1,656,700
2,551,000
17,615
275
28
96,000
655
1 Probably includes a considerable amount of the lighter fractions of pine-tar oil.
2 The crude light oil would probably come in this class.
3 The crude heavy oil would probably come in this class.
It has been pointed out that combinations of different oils are
used by mixing the more expensive pine- wood distillates with crude
petroleum, coal tar, etc., in suitable proportions to obtain the de-
sired foaming and collecting effect for the kind of ore to be treated.
While this is to a large extent done at concentration plants, some pro-
ducers in the East market blended oils on this same principle. This
should, of course, be given careful consideration by those-who may
56 BULLETIN 1003 U. S. DEPARTMENT OF AGRICULTURE.
engage in the production of flotation oils from resinous wood wastes
in the Northwest. A list of uncompounded pine oils and other dis-
tilled wood products used, either alone or for producing blended oils
for flotation, is given herewith. Some idea of the required proper-
ties may be derived from the specific gravities :
Crude pine oil. Pine-tar oil, double refined (sp. gr.,
Crude wood turpentine. 0.965 to 0.990).
Pine oil, steam distilled (sp. gr., 0.925 Pine tar, thin (sp. gr., 0.980 to 1,0<M.
to 0.940). Wood (pine) creosote, refined.
Pine oil, destructively distilled. Hardwood oil (Michigan) (sp. gr.,
Pine-wood oil (light) (sp. gr., 0.950). 0.960 to 0.990).
Pine-wood oil (heavy) ( sp. gr., 1.025 ). Hardwood oil (Michigan) (sp. gr.,
Pine-taroil (sp.gr., 1.025 to 1.035). 1.06 to 1.08).
REFINING CRUDE WOOD TURPENTINE.
The crude wood turpentine is a complex mixture of oils, both
lighter and heavier than pinene, certain of which impart to the tur-
pentine an objectionable, penetrating odor and dark color, from
which wood turpentine having the accepted commercial require-
ments, and of uniform quality, is to be obtained. To compare favor-
ably with gum spirits the refined product should, in addition to its
odor and color, have a correspondingly narrow boiling-point range
or distillation-temperature limits.
In refining crude wood turpentine it is customary to subject it to
steam distillation, after thorough mixing with caustic alkali to re-
move or hold back certain constituents, whereby it is separated into
a fraction lighter than turpentine, having a yellow color and pene-
trating odor, a turpentine fraction, and a pine-oil fraction. The de-
tails of operation and the proportion and quality of the products
thus obtained vary greatly with the quality of the crude oil, as well
as with the care observed in dividing or cutting the fractions. In
doing this the still operator is commonly guided by the density, odor,
color, etc., of the oil in changing over from one fraction to another,
which is not conducive to uniformity of results. This insufficient
standardization of the product has contributed materially to the un-
favorable attitude of consumers toward wood turpentine, as well
as to the lower price commanded by and greater difficulty in market-
ing this product as compared with gum spirits.
The necessity of separating a light fraction that must be marketed
as an inferior turpentine or special product because of its objection-
able odor and color, moreover, is a wasteful practice, in that this
product is made up largely of pinene which properly belongs in the
turpentine fraction. Owing further to imperfect fractionation, or
the tendency of the heavier oils to pass over with the turpentine,
only in part overcome by the use of column stills, a considerable
DISTILLATION OF STUMPWOOD. 57
proportion of the turpentine fraction is retained in the residual
pine oil.
Because of these defects in refining processes, efforts were di-
rected in the beginning of this work to devise a laboratory method
for recovering a maximum of high-grade spirits from the crude oil
that would be applicable to the operation of a commercial plant, on
the basis of which yields of commercial turpentine from different
woods could be compared. It soon became apparent that sufficient
importance is not attached to the amount of alkali required and to
the manner of its application. Instructions merely to distil with
alkali or to treat with alkali until action ceases are entirely inade-
quate, because the amount of alkali used materially affects the pro-
portion of the light fraction, the sharpness of the fractionation, and
the quality of the turpentine as indicated by its odor, color, and boil-
ing point limits. The intimacy and period of contact of the alkali
has equal or greater influence.
