Reprinted from the JOURNAL OF FORESTRY

Vol. 76, No. 12 December 1978

Peter Koch

ABSTRACT - Mi.f~d south~rn pin~-hardwood stands now yi~/d 20 to 22perc~nt of th~ir biomass in wood prod-ucts. A n~w ~n~rgy s~lf-suffici~nt sys-t~m using tr~~ pull~rs. w~t-fu~1 burn-~rs. mobil~ chippen. shaping-lath~h~adrigs. and continuous kilns canconv~rt 67 perc~nt of th~ biomass(abov~- and ~/ow-ground parts oftr~~s of all speci~s) into products worthabout $150 per dry ton. Products ofth~syst~m ar~ pall~ts; dow~I-Iaminat~dcross ties (no adh~sive); structural ~x-terior jlak~board; structural lum~rglue-laminat~dfrom vene~r; studs; andhogg~d fuel for plant ~nergy. Compo-si,~ structural pan~/s or fi~rboardscould be made also. Application of th~system could provid~ high r~turns toprivat~ landhold~rs whi/~ halting incur-siQn of low-grad~ hardwoods into th~south~rn pin~ry.

plete biomass harvest followed byimmediate replanting, will not beattractive to all landholders. If re-muneration to the landholder is suf-ficient, however, significant ac-reages should be available. An in-dication of the return required toinduce such commitments issuggested by the market for indus-trial and utility bonds. Well-ratedbonds redeemable in 30 years sellbriskly if they yield 10 percent an-nual interest. Should not a com-mitment of land for 30 years also bepopular if annual rent is 10 percentof market value today? At bondmaturity the investor receives onlyhis purchase price in dollars unad-justed for inflation; the landownerwho makes a 3O-year rental agree-ment continues to hold his land-thus protecting himself against in-flation.

To contribute significantly tosolution of the hardwood problem,large acreages must be treated. Inthe concept I propose, the man-ufacturing plant will annually useabout I ,800,<XX> hardwood and pinetrees with total ovendry biomass ofabout 585,<xx> tons (650 pounds pertree) cut from 18,<xx> acres (100trees per acre). Over a rotation of25 years, total cut would be45,<XX>,(XX) trees harvested from450,<XX> acres. If centrally locatedin a procurement area 106 miles inradius, the plant could be suppliedfrom 2 percent of the gross area.

As explained in another article(Koch 1976a, part III), a rental of$23 per ace per year, i.e., 10 per-cent of an estimated average valueof $230 per acre, would not result inexcessive stumpage costs; annualstumpage, including regenerationcosts, would total only $5,184,(XK)while annual sales of wood prod-ucts would total about $58,793,(XK).This very low ratio of stumpage

In the opinion of many managersof southern pinelands, invasion byunwanted low-grade hardwoods-to the detriment of pine growth-istheir major silvicultural problem.This statement applies over most ofthe 73 million acres in the southernpinery. On average, about 0.8 tonof hardwood biomass grows forevery ton of pine biomass (biomassis used here to mean all above- andbelow-ground parts of trees).About half of this hardwood vol-ume is in II oak (Quercus) species,with sweetgum (Liquidambarsryraciflua L.) and hickory (Caryaspp.) also comprising importantfractions. About half the volume isin trees 5.0 to 10.9 inches in d.b.h.,with the remainder about evenlydivided between trees 11.0 to 14.9and trees 15+ inches in d.b.h.(Christopher et al. 1976, Murphyand Knight 1974).

The difficulties in utilizing thishardwood resource are many.Trees are often scarred and defec-tive from fires and from previous

pine harvesting. They are slowgrowers because the sites are notright for them-trees 6 inches ind.b.h. are typically 40 years of age(Manwiller 1974). They are shortand crooked in bole. The low cubiccontent per stem, the highly vari-able species mix from stand tostand and even from site to sitewithin stands, and the low cubicvolume per acre all combine toraise harvesting costs. Moreover,their value after harvest is low.Knots and other defects, shortboles, and small diameters pre-clude any hope of sawing qualitylumber in conventional lengths.Not least among the problems isthat of maintaining a species mixsuitable for a manufacturing opera-tion (Barber 1975).

