Possibilities of increasing the use of hardwoods to meet pulpwood requirements


Material Information

Possibilities of increasing the use of hardwoods to meet pulpwood requirements
Series Title:
Report ;
Physical Description:
6 p. : ; 26 cm.
McGovern, J. N
Forest Products Laboratory (U.S.)
University of Wisconsin
USDA, Forest Service, Forest Products Laboratory
Place of Publication:
Madison, Wis
Publication Date:


Subjects / Keywords:
Hardwoods -- Utilization   ( lcsh )
Pulpwood   ( lcsh )
federal government publication   ( marcgt )
non-fiction   ( marcgt )


Statement of Responsibility:
by J.N. McGovern.
General Note:
Caption title.
General Note:
"May 1946"--Cover.
General Note:
"Presented at a meeting of the Wisconsin Press Association at Milwaukee, Wis., May 17, 1946."--P.1.
General Note:
"In cooperation with the University of Wisconsin"--Cover.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 029249155
oclc - 83823600
System ID:

Full Text
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May 1946

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No. 11414

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Madison, Wisconsin
In Cooperation with the University of Wisconsin






J. 1. "crW0VR:-, Chemicanl Er.incer
Forest rodiucts Labora.tory,.2 Forcst service
U. S. Department. of Agriculture

'.b: t tract

Fr,-dictions of increased prner and bor-' dc!-rards for
the 1irmcediate future raise questions ri--r.rdir- possible so';rc.-.s
of fibrous raw material to'satisfy anticipated requircjrnts.
Because the chenr.st source of paper-'-kl:'. fiber will probably
continue to be wood and bec-,cuse rc-'-.dily available surolies of
preferred long-fibered species arc inadequate, new ris.,urc.-s cf
rulpwood will need to be developed if domestic s,.rDlics are to
be utilized. A promising pulpv.'ood source lies in currently
secondary species and low-grade -.'ecd "-.rdwcods -.k.: uo the bulk
of secondary species and their use is necessary to realize a badly
rnecd.,A irrprovcm-Int in silviculture in the woods. Altleugh hr.rd-
woods have been used to ad-'.rt.:e in s7nl2 amounts in thV nulD a.nd
p-.er industry for .r.ny ycars, it is only within. the last flew y.-ars
that advancements in technical knowledge have been 7ade to ovcrcorc
certain difficulties in hardwood harvcstin': and rroccssinr- and in
pulp- and pap:r-mnvking proc:cdur.s. ih. se advnnccs have inreo-cd
the possibilities of increased utilization of hard-;cods.

Nearly 150 years ago the English economic world was introduced
to the startlin,-g theory which predicted larn.ring poverty, if population
increases did not become com-cnsurate with the more -'oecrnte increases in
means of subsistence. Ho-ever, advances in agricultural .rnd other tech-
nologies and in transoortation tended to disprove this famous theory of
Malthus. Today, serious shortag.s rrain confront the Jr.itcd States and the
world. Of particular interest to the For,-st Products Laboratory is the
shertire of paper and paperboard, since these arc chiefly products of the
forest* The dcrn.ds for these products are not lcir.n- met nr.d the predicted
it.,ar.ds in the near future exceed considerably the readily available sun-
plies of the preferred lor.g-fibered raw material. Although the situation
is unlike that d scribed by Iralthus, it will be shown that tcchnolo-ical
. v lopments con n,-air, help meet the present and prospective shortages, r.at
le-.s- the paper r.nd board shortagecs.

-r-*.s:nted at a mcrtinf- of the Wisco:.sin Press Associ.tio. at :'il:auk-:ec,
".'is., :.a'ty 17, 194w.
2" .air tained at .L.adison, -'is., in cooperation with the Univ'crsity d 'iisconsin.

Puport "o. F.1614

As you know, the pulp and paper ind-istry in the United States
has had a rather amazing growth during this century. A lar.Ie increase in
paper consumption has been shown in each decade. In the period from 1899
to 1945 the consumption of paper and board has increased from slightly
over 2 million tons to about 20 million tons. It has been predicted con-
servatively that paper and board consumption will be 24 million tons by
1950. During the period of 1899 to 1943 the per capital consumption of
paper and board increased from 58 to 288 pounds, although it reached a
high of 309 pounds in 1941; it is estimated that this value will be 330
pounds by 1950. It is of interest, incidentally, to recognize that a
close correlation exists between consumers' expenditures for nondurable
goods and services and paper consumption.