The alkali appears to serve a double purpose, aside from that of
neutralizing the free acid present in the crude oil. First, it brings
an apparent polymerization of the aldehydes whereby these are con-
verted into resinous, nonvolatile compounds, in which form their
elimination from the turpentine is effected on distillation. Second,
the action of the alkali, if used in sufficient quantity, results in the
formation of a soap with the tar and resin acids. This, in a man-
ner not understood, although it may be through formation there-
with of a so-called water-soluble oil, restrains the escape of the
pine-oil constituents, while the turpentine distils over, thus effect-
ing a materially sharper separation of the, two. The alkali solution
being immiscible with the turpentine and the polymerization process
partaking in its nature of a catalytic or surface reaction, the effec-
tiveness of the alkali depends on extremely intimate contact with
the turpentine for a sufficient length of time to permit the carrying
of the reaction to completion before beginning the distillation. It
is in this respect that refining methods as ordinarily carried out are
wrong in principle, for the reason that, with the alkali added in the
still, distillation begins before completion of the reactions that "fix"
the aldehyde bodies. These in part pass over with the turpentine
and are removed from the sphere of action of the caustic solution
before the reactions that render them nonvolatile have been com-
pleted. Agitation of the turpentine in a separate vessel and remov-
ing and distilling the oil thus separated from the alkali are also
wrong in principle, because advantage is not taken of the deterring
action of the soap solution on the distillation of pine oils.
To combine the action of the two principles here set forth the
crude oil is agitated with caustic soda solution at boiling tempera-
ture in a return-flow condensing apparatus before distilling. Me-
58 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
chanical agitation with a paddle-wheel stirring device was the first
resort. It was subsequently found, however, that heating over a
flame in a distilling flask fitted with return-flow condenser is equally
effective and much simpler in execution. This method of treatment
thoroughly emulsifies the oil and caustic solution, giving the intimacy
of contact desired, while the inverted condenser continually returns
the aldehyde bodies to the action of the alkali until they have been
changed to the nonvolatile products previously discussed. The in-
verted condenser is then replaced by a Hempel column and the con-
tents of the flask distilled with steam, yielding from the start a tur-
pentine of standard requirements.
Steam distillation is admirably adapted to the production of tur-
pentine of uniform quality, because it affords a simple means of con-
trol, in that the ratio of oil to water in the distillate is an index of
the composition of the turpentine (12). This is a gradually dimin-
ishing ratio in proportion as the oil contains less pinene and corre-
spondingly more of the higher-boiling pine oils. For any observed
oil-to-water ratio, however, the turpentine has a definite composition,
as indicated by its density, refractive index, distillation-temperature
limit, etc. This, of course, follows from the law of relative vapor
pressure of immiscible liquids. Its application as a simple and re-
markably accurate means by which to judge the composition of the
turpentine at any time during the distillation, however, has not
been given the consideration it merits (12) as a means of standardiz-
ing the output of commercial plants. Properly used, the oil-to-water
ratio makes possible the production of turpentine having a constant,
predetermined composition, any consignment of which will be prac-
tically the same as a preceding or subsequent shipment.
Following up preliminary observations, based on the considera-
tions set forth, a series of experiments was conducted to determine :
(a) The relative efficiency of caustic soda, carbonate of soda, and
milk of lime as refining agents; (b) the proportion of alkali to crude
oil and concentration of the alkali solution giving the best results;
(c) the time necessary for the reactions set up by the alkali treat-
ment to produce its full effect ; (d) the effect of drawing off the alkali
after treatment and washing the oil with water before distilling;
(e) the effect of passing a current of air through the oil during treat-
ment with alkali.
In carrying out these experiments 500 cc., taken from a large com-
posite sample of crude western yellow-pine turpentine, were used in
each test. The turpentine fraction proper was continued to where
the ratio of oil to water was 4 to 6, beyond which the proportion
changes rapidly, and a second turpentine fraction collected hot \\ ecu
the 4 to 6 and 3 to 7 ratios. The distillation was continued for the
DISTILLATION OF STUMPWOOD. 59
recovery of pine oil to the point where the oil constitutes but 5
per cent of the distillate coming over. The odor, color, refractive
index, density, where possible, and volume of each fraction thus ob-
tained by the different methods of treatment were noted in order to
determine by the comparison of these constants which process gives
the closest separation and best yield of high-grade product.
