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1 of Forestry, U. S. Dept. of Agriculture.

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U. S. DEPARTMENT OF AGRICULTURE.

BUREAU OF FORESTRY— BULLETIN No. 41

GIFFORD PINCHOT, Forester.

SEASONING OF TIMBER.

HERMANN VON SCHRENK,

In Charge of Mississippi Valley Laboratory, Bureau of Plant Industry,

ASSISTED BY

REYNOLDS HILL,

Agent, Bureaii of Forestry.

WASHINGTON:

GOVERNMENT PRINTING OFFICE.

10 0 3.

Tj-

UonofiW*

-b ^
'b

LETTER OF TRANSMITTAL

U. S. Department of Agriculture,

Bureau of Forestry,
Washington^ D. O. , Feiruary 6', 1903.
Sir: I have the honor to transmit herewith a report entitled "Sea-
soning of Timber," by Dr. Hermann von Schrenk, pathologist in
charge of the Mississippi Valley Laboratory, Bureau of Plant Industry,
assisted by Reynolds Hill, agent, Bureau of Forestry, and to recom-
mend its publication as Bulletin No. 41, Bureau of ForestrJ^ The illus-
trations (of which there are eighteen full-page plates and sixteen text
figures) are believed to be necessary to a full understanding of the
text by the reader.

Respectfully, Gifford Pinchot,

Forester.
Hon. James Wilson, Secretary.

NUV 27 IM)6

D.ofa

CONTENTS

I. Introduction 5

II. Distribution of water in timber 7

Local distribution of water in wood and tree 7

Seasonal distril)ution 7

III. Relation of water to the decay of timber 8

IV. What seasoning is 9

Difference between seasoned and unseasoned timber 9

Manner of evaporation of water 10

V. Seasoning and preservative treatment 12

Seasoning and the leaching of salts 12

Seasoning and the processes of preservation 17

VI. Advantages of seasoning 19

Saving in freight 19

Use of cheap timbers 19

Prevention of checking and splitting 22

VII. How timber is seasoned 24

Kiln drying 24

Seasoning in other countries 24

Seasoning by steaming 26

Seasoning by immersion in water 27

Seasoning by boiling in oil 2S

Out-of-door seasoning , 28

VIII. Plan for seasoning tests. 29

IX. Seasoning tests with Lodgepole Pine .30'

Tests at Bozeman, Mont .31

Making and delivery of ties 31

Piling of ties 32

Wind direction 33

Intervals of cuttings .3.3

Preliminary results of seasoning tests 34

Seasoning after treatment with zinc chlorid 36

Individual variation in seasoning' 37

Variation by months 39

Cost of piling 40

X. Seasoning of oak timber 42

XI. Tests with telephone poles 43

Decay of poles 44

Plans for preventing decay of poles 44

XII. Plans for future work ^ 45

Seasoning of oak timbers 45

Seasoning of pine in the Southern States 45

Seasoning of gum timber ,.'. .'.."j. ■.'•.' 46

Pacific Coast tests ..^ .' 46

XIII. Conclusions and recommendations 46

Appendix 47

.LUSTRATIONS.

PLATES.

Page.
Plate I. Loading seasoned ties of Lodgepole Pine at Shieridan, Wyo . . Frontispiece.
II. Wood-deatroying fungus {Lentinus lepideiis) on Red Fir tie, South

DaliOta _ 8

III. Fig. 1. — Wliite Oali; ties seasoned too fast. Fig. 2. — Pile of poorly

seasoned car lumber 8

IV. Piling Baltic Pine on the Great Western Railway, England 12

V. Fig. 1.— Tie yard, Sheridan, AVyo., April, 1902; solid piles. Fig. 2.—

Tie yard, Sheridan, Wyo., September, 1902; open piles 12

VT. Making a tie out of Lodgepole Pine timber, Bozemau, Mont 16

VII. Fig. 1. — Lodgepole Pine forest after tie timber has been cut out.

Fig. 2. — Cutting of ties in the woods 16

VIII. Fig. 1. — Dragging ties to the flume. Fig. 2. — Tie piles at the flume.. 20
IX. Fig. 1. — Throwing ties into flume. Fig. 2. — Ties ready for the

flume 20

X. Fig. 1. — Tie flume. Fig. 2. — Another view of flume 20

XI. Fig. 1. — End of flume at railroad track. Fig. 2. — Another view of

same 20

XII. Fig. 1. — Landing platform, Bozeman, Mont. Fig. 2. — Another view

of landing platform 24

XIII. Fig. 1. — Lodgepole Pine, solid pile. Fig. 2. — Lodgepole Pine, half-

open pile 24

XIV. Lodgepole Pine, open-crib pile. Fig. 1. — Before treatment. Fig. 2. —

After treatment 32

XV. Fig. 1. — Triangular tie joiles. Fig. 2. — Lodgepole Pine piled to test

influence of prevailing winds on dr}'ing 32

XVI. Oak piles, showing lowest tier on the ground — a poor method 32

XVII. Oak piles, showing methods of building a roof 40

XVIII. Open-crib oak piles, southern Illinois , 40

TEXT i'TGURES.

Fig. 1. Diagram showing absorption and loss of water by dry wood 11

2-6. Manner in which soluble salts leach out from treated timber 12-14

7. Diagram showing length of life of Oak and Beech ties, French Eastern

Railway , 21

8. S-irons used to prevent checking 23

9. Method of applying S-irons to prevent splitting 23

10. Pile of ties on French Eastern Railway 24

11. Diagram showing average loss in weight by seasoning of Oak and

Beech timber during one year, French Eastern Railway 26

12. Diagram showing rate of drying of green ties 35

13. Diagram showing rate of seasoning of Lodgepole Pine ties treated

with zinc chlorid 36

14. Diagram showing loss of weight of 3 ties, a mean and two extremes. . 37

15. Diagram showing percentage loss of water of Lodgepole Pine timber

during various months, Bozeman, JMont., 1902 40

16. Diagram showing specific gravity of Lodgepole Pine timber cut

during successive months 41

SEASONING OF TIMBER.

I. INTRODUCTION.

In a recent report on the general subject of timber pi-eservation " it
was pointed out that there were a number of problems in connection
with this subject requiring further investigation. These problems
related to various stages in the preservation of timber, the prepara-
tion of timber for treatment, methods of treatment, and the final
disposition of treated timber. The present bulletin is the first of a
series which it is intended to issue from time to time, and deals with the
preliminar}' seasoning which precedes the actual chemical treatment.

In the report referred to, it was pointed out that one of the problems
requiring further investigation was the length of life of anj' given tim-
ber as affected by seasoning. Although it has been known for a long
time — and the fact is daily in practical evidence — that there is a marked
difference in the length of life of seasoned and of unseasoned timber,
the consumers of lumber have shown verj^ little interest in the season-
ing of timber except for the purpose of doing away with the evils
which result from checking, warping, and shrinking. For this pur-
pose both kiln diying and air seasoning are largely in use. Kiln dry-
ing, which dries the wood at a uniforml}' rapid rate by heating it in
inclosed rooms, has become a part of the car-building industry and of
the manufacture of furniture, vehicles, tools, and many other articles
in ordinaiy use. Without it the construction of the finished product
would often be impossible. Nevertheless, much unseasoned or imper-
fectl}^ seasoned lumber is used in car construction, as is evidenced by
subsequent shrinkage and warping.

Complaints are dailj^ made b}^ railroad managers that their freight
cars twist and warp out of shape more than they did years ago. The
explanation for this is probabl}- to be found in the tremendous devel-
opment in recent j'ears of the industries which require lumber for
building purposes. The manufacturer of structui'al lumber is so hard
pressed for lumber that he is forced to send out a poor product, which
the consumer is willing to take in that condition rather than to wait
several weeks or months for thoroughly seasoned material. As a
result, properly seasoned wood commands a high price, and in some
cases can not be obtained at all. Wood seasoned out of doors, which
by many is supposed to be much superior to kiln-dried timber, is

«The Deca}' of Timber, and Methods of Preventing It. By Hermann von Schrenk.
(Bull. 14, Bureau of Plant Industry, U. S. Dept. of Agriculture, 1902.)

6 ■ SEASONING OF TIMBEE.

becoming very scarce indeed, as the demand for any kind of wood is
so g-reat that it is thought not to pay to hold timber for the time neces-
ssivj to season it proper!}-.

How long this state of affairs is going to last it is difficult to say,
but it is believed that a reaction will come when the consumer learns
that in the long run it does not paj' to use poorly prepared material.
Such a condition has now arisen in connection with another phase of
the seasoning of timber. As alreadj' said, it is a commonly accepted
fact that dry timber will not decay nearlj- so fast as. wet timber.
Nevertheless, the immense superioritj^ of seasoned over unseasoned
wood for all purposes where resistance to decay is necessary has not
been sufficiently recognized. In the times when wood of all kinds was
both plentiful and cheap it mattered little in most cases how long it
lasted. Wood used for furniture, flooring, car construction, etc.,
usually got some chance to dry out after it was placed in use. The
wood which was exposed to decaying influences was generally selected
from those woods which, whatever their other qualities might be,
would resist deca}' longest. At first ties were made wholly of White
Oak, and, judging from recently compiled data, this wood alone was
used for many years. It lasted longer than other timber, and was hard
as well. The service which it gave was an ample return on the invested
cost, and no one thought at that time that it was at all necessarj^ to
devise means for lengthening that ser^aee. Ties were cut in an}' way
and at an}^ time, and were laid sometimes two days after cutting, some-
times not for six months or a year, during which time they may have
Iain in the woods, in a ditch full of water, or piled haphazai'd.

To-day conditions have changed, so that the 'White Oak can no longer
be used economically to the same extent as in former j-ears. Inferior
timber with less lasting qualities has been pressed into service, not
onlj' for ties, but for fence posts, bridge material, piles, etc. Although
haphazard methods of cutting and subsequent use are still much in
vogue, there are many signs that both lumbermen and consumers
are awakening to the fact that such carelessness and wasteful methods
of handling structural timber will no longer do, and must give way
to more exact and economical methods. The reason why many timber
merchants and consumers are still using the older methods is perhaps
because of long custom, and because they have not vet learned that,
though the saving to be obtained by the application of good methods
has at all times been appreciable, now, when timber is more valuable,
a much greater saving is possible. The increased cost is really very
slight, and is many times exceeded by the value of the increased service
which can be secured.

In the following pages a discussion of the principles applying to the
seasoning of wood is presented, together with some preliminarj' results
of tests made during the past 3'ear. It is thought advisable to publish
these results at this time, because the preliminary figures obtained are
so suggestive that thej^ may prove of value even in their present
incomplete form. It is to be understood, however, that the experi-

DISTRIBUTION OF WATEE IK TIMBER. ' 7

ments described are merely the first of a large series, some of which
are now under way, and which it is hoped will be carried on continu-
ouslj' for as manj' years as may be necessary to obtain sufficient data
to make the conclusions reached pei-fectlj^ accurate.

II. DISTBIBUTIOIT OF WATER IN TIMBER.

As seasoning means essentially the more or less rapid evaporation
of water from wood, itVill be necessary to discuss at the ver}' outset
where water is found in wood, and its local and seasonal distribution
in a tree.

LOCAL DISTRIBUTION OF WATER IN WOOD AND TREE.

A concise description of the distribution of water in wood was pre-
sented in an earlier bulletin of this Bureau, and as it covers the matter
fully, it is quoted in full here: "

Water may occur in wood in three conditions: (1) It forms the greater part (over
90 per cent) of the protoplasmic contents of the living cells; (2) it saturates the
walls of all cells; and (3) it entirely or at least partly fills the cavities of the lifeless
cells, fibers, and vessels; in the sapwood of jjine it occurs in all three forms; in
the heartwood only in the second form, it merely saturates the walls. Of 100 pounds
of water associated with 100 pounds of dry-wood substance taken from 200 pounds
of fresh sap^'ood of White Pine, about 35 pounds are needed to saturate the cell walls,
less than 5 pounds are contained in living cells, and the remaining 60 pounds partly
fill the cavities of the wood fibers. This latter forms the sap as ordinarily under-
stood. It is water brought from the soil, containing small quantities of mineral
salts, and in certain species (Maple, Birch, etc.), it also contains at certain times
a small percentage of sugar and other organic matter. These organic substances are
the dissolved reserve food, stored during winter in the pith rays, etc., of the wood
and bark; generally but a mere trace of them is to be found. From this it appears
that the solids contained in the sap, such as albumen, gum, sugar, etc., can not
exercise the influence on the strength of the wood which is so commonly claimed for
them.

The wood next to the bark contains the most water. In tlie species which do not
form heartwood the decrease toward the pith is gradual, but where this is formed
the change from a more moist to a drier condition is usually quite abrupt at the sap-
wood limit. In Longleaf Pine, the wood of the outer 1 inch of a disk may contain
50 per cent of water, that of the next, or second inch, only 35 per cent, and that of
the heartwood onlj' 20 per cent. In such a tree the amount of water in any one sec-
tion varies with the amount of sapwood, and is therefore greater for the upper than
the lower cuts, greater for the limbs than stems, and greatest of all in the roots.

Different trees, even of the same kind and from the same place, differ as to the
amount of water they contain. A thrift}' tree contains more water than a stunted
one, and a young tree more than an old one, while the wood of all trees varies in
its moisture relations with the season of the year.

