Chemical utilization and forest management

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Chemical utilization and forest management
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Locke, Edward G
Forest Products Laboratory (U.S.)
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U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory ( Madison, Wis )
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FCOEST Pit:.LIJ:TS LAB',.'rATORY
(Madison 5, Wis.)
FOREST SERVICE
.. U. S. DEPAI-TMENT OF tGi-ICUiLTFZE
Approved Technical Article


Chemical Utilization and Forest


511


Management'


EDWARD G. LOCKE
Chief, Division of Derived Products, Forest Products Labororay, Forest Service, U. S. Department of Agriculture


N ANY DISCUSSION of chemical utili-
zation of wood, two facts should be
kept in mind. One is that a forest will
produce a great many products; it will
produce sawlogs, veneer bolts, poles,
ailing, fence posts, pulpwood, and I
large amount of material that we now
call "logging residue."
The second fact is that utilization
practices dictate how the forest will
managed. If a sawmill is the onl'
outlet in the area, the forest wdI be
managed to produce sawlogs; if a
pulpmill is the only outlet, the land
will be managed for pulpwood.
Here in the Southeast you have seen
a one-product farm economy in opera-
tion. You know that to have stabilized
agriculture farms must produce not
ole, but a number of products. The
same is true in the management of for-
est lands. To manage timber holdings
most profitably we must consider all
the products that could be produced
on the land and the markets that
would bring the highest return (6).*
We must consider the quality of the
wood needed by these markets as well
as the quantity. The greatest possible
volume of wood from a tract of timber
is not always the most desirable, even
for pulpwood. Quality and density are
very important. Longer rotations with
an end crop of sawlogs and veneer
bolts and intermediate harvests of
other crops appear to be the most
effective management plan of the
future. From such management I/,
to 3/4 of the total wood grown would
be available for some form of chem-
ical utilization. Diversified utilization
processes and plants must be deel-
oped before intensive forest niman.L,
ment is possible or profitable.
Prescnied at mr lei,,i i itc Pbietit t'od,.,
Reitirch Sociert Flo,, di i-.rjAi Alh' aimi St,
ions, Oct. 10 Mill ai Radium Spri'gi I i
'IMaintained it Madison. Wii, in cooperation
with tMh Lin,v'erililt of iluconsin.
'Numbers ;n parentheses sreit to litiertuie
cited at the end to this report.


But first, wood utilization in i., r i
must be consiered. There are two
broad types of utilization-mechanical
and chemical. Under mechanical utili-
zation would be L""1i-. I such prod-
ucts as lumber, veneer and plywood,
poles, piling, and fence posts. Under
chemical utilization would be the
whole range of fiber products, from
those made from coarse whole wood
fibers to the most highly refined and
purified chemi ical I; ,', A i., pulps.
Also included would be products made
by processes in which the chemical
constitution of the wood rather than
its size or shape is all important.
Even in the mechanical uses of
wood, chemistry plays a large role.
Many new products are the result of
.iibinii-IC paper, resin, and wood.
Low-grade lumber, for example, can
be covered with a resin-impregnated
paper overlay to mask gaps, checks,
and knots and to give a highly paint-
able product. With specially I `LI i
papers the i.: .t IL and I -'_llin- of
lumnbcr may be -partially controlled.
For a long time I have felt that we
have devoted too mu h time to inves-
tigating thle cutting and uses of high-
grade clear veneers. '.'.. should spend
more time cutting vneer from low-
Lr.!,- logs and finding ways of1 ',I I.
the resulting material. One company
has done just that and is ..i a
paper-covered veneer from a hardwood
species that is so poor it has no other
use (12) Another is ', a softwood
species H,:-. r.i i... the operations with
a plywood plant (13). At least four
companies are in production of a prod-
uct of this type.

Resin Combinations
I'Lpci" tot r' I vencer is cx
-iiin ly u 'ClIl in such varietyt d products
i l ,,pi'e' ititnecrs .a d furitturi
It seems to ha' e one ot1 the brightest
futures ot ani reently Ideeloed prod-
ucti


Forest management plans must be intimately related to the
way the crop is to be used. Diversified processes and plants must
be developed before intensive forest management is possible or
profitable. The relation between chemical utilization and forest
management is discussed in some detail.