Accepting the predicted increase of 20 percent in paner and
board consumption by 1950, the question then arises as to where this
increase is to come from. It seems likely now that the added require-
ments will be met to a greater or lesser degree by the following alter-
natives, assuming that wood will continue to be the cheapest source of
primary fibrous raw material:

(a) Importing more pulpwood, pulp, and paper.
(b) Using more waste paper.
(c) Increasing domestic pulpwood production by going farther
afield for preferred long-fibered species, by using new species, or by
using more of the little-used species.

Part of the increased requirements will undoubtedly be met by
increased imports, although there are increasing demands elsewhere for
Scandinavian pulp and paper products and it will be a few years before
those countries have recovered from the effects of World War II. In this
connection it is interesting to note that before the war the amount of
paper imported or made from imported pulpwood and pulp nearly equaled the
amount of paper made from domestic pulpwood. Waste paper will continue to
be used in large quantities in numerous grades of paper but it is doubtful
if the war-time collection level can be maintained unless the situation
becomes critical. Thus a large part of the increased requirements for the
future will probably need to be met by domestic pulpwood.

During 1945 close to 86 percent of the pulpwood consumed in the
United States was in the form of the preferred long-fibered species, the
softwoods. The possibilities of cutting more preferred softwood pulpwood
and maintaining this high percentage of long-fibered wood appear to be
limited because additional supplies of the desired species are not readily
available or cutting at an increased rate will impair the forests. In the
Northeast, for example, the available supplies of softwoods have been
inadequate for years and a considerable percentage, 31 percent in 1944,
of the softwood pulowood consumed has been imported. A similar situation
exists in the Lake States. In the South the re is a sufficient over-all
supply of pine pulpwood for the future, but concentration of mills in
certain areas has reduced the availability of the pine, or cutting at a
higher rate is contrary to good forest practice. Finally, the supplies

Report No. R1614


of the '-r.'err-(1 h,n.lock in the- "crthwest have -ecome increasingly less
avail'.J.le so that an incrcasc unccr rast conditions is i::,robablc. In
all ri.ions, ho-,..vcr, thi-re is a tremendous surely ofr lcv:-grade wood and
little-used spocies .,'. utli,-ation is iir-er...ive if badly needed
-. rovements in the con1 c tionis and future productivity of the forest are
to be realized. In the "irthcst, Lan!e states, ane the S3outh thcsL- uruscd
fori -t resources are largely in the form of thc hroa.d-l-'.fc-d hrir--.':oods.
This source of wood a!-,c.ars to of'er ar. attractive -cossilility for incrvi.sing
the s' l-.1y of pul;-:ood. "ier.lock and Douglas-fir lodging ind ill *""ates
comprise the prcl.rable source of rul. rocd in the 'orth-.',cst. Thus, the most
likely: resources in three of the. four major pulring regions exist in hard-
W OS. s

B,.fore discussing the possibilities of utilizing hardy:cods to
meet a substantial portion of pr.r-sent n-.rd future -,upfv:cod re : .r'rmncnts,
it is v.....ous to review the history of th.e use of wood z. a fibrous
raw material for anr.r ix order to help deter-.ino nossirbl- future trends
in nilowcrd use. ThCL first wood snpcies used in th "I-,,In .:.3 pn.'er industry
were poolac.r and basswood, both h..rd'.ood species al.',o.. -: soft in texture.
These woods were p.rtcularl:.,' s,;itcrA for sod-. pulpin., the first chemical
rtiloing process. The invention of the sulfite -ul'nsin- pro(:.ss and develop-
ments in groundwood pulpinr soon changed the reference to .r-ruce. In
lG'. srruce alone mnde up 76 percent of all the Dulr-"ood cc-sumed. Because
the supplies of spruce did not -ro7c i.ncxh.ust.ble !-nd because .-ncr
dcm'nads were increasing rapidly, other species had to be used to meet
these demands, in this way :,stern and :cstern he.lock, Souihern yellow
pine, balsam and white fir, and jack pine werr "ddcd to the, list of so-
called pulninr species. To the ori !..l harr".'oods, --.L-..r :.nr.d basswood,
were ad c-d smT.ll -amoun+s of yellov-rnolar, gum, chestnut, birch, marnlc,
and cottonwood. These additionns came about as a result of both economic
pressurr- and advances in technical knowled.-c. Te ir nortance of spruce
in the over-all picture has thus dim'nishird -.rd in 1941 sr.i'cc represented
only 22 percent of the U. S. plr.vood consumrtion. It is incscar- .ble,
however, that the trend has rcn for new, lnr -fibercd sc ces like .'s-stcrn
hemlock or southern pine to satisfy the incr....sing drr--nds for rul-'Ncod.

