Forest Utilization^ and Products of the Future

Research fer Temerrow

tomorrow. More efficient use also is Forest contributing to an effective extension of timber supplies. Future research will be focused on more closely matching product end- Wood use requirements with raw material quality and processing technology. In Utilization^ 1952, only 60 percent of the residues generated at forest-products manufac- and Products turing plants were used for other purposes, but in 1976 all but 4 percent of of the Future timber brought to the mill was used. H. M. Mon trey, deputy director, Nearly 60 percent of processing residues were used for pulp and about 20 Forest Products Laboratory, and John L Zerbe, manager, Energy percent for fuel. The remainder was exported or used in particleboard and from Wood Program, Forest Products Laboratory, Forest a variety of other products. In the future, more of the residues Service, Madison, WÍ are expected to go into composite panel products that may be used in #n the United States, wood is still a structural applications which previ- major construction and industrial ously required boards or plywood. material. Wood housing has been the Research over the past decade has mainstay of the American family from the time of the first European set- accelerated the manufacture of non- tlers, and it remains important to our veneered structural panels such as way of life. Today most of our hous- oriented Strandboard and waferboard. ing is predominantly wood framed. As for other particleboard and fiberboard products, manufacturing of Even single-family houses and low- these nonveneered structural panels rise apartment buildings with ma- does not require large or straight- sonry walls often have wood framing growing trees. Composite panel also behind the masonry veneer and fram- can be made from a large variety of ing in floors, partitions, and roofs. Re- species, including hardwoods, which sults of today's research in improving are often produced in excess. the use of wood from foundation to Growth and use of forest products rooftop will ensure an adequate sup- may be managed to enhance the en- ply of comfortable housing at a rea- vironment through resisting erosion sonable cost of construction in the by water and damage by wind. Well- future. managed forests also may help in soil The United States is fortunate that conservation by maintaining a desira- it also has adequate wood supplies. ble soil nutrient balance. Harvest rev- Improvements in harvesting methods enues may pay for better forestry and forest-management practices are practices as well as other forest uses helping hold costs of timber to afford- such as recreation. Research and de- able levels. Production of this versa- velopment efforts can lead to im- tile, renewable, and abundant mate- proved harvesting methods, higher rial now exceeds harvest, and levels of forest land management, and available supply is increasing by 1 increased benefits. percent a year. Today much of the ex- Just as housing construction has cess is in lower grade hardwoods been based on wood, U.S. industry (broad-leaved trees), but research also has long depended on wood as an im- is leading to ways of making these portant raw material. In 1972 the Na- trees attractive for use in products of

Forest Harvesting, Wood Utilization, and Products of the Future 2S3 Research for Tomorrow

energy crises of 1973 and 1979, generally use blades made of wood.

Mfood Use in Housing One of the most innovative uses of wood in housing construction and one likely to grow significantly in the future is wood foundations. Histori- cally, builders have contended that durable foundations have to be built of masonry. But research has shown that suitably treated wood and plywood foundations with proper drain- age of water away from the foundation wall can provide some economic, structural, and esthetic design advantages. Wood foundations should prove to be particularly beneficial in colder Spaceboard—a molded structural cUmates where they may be erected sandwich product made from paper—will during most of the year and easily fit- be used for a variety of applications, including wall and ceiling panels and ted with insulation. decking. Mfood Floor Framing. Wood floor framing has been improved recently tional Commission on Materials Policy with the acceptance of a construction found that, of the 21 tons of material method in which floor surfacing, per capita required annually in indus- such as plywood, is glued to load-car- trial operations, 9 tons were for fossil rying floor joists to provide composite fuels, % ton for metals, and 1 'A tons structural action. The result is more for forest products. Comparing dollar stiffness and strength with less mate- values for these materials is difficult, rial. Increased use is being made of but the value of primary forest prod- parallel chord trusses and I-beams, ucts is clearly comparable to that of particularly for long spans, as availa- metal products. bility of wide lumber decreases. In Besides its obvious uses in indus- the future, floor joists may be molded trial and consumer products, wood into structural shapes, such as I- has several intriguing applications in beams, from available particulate ma- national security and emergency pre- terial as is used in the manufacture of paredness. Wood is not comparable to oriented Strandboard. Already, the metals in importance for armaments first plant is being built to construct and ammunition, but it can replace framing members with an inner core scarce metals in other applications weaker material and an outer web of and has some unique uses for which stronger material. The plant wül metals cannot compete. Last year manufacture Com-PIy®, which forms marked the first time since World a rectangular cross section like con- War II that the Department of De- ventional lumber studs and joists but fense awarded a contract for mine- has a particleboard core and veneer sweepers, and these ships wül be surface layers. made entirely of wood. Successful large wind electrical generators, Wall Framing, Future wall framing which have been designed since the for houses wiU likely see more appfi-