Reprincted tr ioi th Journ l 1 t- ,n s P-t ,d I o V15 1
P. 0. B1,x ;01i, \'ni+cr ty >

Several types of resin bonded pa-
per honeycomb cores have been de-
signed for use as core material for
sandwich panels. In this type of con-
struction most of the stresses arc taken
by the facings; however, the core may
be chosen for its insul.iuh., or sound-
absorption value, li i ., orl, vas
completed about 8 years .,.' At pres-
ent three companies are producing a
resin-imipregnated paper honeycomb
core material.
One combination of resin and wood
that has reached the proportions ol
a new industry is laminating in which
wood is glued, together parallel to its
rlii The performance and strength
properties of laminated timbers are
better than solid ones. Checking and
splitting during ,..Aui1n ki may be
eliminated. The lower moisture con-
tent and the most I ,. ,it arrange-
ment of er.i.l, characteristics of the
wood permits higher si' [Ii,i values.
The parts of .: stress- -the face
lamination.s-- miay be of clear mate.
rial with center lamina of lower grade
knotty material. Not only arc timbers
laminated but also curvcd structural
members.
Thlie most recent development has
been the production of lami, d di
mension atid finish lumber h at-
tcr permits the upgradn1 ,f 14 lo r
construction grades b Nt. ou
knots and other de ii, glu-
ing and en-d products
as i ] floor r,,
and styles. /.

1,, C.
<3ili.- it,,,, J\-,/
confronting users <,N
rI! ,l',.L- ..nd ,'. ,, lh ',ri K I /
o 'ood und r moistu r
. Atthcl b Ioory wea b'cr
work a .rs on tht.!:. j h
ioal stab aton1' .j an ,av
c npt ix' j^nnow
cdevecloped tspo!t o
n i aitid 1:, compreg
(9. 15) 't*l< are costly
be i s( I phI otI Is imnorpo-
acd in the wood stru itutrc 'X 30
cr cnit resin thc I k and swell-
,. of wod a0 a c redi cid by about


1954


*MtCULruH Ut.nna-








Impreg, the resin-impregnated
wood, is being manufactured by one
company, not for its dimensional sta-
bility but for its resistance to acids.
Material for wood tanks to be used
for storing acid is being impregnated
with a phenolic resin. A small amount,
of the material has been used in a
number of other products.
Two companies are manufacturing
the rcsin-impregna.ted compressed
ood, compreg. Most of it is being
.,icl for tooling jigs and forming dies.
Its light weight compared to metals,
icati cely low cost. and ease of repair-
,L make it highly desirable for these
uLe,. One plant reported that its pro-
duction wsas increased by as much as
tour times by thle use of compreg dies
instead of metal dies. If the resin con-
tent is reduced to 5 to 10 percent, the
toughness of the product is increased
and its resistance to impact or shock is
improved. Such material is more suit-
able for shuttles and picker sticks in
the textile industry than the higher
iesin containing products.
The Forest Products Laboratory is
still working on improving the dimen-
sional stability of wood. Much funda-
mental work remains to be done be-
fore a low-cost method will be de-
veloped that .,.ill have universal
application for such highly competi-
tive products as doors, windows and
drawers.
Before leaving the subject of im-
proved wood, we should consider the
preservative treatment of wood, since
that is one way of making an "im-
proved" wood. As the result of more
than 10 years of research, Dr. Roy
Bacchler of the Forest Products Labo-
ratory has developed a new process
for preserving wood called the double-
diffusion process (1). Although the
process was developed primarily for
small-scale nonpressure treatment of
fence posts, it shows considerable
promise for trc-ating lumber. Green
posts arc- placed upright in a barrel
ii, iijiL;, a a opper sulfate solution,
and the hIemical dillf,. into and up
the posts. After about 2 days the
posts are transferred to a barrel con-
taminig sodium (hliromiate solution and
permitted to soak for 2 days. The sec-
ond chemical is taken into the wood
structure and thie two chemicals conm-
bine within tile wood struck t iure to
form insoluble copper chromate, a
(omrnpound toxic to insects and fungi.
O)ne hundred posts treated by this
imimeod have been in a test plot in
Mississippi for more than 13 years.
TIo date only one of this group has
failed. Other dicremicals and many spe-
(its arc undcr investigation.


