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'^BUCUBRMW APR 1. s 1986 ..-*s» UTILIZATION OF HARDWOODS GROWING ON SOUTHERN PINE SITES Peter Koch Southern Forest Experiment Station Agriculture Handbook No. 605 Volume III of three volumes: I The Raw Material II Processing III Products and Prospective U.S. DEPARTMENT OF AGRICULTURE, FOREST SEVICE For sale by the Superintendent of Docunnents, U.S. Government Printing Office Washington, DC. 20402 2543 CONTENTS VOLUME III— PRODUCTS AND PROSPECTIVE Page PART V— PRODUCTS 22 SOLID WOOD PRODUCTS 2546 23 FIBERBOARDS 2735 24 STRUCTURAL FLAKEBOARDS AND COMPOSITES 2897 25 PULP AND PAPER 3075 26 ENERGY, FUELS, AND CHEMICALS 3149 27 MEASURES AND YIELDS OF PRODUCTS AND RESIDUES 3247 PART VI— PROSPECTIVE 28 ECONOMIC FEASIBILITY ANALYSES 3492 29 TRENDS 3579 INDEX 3641 GENERAL 3641 SPECIES 3675 2544 PART V— PRODUCTS Chapter Title 22 SOLID WOOD PRODUCTS 23 FIBERBOARDS 24 STRUCTURAL FLAKEBOARDS AND COMPOSITES 25 PULP AND PAPER 26 ENERGY, FUELS, AND CHEMICALS 27 MEASURES AND YIELDS OF PRODUCTS AND RESIDUES 2545 22 Solid Wood Products Eight sections or subsections in chapter 22 are condensed from other work as follows: Section Source 22-1 STRUCTURAL COMMODITIES- WOOD AND NONWOOD Boyd et al. (1976) 22-2 WOOD AND NONWOOD MATERIALS IN HOUSE CONSTRUCTION Boyd et al. (1976) 22-6 TOYS International Trade. Centre, UNCTAD/GATT (1976) 22-7, subsection STIFFNESS AND RIGIDITY OF 28- BY 40-INCH NAILED PALLETS of 22 PINE-SITE HARDWOODS Stern (1978) 22-10, subsections TRUCK TRAILER FLOORING and RAILCAR FLOORING Fergus et al. (1977) 22-15 ENERGY WOOD U.S. Department of Agriculture, Forest Service (1980) 22-16, subsection METALLURGICAL CHIPS Wartluft (1971) 22-16, subsection EXCELSIOR U.S. Department of Agriculture, Forest Service (1956) Other major portions of data were drawn from research by: R. B. Anderson L. D. Garrett H. R. Large M. Applefield C. J. Gatchell J. W. Lehman P. A. Araman H. Hallock G. R. Lindell F. C. Beall R. A. Hann E. L. Lucas D. F. Bertelson B. G. Hansen J. F. Lutz R. H. Bescher J. T. Hardaway R. R. Maeglin S. A. Bingham M. R. Harold D. G. Martens G. W. Blomgren, Jr. G. B. Harpole R. W. Merz P. J. Bois G. E. Heck D. G. Miller R. S. Bond B. G. Heebink H. L. Mitchell J. L. Bowyer T. B. Heebink R. T. Monahan R. L. Boyer A. M. Herrick P. R. Mount M. O. Braun W. L. Hoover W. K. Murphey S. M. Brock J. P. Howe National Hardwood T. W. Church, Jr. R. W. Jokerst Lumber Association R. E. Coleman H. R. Josephson W. T. Nearn E. P. Craft C. T. Keith J. R. Neetzel E. M. Davis G. C. Klippel C. H. Nethercote D. V. Doyle H. A. Knight G. R. Niskala D. E. Dunmire R. Knutson B. H. Paul G. A. Eckelman C. B. Koch E. Perem G. H. Englerth P. Koch J. D. Perry A. D. Freas H. Kubler R. Peter F. Freese J. G. Kuenzel M. Y. Pilllow R. E. Frost R. S. Kurtenacker D. N. Quinney 2546 2547 J. R. Reeves W. H. Reid G. Reynolds E. L. Schaffer B. A. Schick J. G. Schroeder A. T. Shuler M. L. Selbo P. E. Sendak J. F. Siau W. T. Simpson W. R. Smitii H. Spelter E. G. Stem R. K. Stem J. J. Strobel O. Suchsland Tennessee Valley Authority F. G. Timson J. L. Tschemitz U.S. Department of Agriculture, Forest Service H. M. Vick W. B. Wallin A. C. Worrell J. Yao W. G. Youngquist CHAPTER 22 Solid Wood Products CONTENTS Page 22-1 STRUCTURAL COMMODITIES— WOOD AND NONWOOD 2556 ENERGY REQUIREMENTS FOR WOOD-BASED COMMODITIES 2556 ENERGY REQUIREMENTS FOR NONWOOD-BASED COMMODITIES 2557 MAN-HOUR REQUIREMENTS FOR STRUCTURAL COMMODITIES 2560 CAPITAL DEPRECIATION ASSOCIATED WITH COMMODITIES 2561 22-2 WOOD AND NONWOOD MATERIALS IN HOUSE CONSTRUCTION 2561 22-3 LUMBER, MILLWORK, FLOORING, AND DIMENSION STOCK 2564 LUMBER 2564 Lumber yields 2564 Sawlog values 2565 Drying and planing 2566 Grading lumber by computer 2567 Laminated lumber 2568 MILLWORK 2570 FLOORING 2571 Species preferences 2573 314-inch-thick tongue-and-groove strip flooring 2573 5/ 16-inch'thick face-nailed strip flooring 2575 Parquet flooring 2577 DIMENSION STOCK 2581 Edge-glued core stock 2582 Use of hardwood dimension stock by the southern furniture industry 2583 2548 2549 22-4 TOOL HANDLES 2584 WHITE ASH SELECTION FOR HANDLE STOCK . . . 2584 HICKORY SELECTION FOR HANDLE STOCK 2584 REQUIREMENTS FOR HICKORY BOLTS 2585 TYPES OF HANDLES 2586 Striking tools 2586 Lifting and pulling tools 2588 Other tools 2588 MANUFACTURE 2588 Sawing 2588 Drying 2589 Machining y bending, and finishing 2589 YIELDS 2589 22-5 FURNITURE AND FIXTURES 2589 KITCHEN CABINETS 2593 FURNITURE PLANT LOCATION 2594 WOOD SPECIES FAVORED FOR FURNITURE 2596 FIBERBOARDS AND PARTICLEBOARDS 2596 FURNITURE FRAMESTOCK OF PARALLEL- LAMINATED VENEER 2597 22-6 TOYS 2599 TRADE CHANNELS 2601 DEMAND STRUCTURE 2601 COMMON TYPES OF TOYS 2603 Wood species 2603 Finish 2603 SPECIFICATIONS AND SAFETY 2603 22-7 PALLETS 2603 PALLET POOLS 2608 PALLET TYPES CLASSIFIED BY USE 2609 Expendable pallets 2609 General-purpose pallets 2609 Special-purpose pallets 2609 PALLET TYPES CLASSIFIED BY CONSTRUCTION 2609 PALLET STANDARDS 2609 Standard sizes for general-purpose pallets 2611 Performance standards for general-purpose pallets 2611 SPECIES GROUPINGS 2617 STIFFNESS AND RIGIDITY OF 48- BY 40-INCH NAILED PALLETS OF 22 PINE- SITE HARDWOODS 2617 Pallet weight 2618 2550 Specific gravity 2618 Pallet stiffness under static load 2618 Impact rigidity of pallets 2620 STAPLED PALLETS OF PINE-SITE HARDWOODS . 2622 OTHER TEST DATA 2623 LUMBER GRADES FOR DECKBOARDS AND STRINGERS 2623 Below-grade pallet shook 2623 Quality distribution of pallet parts from low-grade lumber 2624 PARALLEL-LAMINATED- VENEER 2624 PLYWOOD 2626 COMPOSITE BOARD 2627 FLAKEBOARD 2628 Molded flakeboard pallets 2628 FIBERBOARD 2628 Block pallets 2628 Stringer-type pallets 2628 PALLET DESIGN 2629 Block versus stringer design 2629 Deckboards of stringer-type pallets 2629 Stringer design 2631 Strength and durability computations 2631 Test methods 2631 PALLET FASTENERS 2632 Nail styles 2632 Performance of pallet nails in 22 pine-site hardwoods 2633 Nailing standards 2633 Staples 2635 Performance of staples in 22 southern hardwoods 2635 DECKBOARD AND STRINGER MANUFACTURE. . . . 