254 OUR FOREST RESOURCES Research for Tomorroiv

The Truss-Framed System uses less lumber and requires tewer supports than conventional framing. cations of composites and other im- board is composed of three layers of proved structural shapes that may be aligned strands bonded together with fabricated from more abundant lower- a liquid phenoUc resin. The wood value materials such as strands from strands in the top and bottom layer hardwoods. A new product type from lay parallel to panel direction; those pulp fiber being studied at the Forest in the core lay perpendicular to the Products Laboratory shows promise panel direction. for building modules as well as im- In 1980, there was only one struc- proved paperboard containers. This tural flakeboard plant in the United product—Spaceboard—is a molded States. Today, there are over 15, and structural sandwich that has superior construction of other facilities has strength-to-weight characteristics and been announced. Future research will is not as limited in orientation to load lead to molded oriented strand prod- application as conventional framing ucts tailored for specific end-use materials. Engineered paperboard application. structures could become a reality and make better use of our wood re- Prebuilt Frames. A new develop- sources if adverse effects of moisture ment gaining acceptance for floor, and humidity can be overcome. waU, and roof framing is the Truss- Oriented Strandboard is a new Framed System developed by Forest product that fulfills a need for a com- Products Laboratory engineers. The posite panel board with mechanical system incorporates an open-webbed properties equivalent to those of floor truss, an open-webbed roof structural plywood. Oriented strand- truss, and conventional wall studs in

Forest Harvesting, Wood Utilization, and Products of the Future 255 Research for Tomorrow a unitized frame. These frames are New Ways to Use Hard- delivered prebuüt to the construction WOOdSm A new process, Saw-Dry- site and erected on the foundation. Rip, uses medium-density hardwoods The frame is constructed primarily to make structural-grade lumber, from 2 by 4 lumber instead of the which is normally made from scarcer more expensive and less available and more expensive softwoods. Cur- 2 by 8 and 2 by 10 lumber common rently, little or no structural lumber is in conventionally designed homes. made from hardwoods, in part be- Because the trusses can span the cause it warps and twists when it is v^idth of most homes, supports are sawed and dried conventionaUy. With not needed in the basement and load- Saw-Dry-Rip and with additional ben- bearing waUs are not necessary on efit from high-temperature drying, the first floor. This vñll provide for stresses in the wood are relieved and more flexibility in using space to best warp is reduced. This means the advantage. Future construction prac- wood is cut straight and stays tice will incorporate increased use of straight. this and other innovative modular Press drying of paper will also per- systems. mit the use of hardwoods for more As pressures build within the wood- conventional purposes, Traditionally, products industry to penetrate new papermakers prefer softwoods be- mai'kets, innovative building systems cause their fibers bond more easily will be developed to allow wood to than high-density hardwood fibers, substitute for steel in nonresidential which are short and stiff. By applying construction. heat and pressure to a wet web of wood fibers simultaneously rather Exferfor House Materials, Al- than separately, press drying pro- though the use of wood for exterior duces strong paper from 100-percent house siding has decreased, exterior hardwood pulp. forest-products finish materials will continue to be used extensively in Steam Injection Pressing, in house construction and their charac- the manufacture of waferboard, teristics will be improved. Since some particleboard, and medium-density type of finish is generally preferred fiberboard, a new steam injection for protection, performance, and ap- pressing process wül reduce press pearance of the wood itself whenever time up to 90 percent on thick wood is used outdoors, research ef- boards. With this new process, resin- forts are aimed at developing more re- coated flakes are formed into a mat liable pretreatments and finishes to and loaded into a press as in conven- increase wood's longevity. Better tional processes. Then, under com- paints, stains, water repeilants, and puter control, saturated steam is in- other preservative treatments will be jected into the mat. This permits the developed as weU as better wood and center of the board to quickly attain wood composite substrates on which high temperatures as the board is to apply these products. compacted, and the high temperature accelerates the resin cure. Besides re- Processing ducing the press time significantly, the process also permits use of Improvemmnts smaller equipment. The end result is Increased benefits should come from large savings in energy and capital improvements in processing wood costs. Steam injection pressing also raw materials to make the products can incorporate additives for greater better and more economicaUy. durability and fire resistance.