Because of the vast area in-volved, the huge volume of unusedhardwood biomass, and the diver-sity of species, solutions should beappropriate for extensive acreagesand designed to use very largenumbers of trees of all species andsizes. Intensive harvests and clearfelling will likely be the pathway toany such solution. Because of landholding patterns, equipment andprocedures must also permit eco-nomic harvests of tracts as small as40 acres.

To increase pine growing stock,the clearcut land should bepromptly planted or seeded. To ac-complish this, I propose the con-cept of leasing land for immediateclear felling and harvest ofbiomass, followed by replanting tosouthern pine, periodic thinning,final harvest of pine, and a secondplanting of pine-a1l at the expenseof the company to whom the leaseis given.

Solutions that require 25- to 35-year commitment of land, com-mencing with more or less com-

December 1978/JouRNAL OF FORESTaVn67

and regeneration costs to gross an-nual sales is achievable becauseharvest is intensive and manufac-turing procedures waste littlebiomass.

. -

Present and Proposed Use asBiomass

Components of southern pinebiomass are as follows (Howard1973):

Percent

The Concept

More complete harvesting andutilization of all species from thesouthern pinery will permit mills tokeep up with the increasing de-mand for wood products. The fivenew machines and six products thatI will describe are the elements of aconcept that make such intensiveutilization feasible. Implementa-tion of the concept, called BiomassRetrieval and Utilization withShaping-lathe Headrigs (BRUSH),can triple the commodity recoveryon southern forestland. And themanufacturing plant should beself-sufficient in energy.

The machines and products areas follows:Machines

I. Tree puller (harvests centralroot mass along with stem)

2. Mobile chipper (recovers tops,branches, and standing cull trees)

3. Green-fuel burner (bums wetwood and bark that has been ham-mermilled into small particles)

4. Shaping-lathe head rig (makescants. cylindrical peeler blocks forveneer. and flakes for structuraltlakeboard)

5. Continuous dry kiln (driesstraight 2 by 4 or 2 by 6 studs madefrom juvenile southern pine wood).Products

1. Pallets2. Dowel-laminated crossties (no

adhesive needed)3. Structural exterior tlakeboard

from mixed species4. Lumber laminated from ve-

neer5. Studs6. Hogged fuel for plant energy.In the BRUSH system, as

schematized in figure /. hardwoodand softwood biomass from acresharvested enters the mill as tree-length stems (with central rootmass attached) or as chipped woodfrom tops and standing culls.

of paper for each pound of stem-wood pulped, and for every poundof pine perhaps 1/4-pound ofhardwood is pulped. Output ofpaper expressed as a percentage oftotal biomass of cordwood stands isabout 20 percent.

As the BRUSH system can re-cover about 67 percent of treebiomass of all species as solid woodproducts (table 1), worth in early1978 at least $150 per dry ton, theyield would be three times that cur-rently available in sawmills (67 +22 percent) and 3.3 times that ob-tained in kraft pulp mills (67 + 20percent).

can be accomplished promptly.The mobile chipper is being de-veloped by the Southern ForestExperiment Station in cooperationwith Nicholson ManufacturingCompany, a consortium of fiveforest products companies, and theDepartment of Energy .

At the mill the chips are screenedand the fraction that is bark-freeand clean-about half of thetotal-is processed through a ringflaker (a machine that convertschips to flakes) for inclusion in theinterior layer or core of structuralflakeboard. The other chips areburned for fuel.

Full-length stems, on arrival atthe mill, are conveyed through themerchandising deck, where rootsand bark are removed. The barkand most of each root are used forfuel in a burner under developmentby the Southern Forest Experiment

--'50 percent recovered as flekeboerd fur.ni.h.'25 percent recovered as flekeboerd fur.nlsh.3The. residues recycled by flberlzlngend using .. f/8keboerd furnish.4Most of this, except foliage, ends e. fuel.

-

.-

How BRUSH WorksTrees S to 12 inches in d.b.h. and

of all species are harvested, withthe central root mass intact, by atree puller developed cooperativelyby the Southern Forest ExperimentStation and Rome Industries (fig.2). Trees larger than 12 inches arecut 6 inches above ground level.Tops and limbs are severed on thesite, and full-length stems (includ-ing central root mass) are skiddedto roadside and transported to themill.