2636 From random-length long logs 2636 From short logs 2636 From random-length cants 2636 From deckboard- and stringer-length bolts 2636 From thick veneer 2637 Notching of stringers 2637 Chamfering of deckboards 2637 PALLET ASSEMBLY 2637 Hand assembly 2637 Partially mechanized assembly 2638 Mechanized assembly 2638 PALLET MANUFACTURING-COST DISTRIBUTION 2639 RESIDUES FROM PALLET MANUFACTURE 2640 PALLET REPAIR 2642 2551 FORKLIFT-TRUCK MODIFICATION TO REDUCE DAMAGE 2643 OTHER REFERENCES 2644 22-8 CRATES AND CONTAINERS 2644 CRATES 2645 BOXES 2645 Odor and taste imparted to food by wood boxes 2645 TIGHT COOPERAGE 2647 VENEER CONTAINERS 2647 Veneer baskets 2647 Veneer crates 2648 Paper-overlayed veneer 2648 22-9 DECORATIVE VENEER AND PLYWOOD 2649 PREFINISHED HARDWOOD PLYWOOD 2651 VENEER SPECIES CUT IN THE SOUTH 2651 SPECIAL PROBLEMS IN USING PINE-SITE HARDWOODS 2652 SPECIFICATIONS AND STANDARDS 2654 Decorative plywood 2654 Block flooring 2655 Stock panels 2656 Wood flush doors 2657 LINEAR EXPANSION OF VENEERED FURNITURE PANELS 2658 SURFACE CHECKING IN VENEERED FURNITURE PANELS 2659 22-10 STRUCTURAL WOOD 2659 TIMBERS VS. LUMBER FROM LOW-GRADE LOGS 2660 CROSSTIES 2664 Annual production 2665 Species 2665 Sizes and specifications 2665 Ballast for crossties 2666 Tie spacing 2666 Methods to secure rail to crosstie 2668 Crosstie life 2669 Reasons for crosstie failure 2669 Crosstie initial cost 2672 Annual cost per mile of mainline track 2674 Dowel-laminated wood crossties 2674 Crossties from parallel-laminated veneer 2674 Recycled crossties 2675 Crosstie manufacture 2675 2552 Lumber and residue yields in crosstie manufacture 2675 Concrete crossties 2675 Landscape ties 2676 MINE TIMBERS 2678 Mine timber specifications 2679 Species preference 2679 OTHER TIMBERS 2682 HIGHWAY POSTS 2683 Impact strength of wood and steel posts 2683 Machine driving of pressure-treated wood posts 2683 Damage to wood and steel posts during driving 2684 Comparison of installed costs of wood versus steel guardrail posts 2684 Strength of roundwood compared to sawn posts of three species 2684 FENCE POSTS 2685 Fence post size 2685 Species preference and durability 2687 Strength of hickory , oaky and pine fence posts 2687 Machine driving offence posts 2687 POLES AND PILING 2688 RIVER-BANK AND ROAD MATS 2688 STRUCTURAL LUMBER 2689 STRUCTURAL PLYWOOD 2692 Yield of structural veneer from trees of four southern hardwoods 2693 Yield of veneer from grade 3 Appalachian logs 2693 Gluing of oak faces to less dense hardwood inner plys 2694 Weight of hardwood plywood 2695 Face-glued blockboard 2695 LAMINATED BEAMS AND LUMBER 2697 Flat-grain white oak versus vertical-grain for lamination 2698 Effect of laminae thickness and width on glue-line durability 2699 Effect of laminae thickness on beam strength 2699 Safe bending radius for white oak laminae 2699 Effect of water soaking on strength of laminated beams 2699 Effect of preservatives on shear strength 2699 Strength of laminated oak beams 2699 2553 Gluing green oak 2700 Two-ply laminated hardwood lumber 2700 TRUCK TRAILER FLOORING 2700 Manufacturing processes 2701 Strength 2702 Durability 2702 Nailability 2703 Coefficient of friction 2703 Weight-to-strength ratio 2703 Trend 2703 RAILCAR FLOORING 2704 PARALLEL-LAMINATED VENEER 2705 WOOD-DISK PATIOS 2707 22-11 WOOD STRUCTURES 2708 22-12 HANDCRAFT PRODUCTS 2709 22-13 CHEMICALLY MODIFIED WOOD 2710 WOOD-PLASTIC COMPOSITES 2710 PRODUCTS STABILIZED WITH POLYETHYLENE GLYCOL 2711 22-14 PULPWOOD AND PULP CHIPS 2712 22-15 ENERGY WOOD 2713 RESIDENTIAL USE OF FIREWOOD 2713 INDUSTRIAL AND COMMERCIAL USE OF FUEL WOOD 2713 22-16 OTHER PARTICULATE WOOD 2715 METALLURGICAL CHIPS 2715 Annual demand 2716 Wood species and form 2717 Chip manufacture 2717 FLAKES FOR STRUCTURAL PANELS 2718 EXCELSIOR 2718 22-17 LITERATURE CITED 2721 CHAPTER 22 Solid Wood Products As used in this chapter the term "solid wood products" includes not only lumber, but most products except pulp and paper (chapter 25), fiberboards (chapter 23), and reconstituted wood (chapter 24) such as particleboard, flake- board, and composite board having veneer faces over a flake or particle core. Furniture, plywood, glue-laminated beams, glue-laminated veneer, pulp chips, and energy wood are considered solid wood products under this definition. Mulches and soil conditioners of both wood and bark are discussed in chapter 13. Analysis of materials flow from forest to mill (figs. 2-1 and 2-2) indicates that the largest portion of hardwood roundwood harvested in 1970 in the United States was converted into solid wood products — principally lumber; by the year 2000, however, consumption of pulp and fiberboard will predominate, as fol- lows (Boyd et al. 1976): Hardwood barky roundwood consumed in Commodity 1970 2000 Million tons, ovendry Sawlogs for lumber 24.51 42.16 Veneer logs for plywood 2.28 3.09 Veneer logs for lumber laminated from veneer — 1 .59 Roundwood for structural flakeboard — 1 .22 Roundwood for pulp and fiberboard 19.70 78. 14 Miscellaneous industrial wood and fuel wood 1 1 .56 7.21 Total 58.05 133.41 As industry progresses .toward more complete utilization, products such as energy wood, chips for fiber, and wood for structural flakeboard will signifi- cantly increase commodity recovery per tree and per acre. Solid- wood products recovered from hardwoods considered culls in the 1970's will also increase. Trends in consumption of species and products, and product prices, are graphed in chapter 29. In chapter 28, economic feasibility studies of enterprises manufacturing solid wood products are abstracted. Some of the key processes by which hardwood is converted to solid wood products are discussed at length in preceding chapters, as follows: Process Chapter Harvesting 16 Bark removal 17 Milling and machining 18 Bending 19 Drying and storage 20 Treating 21 2554 Solid Wood Products 2555 Not completed in time for incoq^oration in these volumes, but supplemental to them, are three comprehensive reviews on gluing and finishing, as follows (titles are tentative):' • Sellers, T. Gluing eastern hardwoods — with emphasis on southern hardwoods. (A review intended for 1986 publication; for publication details consult the author, at Mississippi State Forest Products Labora- tory, Mississippi State, Miss.) See also: Sellers, T. and J.R. McSween, 1983. Glueing structural plywood from medium-density southern hard- woods. Plywood Research Foundation, Tacoma, WA. 15p. Hse, C.-Y. Technology of phenolic resins. (A text intended for publica- • tion in about 1986 as a General Technical Report of the Southern Forest Experiment Station, USDA Forest Service, New Orleans, La.) • Carter, R. (ed.) 1983. Finishing eastern hardwoods. Proceedings No. 7318. Forest Products Research Society, Madison, Wisconsin. 