SEASONAL DISTRIBUTION.

It is generally supposed that trees contain less water in winter than
in summer. This is evidenced bj' the popular saying that "the sap is
down in the winter." This is probably not always the case. Some trees

aXimber. By Filibert Eoth. (Bull. 10, Division of Forestry, U. S. Dept. of Agri-
culture, 1895.)

8 SEASONING OF TIMBER.

contain as much water in winter as in summer, if not more. The aver-
rage weight of Lodgepole Pine ties of the same size cut at Bozeman,
Mont., in June, 1902, was 1.57 pounds; in July, 144 pounds; in August,
160 pounds; in September, 157 pounds; in October, 164 pounds. It is
probable that this increase would keep up throughout the winter.

Of the varying amounts of water in the trees of one region during
the same period of different 3rears, little or nothing is known. It is
hoped that the tests now in progress will give some indications in that
direction.

III. RELATION OE WATER TO THE DECAY OF TIMBER.

The intimate relation existing between the presence of water in wood
and the rate at which wood decays requires a brief reference to the
causes of wood decay. A full account of the factors which bring,
about deca}^ has recentl}^ been published," and those interested are
refei'red to that publication for details. It will be sufficient at this
point to say that low forms of plant life called fungi grow in wood,
and by so doing disintegrate and dissolve portions of the wood fiber.
As a result of this, the wood changes in its physical properties and is
called decayed. When the fungus has extracted a sufficient amount
of material, it forms, on the outside of the wood, fruiting bodies
known as punks or toadstools, containing spores, which are blown
about and infect sound wood. PL II shows a Eed Fir railroad tie in
position, with the fi'uiting body of one of the most common of these
wood-destroying fungi {Lentinus lejyidexhs) gi-owing out from one side.
The ballast has been partly scraped away to show the whole fungus.
Fig. 2 shows the fungus on a larger scale. White, filmy fungus
threads grow through the mass of sandy ballast and spread to adjacent
ties.

The conditions necessary for the growth and development of wood-
destroying fungi are (1) water, (2) air, (3) organic food materials, and
(4) a certain amount of heat. The wood fiber and the organic substances
found in the living cells of sapwood, such as albuminous substances,
starch, sugar, and oils, form the food supply necessary to start the
growth of the fungus threads. A further requirement is oxygen; no
growth will take place under water or in the ground at depths of 2
feet or more, the depth varying with the character of the soil. The
best examples of this necessity for oxygen can be found in the way in
which fence posts and telegraph or telephone poles decay at points
just at or just below the surface of the ground, where there is a
balance between the supplj^ of air and of water.

For practical purposes water is the most important factor. With-
out water no fungus growth, and consequently no decay, is possible.
"Dry rot," a form of decay in which the wood turns to a drj"-, brittle.

a The Decay of Timber, and Methods of Preventing It. By Hermann von Schrenk.
(Bull. 14, Bureau of Plant Industry, U. S. Dept. of Agriculture, 1902.)

+ 1, Bureau of Forestiy, U. S- Dept. of Agriculture.

FiQ. 1.— Fruiting Body of Fungus on Tie in Position,

Fig. 2.— a Near View of Fig. 1.

WOOD-DESTROYING FUNGUS iLENTINUS LEPIDUSi ON RED-FIR TIE, SOUTH

DAKOTA.

3ul. 41, Bureau of Forestry, U. S. Dept. of Agriculti

WHAT SEASONING IS. 9

charcoal-like substance, is commonh' supposed to take place without
any water. Such is not the case, however. The atmospheric mois-
ture is sufficient to permit growth of the dry-rot fungus even if no
moisture is contained in the wood. Too much water will prevent
fungus growth, because it shuts off the air supply. The amount of
water necessarj^ to ]iermit the growth of fungi is very small. Wood
freshly cut contains more than enough at all seasons of the year to
support fungus growth.

From the foregoing it will be clear that the removal of water from
timber brings about a condition which during its continuance does not
allow of the growth of wood-destroying fungi. In other words, din/
wood will not rot or decaj^.

IV. WHAT SEASONING IS.

DIFFERENCE BETWEEN SEASONED AND UNSEASONED TIJVIBER.

Seasoning is ordinarily understood to mean drjdng. When exposed
to the sun and air the water in green wood rapidlj^ evaporates. The
rate of evaporation will depend on the kind of wood, the shape of the
timber, and the conditions under which the wood is placed. Pieces
of wood completely surrounded by air, exposed to the wind and the
sun, and protected b}^ a roof from rain and snow, will dry out very
rapidlj^; while wood packed close together, so as to exclude the air, or
left in the shade and exposed to rain and snow, will probably dry out
very slowly.

But seasoning implies other changes besides the evaporation of watfer.
Although we have as yet only a vague conception as to the exact nature
of the difference between seasoned and unseasoned wood, it is very
probable that one of these consists in changes in the albuminous sub-
stances in the wood fiber, and possibly also in the tannins, resins, and
other incrusting substances. Whether the change in these substances
is merely a drying out, or whether it consists in a partial decomijosi-
tion, is as yet undetermined. That the change during the seasoning-
process is a profound one there can be no doubt, because experience
has shown again and again that seasoned wood fiber is very much
moi'e permeable, both for liquids and g'ases, than the living, unsea-
soned fiber. One can picture the albuminous substance as forming a
coating which dries out and possibl}' disintegrates when the wood
di-ies. The drying out may i-esult in considerable shrinkage, which
may make the wood fiber more porous. It is also jDossible that there
are oxydizing influences at work within these substances, which result
in their disintegration.

Whatever the exact nature of the changes may be, one can say
without hesitation that exposure to the_wind and air brings about
changes in the wood which are of such a nature that the wood becomes
drier and more permeable. When seasoned by exposure to live

SEASONING OF TIMBER.

steam, similar changes maj- take place. The water leaves the wood in
the form of steam, while the organic compounds in the walls probably
coagulate or disintegrate under the high temperature.

MANNER OF EVAPORATION OF WATER.

• The evaporation of water from timber takes place largely through
the ends, i. e., in the direction of the longitudinal axis of the wood
fibers. The evaporation from the other surfaces takes place very
slowly out of doors; with greater rapidity in a kiln. The rate of
evaporation differs both with the kind of tim ber and its shape. Thin
boards and beams dry faster than thicker ones; sapwood dries faster
than heartwood. and j)ine more rapidly than oak. Tests made during
the past summer showed little difference in the rate of .evaporation in
sawed and hewn ties, the results, however, not being conclusive.
Air-diying out of doors takes from two months to a year, the time
depending on the kind of timber and the climate. No data have been
obtained as to the rate of evaporation out of doors. This is one of
the questions now under investigation.

After wood has reached an air-dry condition it absorbs water in
small quantities after a rain, or during damj) weather, much of which
is immediately lost again when a few warm, dry days follow. In this
way wood exposed to the weather will continue to absorb water and
lose it for indefinite periods. When soaked in water, seasoned timber
absorbs water rapidty." This at first enters into the wood through
the cell walls. When these are soaked the water will fill the cell
lumen, so that if constantly submerged the wood may become com-
pletely filled with water. The following figures show the gain in
weight by absorption of several coniferous woods, air-dry at the start,
expressed in per cent of the kiln-drj- weight:

Table I. — Absorption of icater by dry loood.

Air dried

Kiln-dried

In water 1 day . . .
In water 2 days. . .
In water 3 days. .
In water 4 days..
In water 5 days..
In water 7 days..
In water 9 days...
In water 11 days.
In water 14 days.
In water 17 days -
In water 25 days.
In water 30 days.

White
Pine.

Red
Cedar.

Hem-
lock.

Tama-
rack.

lOS

109

Ill

108

100

13.5

120

133

129

147

126

144

136

\ai

132

149

142

162

137

154

147

165

140

158

150

176

143

164

156

179

147

168

157

184

149

173

159

187

150

176

159

■ 192

152

176

161

198

155

180

161

207

158

186

166

«See tables given by S. M. Rowe: The Preservation of Timber (souvenir edition).
Chicago, 1900.

WHAT SEASONING IS.

It will be noted that almost half of the increase in weight came dur-
ing the iirst two days of soaking. The woods were kiln-dried after a
long air seasoning. A similar test was made with pieces of the same
woods which had not been kiln-dried; the only difference found was
that they absorbed water more readily during the first few days. Fig.
1 gives an indication of the rate at which air-dried wood will absorb
water when submerged and lose it again when exposed to the air and
sun. A number of absolutely air-dry blocks were kept submerged in
water for five days. The gain in weight was noted from day to day.

^f^

.fj:::^-'

/ /

5;::^^'^

\^^

•^^Y^

■^^^

s /

Fig. 1. — Diagram showing absorption and loss of water by dry wood.

After fire daj^s the same blocks were placed out of doors, exposed to
sun and wind. The curves show the rate of absorption up to the sixth
day, and the corresponding rate of loss thereafter.

While this series of curves will, of coui'se, hold only for the par-
ticular conditions under which this test was made, especiallj^ as
i-egards drying, it nevertheless indicates how rapidly dry wood will
absorb water and lose it again. It shows likewise that light, por-
ous wood will absorb more water in a given period than heavier
and denser wood.

12 SEA80NINC4 OF TIMBER.

V. SEASONING AND PRESEEVATIVE TREATMENT.
SEASONING AND THE LEACHING OF SALTS.

Where timber is chemically treated with salts dissolved in water, it
will be absolutelj' necessary to season it after the treating process, for
two reasons: First, to prevent the rapid leaching out of the salts
pressed into the wood; second, to prevent subsequent decay. The
practice, unfortunately in vogue in many cases, of placing timber
treated with a water solution in positions where it comes in contact
with water, can not be condemned too strongly. In the case of ties,
the leaching out of salts takes place with startling rapidity when they
are laid immediatelj^ after treatment.

The manner in which salts soluble in water leach out, and the rela-
tion of seasoning to this, is illustrated in a diagrammatic manner by
figs. 2 to 6. Let us sujapose for the sake of illustration that a
piece of nine wood is treated with a 20 Der cent solution of

.r— -^ )

loz^ L_

1Q% ^]\

20 1

-7

20?

1 ^^^^

20 ;

'j^iL..

20*

20?

Fig. 2. — Manner in which soluble salts leach out from treated timber.

zinc chlorid. In consequence the cell openings are filled with this
solution for some distance into the wood. Fig. 2 represents sev-
eral series of wood cells, very much shortened for the sake of bringing
them into the diagram. The dotted areas indicate water or watery
solution of zinc chlorid. Let us assume that these cells are situated
at the end of a tie, and that the ballast of sand touches them. The
rounded masses marked .s represent the sand grains, with air spaces
between them. Immediately after treatment the cells are filled with
the 20 per cent solution of zinc chloxid, and the spaces between the bal-
last particles are filled with air. Several days later a rain storm fills
these air spaces with water. We then have pure water touching
directly a 20 per cent solution of zinc chlori'd. It is a well-known law
of solutions that solutions of different densities tend to mix until a
solution of medium density is foi-med. Shortly after the rain storm,
therefore, the 20 per cent solution of zinc chlorid in the outer wood
cells will have been reduced, let us say, to a 10 per cent solution, and

Bui. 41, Bureau of Forestry, U. S. Dept. of Agriculture.

FiQ. 1.— Scotch Pine Ties Seasoning, Great
Western Railway, England.

FiQ. 2.— Piling Baltic Pine on the Great
Western Railway, England.

■k

' > i

^^H^ ^^^irl

■^y^^i

Fig. 3.— Ties Arriving in Canal Boats, Great
Western Railway, England.

Fig. 4.— Another View of Fig. 2.
PILING PINE ON THE GREAT WESTERN RAILWAY, ENGLAND.

ul. 41, Bureau of Forestry, U. S. Dept. of AgricuUurs

Fig. 1.— Tie Yard, Sheridan, Wyo., April, 1902— Solid Piles.

Fig. 2.— Tie Yard, Sheridan, Wyo., September, 1902— Open Piles.

SEASONING AND PBESERVATIVE TREATMENT. 13

the pure water in the Ijallast has become a 10 i^er cent solution of zinc
chlorid (fig. 3). There has been, in other words, a transfer of some of the
zinc salt from the wood into the ballast. When the rain stops, all the
water in the spaces between the sand o-rains runs off into the lower
strata of the JDallast. Meanwhile a process of equalization has been
going on among the various wood cells, which began as soon as some
of the salt left the outermost cells. Fig. -i shows in a diagrammatic

10%

,.^^-^^^^^^ !0|.

Fig. 3. — Manner in which soluble salts leach out from treated timber.

way what this process is. Some of the zinc chlorid in the second tier
of wood cells passes through the walls into the outermost cells, and
this continues until the solutions in the two series are practicall}' of
equal strength, i. e., about 15 per cent. In the same way the third
tier of cells loses some of its salt to the second, the fourth to the third,
and so on. This practically amounts to a gradual traveling of the zinc
salt outward in the tie toward the end; The next rain storm will

'¥''L

rat

10% — *-

!Qi

20Z

10 o-

'j^jiC.