Tops, branches, brush, and allresidual standing trees are chippedin place with a mobile chipper (fig.3), and the chips are hauled to themill. Thus, site preparation for re-generation is simultaneous withharvest, and planting or seeding

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Figure J. Mobile chipper and forwarders for retrieval of cull trees and loggingresidues. The machines are capable 0/ traversing an acre an hour and deliveringchips to roadside inventory (Koch and Nicholson /978).

December 1978/JOURNAL OF FORESTRVn69

-~--. / =-~'~~-

Station and Moore-Oregon (fig. 4);about one-quarter of each root be-comes core flakes.

The few high-grade sawlogs andveneer logs in the hardwood stemsare removed and resold. Remaininghardwood logs down to 8.S inchesin diameter are cut in 8.S-footlengths and a shaping-lathe headrig(fig. 5, bottom left) converts them

Figure 4. Suspension burner for hog-ged green wood or bark. Exiting hotexhaust gas can dir~ctly h~at kiln. orcan heat a boil~r to produc~ steam forproc~ss U$~ and pow~r g~neration.Left: Diagram offlow offu~l, combus-tion air, and exhaust gas. Right: Com-pl~tt' burnt'r operating in North Port-land, Or~gon, test facility (Koch, Day,and Jasp~r 1978).

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I Fig urt' 5. Schematic of shaping-latht' ht'adrig and thrt't' configurations for making cants or cylinders plus flakes. Top '-.It: A camarrangement governs shapt' and dimensions of product. Top rir6t: Machine for logs 40 to 53 inches long and 4to 12 inches indiamt'ter; it is primarily a pallet-cant producer. Bottom kft: Nine-foot model for production of railroad cross tit's. posts, andcants to be resawn from logs 6 to 9 feet long and up to 15 inches in diameter. Bottom Ii",,: Roundup machine to produce flakesplus perfect cylinders, i.e., peeler bolts, from logs 8~ feet long and up to 30 inches in diameter. For description of these

I mac~!.set' Koch (1975), Koc_h and Caligh~ (1978), Sprlngale (1978),~pringale et.!!'. (1978).

77WJOURNAL OF FoRESTRv/December 1978

Figure 7. Whensquare-edgedlumber is rippedfrom the center ofoctagonal cantsand bevel-edgeddeckboards arecut from outerportions. lumberrecovery fromdiameter-sortedlogs should beabout 7.5 boardfeet of ~inch-thick boards percubic foot of log.Properties ofsouthern hard-wood pallets aredescribed by Stern(1979).

:t';~

~

Figure 6. Cants produced on theshaping-lathe headrig may be rectan-gular or octagonal as well as square.hexagonal. or round. Flakes residualfrom the machining operation are typi-cally 3 inches long and 0.015 or 0.025inch thick. With addition of phenol-formaldehyde resin, these flakes can behot-pressed to yield exterior structuralpanels of exceptional strength anastiffness (Hse et al. 1975, Price 1978).

T

eer faces over a flake core will bemarketed to compete withplywood. Only slight revision ofthe layout shown infigure 1 wouldbe required to manufacture suchpanels. To this end, logs would berounded on a shaping-lathe to per-fect cylinders (resulting flakesgoing into panel cores) and thesecylinders rotary-peeled to yieldpanel faces. Springate (1978) andSpringate et al. (1978) have ex-plained the profit potential of sucha manufacturing system.

Fiberboard .-Also, with addi-tion of disk defibrators, tiberboardsof low, medium, or high densitycould be manufactured from flakesand residual chips instead of thestructural flake board called for infigure 1 (Woodson 1976a, 1976b,1977; Suchsland and Woodson1976).

four or five 8.S-foot hardwood logsper minute large enough (8.5 inchesminimum diameter) to contain ahalf-tie and four or five 8-foot pinebolts large enough to be peeled (8-inch diameter or larger). Thus, one8.S-foot crosstie headrig would berequired for hardwoods and one8-foot roundup headrig and a rotaryveneer lathe for pine.