241 p. Mechanical fastening is discussed at length in chapter 24 of Koch (1972). More recently. Stern et al. (1974) provided a state-of-the-art review, and the Forest Products Research Society (1976) described recent research with me- chanical fasteners. Also in 1976, the U.S. Forest Products Laboratory listed their publications on the subject-. Some references published since these reviews include the following: Reference Subject Eckleman (1978a) Withdrawal strength of sheet-metal-type screws in hardwoods Eckleman (1979) Withdrawal strength of dowel joints Ehlbeck (1979) Nailed joints in wood structures Jung and Day (1981) Strength of fasteners in parallel-laminated veneer Stem (1964) Nail and spikes in hickory Stern (1975a) Performance of 14-gauge sencote staples Stern (1975b) Performance of 15-gauge pas-kote staples Stem (1976) Performance of pallet nails and staples in 22 pine-site hard- woods (summarized in sec. 22-7) Stem (1977a) Toughness of pallet nails Stem (1977b) Mibant tests of pallet staples Stem and Franco (1979) Predrilling pallet deckboards of very dense hardwoods 'All were funded by the Southern Forest Experiment Station as part of an overall effort to advance the technology for utilization of hardwoods that grow among southern pines. ^U.S. Department of Agriculture, Forest Service. 1976. Forest Products Laboratory list of publications on joints and fastenings in wood. 6 p. U.S. Dep. Agric. For. Serv., For. Prod. Lab.. Madison, Wis. 2556 Chapter 22 Yields of solid wood products are given in chapter 12, in section 18-12 (see figs. 18-126 through 18-129), and in chapter 27. Chapter 27 also contains conversion factors useful in yield studies of solid wood products. For page references, see the index heading Yields and measures, products. The balance of the present chapter discusses classes of solid wood products, including, where appropriate, manufacturing procedures and references to prod- uct standards. These are preceded by comparisons of wood construction materi- als with nonwood commodities in terms of energy, manpower, and capital inputs. Most of the products described are important in commercial production, but some have been made only on a laboratory or pilot-plant scale. 22-1 STRUCTURAL COMMODITIES— WOOD AND NONWOOD' Wood as a structural material competes with aluminum, concrete, steel, brick, and petrochemical derivatives. Within the wood sector, solid wood prod- ucts of both hardwood and softwood may compete with reconstituted products. On an ovendry basis, structural wood commodities require from 1 to 3'/2 tons of woody furnish per ton of commodity manufactured (table 22- 1 ); reconstituted boards have highest product yield, and lumber the lowest. Veneer products are intermediate. ENERGY REQUIREMENTS FOR WOOD-BASED COMMODITIES Energy expended during harvesting and manufacture is comprised of three major components: • Diesel fuel and gasoline for forest activities and logging • Mechanical energy (horsepower-hours) expended in the mill • Process heat consumed in the mill Additionally, energy is consumed in manufacture of resin and wax additives to reconstituted commodities. Also diesel fuel and gasoline are consumed deliver- ing the commodities to the construction site. To achieve a uniform mode of expressing energy consumed and available from residues, the unit million Btu thermal (oil) has been used. For example, a gallon of diesel fuel contains 138,336 Btu or 0.138 million Btu thermal (oil). A mechanical horsepower-hour was assumed equivalent to 7,825/10^ million Btu thermal (oil); this equivalency is based on the assumption that oil can be convert- ed to mechanical power with about 32.5 percent efficiency. A pound of process steam was assumed to contain 1,200 Btu which, if generated with an oil-fired boiler at 82.5 percent efficiency, would require about 1,455/10^ million Btu thermal (oil). •'Text under this heading is condensed from Boyd et al. (1977) and Koch (1976a), both based on Boyd et al. (1976). Solid Wood Products 2557 Table 22-1 — Input of woody furnish required to yield a ton (ovendry basis) of product (Koch 1976a) Form of Input of Commodity woody furnish woody furnish Tons, ovendry Insulation board 50-50 mix of bark-free and barky chips of mixed species 0.96 Underlayment particleboard Planer shavings, sawdust, and plywood trim 1.02 Wet-formed hardboard 50-50 mix of bark-free and barky chips of mixed species 1.15 Medium-density fiberboard 50-50 mix of bark-free chips and barky roundwood of mixed species 1.16 Structural flakeboard and pallet Mixed-species barky logs 1.24 lumber Lumber laminated from veneer .... Barky logs 2.13 Softwood sheathing plywood Barky logs 2.22 Softwood lumber Barky logs 2.86 Hardwood plywood paneling Barky logs 3.33 Oak flooring Barky logs 3.57 In computing energy credits for manufacturing residuals (e.g. , green bark and sawdust), it is assumed that exhaust steam from turbines or steam engines will be used for process steam. Thus, a non-condensing turbine connected to an AC generator should consume about 16.3 pounds of high-pressure steam to deliver one brake horsepower-hour of mechanical work. The 16.3 pounds of spent steam at low pressure is then available for process heat. It has additionally been assumed that 1 pound of green bark (half water by weight) will generate about 2.6 pounds of high-pressure steam. Production of hardwood flooring, softwood lumber, or decorative hardwood plywood — including logging and transport to construction site — calls for net expenditure of about 3 million Btu of oil equivalent per ton (ovendry basis) of product if mill residuals are credited against energy demand of the milling process. Reconstituted boards, i.e, fiberboards and particleboards, require S'/z to 21 million Btu per ton produced (table 22-2). ENERGY REQUIREMENTS FOR NONWOOD-BASED COMMODITIES Production of structural commodities from nonrenewable resources and trans- port to building site requires net energy inputs ranging from less than 4 to as much as 200 million Btu oil equivalent per ton (table 22-2). 