Chemical Utilization
Now let us turn to the chemical
utilization of wood. The raw material
for chemical utilization should be ma-
terial that has no value for structural
purposes, that is, the residues from
logging and manufacturing. It has
been estimated that over 100 million
tons of this material are produced
each year in the United States (11).
Residues can be classified as chip-
pable-slabs, edgings, and trim-and
nonchippable-shavings and sawdust.
Chippable residues can be used for
any form of chemical utilization, but
the nonchippable residues are the
problem children. At present they are
suitable only for such low-grade uses
as animal bedding, mulching, fuel
and a few specialized uses such as
floor sweeping compounds and fur
cleaning preparations.
At present the most profitable way
to use wood residues is to convert them
into chips and to process them into
pulp. Both softwoods and hardwoods
can be used. Each year more barkers
(both whole log and slab barkers)
and chippers are being used at saw-
mills and veneer mills to produce pulp-
able material. In the Pacific Northwest
more than 100 chipping plants have
been built at sawmills and plywood
plants. The advent of the semichem-
ical process now makes feasible the
utilization of the cull hardwoods. An-
other new process, prehydrolysis kraft,
is being used to convert cull hard-
woods into high-grade dissolving pulp,
the rayon from which is superior for
tire cord. However, in spite of the tre-
mendous expansion in the pulp and
paper industry, this cannot possibly
be the complete answer to the problem
of utilizing wood residues.
Recent studies have shown that the
residues of most species can be proc-
essed into liardboard. Since 1948 the
productive capacity for hardboard has
doubled and still more plants are being
planned (5). Muchl of this material
goes to the industrial market where it
is cut up and fabricated into other
products. It is made from chips that
have been fiberized, formed into mats,
and pressed into il r sheets. Resin bind-
ers arc often uIsedl to strengthen the
product.
Particle Boards
There is a whole new class of
boards called particle boards that are
also produced from the chippable por-
tion of wood residues. The wood is
usually defilsrized in a hammer mill,
resin is added, the moisture content
is controlled, and the material is pressed
into sheets. The Forest Products Labo-
ratory is now evaluating the Ili. i of
particle size and shape on the proper-
ties of such boards. (Core material pro-


duced by this method is competing
satisfactorily with lumber core in a
number of plants. It can be surfaced
with paper, specially prepared flakes
of wood, veneer, plywood, or even
hardboards. Boards made from wood
residues are one of the coming indus-
trial materials. I believe we have seen
only the beginning of the manufacture
of this type of product. One of the
most promising products is a board of
medium density.
A large unexplored field is the man-
ufacture of a fiber that is suitable for
producing molded products with either
high or low resin content. These might
vary all the way from toy parts and
toIlet seats to moldings and parts for
kitchen cabinets. Experimentally, win-
dow frames and sills have been pro-
duced. Extrusion molding of shapes
shows great promise.
Now let us consider the problem
children among wood residues-saw-
dust and shavings. Wood hydrolysis is
the most promising means of chemi-
cally utilizing these materials because
it is adaptable to all species and all
forms of residue (7). This process al-
lows us to separate wood into two ma-
jor components-cellulose or its prod-
uicts, and lignin.
Theoretically, complete hydrolysis
should produce about 1,300 pounds
of sugar and 500 pounds of lignin per
ton of dry wood. Since some sugar
is destroyed by the li,, tr.,l I'n klemi
cals, the theoretical yield is never ob-
tained. However, a percolation process
now in use yields about : pounds
of fermentable and nonfermentable
sugar per ton of dry wood.
The cellulose fraction of wood con-
tains not only a material that is made
up of a building block of glucose
(corn sugar), but a material called
hemicellulose that contains an appre-
ciable amount of pentose ,,.ii -.
mainly xylose. Xylose, which will run
as high as 30 percent of the cellulose
in hardwoods, appears to have a 11 i. Iit
future as a raw material for the pro-
duction of furfural. All of the readily
available agricultural residues, such as
corncobs, oat hulls, and rice hulls, now
are being used to produce furfural,
so any increase in production of this
chemical must come from a new
source. That new source appears to be
hardwoods.
Furfuiral is the final decomposition
product of the pentose sugars duri' :
the acid hydrolysis of wood. The final
decomposition product for the hexose
sugars is levulinic acid. Both are valu-
able intermediate Ur, riiin chemicals.
Levulinic acid now sells for $5.00 a
pound and is being used only in tilhe
pharmaceutical industry. Its future will
be very ,'r;_Ilv indeed for synthetic
fibers if it becomes available in the