As was to be expected the best results were obtained by the use of
caustic soda. With carbonate of soda, used in such proportion that
its hydroxyl strength was equivalent to that of the hydrate, the quan-
tity of the turpentine recovered from the crude oil was the same as
that obtained with caustic soda, but of inferior quality with respect
to odor. For commercial use, moreover, the fact of its being cheaper
than the hydrate is offset by its greater equivalent weight and the
correspondingly larger quantity required to produce the effect of an
equivalent amount of sodium hydrate. Milk of lime has only low
cost to recommend it. The calcium resinate or lime soap formed,
being insoluble, does not form the pine-oil emulsion that helps ma-
terially to effect a sharp separation of the turpentine. The yield of
the turpentine is lower by 10 per cent than when sodium hydrate is
used, and the product is inferior in odor. Moreover, the lime soap
seriously fouls the apparatus with an incrustation difficult to remove.
It was found that the quality improved and the percentage of tur-
pentine recovered increased with increasing amounts of alkali up to
75 cc. of 20 per cent caustic-soda solution per 500 cc. of crude oil, or,
in industrial terms, 75 gallons of 20 per cent caustic-soda solution
(containing 20 parts per hundred of actual sodium hydroxid) to 500
gallons of crude turpentine. This proportion was found to be satis-
factory for refining' the crude second turpentine. For the crude first
turpentine the amount of alkali probably could be diminished. The
concentration of the alkali solution is not so important, since the use
of half this quantity of 40 per cent alkali solution does not materially
affect the results. The duration of the chemical treatment before be-
ginning the distillation is of great importance, and at least 30 min-
utes after the mixture reaches the boiling point should be allowed for
the completion of the reactions involved. Separation of the alkali
solution from the turpentine before distilling has a profound effect.
Not only is the quality of the turpentine much inferior to that of the
turpentine obtained when the distillation is made in the presence of
the alkali solution, but the yield is lower by 20 per cent, with a corre-
sponding increase in the second turpentine and pine-oil fractions,
showing that, however brought about, the soap solution exerts a re-
straining influence over the pine oil, the complete separation of which
from the turpentine is most essential to the production of an article
possessing the properties demanded by the trade. Passing air through
60 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
the oil during the alkali treatment yields a turpentine having a
sweeter odor than that obtained without aeration. The other prop-
erties and the yield of turpentine recovered, however, are not mate-
rially influenced thereby. In refining a crude oil which is heavily
charged with the decomposition products of destructive distillation,
aeration to improve the odor may be found advantageous.
This procedure was followed in refining the various crude turpen-
tine samples obtained:
Transfer a 500 cc. portion to a round-bottomed liter flask, add 75 oc. of 20
per cent NaOH solution, and some finely broken pumice. Attach a I a 1-1:0 n-tlux
condenser and heat the contents to and maintain at the boiling temperature,
over a gas flame, for one-half hour. When sufficiently cooled, to avoid loss,
remove the reflux condenser, attach a Hempel column of fairly good size
filled three-fourths full with short pieces of glass tubing, and a condenser in
the ordinary position, and distil the contents of the flask with steam in the
usual manner. The oil coming over to where the ratio of oil to water is
4 to 6 is first-quality commercial turpentine, ready to enter the trade as such.
That coming over between the 4 to 6 and 3 to 7 ratio contains a small pro-
portion of lighter pine-oil constituents, and needs to be distilled a second time
for their complete removal. The distillation is continued for the recovery of
pine oil to the point where the pine oil forms 5 per cent of the distillate
coming over at the time, below which ratio it was not deemed economical to go.