2558 Chapter 22 1 o in o 8 O OS r^ (^ r- oo o OO lO 1^ r-) r<-, in O (N oo — r<-, r^i ^ ^ r- i^ o DQ a ^ oo oo lo \0 ON ON in ON ON ON oo ~ r<-) r*-) 00 tN o — m, m ON ON ON 00 m s ■^ 8 ON in in vC t^ ON ON ON ^ Solid Wood Products 2559 S ON s — (N — r<-i (^1 00 o o m ro >n vO OO oo ON in OO ^ ^ O O g in r^> O «n r<-> ro (^ O «n vo >1 •a o o a. •^ 3 a. c t; c 2. tij ■,^ Q. o c J= = o oil 7i ca ^ . ""7 yi D. s: j^ CX ^ ~«- :« SI CX X5 ^ 3 '-J o n o C o CXJ (TJ K3 Ot) c s. a g* >. D. ex _c .w C 3 3 ex - it • CM $ 2580 Chapter 22 DESTINATION OF SHIPMENTS WEST NORTH CENTRAL 2 1% Figure 22-10. — Producers, distributors, and destination of parquet flooring in 1969. See figure 22-6 (bottom) for geographic divisions. (Drawing after Miller 1972.) Miller found that essentially all of the parquet flooring is produced in the southern and Appalachian hardwood areas of the United States. The Middle Atlantic, East North Central, and South Atlantic Regions were first, second, and third, respectively, in total shipments; and the Mountain Region was last. The channels of distribution (fig. 22-10) are dominated by wholesalers and flooring subcontractors; however, wholesalers are stronger in the New England, East South Central, Mountain, and Pacific Regions; and wholesalers and floor- ing subcontractors are about equal in the Middle Atlantic, East North Central, and South Atlantic Regions. According to most parquet manufacturers, the geographic market area and channels of distribution for parquet flooring have changed since 1960 and will change even more. From 1960 to 1969, increases in shipments to regions east of the Mississippi River and decreases in shipments to regions west of the Missis- sippi River accounted for most of the geographic distribution changes. The economics of parquet flooring manufacture are examined in section 28- 15. Parquet manufacturers reported that from 1960 to 1969, distribution shifted from retail lumber yards to flooring subcontractors because flooring subcontrac- tors provide better consumer service. Manufacturers also reported more direct sales to specialty flooring distributors, larger purchasers, mobile home manufac- turers, and builders of modular or unitized units. Manufacturers expect to Solid Wood Products 2581 channel a greater proportion of the flooring through the distributors who have both the expertise and the facilities to offer consumers a complete floor system (Miller 1972). DIMENSION STOCK Hardwood dimension stock includes almost any cut-to-size wood compo- nent, usually in the kiln-dried condition, produced for resale to a manufacturer. The term is principally used with reference to furniture components, handle blanks, and squares or rounds; it may include parts for caskets, toys, and specialty items. Flooring and pallet parts are not considered dimension stock. The term includes lumber core stock and laminated components, however, and is sometimes expanded to include flat or moulded plywood components (Flann 1963). Dimension stock is sold in three classes, depending on degree of processing. Rough dimension stock consists of blanks sawed and ripped to specific sizes, and possibly planed hit-and-miss on one side to eliminate excessive thickness variation. Semi-finished dimension stock is rough dimension stock further processed by edge- or face-gluing, surfacing, moulding, tenoning, boring, sand- ing, or other machining; such stock is not, however, completely fabricated and ready for assembly. Finished dimension stock is completely machined or fabricated; no additional machining is required by the customer, with the possi- ble exception of a light sanding operation. Grading rules for dimension stock have been published by The Hardwood Dimension Manufacturers Association (1961) and by the National Hardwood Lumber Association (1978, p. 52). Text sections 18-11 and 18-12 discuss in considerable detail the rationale for bucking low-grade hardwood logs to short lengths, e.g., 6-foot-long, and then sawing these short logs into lumber for direct conversion to dimension stock — thereby bypassing the manufacture of graded lumber in lengths and widths acceptable to the graded-lumber trade. These text sections describe cutting patterns, cutting procedures and costs, cutting yields, and sawing equipment. Also discussed are cutting-length requirements of the furniture industry. For example, Bingham and Schroeder (1976, 1977) found that the average cutting length in one furniture factory was 24 inches, a second averaged 23 inches, and a third averaged 31 inches. These findings are a strong argument for manufactur- ing dimension stock directly from short logs. The technology of sawing rounds is illustrated in figure 18-91; drying data for rounds are graphed in figure 20-26. Drying of squares is described in chapter 20, as follows: Subject Text Air-drying Figure 20-6 Kiln-drying hickory handle blanks Tables 20-23 and 20-24 Kiln-drying 10/4, 12/4, and 16/4 squares of 10 hardwood species or species groups Tables 20-25 2582 Chapter 22 Equipment to turn and sand squares and other shapes is shown in figures 18-175 through 18-190. The economic feasibility of hardwood dimension manufacture is examined in sections 28-4, 28-8, and 28-13. Consumption of hardwood lumber used to manufacture furniture in 1960, 1965, and 1977 is graphed in-figures 29-26 and-- 29-27. Edge-glued core stock. — Core panels, a class of dimension stock, are used as center fill material for laminated products. High-grade lumber core cuttings for use in tops, shelves, doors, and drawer fronts can contain only minor defects such as stain, small bird pecks, small burls, pin knots, and pinworm holes (Araman 1978). Yellow-poplar has traditionally been favored in manufacture of such cores. Araman (1978) observed that in recent years, yellow-poplar has become abundant, especially in the lower grades. Because of this increase in availability, continued use of yellow-poplar as furniture core material should be assured if cost of the lumber core is maintained or lowered. Failure to control cost will result in loss of the furniture core market to other materials, principally particle- boards and fiberboards. From his analysis of alternative production procedures, Araman (1978) con- cluded that 2A Common lumber is the most economical grade when converting low-grade yellow-poplar lumber into furniture core material; ideally, a combina- tion of 2A Common and 2B Common lumber should be used. In the most economical manufacturing procedures, narrow strips from a gang-ripping oper- ation are sent to a defecting station where objectionable defects are removed by crosscutting. From this point, one of two procedures should be employed, as follows: • Each random-length, defect-free piece is cut to the longest needed length that the piece will yield • Or, resulting random-length pieces (minimum of 8 inches) are sent to a finger jointing station where the ends are machined and glued to yield a continuous strip which is then cut to required lengths. Finger jointing results in a loss in usable length of about 7/8-inch per joint; because edges must be remachined prior to edge gluing into