price range of turfural, that is, 9 celts
a pound.
Three companies now have ;
plants in operation for the production
of furfural and leivulinic acid. Tihe
Forest Products Laboratory has been
..' rin fundamental recsearth along
these lines for a number ot years.
W.' L. i..:.r mola.,sses with a sugar
concentration of 45 percent cart be
used for animal feeding (4). F ceding
tests have shown that the sugar li
wood molasses is equal to the sugar
in blackstrap molasses in feed value.
\\ %_., I -.. can be 1,.r.i. n1`101.1
to sorbitol (a commercial humectant),
ih-;vln.. and propylene glycols, glyc-
erine and erythritol.
A number of .i rier,.i yeasts ani
be grown on wood ,LJOHl Depending
on the type and the r,,ii,. condi-
tions, they may be high in fats, high
in B vitamins, or as much as half pro-
tein. One plant now is ,r.. I,, ir.iL.
Torula yeast from the sugars in spent
sulfite liquor, and another 21.2 million
dollar plant is under construction. The
yeast is used as a high vitamin protein
feed and as a source of pharmaceu-
ticals.
The ori.j.ili objective of hydrolyz-
11;, wood to ,ugjir, was to produce
alcohol by fermentation. However, a
number of other fermentation products
can be obtained utinder properly con-
trolled conditions. I These include a(etic,
butyric, lactic, and citric acids, and
acetone, butanol, l'u,' .''..I and
glycerine.
The use of wood sugar depends
upon its production at a cost compar-
able to the i'l:,;.il, sugar whether
it is black strap molasses, invert sugar,
or corn sugar. Muth of the econonis
of any process of wood hydrolysis is
dependent upon a profitable uise for
the lignin residue or upon a uniform
constant i'; I. of sugar at a fixed
price.
A number of uses haIe beIn touind
for l.,'rn (3), but 11u4h more basit
research is needed to establish its ex-
act nature and to put it to best use.
It differs from the other constituentss
of wood in that it is not converted to
low-molecular weight compounds when
hydrolyzed with acids. It is a store
house of aromatic materials whose
building block is phenyl propane
The lignin residue from the sulfite
,uI'i rg process consists of lignosulfo-
nates that can be converted into vanil-
lin, the vanilla r''..',,,, in your ie
cream, and such products as oil-wellI
trillin-, compounds, I '' L materials,
and linoleum adhesivcs. These mate-
rials do not use much of thle available
lignin, but the '-ili',. Pulp Mill
League of \'. .....1 located at thel In-
stitute of Paper Chemistry anid many
other groups and pulp mills are doing


utilizat on reUar h tha ati tcl
prov d .1' .sale us t tths prod-
umi ()t mos t ovIou tses tor
l1gnI, ic t the bindt mate i
Sd s s11 a o s .1
o 5po t ot .1 plastic }owev. r it.s
, p ot p rsl USt l )e ipro 1d.
s tfin1.t( 1, ii j 41701, ot 1 th sral k
utit s am ailabl to bh st
nitics for the Cc ot may bt in
Ic m i. t I gradaton .i d otI
thn: various products. Su, h processes 'Is
a.iustiv tretment, pyroly',i, hydro
., ,I ;is, a1nd 0 .lhXrl5oi visl or oh1tcr
oxidation pro cesscs fri C .
but much bVis rcseir~h is needed.
lFrom tle .' I residue of the
acid hydrolysis procti it lira be po,-
siblc to produce an activated har, pr-
haips by the tluidizd bedA ct lo:quc
.worked out in the petroleum industry.
T he C ".. . Institute ot "lci: .... "'*...
made t V.iya ble conI i AU) t1 o to tlre
study of wo O arhOnization t\ in\'e, -
tigating the ti izcd I d I for
produc._ clhar oa froi savwdust (14)
'', carbonization, v,'e
should ml itiol tihe in
the domet ) ad rcr .at m.al market
for tarioal 1hroduc 1d in smNall kilns'
close to the mirkt. Although this use
of charcoal appears to L -. ... II.t
little has been done in thle way ot
intensive of a spe ialty
product for !he small -onsumer. It
appears ttasihI that a ,inall i nder
block (onit ti ut type kiln might be
integrated wth intensive forest man-
residues into a c in areas wjfere low-Vost laI or is a,
able. The hartdwods arI 1 lhe pref erred
spedces.
Eixtractives. atnother- (oiponeiit ot
wood. form t},: l).sis ol thie lar:Ltc naval