25@ OUR FOREST RESOURCES Research for Tomorrow

Automation of Lumber Pro- Modem engineering design practices ducfjon. Perhaps the greatest im- require a more precise estimation of provement in wood processing will be lumber properties than can be full automation of lumber production, achieved with current procedures. To- since lumber is the most important day, strength properties are usually manufactured solid wood product. assigned by visual grading and corre- Wood processing centers will depend lating appearance with recorded val- less on human decisionmaking and ues from tests of specimens that did physical labor. Skilled technicians will not have apparent strength-reducing monitor the automated operations us- characteristics. In the future, we will ing advanced computerized devices. see more improved systems for auto- These techniques, coupled with state- mated lumber grading in which of-the-art processing techniques such structural pieces are nondestructively as laser cutting and use of advanced evaluated and assigned strength val- cutting materials, show much prom- ues. As characteristics of the softwood ise for the future. resource change because of increasing volumes of plantation-grown Advanced Drying Technol- trees, automated lumber grading will ogy. For wood to perform satisfactor- become pervasive. ily in many applications, it must be dried to a moisture content in har- Industrial Chemical mony with the environment where it is used. Otherwise, splitting, twisting, Products and shrinking, swelling, and warping in Biotechnology place will cause problems. Advanced The promise for industrial chemical drying technology should result in and biotechnology products from improved quality and shorter drying wood is bright. Industrial chemical times. Savings will then result from products from wood have a long his- elimination of drying defects, conser- tory and form the basis for the large vation of energy, and reduction of pulp and paper industry and other storing and handling costs. significant segments of our economy. Design Improvements Research is building on this foundation to provide successful new prod- Because of past utilization practices, ucts to replace those made from pe- much of the hardwood forest is com- troleum and other materials. Products posed of low-quality trees. So it is be- from biotechnology are just beginning coming increasingly important to use to leave the laboratory, but success in this lower value material more effec- areas such as waste treatments is an tively. Haivesting removes only about indication that this technology will half of the woody material, and each have a strong impact on our future subsequent step in the processing progress. chain generates additional residues. Some industrial chemical products Even the best grades of wood are not from wood are such diverse, long- used to maximum efficiency because established commodities as charcoal, we do not know enough about wood's rayon, and natural rubber. An exam- material properties. ple of a product from biotechnology For the future, reconstituted panel that has penetrated the market is and fiber products provide an oppor- mushrooms grown on wood. tunity to produce engineered mate- The potential for increased use of rials that optimize particle or fiber wood for industrial chemicals and properties to meet specific end-use products from biotechnology is closely requirements and reduce overdesign. tied to the productive potential of

Forest Harvesting, Wood Utiiization, and Products of the Future 2^7 ñesBBrch for Tomorrow

Futun Pfoaueî PommiMIitíms

Millwork Parts

Purlins Utility Poles, d5 Crossarms, Lighting Standards wood biomass systems. Approximately esses are being improved to make this 20 billion dry tons of standing ligno- feasible. Extracting ethyl alcohol firom cellulosic biomass in the United wood is based on a hydrolysis process States could be doubled or tripled known for 150 years, but improve- with intensive forestry. Each year ments in the common chemical re- about 6 mulion dry tons of wood are action with water in the presence of generated and recycled to the soil acid catalysts are making the end without further use. Shrubs, small product more competitive with ethyl trees, bark, foliage, and harvesting alcohol from other sources and with residues occur in large quantities in other fuels. many localities. Much of this woody A significant new development is biomass is suited for use in industrial the proven feasibility of biological en- chemical or biological products. zyme hydrolysis of cellulose, which Among the products that will be comprises about 50 percent of wood, derived increasingly from wood are to glucose. Glucose is a sugar that fuels, pharmaceuticals, adhesives, can be fermented readily to ethyl al- plastics, and resins. New chemical cohol. Biological enzyme hydrolysis and biological modification of wood can convert 80 percent of the cellu- and paper will produce materials that lose, while acid hydrolysis, in its pres- are more moisture-,fire-, and decay- ent state of development, converts resistant. only about 50 percent. Perhaps of even more significance, Fuels. Fuels are an obvious outlet biotechnology research at the Forest for some of the presently unused Products Laboratory and elsewhere wood that can be chemically or bio- has shown how to ferment another logically processed but is unsuited for sugar, xylose, to ethyl alcohol. Xylose lumber, veneer, paper, or other con- is a common derivative of hemicellu- ventional products. Alcohol fuels for lose from hardwoods. (Hemicellulose blending with gasoline are derived makes up about half of the noncellu- from wood in insignificant quantities losic portion of wood; the other main (4 to 5 million gallons a year) but in constituent of wood is lignin.) the future this output is likely to in- Other alcohols that are used increase many times. creasingly as octane enhancers with Both chemical and biological proc- gasoline are methyl alcohol and butyl