20% ^ ^

JO°Q — *■

20^

15% —^11 15%

-0%

IS% ^ 15%

'~20%J^(~

" 15% --,| I5%1('

Fig. 4. — Manner in which soluble salts leach out from treated timber.

reduce the 15 per cent solution in the outer wood cells to a 7.5 per cent
solution, which will again be strengthened from the mner cells. Thus
the zinc chlorid gradually leaves the wood until none is left. This grad-
ual traveling outward of the zinc chlorid goes on with varying rapidit}^
depending on the amount of water in the ballast, the frequency' with
which the water is renewed, and its temperature.

In the case of seasoned wood something ver}' ditt'erent takes place.
When the wood dries the zinc salt is deposited in crystalline form in the

14 SEASONIJS^G OF TIMBER.

wood cells and walls as shown in fig. 5. When the rain water fills the
spaces between the sand grains, as represented in fig. 6, it passes into the
outer wood cells and dissolves some of the zinc salt there. This passes
out just as it did in the first case, except that in this instance the water
must first of all dissolve the zinc chlorid, which in the former instance
was already in solution. Only a portion of the salt is thus dissolved.
Moreover, the water does not penetrate very far, for the air in the cell

Fig. 5. — Manner in which soluble salts .leaeli out from treated timber.

cavities forms a considerable obstacle to its entrance. When the rain
ceases the water in the outer cells evaporates, leaving some of the salt
in the cells. After this evapoi'ation there is no transfer of zinc salt
from the inner wood cells toward the outer cells. This is a matter of
great importance, for it means that the salt injected remains for a much
longer period in the seasoned than in the unseasoned wood. Subse-
quent rain storms do not material^ change the conditions, for with
every one only the outer cells are aot to have salt leached out from
their cavities.

Fig. 6.— Manner in which soluble '•alts leach oiit from treated timber

The cells shown in figs. 2 to 6 might represent wood cells from any
part of a tie. In practice the leaching out of salts usuallj' takes place
first in the middle of the tie, and around the spike and under the rail
or tie plates. The water collects in the spike holes or in any crack

SEASONING AND PRESERVATIVE TREATMENT.

or check in the tie, aucl the conditions described are therebj' pro-
duced. Ends of fibers are exposed in the spike hole and in every
crack, or wherever the wood fibers are torn or broken.

A crude test was made with several Lodgepole Pine ties for the
purpose of giving at least a partial indication of the different rates at
which zinc chlorid leaches out from treated ties with and without sea-
soning after treatment. Two ties were taken — one which had dried
for three months, the other fresh from the treating cylinder. The
calculated amount of zinc chlorid in each was about 24 ounces. After
twenty-four hours soaking it was found that the seasoned tie had lost
3 ounces of zinc chlorid (calculated from the amount of zinc chlorid in
the water), while the newly treated tie had lost 5.5 ounces, or almost
twice as much. Stating these figures in another way, the seasoned tie
had lost in twent3'-four hours about one-eighth of the salt injected,
and the freshly treated tie about one-fourth of its salt.

A test which gives more reliable figures was conducted as follows:
A number of Lodgepole Pine ties were treated with zinc chlorid, and
the amount of salt absorbed was determined by weighing the tie before
and after treatment. The ties were then sawed in half. One-half of
each tie was placed in water for twentj'-four hours, at the end of which
period the amount of salt leached out was determined and the half ties
allowed to dry for twenty-four hours, after which they were again
submerged. This process was kept up for several days. The second
half of each tie dried imtil air-dry, and was then alternately submerg;ed
and dried just as the first halves had been, the amounts of salts leached
out being determined after every leaching. The following table shows
the results obtained:

Table II. — Leaching of zinc chlorid.
FRESHLY TREATED LODGEPOLE PINE (12 HALF TIES).

Number of tie.

Grains leached in 24-hour periods. 1

First
period.

Second
period.

Third
period.

Fourth
period.

Fifth
period.

Sixth
period.

720
oOO
600
330
375
500
370

eso

937
630
650
735

247
378
405
324
255
255
126
2.50
570
307
345
360

270
210
380
323
290
360
250
350
412
290
291
250

1.50
187
307
140
209
437
125
212
292
210
214
236

168
120
285
210
153
405
255
210
170
159
220
107

161
131
262
187
120
310
202
237
220
225
205
157

4-..

0..

Average . . .

.585

318 1 306 1 226

1 i

205

201

SEKSONINa OF TIMBER.

Table II. — Leaching of zinc chlorid — Continued.

SEASONED LODGEPOLE PINE (12 HALF TIES).

Number of tie.

Grains leached in 24-hour periods.

First
period.

Second
period.

Third
period.

Fourth
period.

Fifth
period.

Sixth
period.

555
460
439
1,250
620
675
512
770
805
675
800
562

600
337
365
300
157
472
350

127
197
212
82
236
140

92-

67
131
150

92
147

81
105
1.50

90
150

125
60
100
1.56
120
162
137
137
86
• 123
150
115

62
31
45
62
57
80
57
78
87
55
92
45

332 , 200
390 117
260 ' 127
405 2.50
360 92

Average - . .

677

3.52 154

109 122

It will be noted that the first two column.? show an even larger
amount of leaching from the dry than from the seasoned ties. This
was probablj^ due to numerous small checks caused by rapid drying,
which exposed a larger surface to the action of the water. Later
determinations, however, show a very marked falling off in the amount
of leaching from the diy ties compared with the freshl}" treated ones.
This is exactly what ought to have taken place according to the theory
of leaching set forth above. The salt which leached out from the
diy ties at first came from the outside of the wood. When it was
removed the leaching was materiallj' reduced, because there was no
chance for the salts within the tie to move toward the ' ■i^-'''?. These
tables are still incomplete. Completed tables will be published in a
succeeding bulletin.

Attention is here called to the results obtained in seasoning Lodge-
pole Pine ties after treatment, given on page 38. It will be suificieut
to say at this point that ties treated in June, 1902, lost 2i to 26 per
cent of their weight after seasoning three weeks.

Lodgepole Pine fence posts, treated with zinc chlorid June 2. 1902,
and then piled in an open pile to season, lost water in the next sixty-
five days as shown in the table on the following page.

Bui. 41, Bureau of Forestry, U. S. Depl. of Agriculluri

Fig. 1.— Tie Chopper Making Two Straight Faces on the Stick.

Fig. 2.— Peeling the Bark from the Lodqepole Pine.
MAKING A TIE OUT OF LODGEPOLE PINE TIMBER. BOZEMAN, MONT

Bui. 41, Bureau of Forestry, U. S. Dept. of Agriculture.

^WR^^^

f Z'-fll £ S^JS Mt -s^ H-H ftW^ ^ '

ml- W^m

Ni^^Ki^^' ^^^i

■HMm

^SWSJ^i

v^^^Tw^^^ w^HR|^^^g<^^^^B^^^^^uK^9

•^s
Ai

i,i^^^^/'=^<J,

wsf i^rm

1^^ im^^r^-i^-t^

Fig. 1 .— Lodqepole-Pine Forest with Tie Timber Cut Out.

Fig. 2.— Cutting of Ties in the Woods.

SEASONING AND PRESERVATIVE TREATMENT.

Table III. — Lodgepok Pine fence posts — Eiaporation of water after treatmetit u'itli, zinc

chlorid.
[Thirty-nine posts. Treated June 2, 1902.]

Before treating

1 hour after treating

1 day after treating. .
' 2 days after treating.

3 days after treating.

5 days after treating.

7 days after treating.
10 days after treating.
15 days after treating.
23 days after treating.
31 days after treating.
35 days after treating.
42 days after treating.
50 days after treating,
55 days after treating.
61 days after treating.
65 days after treating.

Weight of
39 posts.

4,660
4,450
4,325
4,190
4,0.55
3,860
3, 657
3,488
3,295
3, 162
3,072
2,996
2,900
2,844
2,780
2,716

Average
weight per
. post.

^loss^/i'^in P"<^™t

Pomuis.
66. 03
119.48
114.10
110.90
107. 43
103. 97
98.97
93.77
89.43
84.50
81.08

74.36
72.92
71.29
69.64

post.

-15.51
-20. 51
-25.75
-30. 05
-34. 98
-38. 40
-40.71
- 42. 66
-45.12
-46. 56
-48. 19
-49.48

orloss( — ).

+80.94
-10. 06
-16.05
-22. 54
-29. 02
-36.37
-48. 10
-56. 22
-65.44
-71.83
-76. 16
-79. 81
-84.41
-87. 11
-90. 16

It will be seen that in the two months about 93 per cent of the water
injected into the posts by the treatment evaporated, leaving practically
dry zinc chlorid in the wood cells. Most of these posts were set in
Nebraska and Wyoming, together with some untreated posts. Six are
still piled and will be placed in the ground in a Southern State during
the winter of 1902-3.

SEASONING AND THE PROCESSES OF PRESERVATION.

The cjuestion of the relation of the water content of timber to the
various treating processes has so far received but little attention in
this country. The subject is one of the greatest importance, for much
of the ultimate success of most forms of timber treatment depends
upon the amount of water in the wood before treatment. Mr. O.
Chanute and others have repeatedly urged the absolute necessit}' for
thorough seasoning of timber before treatment with zinc chlorid.
The success of timber treatment depends upon a series of factors
entirely apart from the mere impregnation of the wood with one sub-
stance or another, and the sooner it is realized that the actual treat-
ment is only one small part in the operations tending to obtain increased
length of life, the better it will be.

The object of timber treatment is to get certain chemical compounds

into the wood with as much thoroughness as possible. Because of its

peculiar structure, wood will not allow of the penetration of liquids into

its mass as does a sponge. The solution must work its way into the

19704— No. -41—03 2

18 SEASOKING OF TIMBER,

wood libers through walls of wood substance. If a water solution is
used for the impregnating material, it ought to fill ever}" cell and per-
meate every wall, at least in the sapwood. The most successful
method for timber treatment (excepting the boiling process) so far
used consists in pi-essing the solution into the wood. If the wood cells
and the walls are already full of water, it is eas}^ to see that there will
be great difficulty in making the water already in place give way to
the solution. When walls and cell cavities are free from water the
process of absorption of a solution is facilitated by the readiness with
which the capillary forces operative in wood fiber aid the absorption.
Nor is this all. Seasoning not onlj* brings about a reduction in the
amount of water, but also results in the partial disintegration of the
albuminous substances which ofi^er more or less . resistance to the
entrance of solutions. The steaming of wood before the injection of
the solution can never replace seasoning as a means of preparation for
treatment, for at best it does no more than drive off part of the water.

When the substance used is ordinary creosote or tar oil, the matter
of seasoning is still more important. At the present time there are
several plants in operation where green or watersoaked wood is steamed
in a cylinder for var3dng lengths of time and then treated with tar oil,
which is I'un in after the formation of a vacuum. The I'eason given
for this method of operation is that just as efiective a penetration of
the tar oil is secured at a lower cost, since the timber does not have to
be held until it is seasoned. An extended discussion of this subject
is reserved for another report. It is enough to say now that tar oil and
water do not mix, and that a porous medium entirely or partially filled
with water will not become so thoroughh' penetrated as one which is
dr}'. T>ry wood fiber absorbs tar oil with great readiness, as anyone
can prove who will pour tar oil into the ends of two pieces of wood,
one drj' and one moist. To the claim frequently made that wood
when steamed is absolute^ dry, one may answer that such is indeed
true when the temperature is raised sufficiently high to reach to the
very center of the piece of wood treated, but such temperatures are
frequently so high that the wood fiber itself is materially injured.

The experience of the European railroads and other consumers of
treated timbers is so ver^^ conclusive that it seems almost needless to
contend for a careful seasoning of timber before treatment. The great
objection made against it is the time required. The risk taken when
timber is held, as well as the interest on the investment, is sometimes
considerable; but it is believed that the tests already made and those
in progress will serve to show that in the long run the saving from
better service far exceeds the cost.

Another consideration of decided hnportmce is the time required for
the treatment. No definite data are yet at hand which will admit of a
fair comparison, but it is a matter of experience that the length of time
necessary to treat seasoned wood with an}' of the ordinary preserva-

ADVANTAGES OF SEASONING. 19

tives is very much shorter than foi' unseasoned. (Careful tests are now
in progress with Lodgepole Pine, and similar tests will be made with
other timbers this 3-ear.

If, therefore, we take into consideration the greater thoroughness
with which timber can be treated after ample seasoning, as well as the
larger amount which can be treated in a given time, it would appear
that any treatment which does not accuratelj' specif}' that all wood
must be thoroughly seasoned befoi'e treatment with zinc chlorid, tar
oil, or both, or any combination which contains salts, should be regarded
with disfavor. It is claimed for several processes, notably for the
Hasselmann and the electrical treatments, that green wood can be
treated as well as seasoned wood. Should this prove true, the objec-
tions made to the ordinary methods of treatment would not apply to
them.

VI. ADVANTAGES OF SEASONING.

Two most important advantages of seasoning have already been made
apparent:

(1) Seasoned timber lasts umch longer than unseasoned. Since the
decay of timber is due to the attacks of wood-destroying fungi, and
since the most impoi'tant condition of the growth of these fungi is
water, anything which lessens the amount of water in wood aids in its
preservation.

(2) In the case of treated timber, seasoning before treatment greatlj'
increases the effectiveness of the ordinary methods of treatment, and
seasoning after treatment prevents the rapid leaching out of salts
introdv;ced to preserve the timber.