Such an Idutr an ao intgratd
into a Ama.acinini pl. Ti e L or1 st
ProduOts IIora for !, done lhttl-
wVork iI t s iti iI rtcnIt yars be-
kaust f flit kkt, V 1 Vo rk dIrl(d
onil by tile Bliuai oI A riilh i.irc and
I idustrial ( cm ist:. 1 Il ,t Stu' r ef
pill)
iCe has Oi0q~[f cnra'd ol (hic foreUt nI"11-
. ',, .' phases,.


Now I wotld
three fundamLent1
Ions being rati. Itrled
Iaboratory. hI t}ie


like to mention
Lic4m al i
on at the Ma.dison
7rs4 of thse, ctlSu-


lose was tr1ited with hligene
radIiation to m. ik a1 p rodu1 ct tiat
essentially so lble 11 Va.' r (81 ). I
1s a drast5 d i oslf h triLati 117itt
e,,cr, a similar butmilder tr ainm,
nIay be u1se7ful 1 iincr the
,ct ton sp.eiei(d o t t in ts 117
,,ersion to> [:1,:,,:, rayon, and ot,
products. This fuludamerntal reseu
[iro){C:t hl a pru>d : d some iiercvs:
and vahuable mt:ormation.


rgy
is
his

rnt
re-
Ofk1
SI-
her
rt li


Mt I y a
partod U.
know ,er}

dA' eloped
methodi .
dhlr .'..
Iears, res


Iis I iiu
tLi 11 til- :
tlial bind

: ye i
:ing, ,and
tiki sLi I
third part
Dri[I li 'i


o1 di new,', in
iation, deeind upon .'
wovd 1 adl yet ,we
.1 tt V.t
i t )x it tis pLi nom-
iand I ttr a hiies t es area
lartgely b tr ial and error
Laboratory now is un-
fitt r i 1 lia]e of some 20
earhl oni the tunidaunntal
1 v t .1d1 a '1: o fl Tro lhni
a tproa ihed i from three ,i-
l 7) t1l to I es lti adhesion

tSl It V tood. (o2)
l (k lit 01i tLhat hold tPile
and resist us break
(2, thie stick s-rs tr n rela-
Lihi a iglI film. This
should 1 1ro 1 t, i tri tP on
ot addittive, o:: the prop-


Irtics of an ad'o ,Ive
i ", proj ct i, srictly basic
r, s car bL t we the reutIlts will
IC useful it I' I a d form ulat-
in i. ' es to d(1 spCuin0 jobs For
partkc boarJ and1 lamintiatcd lum-
ber, ai I Itrn h lo w-cos> t I. isl
7eded.L I i ' aiirplanes, oil
tie other hind it cos15 of the adlihe-
sive i, Si o dry to its performance.
Tets haL alrtadI shovttn that, pro-
the sr fa c is properly pre-
pa -ed, te Aiohsive forces are always
waker than the t ''. forces; the
lliAd kbjLt' dots not break at tlhe
point ot oict between l tilhe adhilesive
and tl e oL c, bi1 ut rather it th glue
fit or i tle material Lcn .' i
A iotL r r nvestigitioi that wVill be
starred shortly is o t lie fmld.iii 'ntal
mehalnsI'll of natural durability; thai
Is, wtat is it 01,l makes menlt woods
durable 1 hil c, others dtt ay rapidly?.
Previol s. work in ti s ficld wL as riot
Ait ed spii iiL l1y tilt t lte fi tIda ir ntal
ntchanisin. but rather at tlle relation
ot te iolc ,uir i(o0 tiguratioln Includ-
'14 the bde to to, ity. TL hs
Iwork ai [le [orei t Produo Ibora
tory }b\ } .i'e:m:ll :ltld 1lecvlllr ( 2)
led So tle de lopIt O t1tr.ichloro-
plinol rid ao Ip t >, tlloro-
I .li l} low P, a recognized


de ia},
IAU
S}otol
Li~t~


Vi[ive
ru1a n tor i 0 11,k l 1r.