Since the rotary veneer lathewould turn out four or five pineveneer cores per minute and themerchandising deck would deliverfive or six pine stud logs per min-ute, two more 8-foot headrigswould be needed to make cantsfrom which studs could be resawn.

Finally, one might expect thatthe tree merchandising deck wouldyield 15 to 18 bolts per minutemeasuring 40 to 53 inches long and5 to 8.5 inches in diameter; conver-sion of this boltwood (mostlyhardwood) would call for three 54-inch shaping lathes.

Total headrig complement wouldtherefore be seven shaping lathes:an 8.5-foot crosstie machine, an8-foot roundup machine, two 8-footcanters for studs, and three 54-inchmachines for pallet cants. Addi-tionally, an 8-foot veneer lathewould be required, as well as cantresaws. These machines wouldproduce about 585,000 tons ofproduct annually (table 2) and beenergy self-sufficient.

Alternative Products

Composite panels .-It is possi-ble that, rather than flakeboard, astructural composite panel of ven-

into high-quality flakes for outer-most face layers of structuralflakeboard and cants (fig. 6) thatare later dowel-laminated into 7- by9-inch mainline crossties (Howeand Koch 1976).

Hardwood bolts 5 to 8.5 inchesin diameter are converted on a .54-inch shaping-lathe headrig (fig. 5,top right) to face flakes and palletcants for deck boards and stringers(fig. 7). Hardwood less than 5inches in diameter and any boltscontaining rot are chipped andring-flaked into core stock.

With pine, 8-foot logs withdiameters as small as 8 inches arerounded on a shaping lathe (fig. 5,bottom right), producing faceflakes and perfect cylinders to bepeeled into 1/4-inch veneer. Theveneer is then parallel-laminatedinto structural lumber of any de-sired length or width (Koch 1973).Veneer cores and small pine logsare converted on another shaping-lathe headrig into face flakes andcants for resawing into 8-foot 2 by4s to be kiln-dried under restraintto yield straight studs (Koch,Wellford, and Price 1978). Verysmall bolts are chipped and ring-flaked into core flakes. Theshaping-lathe headrigs in three con-figurations (crosstie or stud, palletcant, and veneer bolt roundupmachines) are being cooperativelydeveloped by the Southern ForestExperiment Station and Stetson-Ross Machine Com~y.

Shaping-lathe headrig capacity.-Six trees per minute crossing themerchandising deck could yield

ConclusionThe flexible system that I have

proposed can yield a range ofcommodities that would satisfymajor product demands on south-ern forests and triple commodityrecovery from them. Other reasonsfor seriously considering the pro-posed manufacturing system are:

eThe raw material is nowunder-used and is available in manysouthern (or eastern) locations.

e Recovered but unused treeportions amounting to nearly200,(XX) dry tons annually (table 2)should be adequate fuel for energyself-sufficiency in the manufactur-ing plant.

e Marlcets for the products

December 1978/JOURNAL OF FoaEsravml

. The processes are nonpollut-ing.

. Ecologically and silvicultur-ally, the processing cycle is sound.As duff and foliage on the forestfloor would not be harvested, nu-trient cycles should not be upset

beyond ready remedy.. Raw material feeding the sys-

tem will be regenerated at an ex-panding rate.

. The system appears capable ofalleviating impending nationalshortages of sheathing, long andwide structural lumber, cross ties ,and pallets.

. The intensive utilization pro-posed should yield generous net re-turn to the landholder, thereby en-couraging increased productionfrom now poorly managed privatenonindustrial woodlands in theSouth.

. Yet, cost of raw material tothe mill is low.

. Application of the BRUSHsystem would halt incursion oflow-grade hardwoods into thesouthern pinery. .

should be strong.. The manufacturing processes

are simple.. The processes have minimal

water demand.. Degree of utilization of the

wood resource is high.

BADEa, J. C. 197~. UtiliDtioo of laId~sIIOWiIII ~ .-hem p8Ie sita-lial8ties ~aaeta. FPRS Scp. MS- 75-5$8. 4 p. For. Prod.Res. ~.. Madison. Wis.