Additional advantages of seasoning are:

SAVING IN FREIGHT.

Few persons realize how much water green wood contains, or how
much it will lose in a comparatively short time. Experiments along
this line with Lodgepole Pine, White Oak, and Chestnut gave results
which were a surprise, not onlj- to the companies owning the timber,
but also to the writer. Freight charges vary much in different parts
of the country ; but a decrease of 35 to 40 per cent in weight is impor-
tant enough to deserve everj'where serious consideration from those
in charge of timber operations. When timber is shipped long dis-
tances over several roads, as is coming to be more and more the case,
the saving in freight will make a material difference in the cost of
ties, bridge materials, etc., irrespective of an}^ other advantages of
seasoning.

USE OF CHEAP TIMBERS.

One of the questions which is engaging the attention of all large
consumers of timber is the possibility of substituting low-grade tim-
bers for those of a higher grade now in use. High and low grade are

20 ■ S2AS0NING OB" TIMBER.

of course relative terms; a timber which is called low grade to-day
maj- a few j'ears hence be classed as high grade. Such a change has
taken place in the past in the case of White Oak. From the point of
view of the railroads the question of high or low grade is primarily a
question of the durability, or "length of life," of difl'erent kinds of
timber for their particular needs — as ties, fence posts, and telegraph
and telephone poles. This, however, is complicated by the efiect on
prices of the general market demand. The price for a hewn White Oak
tie in southern Illinois, delivered on the right of way, is 35 cents. But
White Oak timber will bring twice this price, and frequently more,
for boards, staves, etc. This discrepancy in prices is bound to increase
with the increasing use of White Oak timber in the form of lumber,
and ^vith increasing scarcity. It is very obvious that it is a poor
business policj^ for anyone owning timber to sell it for ties when he
can get more for it in the form of lumber. Consequently the railroads
niust pa}' more and more for their ties, or find a substitute for "^Miite
Oak in some cheaper material. In former years an investment of
from 20 to 30 cents was amply repaid by the five to seven years" serv-
ice ordinariljr obtained from White Oak ties in the North. Such
service will not pay for an investment of 50 to 75 cents. It is very
evident to most railroad men that some change will have to be brought
about, and in fact such a change is actually taking place now.

A further consideration lies in the interest of other industries which
depend on a constant supply of White Oak. The manufacturer of
tight barrels, for instance, must have White Oak, and can not substi •
tute the porous Red Oak. If the railroads continue to use White Oak
for ties, they are cutting off a supply which will seriously affect such
industries. If White Oak were the only available material for ties,
this consideration would have no weight; but such is not the case.
In the regions which now contribute most largely to the White Oak
supply, a number of infei'ior oaks are found in even greater abun-
dance, and it will probably be only a short time before most railroad
companies will learn that these timbers can be used just as well as
White Oak. In a number of recent contracts, lumber contractors
have been allowed *the option of furnishing Eed Oak " properly
treated " in place of White Oak.

The same facts hold true for other classes of timber. During the
past year the Lodgepole Pine of the Northwest has been substituted
for the higher grade Bull Pine. It is believed that the time is not
far distant when the Longleaf Pine will no longer be used for ties,
particularly in Mississippi, Louisiana, and Texas, for its value in the
form of lumber is already so high that any marked increase will
bring about a situation very much like that which now obtains in the
case of White Oak. The Shortleaf and Loblolly pines will then find a
use for which they can be prepared at a cost low enough to permit of
their economical emplojauent.

41, Bureau of Forestry, U. S. Dept of Agncul;i

FiQ. 1.— Dragging Ties to the Flume.

Fig. 2.— Tie Piles at the Flume.

3ul. 41, Bureau of Forestry, V. S. Dept, of Agricutturt

Fig. 1.— Throwing Ties into the Flume.

Fig. 2.— Ties Ready for the Flume.

ul 41, Bureau of Forestry, U. S. Dept. of Agriculture.

FiQ. 2.— Another View of Flume.

u[. 41, Bureau of Forestry, U. S. Dept. ot Agricutturc

Fig. 1,— End of Flume at Railroad Track.

Fig. 2.— Another View of Same.

ADVANTAGES OF SEASONING.

One of the lirst questions to arise when we consider the substitution
of Red and Swamp Oak for White Oak, Loblollj- Pine for Long-leaf
Pine, or Hemlock and Tamarack for oak and pine, is. What shall be
done to these timbers so as to get the maximum value out of the
investment? The crux of the situation is the comparative lasting
powers of the various timbers. That which applies to ties holds true
also for telephone and telegraph poles, fence posts, bridge material,
etc.; in short, for all timbers which are exjDosed to deca3\ It is
believed that, b}' proper treatment, timbers which otherwise could
not be used for the purposes specified above can be made to serve
longer than the uuti'eated timbers in use up to the present time.

loo

■^—

—

-"■

— .

—

■

"~~

—

—^

0 So

n' '^^

^<>-

-^;

—

— -

—

3 4 5 c T © 3 »o 11 la 13 w 15 »c VT la >3 ao ai 2^^ 23 -ZA T.G

-Diagram showing lengtti of life of oak and beech ties, French Eastern Railway.

The relative ease with which so-called high and low grade timbers
can be treated is another matter requiring consideration. As a rule,
high-grade timbers — Longleaf Pine or White Oak, for instance — are
very much denser than the lower grades, sixch as Loblolly Pine or
Red Oak. The latter generally have a higher percentage of sapwood,
which can be peneti'ated b}^ a treating iiuid verj' much more readily
than heartwood. On account of this greater porosity it is very much
more economical to treat a porous wood thoroughly with a good pre-
servative than to treat a more expensive denser wood with a cheaper
preservative. The cheap and porous wood well treated will outlast
the other in every instance. Fig. T shows this graphically. The
short-lived, porous Beech, which ordinarily lasts but four to five

'^2 SEASONITSTG OF TIMBEE.

years, has outlasted the Oak several times over. It would be a
great waste, therefore, to attempt the treatment of White Oak or Long-
leaf Pine when better results will be obtained by using Loblolly Pine
or Red Oak.

One of the tirst steps in the process of making short-lived timbers
fit for treatment consists in a proper seasoning. More benefit will
result from taking care of the short-lived timbers than from similar
treatment of those with longer life. The former are frequently short
lived because of their greater porosity, which may mean a higher water
content, and which always means a greater power of absorbing and
holding water. The economical substitution of cheap for high-priced
timbers is impossible without proper seasoning. The loss from the
shortened term of service of unseasoned timber is very, much greater in
the case of porous than of the denser kinds, which are much less per-
meable by water, and consequenth^ offer greater resistance to decaj'.
Susceptibility to decay in timber is a consequence both of relatively high
porosity, which may mean a high water content, and always means a
greater absorptive power, and of a large percentage of sapwood, which
furnishes, by its stores of organic matter, food for wood-destroying
fungi. Seasoning greatlj^ lengthens its life, because it rids it as far as
possible of its water and brings about a disintegration of much of the
organic matter, in both ways lessening the chances for destruction of
the wood by its fungus enemies. Seasoning is therefore of the first
importance for the utilization of cheap timbers hitherto regarded as
short-lived.

PREVENTION OF CHECKING AND SPLITTING.

Under present methods much timber is rendered unfit for use by
improper seasoning. PI. Ill furnishes a good example of this. Green
timber, particularlj^ when cut in the fall or winter, contains a large
amount of water. When exposed to the sun and wind the water will
evaporate more rapidly from the outer than from the inner parts of
a log, and more rapidly from the ends than from the sides. As the
water evaporates, the wood shrinks, and when the shiinkage is not
fairly uniform the wood cracks. When wet wood is piled in the sun,
as were the ties and timbers shown on PI. Ill, evaporation goes on
with such unevenness that the timbers split and crack so badly as to
become absolutely useless. Such uneven dicing can be prevented by
careful piling. A very large number of ties and timbers split from
this cause are thrown out of use every year, and it is time that more
attention were given to prevent this waste.

In Europe many railroads use S irons, which are driven into the
ends of timbers in danger of splitting, and effect a great saving.
Fig. 8 shows such an iron," and tig. 9 its manner of application.

« Eeprinted from Bull. 14, Bureau of Plant Industry, U. S. Department of Agricul-
ture, 1902.

ADVANTAGES OF SEASONING.

Len&tm of piece. =■ 5.13

es t^*^

jj:^ o.o's*

-H ;♦- 0.076

LeiS&TH OF PIECE. = €>.S

^'.7 3

a.-^'S.

,<>.A7

DIA11-6.S9

->Jf- 0.039

-^u. o.o'ss

Fig. 8. — " S " irons used to prevent checking

Dl>^^1= 1.16

Fig. 9.— Method of applying "S" irons to pre-
vent checking.

SEASONING OF TIMBER.

VI. HOW TIMBER IS SEASONED.
KILX DRYING.

As kiln drying is emploj'ed mostly to prevent the warping and
checking of wood, and only rarely to prevent decay, it is not necessarj'
to dwell at length upon this method of seasoning. In the Southern
States it is often used to prevent the development of the blue fungus
during the sjM'ing, when the percentage of moisture in the air is very
great.

SEASONING IN OTHEK COUNTKIES.

Seasoning of timber has been carried on in a practical way for manj^
years in Europe. Most of the European railroads season their ties
for many months before they treat them. The tie piles of the Great

Fig. 10. — Pile of ties on Freneti Eastern Railway. (Reprint from Bull. 14, Bureau of Plant Industry,
U.S. Department of Agriculture, 1902. )

Western Kailway of England (PI. IV) are a novel sight to the Ameri-
can obsei'ver. The ties are piled by means of a donkey engine, and
remain in piles for from five to twelve months. The Baltic Pine used
hy this road is very moist when it arrives; but in the high, open piles
it dries out very rapidly, and when finally seasoned it absorbs in a few
hours the tar oil with which it is treated. The French Eastern Rail-
way piles its ties in open piles (fig. 10) 3.50 meters (11.4 feet) high,
2.7 meters (8.8 feet) wide, and 2.7 to 20 meters (8.8 to 65.6 feet) long.
The piles are 1.5 meters (about 5 feet) apart. The ties are spaced with
intervals of IM meter (1 inches) between ties, except that the top tiers
are inclined, as shown in the figure, to shed rain water. At Amagne
some 400,000 untreated and treated ties can be placed. Oak ties are
allowed to remain in jailes for from fifteen to twenty months; Beech
ties, six months. The French engineers assert that a good uniform

ul. 41, Bureau of Forestry. U. S. Dept. of Agriculh

Fig. 1.— Landing Platform, Bozeman, Mont.

Fig. 2. -Another View of Landing Platform.

Bui. 41, Bureau of Forestry, U. S Dept. of Agriculture.

Fig. 1.— Lodgepole Pine— Solid Pile.

<^^L^:^ - ^j

L^I^-^^^iP-^^

I^J^

set

--...^i^^sdneL 1

*^;®***. ^*f^:,^

fin^^

^^i^s^^m

m^ -«*... m. ■ ,M

^^^

*^ . :^.- '^t^S^^ff^^BI

■S^HkP^SHb^^-^^k

■Bi^^—i-j- '

MPin§

^(I^S

^.^7 11

^^^H^^^^BL'. jt*^"^ '-- '^- ji^iEI^M

^^ji^ - --ajuiii

K^MJ

FiQ. 2.— Lodgepole Pine— Half-open Pile.

HOW TIMBER IS SEASONED.

treatment with tai- oil can not be obtained even with air-dry ties, which
thej' therefore drj' in a kihi before treatment for from sixty to eight}'
hours at a temperature beginning at 35° C. and gradually brought to
75° C. A complete description of the method of kiln-drjdng will be
found in the Appendix.

The following table shows the importance of kiln-drying to secure
the most perfect removal of water:

Table IV. — Loasi of weight by out-of-door seasoning and kiln drying — French Eastern
Railway.

Kind of tim))(

Aver.age -weight per tii

After a
ing.

Average weight per cubic
meter.

After ai]
season-
ing.

After

kiln

drying.

Loss in weight in

per cent of
original weight.

After air
season-
ing.

Oak (IS months airdry-
ing: 14i hours in dry
kiln; size of tie, 0.09
cubic meters),

Beech (6 months air
drying; 72 hours in
dry kiln; size of tie,
0.097 cubic meters) . . .

It appears from this table that the kiln drying removes 3 to 4 per
cent additional water from the wood after the out-of-door seasoning.

Fui-ther advantages of the French method of kiln drying are speci-
fied as follows:

But the kiln drying is not, only for the purpose of completing the open-air season-
ing. It also assures a perfectly uniform preparation at all seasons of the j'ear, and
sometimes with woods M'hich could not be left long enough to dry in the yards.
Further, as the kiln-dried woods are hot when they enter the cylinders, the heavy
oil which comes into contact with them there, is kept alwaj's fluid and at a nearly
even temperature, and consequently penetrates them so much the deeper. «

Fig. 11 shows the average variation in weight per cubic meter, i. e.,
the specific gravity', from month to month, as determined hj engineers
of the French Eastern Railway. The ties were piled as described, dur-
ing the winter, from two to three months after being cut.