It is now natural to question why hardywoccs have ,tr. nisscd ove.r
in s' ite of their availability in large quantities. Two r.-.sonr.s -tand out
for this rejection. Th.:sc are: (1) Hardwoods are difficult to h:.rv-.st rnd
pre-'.re for Dulpin; particularlyy bark r,:movr.l), and (2) h.rd/ood fibers
arc short (on the ver?,~.. 1/25 inch long in cc..-.risn with I/q inch long
for sof+wfrod fibers) a:.d have bcn used stisf':.ctorily by conefvciio,.nl
methods only in a. few -rneks of parcr where strength is not irncrt-.nt. Th.
question then arises as to -.hCthcr these rcr.sons still liUnit "-rd '.-;ill
continue to handic-.n h-rdvwoods. The answer to this sucend qucstio:-n is t.-.t
har:":'od harv- sn; -in,-, will rroh.bly always be no e di rficult t I-.n softy-ood
hr.rv- st.,- nd that haf--v-od rulps will probably never find usa-.g, h'ire
the gratest str,.-.th is -rcrid,' but recent tcchnicr.l adv."ccs -.rd Ocrcclop-
mrnts hav~- consider-'.le' future -rontisc are sh,.'n h,: t .y for r:. -.uch

R' rnrt :-o. R1614


wider use of short-fiborpd hardwoods than in the Pnast. Discussion of a
few of these advances and developments will illustrate the possibilities
of increasing the use of hardv:oods in the pulp and pafer industry.

Hnrdwond harvestinir and processing is generally more costly
tl-an that of softwoods because har3w,,oods are heavier and more difficult
to saw, handle, and debark. Improvements in mechanization and integrated
legging are expected to reduce costs and difficulties. The hardwood
preling season is shorter than for soft-.'oods end hardwood bark is removed
with considerable difficulty at the mill. However, improved methods of
bark removal which may overcome this objection to hardw.oods arc being

Before the war hardwood pulps were used chiefly as soda -iul in
cert;.in grades of book, writing, and printin paryers, as sulfite pulp in
printing, writing, annd absor'x nt papers, fnd as semichemical pulp in cor-
rugating paper. The amounts of pulp made were not large and the use of
stmi chcmi cal pulp was the only substantial advance made since 1925. The
hardwood soda pulp was used because its soft and bulky nature and its
shnrt resilient fibers made nar, rs with excellent printing char:.ctcristics.
The sulfite pulp was used as a filler pulp to i-pro-:c; paper formation and
surface properties, mainly because of its short fibers. The hard:iood semi-
chemical pulps imparted a desirable stiffn,.ss to the corrugating paper.
All of these uses of the hardwood pulps depc.nded on specific character-
istics of the hardwood fiber. Th-so specific properties at the same time
limited the use of hardwood pulp to the narrow field where strength was not
important. There have been recent developments, however, that indicate
that pulps made from ha-rdwoods can find broader use, and that the nossi-
bilitirs of increasin- the utilization of hardwoods in the pulp and parer
industry are definitely brighter now than at any time in the past.

One important development in hardwood pulping has been the
demonstration that many hardwvoods can be pulped by lthF- conventional sulfate
process to produce pulps having considerable strength and wide use possi-
bilities. Heretofore, the sulfate process has been applied chiefly to
northern and southern pines to produce the strong pine kraft pulps used in
wrapping paner and container board. The hardwood sulfate pulps are much
stronger than the soda pulps. One large northeastern mill has proven to
its own satisfaction that bleached hardwood sulfate nulps can be used for
a majority of the outlets now served by bleached softwvood sulfite pulp
and has started construction of a mill to produce bleached sulfate from
birch, maple, and beech. At least two northeastern soda mills plan to
convert to sulfate pulping to improve the strength and utility of their
hardwood -ulns. During th. war i Wisconsin sulfate mill started usinr
aspen to furnish part of its wood supply when nine end spruce resources
failed. The benefits obtained exceeded expectations and the mill is
continuing the pulling of aspen. One larrc southern sulfate mill has
been pulping southern hardwoods for use in tissue papers; another is
pulping hardwoods for book paper. It has been shown experirentally at
the Forest Products Laboratory that certain proportions of hardwoods, say
10 percent, can be pulped in mixture with pine without sacrifice in pulp