panels, this procedure also results in a width loss of about '/s-inch. With either system, Araman found that yield from 2A Common lumber is about 70 percent when cutting strips 2.25 inches wide. A persistent problem in panel manufacture is sunken glue joints, caused by surfacing the panels too soon after gluing. The wood adjacent to the joint absorbs water from the glue and swells. If the panel is surfaced before the excess moisture is distributed, more wood is removed along the joints than at intermedi- ate points. Then during subsequent equilization of moisture, greater shrinkage occurs at the joints than elsewhere, and permanent depressions are formed. These depressions are visible on the surfaces of veneer laminated to such cores. Solid Wood Products 2583 Selbo (1952) suggested use of one of the following conditioning periods, before planing edge-glued panels, to preclude formation of sunken joints visible in panels that will be given a high gloss finish without veneering: • 7 days at 80°F and 30 percent relative humidity • 4 days at 120°F and 35 percent relative humidity • 24 hours at 160°F and 44 percent relative humidity • 16 hours at 200°F and 55 percent relative humidity For edge-glued furniture panels that are subsequently covered with crossbands (usually 1/16- or 1/20-inch) and face veneers (usually 1/28-inch), Selbo thought that the conditioning times shown above could be shortened — perhaps reduced in half. In his experiment, Selbo used urea resin and animal glue. Use of hardwood dimension stock by the southern furniture industry. — Anderson and Sendak (1972) queried 635 manufacturers of wooden furniture in the 16 States comprising the three southern regions established by the United States Department of Commerce (fig. 22-6 bottom). Of these firms, 544 (87.5 percent) used hardwood lumber or dimension stock in their plants; average consumption in 1967 was 1 ,465,000 board feet per firm. Of the 544 firms that used hardwood lumber or dimension stock, 372 firms (67 percent) purchased hardwood dimension stock. Types most frequently purchased and dollars ex- pended per type, were as follows in 1967: Type Firms purchasing Expenditure Number Dollars Turnings and carvings 173 8,584,204 Rough flat stock 142 12,839,294 Partially machined stock 116 13,147.102 Squares 107 6,379,926 Fully machined parts 78 11 ,442,328 Mouldings and trim 73 1 ,977,176 Most of the furniture firms produce in their own plants the majority of hardwood parts they need. Only 33 percent indicated they manufactured none of the hardwood dimension they used. Anderson and Sendak (1972) concluded from a survey that total use of hardwood dimension stock would increase in the future, but independent dimen- sion manufacturers' share of the market may not. They expect increases mainly in within-plant production by furniture manufacturers. Over half the furniture manufacturers now produce more than half of their dimension requirements in their own plants; four furniture manufacturers planned within-plant increases for every one planning decreases. Most manufacturers' decisions were based primarily upon cost factors, but other factors mentioned included: (1) inability to obtain timely delivery; (2) unavailability of hardwood parts of the desired species; and (3) lack of reliability of some suppliers of dimension parts. An independent dimension manufacturer must aim to be reliable and timely, and to supply parts of acceptable quality, species, and moisture content at a lower cost than the buyer can make them in his own plant. 2584 Chapter 22 22-4 TOOL HANDLES The tool handle industry, while not one of the larger segments of the hard- wood trade (fig. 29-35B), is particularly important in the utilization of ash and hickory. White ash is favored for handles of lifting and pulling tools (and for baseball bats). Hickory and white ash are the premium woods for handles of other tools such as cant hooks, peavies, scythes, crosscut saws, and chisels — and for ladder rungs. For handles of striking tools such as axes and mauls, hickory is the favored wood. WHITE ASH SELECTION FOR HANDLE STOCK The text associated with figures 7-3 through 7-6 and 10-7 discusses selection of white ash for maximum toughness and strength. In brief, upland ash on well- drained hillside coves produces wood that is strong, stiff, and suitable for long, heavy handles for lifting tools. Creek-bottom trees and suppressed trees produce as heavy wood, but it is low in stiffness. White ash trees grow wood of uniformly high specific gravity when they grow rapidly in diameter throughout their life. Baker (1970) found that white ash sapwood does not vary from heartwood in mechanical properties if growth rates are equal; he also observed that ash loaded on the tangential face is tougher than that loaded on a radial face. Pillow (1950) concluded that ash trees of adequate toughness and specific gravity for handle stock have relatively large, upward-tapering, generally well- shaped crowns without large dead branches. Vigorous trees producing desirable wood have tight bark with low ridges and shallow depressions, showing light- colored streaks of inner bark. Non-destructive tests have not been particularly successful in selecting ash handles for lifting and pulling, but handle blanks with highest modulus of elasticity in static bending tend to have highest strength in such service. HICKORY SELECTION FOR HANDLE STOCK Hickory is the premium wood for handles of striking tools such as axes, hammers, hatchets, picks, mauls, and sledges because of its impact resistance, toughness, resilience, stiffness, and hardness. A high degree of hardness in handle stock makes possible accurate machining and smooth finishing and polishing during manufacture; during tool use, hard handles resist abrasion. Stiff handles resist flexure under stress and when flexed are resilient and return immediately to original form after relief. Hickory handles are tough and absorb impact forces that would break most other woods; when hickory handles do break, the failure is progressive fiber by fiber rather than sudden and abrupt as in brash woods. (See figs. 10-7 and 19-1 for illustration of fiber-by-fiber failures compared to brash failures.) Brash failures in hickory are almost always associ- ated with tension wood. Solid Wood Products 2585 There has been considerable controversy over the relative quality of red (heartwood) and white (sapwood) hickory. Specifications frequently call for all white wood, causing much good red hickory to be