To determine quickly the proportion of oil to water in the dis-
tillate it was found convenient to use a coordinate paper diagram
(fig. 5), in which abscissae are the water readings and ordinates the
total distillate readings collected during a short interval. Right
lines are drawn from the origin of coordinates to intersect, at 100
on the ordinate axis, the points 60, TO, and 95 on the axis of abscissae,
respectively, these corresponding to the percentage of water in the
distillate at the transition points. To use the diagram for deter-
mining the end of, say, the turpentine fraction, the volumes of water
and total distillate are read. The volumes of water are transferred to
the horizontal and those of the distillate to the vertical axis. If
the intersection falls above the 60 per cent water line, the propor-
tion of oil exceeds 40 per cent, and similar readings are taken at
suitable intervals until it falls on the line. Similarly, the TO and
95 per cent lines determine the end of the other fractions.
The odor and color of the refined turpentine samples thus obtained
were noted, the specific gravity and refractive index determined, and
a distillation made from which to judge their quality (Table 18).
The distillation temperature limits of turpentine are so suscep-
tible to pressure variation that it is essential, in making such com-
parisons, to conduct the distillation under normal pressure. The
laboratory at Moscow, Idaho, being at an elevation of about 2,800
feet above sea level, it was necessary to increase the pressure in the
distilling apparatus accordingly. This is accomplished by means
DISTILLATION OF STUMP WOOD.
61
of the apparatus devised in the Bureau of Chemistry and described
in detail in Bureau of Chemistry Bulletin 135, " Commercial Tur-
pentines."
The distillation data, along with the other data thus obtained,
bring out a striking uniformity in the physical properties of cor-
responding samples from various sources, differing, however, from
the better quality of wood turpentine from the South Atlantic and
Gulf States in their higher, though equally narrow, boiling points.
*
*
FIG. 5. Proportion of oil to water in distillate.
The major portion of turpentine from western yellow pine dis-
tilling between iTO^and 175 C. instead of 160 and 165 C., as is the
case with gum turpentine obtained from southern yellow pine, in-
dicates that in place of alpha-pinene this turpentine from western
yellow pine is largely made up of beta-pinene (7).
To obtain a closer separation of its constituents, and thereby gain
a better insight into the proportion and nature of the bodies prob-
ably entering into its composition, a composite sample of refined first-
grade turpentine, from first and second crude turpentine combined in
62
BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
proportions as recovered from the crude turpentine, was carefully
distilled from a Hempel fractionating apparatus, and the boiling
point, specific gravity, and refractive index curves plotted from these
data.
The boiling point, refractive index, and specific gravity curves
(figs. 6, 7, 8) point to the presence, to the extent of about 2 per cent,
FIG. 6. Boiling point of distillate.
of a body distilling at a relatively low temperature, having also a
much lower refractive index than the major portion of the distillate.
This is probably alpha-pinene, which in a pure state has a boiling
point of 155 C., a specific gravity of 0.858, and refractive index of
1.4660 at 20 C., whereas the corresponding values of beta-pinene
are 162 C., 0.868, and 1.4784. Polarimetrir readings on the first two
fractions, up to 6 per cent total distillate, showed laevo-rotations, in-
DISTILLATION OF STUMPWOOD.
63
dicating that the pinene present is laevo-alpha-pinene. Subsequent
fractions showed dextro-rotations, in a continually advancing degree.
The extra high density of the first distillate to come over is to be
attributed to the presence of traces of water, held in solution by
small quantities of methyl alcohol, known to occur in this portion of
refined turpentine recovered from crude second turpentine, and also
partly to the presence of the alpha-pinene. As the distillation pro-
/O
J?0
n
Tiff
00
cs/vr
FIG. 7. Refractive index of distillate.
gresses the specific gravity of the distillate slowly rises with the boil-
ing point to where, at about 20 per cent of total distillate, the presence
of a body having a specific gravity lower than that of the distillate
immediately preceding it again asserts itself by a bending back-
ward of the specific-gravity curve at this point. This may be due to
the presence of one or more of several bodies, the most probable
of which is limonene or dipentene (specific gravity 0.845, refractive
64
BULLETIN 1003, U. S. DEPARTMENT OK AGRICULTURE.
index 1.4730, each at 20 C., boiling point 178 C.), dipentene being
known to be a constitutent of wood turpentine. A materially higher
temperature than the boiling point of betapinene at which, even from
the beginning, the turpentine distils, points further to the presence
of appreciable amounts of dipentene, the greater portion of the
turpentine distilling at a temperature intermediate between that of
beta-pinene and dipentene. Above 80 per cent of total distillate the
60 TO #0 00 /Off
FIG. 8. Specific gravity of distillate.
boiling point, specific gravity, and refractive index rise rapidly,
showing that the. composition of the distillate is undergoing a further
marked change.