258 OUR FOREST RESOURCES Research for Tomorrow alcohol. Another name for methyl al- a simñar chemical from more expen- cohol is wood alcohol, as it was origi- sive soybeans, freeing up the soy- nally made from wood. Now it is beans for food and animal feed. Other manufactured more economically related sterol compounds may be from natural gas, and it also may be used as emulsifiers, emulsion stabiliz- made from coal. Nonetheless, methyl ers, viscosity modifiers, and emol- alcohol from wood is a potential fuel lients in cosmetics. The chemical L^ of the future, either for use in blend- dopa, for treating Parkinson's disease, ing with gasoline or without mixing also can be derived from trees. with other fuels. Even today, racing It is impossible to tell how many cars run on methyl alcohol or metha- diseases may be treated with pharma- nol, terms that are used interchange- ceuticals derived from the forest, but ably. It is now possible to ferment species diversity in our forests must butyl alcohol from wood, and this be maintained so that the potentially product will likely become more com- beneficial chemicals contained in dif- petitive in the future. ferent trees will not be lost through their extinction. Many of our medi- Gases and Oils. In the future, cines have originated from plants, in- gases and oils will be derived from cluding trees, and this pattern is forest prcxlucts. Gases are obtained likely to continue. mainly through pyrolysis processes in which wood is heated in the absence Adhesives and Other Prod' of sufficient oxygen for combustion. ucts from Lignfn. The lignin frac- Other products such as charcoal also tion of wood has long been a tempt- may be produced, or the wood is con- ing, but mostly unproductive, subject verted almost wholly to gas. The gas of research in our quest for valuable is most commonly generated as alow chemicals. Today some 20 million dry or medium heat-value gas. A high tons of lignin from pulping operations heat-value gas comparable to natural go unused each year. The lignin by- gas could be obtained only through product of kraft pulping operations is an additional enrichment process. used for fuel. Hydrocarbon oüs can be obtained Waste pulping liquors are processed through naturally occurring chemi- on a small scale to produce commer- cals contained in some trees. One ex- cial vaniUin, dimethylsuLfoxide, and ample is the seed of the Chinese tal- lignosulfonates, but in the future low tree, introduced to the United other products are ñkely to lead to States by Ben Franklin in 1763. It more intensive utilization. VaniUin is has become naturalized throughout important for flavoring, but it is used most of the coastal South and in in such smaU quantities that it does moist parts of southern California. not constitute a major market. Di- methylsulfoxides and lignosulfonates Pharmaceuticals and CoS' have greater established and potential meticSm Among the possible medici- markets as ou field chemicals, surfac- nal chemicals to be derived from tants, dispersants, binders, concrete wood in the future are steroids for admixtures, and sequestering agents. such uses as contraceptives, cortico- Among the most promising prod- steroids, and geriatric drugs. Steroids ucts from lignin are adhesives, phe- are obtained from tail on, an impor- nolic compounds, toluene, and ben- tant extractive compound found in zene. Adhesives derived from wood pines and some other softwood spe- Mgnin are likely to be substituted for cies. Tall oils contain phytosterol for the durable phenolic adhesives now steroid production, which can replace used in the manufacture of plywood.

Forest Harvesting, Wood Utilization, and Products of tlie Future 2B9 ñesBarch for Tomorrow