left in the woods or scrapped at the mill. Tests by the U.S. Department of Agriculture, Forest Service (1936) showed conclusively that weight-for-weight, red, white, and mixed red and white sound hickory all have the same strength, toughness, and resistance to shock. Lehman (1958) explained the basis of discrimination against red hickory. He noted that red hickory is the heartwood and is in the inner part of the tree. On trees from virgin forests this wood may be 100 or more years old and was formed under forest conditions which produced slow growth. Slow growth in hickory produces low-density, lower-strength wood (fig. 7-7). As the virgin forests were cut, and when many of these hickory trees were released by partial cutting, the growth rate increased and the white sapwood in the outer portions was denser and stronger than their red heartwood. Now that much of the virgin old-growth hickory has been cut and the hickory in managed forests is growing at a fairly rapid rate, the heartwood and sapwood should not differ appreciably in density, and red hickory is generally as strong as the white. True hickories, on the whole, shrink more, but tend to have greater shock resistance than the pecan hickories (Lehman 1958). Paul (1947) observed that scrubby hickory trees from poor sites will not supply much defect-free, fast-grown wood for high-class handle stock; more- over, limby trees on poor sites produce cross-grain wood and display more bird peck and insect damage than more thrifty trees grown on sites better suited to hickory. He found that the bark of hickory trees offered clues to wood quality. On slowly growing trees, there are few of the light-colored streaks at the bottom of bark furrows which are evidence of rapid diameter growth. On shagbark hickory instead of light streaks between ridges, fast growing trees shed more bark than those which are stagnating. No non-destructive test has been devised that accurately predicts impact resistance of hickory. Such parameters as static or dynamic modulus of elastic- ity, or velocity of sound in longitudinal transit, seem not strongly correlated with impact strength. Old-time craftsmen, however, found that stiff and resilient handle stock, when dropped endwise onto a concrete floor, produces a clear ringing sound. A dull thudding sound, or even a low-pitched tone, indicates it is likely low in stiffness and probably will not straighten readily after being bent under load (Heck 1949). Paul (1947) proposed that the best grades of striking tool handles should have less than 17 rings per inch or weigh at least 55 pounds per cubic foot at 12 percent moisture content. Crossgrain in handles, resuhing from sawing at an angle to the grain, is the major cause of handle breakage. REQUIREMENTS FOR HICKORY BOLTS Grades for hickory bolts (fig. 22-1 1) representative of those used by midwest- ern and southern handle companies are given in table 22-7. 2586 Chapter 22 Figure 22-11. — Hickory bolts in yard of a handle factory. (Photo from Lehman 1958. Table 22-7 — Typical grades and specifications for hickory handle bolts (Herrick 1958) Statistics Description Species accepted Shagbark, niockernut, and pignut; bitternut hickory not accepted Minimum top diameter inside bark 7 or 8 inches; varies with company Length 38, 40, or 42 inches; varies with company Grade No. 1 (or A) Strictly clear bolts with at least 3 inches (or 3'/2, or 4 inches depending upon the company) of white wood (sapwood) on the small end of the block Grade No. 2 (or B) Generally clear bolts with less than the depth of white wood required of Grade No. 1 Grade 3 (or C) Red blocks with less than 2 inches of white wood, or reasonably clear blocks but permitting small defects such as slight pecks and streaks. Light weight may place bolts in this grade. TYPES OF HANDLES Striking tools. — Striking tool handles include those for axes, adzes, picks, mattocks, mauls, sledges, hammers, and hatchets; all are made almost exclu- sively of hickory. Blanks for striking tool handles are generally graded Extra, No. 1, No. 2, or No. 3. The Extra and No. 1 grades are the same for axe, pick, Solid Wood Products 2587 and sledge handle blanks, but the other grades vary some. Lehman (1958) listed the following specifications as typical for striking tool handles: • Extra: Must be all white, heavy timber, free from all defects, perfect, full size, and straight grain. • No. 1: Must be good weight timber, V^ red wood permitted the entire length of the blank. All white blanks of good weight not sufficiently heavy for extra grade. Two light hair streaks running full length, or their equivalent in shorter streaks permitted. Must be full size, straight grained and free from defects. • No. 2: Must be fair weight timber permitting red, white, or mixed red and white wood (for axe handle blanks not more than 2/3 red permitted). Light streaks permitted. All white blanks can have not more than three small pin knots not to exceed '/s-inch in diameter. Reasonably straight grain required. • No. 3: Includes blanks that will produce serviceable handles but are not admissable to the higher grades because of defects. • Reject: Blanks containing open knots greater than Vs-inch in diameter, worm holes or windshake, or ones that are brashy and not admissable to any grade. Figure 22-12.— Sanding hickory tool handles. (Photo from Tennessee Valley Authority.) 2588 Chapter 22 The size of handle blanks varies according to the tool for which the handle is designed. Thicknesses are generally at least I-Va inch at the head end, with widths up to 3-!