The practice on other European roads differs considerably with the
kind of timber used and the time of felling. In some cases, as in that
of the Hungarian State Railways, the bark is stripped from newly
felled trees and the trunks stacked in the woods for one to two years:
other roads stack only three or four months. New Zealand railroads

"Note sur la preparation des traverses it la compagnie des ehemins de fer de I'Est.
M. \. Dufaux. Extract from Rev. Generale d. Chemins de Fer., Jan. and Mar.,
1898, p. 19.

SEASONING OK TIMBER.

reijort no stacking at all. In Australia the Australian Southern Rail-
road specifies that wood cut in winter must have its bark removed,
while that cut in summer can at once be cut up.

The loss of weight by evaporation in Hungar}- is shown b}^ the
following quotation:

The Austro-Hungarian State Railway has observed that wood when felled contains
40 per cent of water; five months subsequently it contains about 30 to 35 per cent;
and after it has been stored a year it contains about 20 to 25 per cent. (International
Railway Congress. Question VIII, p. 11. Paris, 1900.)

After—

1
§

t 1 ■

5 i

100
CSS
C.90
OSS

— -1

■

V ■■

=f^

__!_

, ^

—

— \

— 1.

:;; —

—

' 1

C.'S
C-70

•3^

•J?K~

c-^

—

,--■"

■*%

■

Fig. 11. — Diagram showing average loss in weight by seasoning of oak
and beech timber during one year. French Eastern Railway.

In Russia oak ties are stacked from three to six months. Treatment
sometimes follows and sometimes not, some lines having found that
the increased length of life of a thoroughly seasoned oak tie treated
with zinc chlorid does not pay for the additional cost. Their oak is
so superior to our best American oaks that their practice affords no
criterion for us.

HOW TIMBER IS SEASONED. 27

In general, all railroad ties, bridge materials, telegraph poles, fence
posts, etc., are commonly seasoned in Europe, and to some extent in
other countries. The time of seasoning varies from several months to
two years.

SEASONING BT STEAMING.

Where time is so important as it is in business affairs to-day, it is
often a serious matter to hold timber for from four to six months
before using it. In addition to the loss of interest on the capital
invested there is also constant danger from fire. Any method by
which timber could be seasoned rapidly and economically would be of
great value. Reference has been already made to the use of live
steam for this purpose. In a number of timber-treating plants in this
countrj^ green or water-soaked wood is steamed for several hours to
prepare it for the injection of chemicals. Steaming is also used to
some extent with material for furniture manufacture. Steaming is
said to coagulate the albuminous substances present in wood, thus
rendering the walls of the wood fibers more permeable. That such is
its effect there can be no doubt, for these coagulated albuminous sub-
stances make up a large proportion of the solid parts of the so-called
"sap" which remains in the retorts after steaming. This "sap "is
water driven out of the wood by the expansion of the air within it and
by the entering water vapor, and it holds in solution and suspension
the albuminous substances referred to, various tannin bodies, resins,
oils, etc. Steamed wood certainly ought to last longer than unsteamed,
and where it is necessary to secure partiallj' seasoned wood the steam-
ing may do. It is, however, at best a makeshift, and unless modified,
materially it can never replace open-air seasoning, supplemented pos-
sibly by kiln-drying. There is danger of injury to the wood fibers
from too high a temperature. There ma}^ be absolutely' no harm in
prolonged steaming at high temperature, but in the present incom-
plete state of our knowledge it is better to be on the safe side. It has
been pointed out that the steaming process after all does not remove
all water unless the temperature is very high. The use of the vacuum
pump does not materially improve matters, for it is not possible to
maintain a sufficiently high temperature in a cylinder in which enough
of a vacuum exists to insure the complete removal of all water.

A recent publication refers to the extensive use of steam seasoning
in Australia. No details, however, have as yet been obtainable.

SEASONING BY IMMERSION IN WATER.

It is an old saying that wood put into water shortly after it is
felled, and left in water for a j'ear or more, will be perfectly seasoned
after a short subsequent exposure to the air. For this reason river

28 SEASONING OF TIMBER.

men maintain that timbei- is made better by i-aftiug. Herzenstein

says:"

Floating the timber down rivers helps to wash out the sap, and hence must be
considered as favorable to its preservation, the more so as it enables it to absorb
more preservative.

Wood which has been buried in swamps is eagerly sought after b}'
carpenters and joiners, because it has lost all tendency to warp and
twist. When first taken from the swamp the long-immersed logs are
very much heavier than water, but they dry with great rapidity. A
Cypress log from the Mississipx^i Delta, which two men could barely
handle at the time it was taken out some j-ears ago, has dried out so
much since then that to-daj' one man can lift it with ease. White
Cedar telephone and telegraph poles are said to remain floating in the
water of the Great Lakes sometimes for several years before the}' are
set in lines and to last better than freshly cut poles.

It is very probable that immersion for long periods in water does
materially hasten subsequent seasoning. The tannins, resins, albu-
minous materials, etc., which are deposited in the cell walls of the
fibers of green wood, and which prevent rapid evaporation of the
water, undergo changes when under water, probably due to the action
of bacteria which can live without air, and in the course of time many
of these substances are leached out of the wood. The cells thereby
become more and more permeable to water, and when the wood is
finally brought into the air the water escapes very rapidly and very
evenly. Herzenstein's statement that wood prepared by immersion
and subsequent drying will absorb more preservative, and that with
.greater rapidity, is certainly borne out by experience in this country.

SEASONING BY BOILING IN OIL.

It is sometimes claimed that all seasoning preparatory to ti-eatmeut
with a substance like tar oil might be done awaj' with by putting the
green wood into a cylinder with the oil and heating to 225- F.. thus
driving the water ofl" in the form of steam, after which the tar oil
would readily penetrate into the wood. This is the basis of the
so-called ' ' Curtiss process ' ' of timber treatment. Without going into
any discussion of this method of creosoting, it may be said that the
same objection made for steaming holds here. In order to get a tem-
perature of 212° F. in the center of the treated wood the outside
temperature would have to be raised so high that the strength of the
wood might be seriously injured.

A compan}' on the Pacific coast which treats Red Fir piling asserts
that it avoids this danger by leaving the green timber in the tar oil at
a temperature which never exceeds 225^ F. for from five to twelve
hours, until there is no further evidence of water vapor coming out of

"Bull. Internat. Railway Congress. Question VIII. Paris, 1900, p. 10.

PLATSr FOE SEASONING TESTS. 29

the wood. The tar oil is then run out, and a vacuum is created for
about an hour, after which the oil is run in again and is kept in the
c^'linders under 100 pounds pressure for from ten to twelve hours,
until the required amount of absorption has been reached (about 12
pounds per cubic foot).

OUT- OF-DOOE SEASONING.

The most effective seasoning is without doubt that obtained by the
uniform, slow drj'ing which takes place in properly constructed jailes
outdoors, under exposure to the winds and the sun. Lumber has
always been seasoned in this wa}', which is still the best and cheapest
for ordinary purposes. The methods in use have been determined by
long experience, and are probably as good as they could be made for
present conditions. But the same care has not up to this time been
given to the seasoning of such classes of timber as ties, bridge material,
posts, telegraph and telephone poles, etc. These have sometimes been
piled more or less intelligently, but in the majority of cases their value
has been too low to make it seem worth while to pile with reference
to anything beyond convenience in handling. A discussion as to pos-
sible methods is given in the following chapters.

VIII. PLAN FOE, SEASONING TESTS.

In the foregoing chapters an attempt has been made to present a
general view of the seasoning of timber — what it is, how it works, and
what its advantages are. Although the general facts are a matter of
common knowledge, there are scarcel}' any exact data in existence
concerning some of the most important phases of the subject. This is
particularly true of timber in the form of railroad ties and telephone
and telegraph poles. The tirst step necessary toward working out
the most practical and economical methods of using timber for test
purposes must be a careful stud}^ of all the processes involved in sea-
soning. To this end a series of tests on a uniform plan has been
inaugurated, applicable both to the kinds of timber now in use and to
kinds which may come into use in the future. It ought to be empha-
sized, however, that to secure reliable data it will be necessary to carry
on these tests for a number of years, with a large number of ijieces of
many different kinds of timber, and in different parts of the country.
The reason for this is thatthevariabilitj'in the physical characteristics
of timber, even of the same kind, is so great that figm-es obtained
from a small number of pieces are very apt to be entirely unreliable.
A glance at some of the figures in the tables given below will show
this. In the case of different kinds of timber, or of different timbers
of the same kind grown under different climatic conditions or seasoned
in different years, the same thing is true in still greater degree.

In determining the amount of seasoning, some standard of measure-
ment had to be taken. As the loss in weight due to the evaporation

30 SEASONING OF TIMBER.

of water forms the largest part of the seasoning- process, it was decided
to adopt the test of the loss of weight as furnishing the nearest
approach to an absolute register of the degree of seasoning which can
be given numerical expression.

The specific questions which it is proposed to investigate in the
series of seasoning tests which has been inaugurated are:

(1) The variation in character and weight of wood, and in the rat§
at which the wood loses water, among trees of the same species grown
under the same conditions and of the same age — that is. individual
variation in seasoning.

(2) The variation in the water content of the same timber in difiereut
months, and the length of time necessary to dr}' it properly at dif-
ferent seasons — that is, seasonal variation in seasoning. This inquiry
will have the important result that it will settle the question of the
best time to cut timber.

(3) The variation in the amount of water in difi'erent parts of the
same tree, or regional variation. Top wood is generally believed not
to be so good as butt wood, and much of it is therefore rejected.
Ties and posts from the tops and bottoms of a large number of trees
will be tested to determine the amounts of water in both parts, and
the rate at which thej- will season.

(4) The effect of bark on seasoning. Although it is universally
known that bark will retard and almost prevent seasoning, un barked
ties and piles are nevertheless sometimes used. A test will be made
to show exactly to what extent this shortens the length of life of
timber.

(5) The rate of seasoning of sawed, hewn, and planed timber. At
present more hewn than sawed timber is in use ; but as sawing is
cheaper, it is probable that this condition will soon be reversed. ItJs
important to know whether there is any material difference in the rate
of seasoning between sawed and hewn timber. The saw cuts many
wood fibei-s so as to expose their open ends, and it is conceivable that
the rate of water evaporation maj- be influenced somewhat by this fact.
Then again, the rough surface of sawed timber may retard evapora-
tion. It is therefore proposed to compare the rate with that of planed
timbei'.

(6) Great practical value is expected to attach to a series of experi-
ments intended to answer the question how ties, poles, and other
timbers should be piled to season them in the shortest possible time.

(7) Getting timber into immediate use counts for so much nowadays
that it is verj' important to know just how long treated timber must be
held to secure the thorough drying on which much of the efficacv of
treatment depends. It is proposed to make accurate tests in various
parts of the country to determine the shortest period during which
treated timber should be held, and what method or methods of piling
will bring about the most rapid results.

SEASONING TESTS WITH LODGEPOLE PINE. 81

IX. SEASONING TESTS WITH LODGEPOLE PINE.

Lodgepole Pine {Pinus murraijana) is one of a number of inferior
timbers growing in the Northwest which are coming into use. This
tree is found in large quantities in the mountains of Wj'oming, Mon-
tana, and northern Idaho. It is very tall and slender. Its diameter
4 feet above the ground does not average more than li inches, and
rarely exceeds 20 inches. At an altitude of about 6,000 feet, where it
reaches its best development, it has a remarkabh- long, straight trunk,
with a very slight taper. This characteristic makes it a good tree for
ties. In the futui'e it ma}'' be used also for telephone and telegraph
poles.

The wood of Lodgepole Pine contains a very large percentage of
sapwood. It is light, soft, and straight grained, and can be worked
easily. In drying it checks badh', even when the drying is slow, but
the checks are small and rareh' extend far into the wood. "The
specific gi'avity of absolutelv dry wood is 0.4096, a cubic foot weigh-
ing 25.53 pounds."" The wood contains a large percentage of water.
It is a very short-lived timber, and for this reason has been but little
used until lately.

TESTS AT BOZEilAN, MONT.

In April, 1902, experiments were begun in cooperation with the
Burlington and Missouri River Railroad in Nebraska, and with Mr.
Walter Cooper, of Bozeman, Mont., to determine whether it would
paj' to season Lodgepole Pine timber. It was believed that with
proper care and treatment Lodgepole Pine could be made to last
almost as long as Bull Pine timber, and certainly longer than has
hitherto been supposed. The experiments are still in progress, and
will be continued until sufficient data have been obtained to warrant
definite conclusions. A description of the tests is given below. It is
preceded by an account of how the ties are made, since a knowledge
of these operations is essential to a complete understanding of what
happens to the timber afterwards.

MAKING AXD DELIVERY OP TIES.

The forest fi-om which the ties were cut grows on a range of moun-
tains at the east end of the Gallatin Valley in Montana, at an elevation
of about 6,500 feet. Most of the timber cut stood in a basin at the
head of Bear Creek, near Bozeman, and was a fair stand of Lodge-
pole Pine as it grows in Montana and Idaho. (PL VII.)

From three to five pole ties are obtained from a single tree under 14
inches in diameter, breasthigh. Many of the trees are fire scarred at
the base, causing a brown rot to set in which makes it necessary to cut
off butt logs from 4 to 10 feet in length. Trees larger than 14 inches
in diameter, breasthigh, are usually cut into logs, which are trans-

" Sargent, C. S., in Silva of North America, XI, 93, 1897.