Report No, R1614


quality. General use of even small proportions of hardwoods will provide
a possible outlct of as much as a -million cords annually in the oulp
industry in the; South, In a recent contest in Canada for the most nra-c-
tical method to us.. hardvwoods in ncwsprint manufacture, the prizc-_rinring
sugiestior entailed th-A use of scnibl-..a.chcd sulf.".tu pulp from birch, in
addition to asn, n groundwood -.uln to nro'idq 40 percent Dortion of
h'rdwcrodn in n,.wsprint. Thus, the sulfate pulping nroccss with little
c'r'inzc in corv,.:ntional oncra.tion offers sC.vcr.l. attrnctivL possibilities
for incr -sinr. har.-voood utilization.
'"ith sli-ht modifications, the sulfitc process also offers
possibilities for incr,-.sir., h.-.rd:ood utilization over nd above rcrescnt
use. Dur.in:. the :;ar period it was r( cognized that hardwood sulfite pulps
rradc accorr.inr- to the best practice h-d more use possibilities than r.rc -
viously rLlized. For exnle, the quality of birch s'-lfito pulp is not
far froi that o:' ".stern h.:mlock sulfite nulvn. 1r.rdrcood sulfite, rui! also
has certain qualities which makes it a rrornising material for ch,1:rcal
convey rsionr.

The c..n,.oc.tional gro-nd-..'vrod rulninp process likwv:isc offers
possibilities for the additional use of hardwoods. During thr war several
Wisconsin ,-ro'.ind':ood pulp mills used a.spn gre';dwcnd puln to gr-,at !d-.--.n-
t+,,c, -T. product nr-r, by one of the m-lls, a coat*.d beok r.n'r, contained
50 r rcont -.srcr V hile this usv,,e was compellAd by wartime dcnands,
certain definite advantr.tes have been reco_-.nizd and at l: .st a T-.rt of
the wartime 7<..;.,s in the rrr,,uction of a.spcn r'Tlrs ''-, the "-.ric'ur.i m-thods
is -". c4,-. to be continued,. Incid,-.ntally, the consum,'tion of asnen has
doubled during the last few years, and the information .obt4-r.i-ed by its
forced use will incrc."se the possibilities for its future utiliz'.tion.

By modifying the relatively new neutral sulfite sr.;michcri.;cal
pulping of hardwcods through ..ddition of a star.c of hlcaching, it is
possible to partially o'.--rcone the low stronmth of hr.rdwcod nulns.
Actu'-lly, hardwood pulps as strong as standard pulps from, many long-
fibered species have been m-ade in mill-scale dcnonstratior.s, Dev- lon-
ments in the s-nlichamical pulling process itself are being nursucd in
several places. One large southern -.ill has s+artcd c-r.struction of
pulpint facilities to produce hardvwce.d s,.'-i chemical c ulo fcr '.vidcr usagc
than heretofore on the basis of successful wartime -nrcration in a snr.llcr
southern mill, Exper;.,-nts at the For..st Froducts Larboratory hanc
-n.icated the possibility `* usir.g hardw-cd scr.ichcnical an-d roundwvood
r.,ips in mixture with softwood -ulps in the manufacture of r.cwsrrint,
Other w.r> at the Laboratcr-, h-,s shown that a lar1rE number of southern
hardwoods ar suitabl for -roducin- an excellent quality of ccrrug-.ting
-c rd fr.:ct s mic rical :ulp miAdc with sulfate rulpinf liquor.

During th last few y,-ars the use cf nrintine r.nycrs, partic-
ularly of hR coated t%.,p, for mq-cazinrs, .r.s increased ast'o-ishi.ngly and
hu-c q'u:.-.titics !.rr -v :-ct.. d to be used in thc future, Tho hardwocd pulps
have an excellent possibility of fitting into this ,x-ansion bK-cc.usL they

T.,:-ort ":o. R1614 -5-

improve printing qualities. Development work recently started has as its
purpose improving the strcrgth of hard&.vod pn'crs by use of resin bondin-g.
If successful, this will increase the utilization of hardwood rulns.

Finally, some of the most attractive opportunities for
utilizing wood waste and low-rrade material, including certain hardwoods,
exist in the field of coarse-fiber materials such as building board a.nd
z.per, insulatirng board, and roofing felt. Use of these products has
increased greatly during the. r.st few yaars and this rapid rxrpansion is
expected to continue.

Thus it appears that the possibilities of increasing the use
of hardwoods in the pulp and paper industry are more favorable now than
at any previous time. The problems connected with hardwood utilization
are far from solved, however, and considerable technical advancement is
still needed before hardwrods may be used to the best advantage.

Report No, R1614


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