/2 inches and lengths to 40 inches (table 22-8). Most companies use standard grade specifications for striking-tool handles. Table 22-9 describes six handle grades taken from standard practice recommen- dation No. R77-45, U.S. Department of Commerce (1945). Note that the grad- ing of handles is based on visual inspection of each handle and on the judgement of the grader. It is not expected that the grader will determine the weight per cubic foot or number of rings per inch for each handle. In case of question, however, one or both of these characters may be measured for conformance with the requirements given in the table for each grade (Lehman 1958). Table 22-8 — Length, width, and thickness of hickory handle blanks commonly used in the manufacture of axe, pick, hatchet, sledge, and hammer handles (Lehman 1958) Cross section Tool Length Head end Eye end Inches — Inches Axe 33-36 and 40 3'/2 x 2Vh 3'/2 x 1 '/s Axe 29-32 3'/8 x 2 3'/8 x 1 RRpick 40 2 X 13/4 3'/2 x 2'/2 Coal pick 40 2 x VA 3V2 x VA Hatchet 19-28 2Vs x PA 278x1 Sledge 29-32, 33-36 and 40 1-78x174 178x1-74 Hammer 15-28 1-78 x 1-74 1-78 x 174 Lifting and pulling tools. — Lifting and pulling tools include hoes, rakes, forks, spades, and shovels. Toughness is a main requirement, but handles for these tools do not have to meet the rigid requirements for striking tools. While ash is preferred for such handles, hickory is also used. Other tools. — Handles for cant hooks, peavies, scythes, crosscut saws, and chisels should be tough and stiff. Cant hooks and peavies, in particular, are subjected to sudden stresses. Specifications for these handles are not, however, as rigid as for striking tool handles. The top-grade cant hook and peavy handles are red or red and white wood of medium weight (46 to 55 pounds per cubic foot). They can have up to 27 rings per inch; some blemishes and defects are allowed. Grades BW, or in some cases AR, are top grades for these handles (Lehman 1958). MANUFACTURE Sawing. — Hickory and ash bolts are usually sawn into handle blanks on a bolter saw (fig. 18-123). One method commonly used by handle sawyers calls for first halving and then quartering the bolt. Tapered long blanks for axe handles may then be sawn. Smaller pieces are salvaged for sledge and hammer handle blanks. Solid Wood Products 2589 Longer bolts for industrial products such as textile picker sticks, pitman rods, and handles for garden tools or brooms may be sawn on short-carriage headrigs equipped with a 54-inch circular saw. Drying. — Air-drying of handle stock is described in text related to figure 20- 6. Kiln-drying schedules for ash squares are shown in table 20-25. Special kiln schedules to avoid pinking in hickory handle stock are shown in tables 20-23 and 20-24. Machining, bending, and finishing. — Rough shaping is usually accom- plished with a circular saw. Irregularly shaped handles, such as those for a single-bit axe are turned on a copying lathe (fig. 18-188). Cylindrical handles can be produced on a dowel machine (fig. 18-189AB). Handles for certain lifting and pulling tools, e.g., shovel handles, may be soaked in hot water and formed by bending (fig. 19-13). After trimming to length with circular saws, handles are smoothed with coarse abrasive belts, polished with finer abrasives (fig. 22-12), and waxed or lacquered. Painting is usually limited to low-grade cheap handles. As one of the final operations, handles are usually labelled or stamped with the name of the manufacturer and the trade name. YIELDS Hickory handle bolts are commonly bought and sold on the basis of estimated handle yield for various diameters. Based on data collected by the Purdue University Agricultual Experiment Station, handle yield from 40-inch hickory bolts is approximately as follows (Herrick 1958; Lehman 1958). Top diameter of bolt inside bark Handle yield Inches Number 7 3 8 4 10 7-8 12 10-12 14 14-16 16 18-19 18 20-22 20 28 22 34 24 40 22-5 FURNITURE AND FIXTURES The furniture industry is the largest user of hardwood lumber in the United States (fig. 29-26 and 29-27). Veneer, plywood, particleboard, and hardboard are also used in large quantities to make furniture and fixtures (table 22-10 and fig. 29-36A). Spelter et al. (1978) found that in 1972 the furniture and fixtures industry consisted of over 9,000 establishments employing 462,000 workers, and used 2590 Chapter 22 a 3 C c x: o c c/2 3 1 t^ 00 (U _c Xi o E ^ 3 z _o O U "11 2 e C C a c^ ^ ^ a ^ o e E ■5 0 z Z o -o 00 "o 1 T3 .9" '-5 E c 0 g .fcj ^ 3 ra c !£ f 0 X 1 a. I/) ^ C 0 g '3 ^ s- c/2 cd &o c 1 ^ 1 0 ^ 0 t: -3 (50 ^- *t; c -^ 1 ^ I: ^ £ S 3 11 f^ . >1 1 0) (/) — ^ K 1 -^"^ o "^ OJ E 'E s 1 5^ >. c 1 "o 1 c < II o c p'-5 e:c (u -a OJ el- 's B B.2 C (=2 2i 3 X c QJ CO c E o /y^ ■^ E 2 2^3 <^ « ". g ?i O CO c cj ^ "i^ <-• '-a 'E ■' fl» c x: X) •tr x: o o ^ ='o E ^' :S 2 ^ ^ .Si III CJJ 3 E OJ qr; ^ dJ i-H c ■" CO '-(r '^ '^ T .E V) C S C V) £: CO CO -^ cj x: jr o - y OJ ^ t^ O O ^ — ■£ W (U .( OJ c^ o ti *:- I % •- x: CO (/5 *- rv <" ^ C x: o .E O H OQ-2^ o .-2 Q &ft6X)> o -o T3 x: -o 2592 Chapter 22 2.6 billion board feet of hardwood lumber. In 1977 this industry shipped $16.97 billion worth of goods (table 22-1 1). Broken into five classes, household furni- ture accounted for two-thirds of the total value of shipments. Next was the partitions and fixtures sector (15 percent of shipments for (1977), followed by office furniture (13 percent), miscellaneous furniture (8 percent), and public buildings and related furniture (5 percent). The industry is highly regionalized with 46 percent of the work force located in the South, 24 percent in the Midwest, 18 percent in the Northeast, and 12 percent in the West. The industry is vulnerable to business cycles. It suffered deep recessions in 1974-1975 and in 1980. In general, however, furniture production is expected to be at high levels during the last decade of the 20th century and early decades of the 21st century. Table 22-10 — Use of seven wood commodities in the furniture and fixtures industry during the years 1960, 1965, 1967, 1972, and 1977^ (Spelter et al. 1978) Commodity 1960 1965 1967 Estimated 1972 1977 Hardwood lumber Softwood lumber- Hardwood plywood-^ Softwood plywood"^ Particieboard"^ Hardboard^ Hardwood veneer^ 'Data include those for kitchen cabinets. ^Billion board feet. •'Billion square feet (ys-inch). "^Billion square feet (yt-inch). ^Billion square feet ('/s-inch). ^Billion square feet (surface measurement) -Billion feet - 1.59 1.98 2.26 2.59 2.59 .37 .61 .49 .73 .67 .33 .44 .62 1.09 1.05 .38 .26 .31 .59 .63 .09 .33 .38 1.27 1.16 .33 .51 .44 .96 .88 .80 1.22 1.31 1.39 1.30 Solid Wood Products 2593 Table 22-1 1 — Value of J 977 shipments of the furniture industry, by sector Sector and sub-sector (with Standard Industrial classification numbers Value of used in Census of Manufacturers) shipments Million dollars 25 1 Household furniture 25 1 1 Wood household furniture 4, 140.3 2512 Upholstered household furniture 2,931 .0 25 14 Metal household furniture 1 ,307. 1 2515 Mattresses and bedsprings 1,398.5 2517 Radio and TV cabinets 304.8 2519 Household furniture not elsewhere classified 301 .9 Sub-total 10,383.6 252 Office furniture 2521 Wood office furniture 612.0 2522 Metal office furniture 1 ,397.4 Sub-total 2.009.4 253 Public building furniture 787.4 254 Partitions and fixtures 2541 Wood partitions and fixtures 1.105.8 2542 Metal partitions and fixtures 1 ,303.0 Sub-total 2,408.8 259 Miscellaneous furniture and fixtures 2591 Draperies, blinds, and shades 675. 