32 SEASONING OF TIMBER.

ported to sawmills, of which there are two in operation on the tract
where the test ties were cut. The ties are mostly hewn, 8 feet long,
6 inches thick, and with two 8-inch hewn faces. In order to get
a tie of these dimensions, the chopper must have a stick of timber
at least 9 inches in diameter at the small end. Much larger ties are
often cut, some reaching a width of from 13 to 14 inches at one end.
As soon as the tree is felled, the chopper, standing on the timber,
makes two straight faces (PI. VI, fig. 1); he then cuts the tree into
8-foot lengths, allowing .3 inches for the cut. Finall}' the ties are
peeled with a tie peeler. (PI. VI, fig. 2.) A skillful man can make
from 4:0 to 50 ties per day in good timber. After the ties are made
they usualljr remain in the woods for several weeks before thej' are
dragged out with chains (PI. VIII, fig. 1). or skidded out on go-devils ,
to the flume, where they are piled, readj"^ for shipment (PL VIII, fig. 2,
and PI. IX).

The ties used in the seasoning tests were taken indiscriminately
from the general run of ties in the woods. The onh* difference made
in handling them was in skidding them out immediately after cutting,
before there was anj^ chance for them to dry. On arriving at the
flume each tie was numbered and weighed.

The timber land operated on in the summer of 1902 is about 9 miles
from the railroad track and about 1,800 feet above it. Early in the
year a flume was built (Pis. IX and X), extending through the timber
to the railroad, where a landing was constructed, reached by a siding
from the main line (Pis. XI and XII). The flume is about 9 miles long,
with an average fall of 200 feet per mile. The water used for float-
ing the timber is obtained from a creek and from a storage reservoir.

It was suggested that drying the ties in the woods would be useless,
since they were to be put into the flume afterwards, where they would
absorb as much water as they had lost. A test was therefore made to
learn how much water dry ties would absorb. A number of ties cut
sixty days before, and fairly well seasoned, showed an average weight
of 116.61 pounds per tie. To float the 9 miles required about forty-
eight minutes. At the end of their journey the average weight was
■117.41 pounds, a total gain per tie of only 0.8 pound. Ties in the
same seasoned state as these, after immersion in a stream for one
hour, showed a gain in weight of 2 per cent, but two hours after they
were taken from the water they had returned to their original weight.
The tests showed that the amount of water absorbed in the fluming
process may be disregarded.

The ties are inspected at the landing, and are then shipped to the
timber-treating plant at Sheridan, AVj-o.

PILIXG OF TIES.

Piling tests were made with Lodgepole Pine to learn exactly the
rate of water evaporation from the ties under varjnng conditions and at

ul. 41. Bureau of Foreslry, U. S. Dept of Agriculli

Fig. 1.— Before Treatment.

Fig. 2.— After Treatment.
LODGEPOLE PINE, OPEN-CRIB PILE.

, 41, Bureau of Forestry, U. S. Dept. of Agriculturf

Fig. 1 .—Triangular Tie Piles.

Fig. 2.— Lodqepole Pine Piled to Test Influence of Prevailing Winds on Drying.

Bui. 41, Bureau of Forestry, U, S, Dept. of AE;ricu!ture,

FiQ. 1.— Oak Pili ■,, ,Sh<',vj,, L<-.vi si Tier on the Ground— a Poor Method.

Fig. 2.— Oak Piles, Showing Lowest Tier on the Ground— a Poor Method.

SEASONING TESTS WITH LODGEPOLE PINE. 33

different seasons of the year. Ties placed in piles of different forms
were weighed every two weeks, and the results tabulated. Although
timber is known to dr}^ most rapidly when exposed on all sides to the
sun and air, close piling was tried as well as open, to show the difference
in the length of time required for seasoning and in the rate at which
water is lost. In all the piles the lowest laj^er rested on two bottom
ties. About 50 ties went into each pile, and the piles were reversed
at each weighing, the top ties of the old pile going to the bottom of
the new.

The forms of piles were:

(1) A solid pile, 9 ties each way with no space between. (PI. XIII,
fig. 1.) This method of piling has been largelj^ in vogue, and is still
used to some extent by man)^ railroads in this country. It affords
very little chance for the circulation of air.

(2) A half-open pile, in which the ties were piled 7 each waj^, with
about 4 inches left between. (PI. XIII, fig. 2.)

(3) An open pile, or open-crib pile, in which the air circulated freely
on all sides of the ties, which were piled in alternate layers, 7 one
way and 2 the other. (PL XIV.) The piles at Bozeman were built
to such a height that men could easilj' place the ties in position from
the ground. At Sheridan, Wyo., it was possible to build much higher
open piles (Pis. I and V) because the ties were unloaded from cars.
Plate XIV, figs. 1 and 2, show in addition to the open crib method of
piling the difference in color between treated and untreated timber.
Treatment darkens the color so much that it is possible to distinguish
at a glance between the two.

(4) Treated ties were piled also in a form which gives even more
air and sun exposure (PL XV, fig. 1), viz, a triangular pile, so con-
structed that no two ties touched at more than one point, and no tie
rested entirelj^ on the ground. Where there is plenty of room, as
there generally is along the right of way, this form of pile is more
rapidly made than the others.

In the diagrams the various forms of piles are designated as follows:
I. Solid pile, 9 by 9 ties.
II. Half-open pile, 7 by 7 ties.

III. Open-crib pile, 7 by 2 ties.

IV. Triangular pile.

WIND DIRECTION.

To test the possible influence of prevailing winds, the open faces of
some of the piles were built facing east and west, and of others north
and south. (PL XV, fig. 2.) One point never lost sight of was to find
a method of piling which would give the most rapid results at the least
cost. A discussion of the results obtained is presented on p. S-t.

INTERVALS OF CUTTINGS.

As one of the objects of the seasoning tests was to determine the
monthly variation in the water content of timber, arrangements were
19704— No. 41—03 3

SEASONING OF TIMBER.

made to test ties cut at intervals of one month. This is still going on.
About 100 ties are taken- ever}^ month and piled in the open-crib form,
which gives the most rapid results.

PRELIMINARY RESULTS OF SEASONING TESTS.

The following tables present the results of the tests made with
Lodgepole Pine timber for the first five months. Although it is per-
haps too early to draw definite conclusions, it is believed that the data
already obtained have sufficient significance to justify their publica-
tion now. They are arranged in two series, of which the first gives
the weights of water lost in pounds and in percentages of the original
weights of the ties; the second, the loss in weight in terms of specific
gravity. A graphical presentation of this second series is given by
curves (fig. 12), which will be extended when the weighing tests have
been carried on for another six months.

Table V presents the results of tests made with ties which had been
in solid piles in the j^ards at Sheridan for about two months. After
the first weighing these ties were piled in three difl:erent wa3's — 9 by 9,
7 by 7, and 7 by 2. The table shows the rate at which they lost weight
subsequently.

Table "V. — Rate of evaporation from partially seasoned ties, Lodgepole Pine,
Sheridan, Wyo.

Date of weigh-
ing.

Solid pile, 9 by 9 (60 ties).

Half-open pile, 7 by 7 (65
ties).

Open-crib pile, 7 by 2 (60
ties).

Weight
per tie.

Loss per
tie.

Per

cent of

loss.

Weight
per tie.

Loss per
tie.

Per

cent of

loss.

Weight
per tie.

Loss per
tie

Per

cent of

losg.

Pounds.
111.93
109

107.15
105.05
102.97
103.42

Founds.

Pounds.
96.80
94.10

. 92. 52
90.75
89.11
89.61

Pounds.

Pounds.
112. 90
109. 43
107.66
105.47
103.27
103.68

Pounds.

2.93
4.78
S.8S
8.96
8.51

2.61

4.27

6.14

7.60

2.70
4.28
6.50
7.69
7.19

2.80
4.42
6.25
7.94
7.43

3.47
5.34
7.43
9.63
9.22

3.07

4.73

August 11

September 11...
October 10

6.68
8.53
8.21

These ties were almost dry when piled; nevertheless they lost con-
siderablj^ more water in the open-crib pile than in the solid pile.

One factor which was not anticipated when the weighing tests were
started must be taken into consideration in all the preliminaiy figures
here presented. The experimental solid piles were placed out on the
open plain, and as a result of the consequent free circulation of air
the rate of drying was much more rapid than it would have been in a
yard. When solid piles are placed side bj^ .side and many together,
the air can not circulate between the timbers. In all future tests
conditions will be more nearlj^ like the actual conditions in a tie j'ard.
The open-crib piles allow full air circulation even when piled closely,
so that the rate of drying shown for such test piles is probably more
nearly correct.

SEASONING TESTS WITH LODGEPOLE PINE.

Table VI. — Rate of seasoning of Lodgepole Pine, green ties.

Solid pile (50 ties).

Open-crib pile (50 ties).

Date of weighing.

Weight
per tie.

Loss per
tie.

Per cent
of loss.

Weight
per tie.

Loss per
tie.

Per cent
of loss.

June 9

Pounds.
152. 75
130. 93
114. 77
104. 24
101.33

Pounds.

Pounds.
155. 39
108. 06
99.30
95.71
93.44

Pounds.

21.82
37.98
48.51
61.42

14. 2S
24.86
31.75
33.66

47.33
56.09
59.68
61.95

30.45
36.09
38.46
39.86

July 15

JUNE JULY AUC SEPT.

Fig. 12. — Diagram showing rate of drying of green ties.

Table VI .shows the rate of diying of green ties, piled in solid and
open-crib piles. The results are regarded as sufficiently marked to
warrant recommending the use of the open-crib pile whenever possible.
The curves in fig. 13 are a graphic presentation of the figures given in
Table VI.

A study of these figures and curves show.s that after three weeks
the ties piled in open-crib form lost more than twice as much water
as those in the solid pile. The great advantage which the open-crib
form has over the other is the rapidity with which seasoning takes
place during the first few weeks. It is probable that the relative

SEASONING- OF TIMBER.

positions of the curves of loss will be changed slightly when more tim-
bers are weighed, but the general result will not be altered materially.

SEASONING AFTER TREATMENT WITH ZINC CHLORID.

Timber treated with a water solution of a salt is, like green timber,
full of water. The results of a test to show the comparative rate of
diying of treated Lodgepole Pine timber piled in the several forms of
piles made at Sheridan are shown in Table VII and fig. 13. The first
weighing was made the day after treatment.

Table VII. — Rate of seasoning of Lodgepole Pine ties treated witJi zinc chlorid.

Solid pile, 9 by 9
(60 ties).

Half-open pile, 7 bv7
(59 ties).

Open-crib pile, 7 by 2
(60 ties).

Triangular pile (33
ties).

weigliiiig.

Weight
per tie.

Loss
pertie.

Per
cent of

loss.

Weight
pertie.

Loss
pertie.

Per
cent of
loss.

Weight
per tie.

Loss
pertie.

Per
cent 6f
loss.

Weight
per tie.

Loss
pertie.

Per
cent of
loss.

Lbs.

lbs.

Lbs.

June 17....
July 11-...

172 10

105. 94

123. 13

40.74

24.86

127. 80

46.64

26.16

122.80

49.30

28.64

118.66

47.28

28.49

July 25....

114.43

49.43

30.16

119.30

55.14

31.03

115.27

56.83

33.02

111.73

54.21

32.67

Aug. 11....

108.60

55.36

33.78

112.84

61.60

35. 31

109. 70

62.40

36.25

106. 54

59.40

35.85

Aug. 25....

105. 67

58.19

35.51

110. 04

64.40

36.92

106.80

65.30

37.94

103.58

62.36

37.58

Sept. 25....

103. 43

60.43

36.89

107. 40

67.04

38.43

104. SO

67.80

39.40

102.33.

63.61

38.33

Oct. 25...-

102.36

61.59

37.54

106. 05

68.39

39.20

102. ,86

69.24

40.23

100.03

65.91

39.66

_I-

r^sS

73.

Ti-
ll -

> f'

HM f

Hav-1

L o.

I -

n -

Ops
Tri.

MB F

Pll_

Fig. 13.— Diagram showing rate of seasoning of Lodgepole Pine ties treated with zinc chlorid.

The chief conclusions to be drawn from this test are that on the open
plains in summer there is little difierence in the rate of evaporation
from the differently built piles, and that in all of them most of the
water evaporates during the first si.x; weeks. Accordingly, ties left for

SEASONING TESTS WITH LODGEPOLE PINE.

six to eight weeks along the right of waj^ may be laid in the track at
the end of that time. This conclusion will hold as j^et only for ^¥3^0-
ming and for the summer months. Great emphasis is to be put upon
this point, for it is more than probable that in other climates this rela-
tion will be verjr different. A test under the most adverse conditions
is now in progress in southern Texas, where timber dries very slowly.

INDIVIDUAL VARIATION IN SEASONING.

The striking difference between pieces of timber from different trees
of the same kind, even when grown in the same locality', is nowhere
shown more conclusively than in the amount of water contained in the
wood and the rate at which it evaporates. This great variability empha-
sizes the necessity for extended tests. Averages made from small
numbers of weighings are likely to be altogether misleading, and ought
never to be taken as a basis for any final conclusion. It is to be under-
stood that all the figures given in the tables of this bulletin are merely
tentative and subject to modification as fuller results become available.