CHalln)ptl8a. J. F.. H. S. STBaNrrzu. R. C.BELTZ. J. M. EAILEI, 8M! M. S. HEDLUND.1m. H81d~ dI~ WI piM si1CI inthe South. USDA For. Serv. Resour. Bwl.50-59. 27 p.

HowARD. E. T. 1973. PbysaI .xl clIemicaI~rtieI of slash pine ~. Wood Sci.~:312-317.

HoWE. J. P.. P. KocH. 1m. Dowel-~ ~rf-- .. .fVU;.tedlJM)k)8y for fa'-icatiml. futln pr0m-ise. For. Prod. J. 26:23-30.

HIE. C. Y.. P. KOCH. C. W. McMILLIN. aIMt E.W. PaK:Z. 197~. LaI.H8tory-«ale develop-n.nt of a ItnlCtuni exterior ftlkctxl8ld from~ 8nJWiDa ~ southern iMne lites.For. Prod. J.lS:42-~.

KOCH. P. 1973. StnEtural hlmber iam8ated from~ch rocary-peeled a}Uthem pine veneer.For. Prod. J. 23:17-25.

KOCH. P. 197~. SbIIIi-.-adle ~ - aim-_rdally available. Salah. Lamberman231:93-97.

KocH. P. I~. Pan 1.-Key to utiIiDticx1 ofhaldwoodl ~ p8Ie sites: die SMPIII-I8tiIe~. For. I"'. IO3:"~I. Pan ".-NewappoaclIel. new madIi-. to IItiizehaIdwo<KiI ~ .._li_. For. I"'. IO3:22-lS.Pan III.-AD pI1)'*IeI ~ ~ize haId'MMIdIon pme lites can be ~ned. For. Ind.103:24-27 .

KocH, P. 19M. New ~ for ~~ .1 with t8I'to« aItKbed ~ ex-tend I"IIPwood - lilnificantiy. P.«I~ In ApPied Polymer Symp)Iiam 28.~ WIley - Sc.-. *.. New Y~.

KocH. P. 1977. HarveatiJW IOudIem ~-. with

Z8IUt 0( ~ ~..' C. W. McMilI8l.ell. For. PnMI. Rei. Soc.. Madison. Wis.

SralNG-'n. N. C., I. PLouGH, aIMi P. KocH.1978. Sh8P8I8"8dIC nII8MkIP n8d1iIe is Ky 10pv6tab1e nl8alfKWIe 0( axnlMJlite .-th~in M..I8CbI8eUI for Maine. For. Prod. J.28:42-47.

SrDN. E. G. 1979. ~ 0( .. by 4O-8IChI8iIed .-lieu 0( 22 soud'8m h~s. Va.PoIytech. Inlt. W~ Res. Lab., Blacksblil1.Misc. Bid! (in ~).

Suc~D. 0., aIMi G. Woo~. 1976. ~el1ies 0( ~tm-d_ity tRJeltM)8rd pnMi\a:edin an oil-heated I"-8fOIY S--. USDA For.Serv. Res. P8P. ~116, 10 p.

Woo~, G. E. I,.. E&cts of but, demayprUiJe. aIMi resin content on medil8ll-ilensicy6be~ from ~uthcm a.nIwoodI. For.Prod. J. 26:39-42.

WOOl*>N, G. E. 197ftI. Propeniel 0( medium-density ~IM related 10 hardwoodlpec'C£ arav'ay. P. 175-192 ill PrIM:. ICkhW8Ih. State Univ. S~. on PartideIx8ld,Nm... Wash.

W~. G. E. 1977. Mediwn denlky ft.bertx.ld fnxn mixed ICMIdIem ~. P.131-1«> ill PrIM:. 11th Wash. ~ Univ.Symp. on Panicletxlanl. NIman. Wash.

THE AUTHOR - Peter Koch is chiefwood scientist, Forest Pnxiucts Utiliza-tion Resean:h, Southern Fmat Experi-ment Station, USDA Forest Service.Pineville, Louisiana. The paper waspresented as the Fourth Annual Com-plete Tree Institute Lecture at the Un;-vesity of Maine at Orono, October 20.1978.

Purchased by the forest ServIce, U.s. Depanment of Agriculture, for oHlcial use.

772/JOUaNAL OF Fo8EITRv/December 1978 '.

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