Other adhesives may be produced hol. In another approach, butane-2, from the tannins and carbohydrates 3-diol is derived from wood through in wood. biological fermentation and used as a The study of biotechnical ap- precursor for synthetic rubber. proaches to converting byproduct lignins to more useful products has only Oleoresins. Oleoresins from tall oil begun. In the future, Hgnin will be and other wood extractive fractions biodegraded to produce many diverse are another reservoir of chemicals for low-molecular-weight products. On the future. Among the products that the other hand, retaining the high- can be derived from them in addition molecular-weight character of lignin to the medicináis and cosmetics men- without breaking it down while tioned previously are adhesives, spe- speeding other chemical interactions cial plastics, and high-value fuels. to provide useful compounds similar to plastics might turn out to be more Food. The concept of feeding ani- advantageous. mals and people from wood is another area in its infancy. Today, the field is Plastic and Plastic Fiber limited to yeast from some pulp mill Products. Although wood is a mag- wastes and molasses from hemicellu- nificent competitor for many plastics lose obtained as a byproduct of hard- in its own right, it is likely to be used board manufacture. Mushrooms are more as a feedstock for synthetic raised on wood substrates to a limited plastics in competition with plastics degree in the united States. Only made from petroleum. Today, polyeth- now has the shutake mushroom in- ylene made from petroleum is the dustry established a foothold, but fundamental building unit for many there is a good opportunity for this in- plastic products, but wood is becom- dustry to benefit from new technol- ing more nearly competitive for this ogy, grow, and displace shiitake market. When oil prices were ap- imports. proaching $40 per barrel, it might Special sugars and related chemi- have been practical to make ethylene cals from wood have advantages over and polyethylene from wood through more conventional products. XyMtol an intermediate ethyl alcohol hydroly- and sorbitol can displace sucrose and sis. As the technology for making help in preventing tooth decay. Glu- ethyl alcohol from wood is improved, cose also has special dietetic the feasibility of deriving polyethylene applications. plastics from wood is enhanced. Other plastic and plastic fiber prod- Other Chemical Products, ucts normally made from wood are Among other potential growth chemi- cellophane, cellulose acetate, and cals fi'om wood are glycerol for explo- rayon. Wood was originally used in sives, tannins for curing leather, am- the manufacture of nylon fiber and is monia and urea for fertilizer, and likely to be used more in the future, if high-quality wax for special applica- a precipitating agent such as furfural tions. Organic acids such as formic, can be made economically from wood. acetic, propionic, saccharinic, suc- Presently, wood hemicellulose can be cinic, and many others are likely to used to produce this agent. be derived from wood and to substitute for organic acids from other Rubber. Synthetic rubber also may sources. These acids may be used in be produced from wood. Normally the manufacture of many other prod- this product is made from butadiene, ucts. As an example, acetic acid may which can be derived from ethyl alco- be processed to such consumer com-

260 OUR FOREST RESOURCES Research for Tomorrow modities as vinyl and ceDulose demonstrated that a virus can kill the acetate. fungus that causes chestnut blight. In the processing of wood, biotech- Siotecfinofogy Applications, nology will affect how pulp and paper Many other biotechnology applica- are made. For instance, pines engi- tions can add to the quality of life in neered to overproduce turpentine or the future. Trees of the future will be pulpwood with a lowered lignin con- superior to those of today, partly be- tent will have to be pulped differently cause biotechnology promises to de- from the way today's wood is pulped. crease the time required for identify- Because certain micro-organisms can ing and propagating selected better partially break down the cell walls of trees, and plant tissue culture will wood, biological (nonchemicai) pulp- provide alternative means to clone su- ing may be possible in the future. perior trees, Traits such as growth ef- Pulp and paper mills also produce ficiency, photosynthetic efficiency, much more waste than the lignin stress tolerance, and resistance to dis- mentioned previously. Based on the eases, frost, drought, salinity, herbi- sizes of U.S. industries and the char- cides, and heavy metals and other acteristics of the waste streams, 1.2 chemicals may be screened in tissue million metric tons of sugar could be culture. available annually from sulfite pulp Biological fixation of atmospheric miUs in North America, and about 1.5 nitrogen has the potential to offset million metric tons of ceUulosic mate- the need for commercial nitrogen fer- rial could be recovered from primary tilizers. It should be possible to de- sludges in kraft pulp muls. Hardboard velop nitrogen-fixing clones of the and insulation board plants produce best tree species that already absorb about 150,000 metric tons of nonuti- nitrogen from the air and fix it in the lized sugar annually. Each of these ground, it may be possible to create byproduct streams could be used for hybrids between species that fix ni- the production of numerous fermen- trogen and other trees that are desira- tation chemicals or microbial protein ble for different purposes. Better with the application of biotechnologi- strains of bacteria that fix nitrogen cal processing. Because lignins do not can be developed. serve as growth substrates for mi- Growth of forest trees may be im- crobes, their use as substrates for proved in the future by inoculating conversion to protein or other fermen- the sou with mycorrhizae, or root- tation products is apparently not pos- fungus structures formed by special sible without extensive pretreatment. types of fungi. Experiments on inocu- The pulp and paper industry al- lation of southern pines with selected ready depends on microbial technol- strains of the fungus Pitholithus tinc- ogy to treat its manufacturing wastes, torius have dramatically increased and microbes are being improved to survival and growth on adverse sites. degrade specific industrial wastes or Spraying chemicals on forests to recalcitrant products. The Forest control insects or disease has met Products Laboratory, in cooperation with only limited success, is environ- with North Carolina State University, mentally questionable, and is often has recently investigated the use of not cost-effective. Biotechnology can white-rot fungi, which degrade lignin, play an important role in developing to decolorize the highly colored first pest-resistant varieties of trees and bio- extraction-stage effluent of pulp miHs. logical control agents, particularly for This process holds much promise for insect pests and, possibly, for forest successful commercial use in the diseases. Italian researchers have future.

Forest Harvesting. Wood Utilization, and Products of the Future 2Bi