The principal constituents of turpentine, collectively spoken of
as terpenes, are a closely-related series of organic compounds pos-
sessing such a close similarity in chemical and physical properties
that precise knowledge concerning their quantitative estimation has
DISTILLATION OF STUMPWOOD. 65
not as yet been placed on a satisfactory basis. The problem is ren-
dered more difficult because of the tendency exhibited by the ter-
penes as a class to pass readily from one form to another, and, in
addition, to combine with oxygen and the elements of water, under
conditions not well understood, to form a series of altogether more
complex, oxygenated bodies possessing properties entirely different
from those of the parent substance.
Hesitation is felt, therefore, in assigning numerical relations to
or making an apportionment of the constituents that appear to enter
into the composition of this turpentine further than to say that it
seems to be largely made up of beta-pinene and dipentene, or its
optically active modification, d-limonene, a small proportion, 5 per
cent or less, of alpha-pinene containing perhaps some camphene,
and about 15 or 20 per cent of relatively high-boiling terpene de-
rivatives of unknown composition. The boiling-point and specific-
gravity curves indicate that the proportion of dipentene, or limonene,
probably exceeds that of beta-pinene.
To what extent ordinary turpentine possesses "drying" power, in
the sense of being an oxygen carrier, is an open question in the
chemistry of paints and varnishes, and the relative oxygen-trans-
ferring power of beta-pinene compared to that of alpha-pinene has
not been determined. Kremers (5) found that limonene absorbs
oxygen quite as rapidly as does pinene, from which it may be in-
ferred that dipentene possesses this property to a like degree.
To what extent the relatively high distilling temperature of tur-
pentine from western yellow pine will influence its value for use
in paints, varnishes, etc., can be definitely determined only from
actual use. The results obtained in comparative evaporation tests,
at room temperature, of gum spirits and wood turpentine from the
South, and wood turpentine from western yellow pine, secured in
the course of this work, however, show that the product from the
western yellow pine is materially slower in evaporating than either
the gum or wood spirits from the South. Moreover, the film re-
maining from the evaporation of the western yellow-pine wood
turpentine after drying twice as long as that from either of the
others could not, properly speaking, be said to have become dry or
resinified, compared with the films from the other samples. This
fact is undoubtedly due to the high-boiling constituents, the approxi-
mately 20 per cent which distils above 175 C. If this material
were not mixed with the turpentine where it does not belong, but
were added to the pine oil which it actually is, the turpentine would
dry much more rapidly and be more acceptable as a paint and var-
nish thinner. For some purposes, however, a slow-drying solvent is
desired, in which case the presence of the high-boiling constituent is
00953 21 5
66 BULLETIN ,1003, U. S. DEPARTMENT OF AGRICULTURE.
beneficial. The solvent power of this turpentine appears to be
equal to that of turpentine from ordinary sources, and it is quite
as light in color. Its odor, while different from that of gum
spirits, is in no way objectionable, the main point of distinction in
this respect being the pine wood odor so characteristic of the better
quality of wood turpentine generally.
While not suitable perhaps for all the technical uses to which
ordinary turpentine is adapted, this turpentine will answer for most
such purposes and it should find a ready market if properly intro-
duced to the trade.
APPLICATION OF METHOD TO THE COMMERCIAL PLANT.