The ties whose weights are shown in Table VIII and fig. 1-t were cut
in June, 1902, at Bozeman, Mont. They were first weighed June 2.5,
the daj^ after they were made. Table VIII gives the successive weights
per tie, the actual loss in %lo;
weight, and the percent-
age of the original weight
lost. Fig. 14 shows the
loss in weight of ties Nos.
26, 13, and 33, represent-
ing a mean and two ex-
tremes. The great vari-
ation shown is probably
due to the fact that the
ties came from trees of
different ages and from
both tops and butts. To
see the great extremes
between which 50 pieces
will vary, one need only
glance at the following
figures, showing weights
of 50 ties arranged in a
series from the lowest to
the highest. It is evi-
dent from this showing
that the variation in 50
pieces is so large that a very much larger number of individual weights
should be taken to furnish data for thoroughly trustwortlw conclu-
sions. Further tests are being made with from 200 to 500 pieces.

Y^ie.

— ■

P,r».

oWi^

—

-Diagram showing loss of weight of 3 tie
and two extremes.

SEASONING OF TIMBER.

Table VIII. — Lodyepole Pine ties, Bozeman, Mont., 1902.
[Ties piled 7 by 2.]

Tie No.

June 25.

July 10.

August 10.

September 10. 1

Weight.

Loss.

Per
cent of
loss.

Weight.

Loss.

Per

cent of

loss.

Weight.

! Per
Loss, cent of
1 loss.

Pounds.

Vounds.

Pounds.

211. b

185.5

42.0

18.46

129.5

98.0

43.08

126.0

101.5

44.61

202.5

175.0

27.5

13.58

125.5

77.0

38.02

118.0

84.5

41.73

182.0

146.5

35.5

19.50

100.0

82.0

45.05

95.0

87.0

47.80

147.0

125.5

21.5

14.62

113.0

34.0

23.13

110.5

36.5

24.89

211.0

172.0

39.0

18.48

130.0

81.0

38.39

120.5

90.5

42.75

162.0

130.0

32.0

19.76

108.0

54.0

33.33

105.5

66.5

34.87

203.0

166.5

36.5

17.98

156.0

47.0

23.15

151.5

61.5

25.13

132.5

110.0

22.5

16.98

100.5

32.0

24.16

99.0

33.5

26.28

190.5

159 5

31.0

16.27

148.0

42.5

22.30

145.0

45.5

23.88

154.0

110.5

43.5

28.24

88.0

66.0

42.85

8B.0

58.0

37.66

174.0

133.0

41.0

23.56

93.6

80.5

46.29

90.5

83.5

47.99

164.0

133.0

31.0

18.90

95.5

68.5

4L79

9L0

73.0

44.61

154.0

126.5

27.5

17.86

106.0

48.0

31.17

102.5

.51.5

33.44

146.0

110.5

35.5

24.31

94,0

52.0

35.61

91.5

54.5

37.33

139.5

102.0

37.5

26.88

93.0

46.6

33.33

90.5

49.0

35.12

146.5

96.5

50.0

34.13

67.5

79.0

53.92

64.5

82.0

55.97

148.5

118.5

30.0

20.20

106.0

42.5

28.61

104.0

44.5

30.00

151.5

125.6

26.0

17.22

110.0

41.5

27.39

108.0

43.6

28.71

176.5

130.5

46.0

26.06

100:0

76.5

43.34

97.0

79.5

45.04

165.0

129.0

36.0

21.81

115.0

50.0

33.33

112.0

53.0

32.12

120.5

105.0

15.5

12.86

101.0

19.5

16.17

98.5

22.0

18.25

156.0

113.5

42.5

27.24

90.5

65.5

41.98

88.0

68.0

43. ,59

146.5

117.0

29.5

20.13

87.0

59.5

40.61

84.5

62.0

42.32

149.0

106.0

43.0

28.85

96.0

53.0

35.56

93.6

55.5

37.25

181.0

161.0

20.0

11.04

154.0

27.0

14.91

151.0

30.0

16,57

13S.0

99.5

33.5

25.20

88.5

44.5

23.44

86.0

47.0

35.34

128.0

92.0

36.0

28.12

80.0

48.0

37.47

77.0

51.0

39.84

184.0

132.5

51.5

27.98

90.0

94.0

51.08

84.5

99.5

54.07

134.0

103.5

30.5

22.74

84.5

49.5

36.92

82.0

52.0

38.80

135.5

98.5

37.0

27.28

72.0

63.5

46.80

70.0

65.6

48.34

193.0

153.0

40.0

20.72

111.0

82.0

42.50

105.5

87.5

4.5.34

162.0

129.5

32.5

20.04

101.5

60.5

37.32

■ 97.5

64.5

39.81

187.0

139.0

48.0

25.66

96.0

91.0

48.60

91.5

95.5

61.07

126.0

89.0

37.0

29.38

79.0

47.0

37.28

77.5

48.5

38.49

159.0

117.5

31.5

19.80

96.0

63.0

39.60

93.5

66.5

41.19

154.5

121.0

33.6

21.64

112.5

42.0

27.17

110.0

44.6

28.80

177.0

156.0

21.0

11.87

144.0

33.0

18.63

140.0

37.0

20.90

154.5

120.5

34.0

22.00

111.0

43.5

28.16

108.0

. 46.5

30.09

133.0

105.0

, 28.0

21.05

96.5

36.5

27.43

94.0

39.0

29.32

182.5

134.5

48.0

20.86

116.5

66.0

36.18

113.5

69.0

37. 80

87.5

83.5

4.0

4. .57

80.0

7.5

8.57

78.0

9.5

10.86

194.5

142.0

52.5

27.00

122.0

72.5

37.21

119.0

75.5

38.81

141.0

102.5

38.5

27.30

90.5

50.6

35.80

89.5

61.5

36.52

168.5

118.0

50.5

29.98

108.0

60.5

3.5.90

105.5

63.0

37.39

132.5

106.0

26.5

20.00

100.0

32.6

24.54

97.0

35.5

26.71

97.5

70.0

27.5

28.22

66.6

31.0

31.80

64.6

33.0

33.84

130.5

82.0

48.6

' 27. 17

74.5

56.0

42.83

71.5

59.0

45.21

147.0

108.0

39.0

26.52

92.5

55.6

37.72

89.5

57.5

39.11

90.0

84. 0

6.0

6.67

81.0

9.0

10.00

79.0

11.0

12.22

Aver-

126.0

106.5

19.5

15.47

102.0

24.0

19.05

100.0

26.0

20.63

21. 40

33.78

35,54

SEASONING TESTS WITH LODGEPOLE PINE.

VARIATION BY MONTHS.

It has been shown in a genei'al waj' that timber will season more
slowly in winter than in summer, and also that the water content dur-
ing various months varies, but no detinite data are as yet at hand. To
secure .such data for Lodgepole Pine the series of tests of ties cut
monthly, already? described, was inaugurated. Later on these ties will
be treated, and the relation between seasonal cutting and timber treat-
ment determined. The relation between seasonal cutting and lasting-
powers will also be investigated.

In Table IX the results so far obtained with ties cut in June, July,
August, and September, of 1902, are given in the form of general
averages. The piles were 7 lyy 2, and were reversed from top to
bottom at each weighing.

Table IX. — Lodgex>ole Pine, Bozeinan, Mont, 1902.
JUNE CUTTING.

Date of weighing.

No. of
ties.

Weight
per tie.

Loss in
pounds.

Percent-
age loss.

1902.

147
147
147
147

156.62
123.22
103.72
100.66

July 10 ...

33.40
52.90
55.96

21.30
33.77
36.73

September 10

JULY CUTTING.

July 20 ;

July 25 ;.

.August 8

August 28

September 10 .

270
90

144. 28
129.90

14.34

9.94

270

108.99

35.29

24.46

105.08

39.16

27.15

270

103.23

41.05

28.26

AUGUST CUTTING.

August 25

September 10 .
September 25 .

October 25

November 25 .

100
100

149.83
119.91

29.92

19.96

100

115. 35

34.48

23.01

100

113.21

36.62

24.44

100

114.02

35.81

23.90

SEPTEMBER CUTTING.

September 25
October 5 . . .
October 25...
November 25

100
100

157.33
153.02

4.31

2.74

100

125, 04

32. 29

20.52

100

120.31'

37.02

23.53

It is yet too early to draw any definite conclusions from these tables.
They indicate, however, a decided variation in the weight of green ties

seasojS^ing of timber.

cut in diflferent months, and a still more striking variatioai in the
rapidity with which seasoning takes place in summer and in fall.

Fig. 15 shows graphicalljr the loss of water in percentages of the
original weights. Although the curves are plotted with but four or
five points, they are fairly correct.

The great deviation of the September curve requires explanation.
Just after the ties had been cut and weighed there was a heavj" snow-
fall, which covered the ties for a week or more. During this time
they did not dry out at all. As soon as the snow melted thej- began
to dry rapidly, as shown bj^ the sudden rise in the curve. The dotted
line indicates the path which the curve would have followed had no
disturbing factor caused a deviation from the norm of the other
months.

Fig. 15. — Diagram showing percentage loss of water of Lodgepole Pine timber during various months,
Bozeman, Mont., 1902.

In the spring the drying out of timber cut in October and Novem-
ber will take place more rajjidlj^, and the depressed curves will prob-
abh' rise to the same height as the first curve.

Fig. 16 shows the changes in specific gravitj^ of the same timber.
The specific gravity of absolute!}' dr}' Lodgepole Pine is 0.109, so that
the June-cut timber has almost reached a dry condition (0.446).

COST OF PILING.

The practicability of piling in open-crib form depends entirely on
the additional cost. Careful records kept at the Sheridan tie plant
showed that it takes no longer to pile ties in open-crib form than in
solid piles. The men who did the piling were paid by the laiece, so it
was possible to keep an exact record. All that is called for is a little

Bui. 41, Bureau of Forestry, U. S. Dept. of Agriculturs

Plate XVII.

Fig 1.— Oak Piles, Showing Method of Building a Roof.

Fig. 2.— Another Method of Roof Building.

Plate XVlll.

tV'

^^^^^^^^QplHfl^^HIHl

'^0rf^^'^^

.^^^^j^BB JB|^B f/^^f ' K^' l^T *

1^^^^

mm -j^n'TJMI qijigjg^ ^'-w^^mSm

■%^ \ _ "^

:.i i^-^t-*i§"™J

■^•,.K

*i#-^^ :

Fig. 1.— Open-crib Oak Pile, Southern Illinois.

Fig. 2.— Another Open-crib Pile.

SEASONING TESTS WITH LODGEPOLE PINE.

more care. The only difference in cost is the increased yard room
necessary. Where land is cheap, this will not amount to much; where
a treating plant is in the neighborhood of a cit}', it will be necessary
to build high piles, or to use half -open piles. The amount of yard
room for storing both untreated and treated ties ought to be one of
the most important considerations in determining the location of a
timber treating plant. Timber piled in high open piles (PI. I) can be
loaded upon the small cars which carry the ties into the treating cyl-

June 30.
July 31.
September 30.
October 31.
November 30.
December 31.

1.00
OSS
•so
.85
■ 80
.IS

. 70

.ss

.60
.55
.50
• 45
-40
.35
. 50
.25
.20
. IS
. 10
.05

\ \

^v^

^-^

Fig. 16. — Diagram showing specific gravity of Lodgepole Pine timber cut during successive months.

inder with as much ease as from high solid piles. The timbers must
be thi'own down in both cases, and in this respect there is no diiler-
ence between open and solid piles.

Experience shows beyond doubt that open piling pays with Lodge-
pole Pine. It will probably pay also in the case of oaks and other
timbers which are to be treated, for, even with expensive storage land,
the gain from better treatment will be great enough to warrant the
expense.

SEASONING OF TIMBEE.

X. SEASONING OF OAK TIMBER.

For several months seasoning- experiments with White Oak timber
have been under way, in cooperation with the Baltimore and Ohio
Southwestern Eailroad, at various points in southern Illinois, Indiana,
and Ohio. The plan of these tests was the same as that for Lodgepole
Pine. Oak ties were obtained as soon as possible after they were cut
from the tree. These, were piled in various ways, as shown in Pis.
XVI to XVIII. Particular attention is called to the two piles shown
on PI. XVI, illustrating- a method still too frequently employed, by
which green ties are piled with the lowest tier of ties resting directljr
on the ground. In the upper figure this lowest tier is almost buried
in the weeds and grass, and it is evident that these ties have little or
no chance to dry out. The better method of using two ties to support
the lowest tier is shown in the piles on Pis. XVII and XVIII.

The two forms of piles shown on PI. XVIII give the most air. Thej^
do not difi'er materially excejjt as to the spacing. PI. XVII represents
an experiment made to test whether it would be possible to use the
method commonly employed in France, of making the uppermost tier
serve as a roof. The ties are placed close together, and are given a
slope by placing a tie under one end. The lower figure shows a
double roof, with the ties so placed that the upper tier covers the
spaces in the lower tier. In a region where the annual rainfall is high,
it is very probable that the seasoning of the whole pile will advance
more rapidl}^ when the ties are in this form than in a pile not covered.
The top tier can always dry out rapidly, even when wet, as it is so
exposed to the sun and air. During the very heavy rains in the
middle of December the ties under such a roof remained almost
entirely dry.