It Ll t}ile tihr ii 1711 of,
t(>v.trl h a l ind rred I, tro-
neiqrv. Thlle slicu',d :oiiirn utc


,)til it


sburt It t


o1rm


.lid m tie ol
*ion ol: wood osfe


eld. \,e 'ust LmphaI

i i h .ind I et


Tie









with unlimited funds and men it is
a rare occasion where a process can be
developed and a full-scale industrial
plant built in less than 5 to 10 years.
Chemical utilization of wood puts
one into the chemical industry where
capital costs are high and manpower
requirements are low. The capital in'
vestment averages about $1.50 for
every dollar of manufactured product.
For example, if the output of a plant
would be valued at a million dollars
a year, the capital investment would
be about 1-1/2 million dollars. To de-
velop the chemical utilization of wood
satisfactorily, it may be necessary for
a number of primary manufacturers
in the forest products industries to
group themselves together as one ma-
jor company that will purchase its raw
materials from the wood residues
of primary manufacturers and forest-
land managers on a long-term basis.
The Forest Products Industry must
not expect the magic wand of research
to turn her into a Cinderella. She
must do her part by sprucing up and
have enough gumption to go to
the ball.
References
1. Baechler, R. H. 1953. How to
Treat Fence Posts by Double Dif-
fusion. Forest Products Labora-
tory Report No. R1955.


2. Bateman, E. and Baechler, R. H.
1937. Some Toxicity Data and
Their Practical SiLnificance.
American Wood Preservers Asso-
ciation Proceedings, vol. 33, p.
91.
3. Locke, E. G. and Johnson, K. G.
Wood Resources for the Chemical
Industry in the East Northcentral
States, Ind. Eng. Chem., March
1954 (In process of publication).
4. Harris, E. E.-1950. Hydrolysis of
Wood for Stock Feed. Fores.
Products Laboratory Report No.
R1731.
5. Lewis, Wayne C. 1952. The Hard-
board Industry in the United
States. Journal of the Forest Prod-
ucts Research Society, vol. II,
No. 4, p. 3.
6. Locke, E. G. 1949. Patterns for
Integrated Complete Wood Utili-
zation. The Timberman, vol. L
(50), p. 44.
7. Saeman, J. F. 1952. Status of
Chemical Utilization of Wood
Waste. Journal of the Forest
Products Research Society, vol. 2,
No. 5, p. 50. (Dec. 1952).
8. Millett, M A., and
Lawton, E. J. 1952. The Effect of
High-Energy Cathode Rays on
Cellulose. Irnd. Eng. Chem., vol.
44, p. 2848.


UNIVERSITY OF FLORIDA
fl 11 I I I I II IT I $ 1i1 111111 1111 II I 1111111
3 1262 09216 2840

9. Stamm, A. J. and Seborg, R. M.
1951. "Forest Products Laboratory
Resin-Treated, Laminated, Com-
pressed Wood (Compreg). For-
est Products Laboratory Report
No. 1381, revised.
10. Stamm, A. J. and Seborg, R. M.
1950. Forest Products Laboratory
Resin-Treated Wood (Impreg).
Forest Products Laboratory Re-
port No. 1380, revised.
11. Winters, R. K., Chidester, G. H.,
and Hall, J. A. 1947. Wood
Waste in the United States. Re-
appraisal of the Forest Situation,
Report 4. Forest Service, U. S.
Department of Agriculture.
12. Whiton, Arthur L. 1953. Crave-
neer as Used in the Packaging
Field. Journal of the Forest Prod-
ucts Research Society, vol. III,
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