1 2599 Furniture and fixtures not elsewhere classified 705.2 Sub-total 1 ,380.3 Grand total for SIC number 25 (Furniture and fixtures) 16,969.5 KITCHEN CABINETS Kitchen cabinets represent an important segment of the furniture and fixture market. Lindell and KHppel (1972) estimated that in 1969 sales of kitchen cabinets totalled $1.4 billion and involved some 3.9 million kitchens, of which only 1.5 million were in new houses. About 71 percent of these cabinets were wood and built in factories, and another 16 percent were factory built of plastic or steel. Mobile-home manufacturers produced about 10 percent; only 3 percent were built on site. Most kitchen cabinet manufacturing plants serve a local market; of the larger firms that market regionally or nationally, many are located in states adjoining the Great Lakes (fig. 22-13). Use of plastics, hardboard, and particleboard have steadily increased. Plastics in 1963 accounted for less than 1.7 percent of total expenditures for materials, but in 1970 for 6.6 percent (fig. 22-14). The use of particleboard core stock for plastic overlays increased from 0.6 percent in 1963 to 4.5 percent in 1970, while hardboard purchases increased from 2.2 percent to 3.7 percent. During this 2594 Chapter 22 Figure 22-1 3. — Location of principal kitchen cabinet manufacturers in the United States. (Drawing after Lindell and Klippel 1972.) period, purchases of hardwood lumber and plywood decreased from 53 to 43 percent of total raw material cost (fig. 22-14). Purchases of cabinet doors and door skins were about 17 percent of total purchases in 1970. (A door skin is the outer visible sheet of material on a panel door.) Hardwood plywood doors were dominant, accounting for nearly two- thirds (by value) of all cabinet door purchases. Plastic and plastic-overlaid doors made up another fourth; the rest were of softwood plywood and miscellaneous materials. About 42 percent of the purchased hardwood plywood doors were birch, and nearly 30 percent were oak. Maple, cherry, walnut, and other hard- woods made up the remainder. FURNITURE PLANT LOCATION As noted previously, 46 percent of the workforce in the furniture industry is in the South. From a poll of furniture manufacturing firms in Virginia and North Carolina, Brock and Hilliard (1977) found that the primary consideration in locating new plants was availability of skilled and unskilled labor. Other impor- tant requirements included transportation facilities, accessibility to regional markets, and availability of raw materials. Many furniture plants, particularly small ones in West Virginia, were located in a particular place because that place was the owner's home. Solid Wood Products lOOi 2595 ir PACKAGING 1963 1964 1965 1966 1967 YEAR 1968 1970 Figure 22-1 4. — Distribution of dollar value of raw material purchases by members of the National Kitchen Cabinet Association during the years 1963-1970. Data for the year 1969 are not available. (Drawing after Lindell and Kiippel 1972.) 2596 Chapter 22 WOOD SPECIES FAVORED FOR FURNITURE Blomgren (1965) concluded that wood has a depth of psychological meaning to people that other materials do not possess. Subconsciously, people feel that wood represents the natural process of life and growth. The tree is a symbol of life; its grows in the earth — and light, air, and water are vital to its growth. Wood suggests strength and security. It is sensuous and intriguing; even the smell of wood is sensuous and suggestive of romantic and idyllic imagery. Wood sug- gests productive human activity — a man building something, a boat sailing, or a tree growing. Wood is distinctive and evokes memories. It is seen as natural, solid, and reliable. In Blomgren's survey of people's image of wood, he found that men and women have different images of some wood species. Oaks emerged as the wood with the most specific personality. Men and women both viewed oak as mascu- line wood and agreed that it is durable, strong, practical, and associated with security. Most men see oak as old fashioned, but only half the women inter- viewed viewed it this way. Much of the furniture industry of the United States is concentrated in North Carolina, and species preferences of the North Carolina furniture plants are perhaps representative of most southern plants. Applefield (1971) determined percentages of total lumber volume purchased by North Carolina plants accord- ing to species and year of purchase (fig. 22-15). He found that in 1953 yellow- poplar purchases were greatest, with gums (sweetgum and black tupelo) second, oaks third, and maples fourth. By 1968, oaks were first, slightly ahead of yellow poplar, and the maples were in third place. A decade later oak furniture dominat- ed the market (Anonymous 1976a), the popularity of oak continues. Figures 29-16A through 29-16H show long-term trends in hardwood lumber manufacture by species. Not all of this lumber went into furniture, but the furniture industry is the largest user. Luppold* found that demand by furniture manufacturers for particular species is price responsive, with demand for open-grain species being more price re- sponsive than the demand for close-grain species. FIBERBOARDS AND PARTICLEBOARDS Multi-layer particleboards with fine particles on the faces have become strong competitors of lumber in furniture and fixtures. Medium density fiberboard — because it can be edge-machined, filled, finished, and printed — is capturing a steadily increasing share of the furniture market at the expense of lumber and plywood. The technology of manufacturing medium-density fiberboard, and a description of its properties, are discussed in chapter 23. Particleboards are discussed in chapter 24. Because of increasing costs of high-quality lumber of premium furniture species, it is likely that use of particleboards and fiberboards in furniture will continue to increase. * Luppold, William G. The effect of changes in lumber and furniture prices on wood furniture manufacturers' lumber usage. Res. Pap. NE-514. Broomall, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station; 1983. 8 p. Solid Wood Products 2597 YELLOW- POPLAR □ UMS- REO &8AP, BLACK & TUPELO ^iMMMMM?My>&mi' ^mm^^m <^^>6oo<><>^^ OAKS- PEO Sl \A/HITE MAPLE - HARD & ^^S^, )<>c>6<>6<>S6o6^^ WHITE & YELLOXA/ ELIVI & HACKBERRY HICKORY & PECAN CHERRY SYCAMORE OTHER HARONA/OODS ^^?^, ^^^^^^S$^ PERCENT OF TOTAL LUMBER VOLUME ia eo 30 mMmmmmmmmM "^V^-;V'Wi>y^i^^^ M^ ^ ^^H 1953 t»S