Some preliminary results of experiments with White Oak ties which
had been cut for some time, showing the rate at which seasoning is
taking place in the difl:erent forms of piles, are presented in the fol-
lowing table. Onlj^ the first and last weights are given, with the aver-
age loss per tie and the percentage of loss. These weighings were
conducted at Fairfield, 111., on the Baltimore and Ohio Southwestern
Railroad. The differences, though not as great as they would have
been had the ties been green, are sufficiently striking to warrant
advocating the open form of piling.

Table X. — Preliminary weights of White Oak.
OPEN-CRIB PILE, 7 BY 2.

Date of weighing.

Number
of ties.

Weight
per tie.

Loss per
tie.

Per cent
of loss.

75
75

Pounds.
166. 47
148.13

Pounds.

October 27

18.34

11.02

TESTS WITH TELEPHONE POLES.

Table X. — Preliminary loeiglUs of While Oak — Continued.
HALF-OPEN PILE.

Date of weighing.

Number
of ties.

Weight
per tie.

Loss per
tie.

Per cent
of loss.

101
101

155.62
147. .=15

8.27

5.31

SOLID PILE.

8.5
85

175.81
166.91

8.87

5.04

In about two and a half months the open pile lost more than twice
as much as the solid pile. There was no additional cost in building-
these White Oak piles in the same manner as the Lodgepole Pine.
Eventually there may be a small increased cost of handling, but the
gain outweighs the cost many times.

XI. TESTS WITH TELEPHONE POLES.

Tests have been made from time to time in this country to determine
the practicability of preserving telephone and telegraph poles. Vari-
ous preservatives have been applied to the whole poles, and in one
instance methods of butt treatment were tried. The results have not
always been satisfactoiy, particularly when creosote or tar oil have
been used. This in most cases was no doubt due to the use of poor
methods and a poor quality of creosote.

Economical treatment of telephone or telegraph poles is veiy much
more difficult than of ties or bridge timbers. The latter are exposed
to decaying influences throughout their whole mass, while a pole is
generally liable to rot only around the point where it enters the ground.
Except in such climates as southern Texas and Louisiana, therefore,
where timber exposed to the air rots rapidly, treatment of the whole
pole is a great waste. Then again, ties and timbers can be taken
without great cost to and from some central jireserving plant. This
is frequently impossible with poles, especially when they are obtained
locall}'; the freight charges would be so great that it would be
cheaper to get new poles. In Europe, however, where the first cost
of poles is very great, and where treated poles last twenty-five to
thirty years, it paj'S to treat the whole pole. Those treated with tar
oil in 1871 for the Prussian postal service are still in use in a line
north of Berlin, and in good condition. The Swiss Government treats
its poles with copper sulphate, after the old Boucherie process.

With the increased cost of poles in this country, it has become a
matter of considei'able moment to find some efficient and economical
method of lengthening their lasting power. To this end some tests

44 SEASONING OF TIMBEE.

were started during the past summer. Before describing them it may
be well to consider how poles give out, and what the conditions are
which favor their decay.

DECAY OF POLES.

Poles set in the ground usually deca}^ at or or just below the surface
of the ground. The reason for this will be plain when one remembers
that two of the conditions necessary for the growth of the wood-
destroying fungi are air and water. Above the ground the poles drj^
out in a short time, and remain dry; they therefore rarely decay in
this part." Below the surface of the ground there is so little oxygen
that the fungi can not grow; hence this part also does not rot readily.
Poles standing in water are in the same class with those in the ground.
Below the surface of the water no rot takes place because of the
absence of air. Decay is at the surface of the water or a little above.
The same thing is true of piles. The reason why poles give out first
at or just below the surface is that both air and water are found there
in sufficient quantities to permit the wood-destroying fungi to grow.

PTAXS FOR PREVENTING DECAY OF POLES.

As has been pointed out above, decaj' can be prevented either by
keeping the wood dry or by chemical treatment. In the case of poles,
if one can keep the butt dry the length of life of the pole will be con-
siderablj' extended. The ease with which this can be done will vary
with the soil conditions. In a heavy clay, where water stands for
daj^s, it will be more difficult to establish drainage than in a sandy
soil. In experimenting with pole treatment two lines of work have
been started, one in seasoning poles, the other in treating the butts
of poles. In the present bulletin we are concerned onlj' with the
seasoning tests. These have been going on since July near Mount
Arlington, N. J., in cooperation with the American Telephone and
Teleg'raph Company. Chestnut poles are being cut in northern New
Jersey for a long-distance line from Providence, K. I., to Philadelphia,
and from these fifty 30-foot poles are taken every month for the sea-
soning experiment. They are weighed one or two daj^s after thej^ are
cut, and are then piled on a side hill, two poles on the ground and the
remainder across them. An air space of about 16 to 20 inches is thus
left under the pile. The poles are weighed every month. Incidentallj^
careful measurements of the circumference are made at three points.
It is yet too early to give a,nj definite account of results, but the poles
cut in August had lost 6.98 per cent of their first weight by October 28.

While the average loss per pole in weight has not been very great

f- An exception to this must be made for regions where during spring and summer
the air holds enough moisture to keep the tops ^\et. AVhere this is the case the top
will decay likewise.

PLANS FOE FUTURE WORK. 45

SO far, it must be remembered that the summer just past was a very
wet one in New Jersej', and that the rate of evapoi'ation was influenced
considerabh" thereby. The weighing of the separate lots is to be con-
tinued until the poles have reached an air-cLy condition. Poles are to
be cut every month throughout the year, so that figures correspond-
ing to the weights obtained from ties will be available. The seasoned
poles will be set in some line together with unseasoned poles, to deter-
mine the difference in length of life. All poles are marked with nails
indicating the month and j'ear during which they were cut.

Similar seasoning tests for poles in other parts of the countrj- have
been arranged for, and will be started as soon as possible.

XII. PLANS FOR FUTURE "WORK.«

Arrangements are pi'actically complete for carrying on further
seasoning tests, as follows:

SEASONING OF OAK TIMBEES.

Two series of tests have been arranged to determine the compara-
tive rate of seasoning and the best methods to season various kinds of
oak. The tests will be mainlj' of White Oak, Ked Oak, Abater Oak,
Black Oak, and such other oaks as occur in anj^ quantity in the
Mississippi Valle3\ They are made in cooperation with the St. Louis
and San Francisco Eailroad Company at several points in southwest
Missouri and northwest Arkansas, and with the Illinois Central Eail-
road Company and the Ayer & Lord Tie Company at several points
in northern Mississippi, western Kentucky, and Tennessee. The
tests with the Baltimore and Ohio Southwestern are being continued
and will be enlarged.

A determination of the length of time required for thorough spason-
ing- is most necessary for successful chemical treatment of the inferior
oak timbers.

SEASONING OF PINE IN THE SOUTHERN STATES.

In the Southern States it is difficult to keep green timber in the
woods or in piles for any length of time, because of the rapidit}' with
which wood-destro^'ing fungi attack it, particularly during warm
weather. It may prove that the piling methods found so successful
in the North will not give satisfactory results in the South, and that
some form of kiln drying may have to be resorted to in order to get
seasoned timber for treatment. An extensive experiment has been
started in southern Texas, in cooperation with the Santa Fe Eailroad
and the Kirbj- Lumber Company, for the purpose of testing (among
other things) the rate of seasoning of ties. Two kinds of pine are to be
tried, the Lobloll3' and the Shortleaf. Both sawed and hewn ties are to
be used, and the experiment is to be as exhaustive as that in progress

"April 15, 1903: The tests with oak and Southern pine have now been in operation
three months.

46 SEASONING OF TIMBER.

with Lodgepole Pine. A similar experiment will be made in Arizona
with the Mountain Pine, and another in northern Georgia and South
Carolina with the Longleaf Pine.

SEASONING OF GUM TDIBER.

The vast quantities of Eed Gum and Tupelo in the Central and
Southern States has led to repeated inquires as to their fitness for
structural lumber, etc. A number of gum ties are now being cut by
the Southern Pacific Railway, which will be piled and tested with the
pine in Texas.

PACIFIC COAST TESTS.

On the Pacific Coast a number of timbers which were formerly
ignored are coming into general use. Piling tests are being arranged
for Western Hemlock and the various species of fir. In southern
California tests are being conducted with the Eucah^ptus, to determine
its fitness for ties and poles.

XIII. CONCLUSIONS AND KECOMMENDATIONS.

Timber seasoning is a practical method for increasing the length of
life of both untreated and treated timber. At the same time it forms
the most important preliminary step to successful chemical treatment.
The cost of seasoning is insignificant, while the returns amount to a
considerable sum in the end. With the increased cost and scarcitj- of
timber, every step leading toward a more economic use of our supply
ought to receive attention.

It is perhaps too soon to draw final conclusions, but the following
genera] recommendations can be confidenth^' made.

(1) Green timber should be piled in as open piles as possible as soon
as it is cut, and so kept until it is air dry. In the case of ties the
7 by 2 form of pile is the best. No timber should be treated until it
is air dry.

(2) Timber treated with a preservative dissolved in water should be
piled after treatment for several months at least to allow the water
pressed into the wood with the salt to evaporate. Under no circum-
stances should timber freshly treated with a water solution be exposed
to weathering influences.

APPENDIX.

METHOD OF KILN DRYING IN USE BY THE FRENCH EASTERN
RAILWAY.

The French Eastern Railway maintains at Amagne a plant for completing the dry-
ing of its ties after they have been seasoned in the open air, which consists of four
kilns. These are structures about 50 feet long by 46 feet wide and contain two pairs
of hot-air galleries, each pair of which is provided with an independent furnace and
can be operated as a separate kiln. Between them is the supporting wall of the other
two furnaces, each with its own chimney. The galleries are formed of vertical walls
about 6 feet 4 inches apart, surmounted by a small circular arch with a radius of 3 feet
2 inches. To diminish the loss of heat, the arches are covered with a bed of concrete
about 8 inches deep over the keystone. Little trams, loaded with ties, travel the
whole length of the galleries upon a tramway 3 feet wide, which, to make the cars
roll easily, has a grade of 1 inch for 5 yards.

The masonry supporting wall of the two furnaces for each kiln is about 16 feet long
and 11 feet wide by 8J feet high. It is strengthened with rails arranged in vertical
trusses, strongly joined at their upper ends.

In escaping from the fire box of the furnaces the products of combustion rise to
enter the uppermost of five horizontal rows of longitudinal conduits, five conduits to
the row. From this they pass down again by circulating successively through the
other four rows. The cross section of each conduit is about lOf by 4J inches. These
conduits are inclosed in hollow brick sheating, through the passages in which a cur-
rent of air is drawn in a direction counter to that taken by the smoke. To this
ascending air the smoke loses all its heat, and is finally discharged into some pipes
under the furnaces, communicating with sheet-iron chimneys about 40 feet high,
placed inside accessory brick chimneys 26 feet high.

The air enters, at first cold, from the outside into a lower chamber of the furnace,
and becomes gradually heated in its upward progress. It is at last discharged into a
hot-air chamber which occupies all the upper part of the kiln. From this it is car-
ried down to the galleries in which the ties are dried by four vertical pipes, having
a cross section of 18 by 18 inches. Two pipes open into each gallery, at the end of
which the trams bearing the ties pass ciut after the drying has been completed.

In passing through the galleries in a direction opposite to that in which the ties
progress, the air becomes cooled, little by little, from contact with the wood. At
the farther end it descends to be discharged into the accessory chimneys, in which
a draft is created by a small fire box at the base.

The opening and closing of all the hot-air pipes is regulated by means of registers.
The smoke conduits may be easily cleaned by lifting the plates or plugs which close
them at one end.

Turntables at the entrance and the exit of the galleries enable the loaded trams to
be started on their journey through, and at the end removed again to undergo treat-
ment with tar oil in cylinders which receive one car at a time. Each tram carries
about 40 ties, slightly separated from each other, so that all the faces may be in
direct contact with the hot air in the galleries of the dry rooms and with the tar oil

4b SEASONING OF TIMBER.

in the cylinders. The four kihis in all contain 16 galleries, with a capacity of 5 trams
each, in all 80 small trams. It is thus possible to dry about 3,200 ties at one time.
With an annual output of 400,000 ties, seventy-two hours would be allowed for the
average drying period.

The temperature of the galleries is at the maximum 30° to 35° C. at the entrance,
and 70° to 80° C. at the delivery. As the trams are taken from the cylinders one at
a time, the drying is progressive, and the wood, for this reason, is less lialile to split
or warp.

The temperature is regulated according to the state of the weather and the condi-
tion of the wood.

The material used for heating the dry room is composed of a mixture of small
coal, cinders from locomotives, trimmings from shoe machines, and all the trash and
chips from the wood yard. To turn out 400,000 ties the furnaces of the four dry
rooms consumed about 200 tons 'of fine coal and 250 tons of the trimmings and wood
trash, making 450 tons of the mixed fuel. This mixture develops a sufficient heat
and offers the additional advantage of not wearing out the fire boxes by a too
intense heat. The accessory fire places put at the bases of the chimneys burn briquets
exclusively. For the output indicated above the eight accessor}^ fires burned 50 tons
of briquets. The expense for fuel is about one-fifth of a cent for each tie.

IB Mr '07

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