The method of refining crude turpentine just described is readily
adaptable to the commercial plant. Two procedures may be fol-
lowed, according to the size of the plant and the available capital
for investment. The simplest and cheapest equipment for refining
the crude wood turpentine is a single copper refining still, so fitted
with a water-cooled return-flow condenser and a short fractionating
column and condenser, of any efficient type, that either one may
be used singly. After suspended and undissolved tarry matter has
had an opportunity to settle out, the crude turpentine is drawn into
the still, where it is mixed with the proper quantity of caustic soda
solution and boiled for the prescribed length of time, with the
return-flow condenser open and the fractionating column shut off
from the system. The heat for bringing the contents of the still to
a boil can be obtained either directly from a furnace under the still
or from closed steam coils inside the still at the bottom. The steam
coils are the safer arrangement. An open steam coil, with a number
of small openings along the length of the coil, is also placed inside
the still with the closed coil. This open coil may be connected by a
proper arrangement of piping and valves to both the boiler and a
small air compressor, and used during the preliminary boiling to
aerate the turpentine and alkali mixture.
At the end of the preliminary boiling period the fractionating
column is opened, the return-flow condenser closed, and steam turned
on in the open-coil system. The turpentine and pine oil are distilled
off with the steam and collected in three fractions, as already out-
lined (p. 58). Toward the end of the distillation additional heat
may be supplied by again turning high-pressure steam into the
closed coil, to help drive over the last portions of pine oil. At the
end of the distillation the alkali residuum is drawn off from the
still. The same still may be used for the subsequent refrartionation
of the various fractions from the first distillation.
A more expensive arrangement, that probably is better adapted
to a larger plant, consists of two separate stills, the first of which,
DISTILLATION OF STUMPWOOD. 67
for the preliminary boiling with alkali, is fitted with the return-
flow condenser. At the end of the period of boiling the contents are
drawn off into a second steam still with a short fractionating column.
With this arrangement the operation can be conducted almost con-
tinuously. As soon as the charge, after preliminary boiling, is
drawn into the steam-refining still, a new charge of crude turpen-
tine can be drawn from the settling tanks into the first still.
In a large plant the final refractionation of the first steam-dis-
tilled fractions can very well be carried out in a small continuous
fractionating still fitted with a short column.
The alkali residuum, which consists partly of pine and tar oil,
with the sodium soaps of tar and resin acids, and an excess of alkali,
has been shown by test to have germicidal properties approximately
half as great as those of phenol. Its probable use as a local disin-
fectant, after partial neutralization of the free alkali with the
waste acid liquor, is thereby suggested. Probably it can be used,
after the addition of a small amount of coal-tar creosote, as the
basis of a dip for hogs to rid them of lice. No actual experiments
to determine the real value of this material have been made. It is
impossible, therefore, to give concise directions for its use.
SUMMARY.
(1) In general, the stumps of western yellow pine are not as
uniformly rich in resin as those of the longleaf yellow pine in the
South Atlantic and Gulf States.
(2) The only wastes from western yellow-pine logging suitable
for profitable distillation on a commercial scale are those resinous
stumps which contain at least 50 per cent or more of resinous heart -
wood, and the resinous heartwood of stumps, dead, down wood, and
limbs from which the sapwood has rotted away.
(3) It is impossible to classify western stumps into such grades
as " rich " or " pitchy," " medium," and " poor " merely by a super-
ficial examination of the quantity of resinous exudation on the face
of the stump.
(4) " Rich " stumps, containing not less than 60 per cent of very
resinous heartwood, probably can be profitably distilled in a com-
mercial plant where the stand of such stumps is dense enough to
keep a plant supplied for a number of years.
(5) Owing to the fact that there is a well-developed market in
the West for crude pine-wood oils for use in the flotation concentra-
tion of ores, and also to the small volume of " rich " wood obtain-
able within hauling distance, it is probable that single retort plants,
which can be dismantled and moved when necessary, are the most
suitable for wood distillation in that section of the country, espe-
68 BULLETIN 1003, U. S. DEPARTMENT OF AGRICULTURE.
cially in regions remote from the railroad. Such plants might be
owned and operated jointly by a number of settlers.
(6) " Medium " grade stumps, though much more plentiful than
" rich " stumps, could be used in a commercial plant only at a cost,
delivered, materially less than the calculated cost per cord of such
wood, $8.37, and at prices for products not materially less than
those given in this bulletin.
(7) The refined turpentine from western yellow-pine stump wood,
consisting mostly of beta-pinene and limonene, has higher boiling-
point limits than similar turpentine from southern yellow pine, and
dries much more slowly. For this reason paints and varnishes
thinned with the turpentine take longer to dry than the same paints
and varnishes thinned with turpentine made from the longleaf yellow
pine of the South.
(8) The solvent power of this turpentine is not less than that of
wood turpentine from longleaf yellow pine made and refined by the
same process. It is suitable for many if not all of the purposes for
which wood turpentine can be employed.
(9) The refined pine oil and the crude oils obtained by distilling
western yellow pine are valuable for ore recovery by the flotation
process. This is probably the most profitable use to which these
products can be put.
(10) The crude light and heavy oils have germicidal properties
approximately half as great as those of phenol, for which reason
they are useful for shingle stains, wood preservatives, vermin killers,
and disinfectants.
(11) The pyroligneous acid or "acid liquor" contains approxi-
mately one-fourth the amount of acetic acid, methyl alcohol, and
acetone ordinarily recovered from hardwood acid liquor, and is
heavily charged with dissolved tarry matter, resembling in all re-
spects the pyroligneous acid obtained in distilling southern yellow-
pine wood. At the usual prices, the recovery of these materials at
a profit is hardly possible by present methods.
(12) A simple method for the commercial refining of crude wood
turpentine, which yields a superior product, has been devised.
The figures given in this bulletin are based on those which pre-
vailed in 1914 and 1915. Prices have increased materially since that
time and estimated profits may be more or less. Material changes in
the ratio of total cost of production to selling value of products
will increase the calculated profits from wood distillation if the
value of products has risen faster than cost of materials and of pro-
duction. Calculated profits will be decreased if the materials and
cost of production have increased more than the value of the products
of distillation. In order to estimate at any given time the probable
DISTILLATION OF STUMPWOOD. 69
profits from distilling western yellow -pine wood, costs and values
must be calculated on the basis of the cost of labor, wood, equip-
ment, overhead, etc., and on the basis of the value of the products,
at the time the estimate is made.
LITERATURE CITED.
(1) BERRY, S. Lumbering in the sugar and yellow pine region of California.
U. S. Dept. Agr. Bull. 440. 1917.
(2) BETTS, H. S. Possibilities of Western pines as a source of naval stores.
U. S. Dept. Agr., Forest Service Bull. 116. 1912.
(3) GRAVES, H. S., and ZIEGLER, E. A., The woodsman's handbook. U. S.
Dept. Agr., Forest Service Bull. 36. 1910.
(4) HALL, W. L., and MAXWELL, H. Uses of commercial woods of the United
States : II. Pines. U. S. Dept. Agr., Forest Service Bull. 99. 1911.
(5) KREMERS, E. Notes on coniferous oils: II. Oil from Pinus sabwiana. In
Pharm. Rev., 18: 165-172. 1900.
(6) HUNGER, T. T. Western yellow pine in Oregon. U. S. Dept. Agr. BulL
418. 1917.
(7) SCHORGER, A. W. An examination of the oleoresins of some Western
pines. U. S. Dept. Agr., Forest Service Bull. 119. 1913.
(8) SHATTUCK, C. H. Methods of clearing logged-off land. Univ. Idaho Agr.
Expt. Sta. Bull. 91. 1916.
(9) SMITH, F. H., and PIERSON, A. H. Production of lumber, lath, and shingles
in 1916. U. S. Dept. Agr. Bull. 673. 1918.
(10) SUDWORTH, G. B. The pine trees of. the Rocky Mountain region^ U. S.
Dept. Agr. Bull. 460. 1917.
(11) THOMPSON, H. Cost and methods of clearing land in western Washington.
U. S. Dept. Agr., B. P. I. Bull. 239. 1912.
(12) VEITCH, F. P., and DONK, M. G. Wood turpentine: Its production, refin-
ing, properties, and uses. U, S. Dept. Agr., Bur. Chem. Bull. 144. 1911.
(13) WOOLSEY, T. S., JR. Western yellow pine in Arizona and New Mexico.
U. S. Dept. Agr., Forest Service Bull. 101. 1911.
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