The Forest Products Laboratory, which is maintained in Madison, Wis., as a unit of the United States Department of Agriculture, conducts research to help conserve the Nation's timber supply and make it serve more satisfactorily the needs of the people for wood products of all kinds.

For nearly 40 years the Laboratory has been doing this work. Today virtually every use of wood known to man is directly affected by it.

Hardly a day passes without visits from representatives of forest-products industries seeking information about wood: What is the correct temperature and relative humidity to use in drying magnolia for venetian blinds? Can the new resin glues be used in piano production? What is the best type of wood sheathing for house construction? What grade of plywood is best for outdoor use? How do you bag mold a plywood boat? What will happen if I apply white paint to my red barn? Am I entitled to the free use of the Laboratory's patents on the semichemical process of paper making? How does the Laboratory make molasses from wood? And many other questions about the thousands of uses to which wood is put.

Each day brings fresh batches of letters, telegrams, and telephone calls from every State—from great corporations and Government agencies, home owners, farmers, and operators of small sawmills, woodworking establishments, and factories. The questions range from the complex problems of aerodynamic design to paint peeling off a house or lumber warping in the seasoning pile. But fundamentally they are alike in that they generally involve the basic problem of wood use—an understanding of its fundamental properties, such as strength, wood-moisture relations, and the physical and chemical structure of this common but highly complex substance. It is toward a better understanding of those fundamental properties that the Laboratory has aimed its scientific inquiries, on the assumption that, if you know what wood is and why it behaves as it does, you have the information you need to solve your practical problems.

The more recent accomplishments of the Laboratory, such as transforming cull trees, sawdust, and other wood residues into sugar-rich stock feeds, or building serviceable house walls from sandwiches of veneer and paper without framing members, may appear most striking. Those and other equally solid applications of its work, however, result from its past research, which not only supplies a basis for new concepts that help make such accomplishments possible, but supplies means of constantly improving established wood uses.

The applications of this work start in the forest, where trees are cut into logs. Except for the variations in diameter, taper, and crook, all logs look much alike. Yet from early lumbering days it has been important that timber owners and mill operators be able to recognize from the outward appearance of logs the quality as well as the quantity of lumber that can be cut from them. A system of grading logs according to recognizable characteristics has become increasingly necessary so that buyers and sellers of logs, particularly from farm woodlands, can have a basis for definite and equitable dealings. Applying knowledge gathered in the woods, sawmills, veneer mills, and elsewhere, the Laboratory has developed a system of grading hardwood logs that is now followed by the Forest Service in making timber inventories and that is gradually coming into use in the commercial buying and selling of logs. When once it is firmly established, this grading system promises substantial aid in forest management.

Kiln-dried lumber has become a standard commodity throughout the United States. To assure that such lumber would be dried to the moisture content most suitable for the use to which it is to be put, the Laboratory developed schedules of temperature and relative humidity for drying lumber of various thicknesses rapidly and with a minimum of damage. It has made available such schedules for almost all native American woods and for some foreign woods. As a result, although there may be local or temporary lapses from good kiln-drying standards, the general level of excellence of wood seasoning in the United States is not equaled elsewhere in the world. The Laboratory began its work on improved kiln-drying methods in about 1913 by working out and making known the physical laws governing the rapid seasoning of wood. Its efforts continue toward development of still better technical control of the drying processes.

Most of the 5,000 or more dry kilns in use in this country have been designed by their manufacturers upon the principles of the original internal-fan kiln pioneered at the Laboratory. Those kilns, including all of the new and most of the remodeled ones, have given satisfaction of a high order.

The man who now buys lumber at a lumber yard for repairs, alterations, or new construction usually gets a product of standard dimensions and pattern that, within reasonable tolerances, will be the same as he bought for a like purpose at a previous time. This was not always true, because the lumber from different mills and areas varied widely in dimensions and pattern until some 25 years ago. About that time the Forest Products Laboratory played an important role, with the United States Department of Commerce, in standardizing lumber dimensions by assisting the manufacturers, distributors, and consumers of lumber in setting up American standards to replace the local and regional standards previously existing. Today, as a result, house flooring, siding, and other lumber can be bought in the same sizes whether made in New England, the Lake States, the South, or the West.

The bountiful supply of woods suitable for structural purposes with which the United States has been blessed has been given added value through more intelligent use and by reliable data on the growth, structure, and strength properties of these species. More than a million tests have provided data on which to base sound working stresses and establish structural grades for use in design and for inclusion in building codes. The test methods developed at the Laboratory were recognized in 1927 by the American Society for Testing Materials and have been adopted in many foreign countries.

More than 175 native woods, as well as some foreign species, have been tested for strength. Companion data needed by design engineers have been obtained on such types of fastenings as nails, screws, and connectors, and studies have been made to determine the effect of loading conditions, defects, and moisture on strength. New constructions, such as plywood and sandwich materials, have been investigated and the strength of these complex materials determined both by actual tests and by means of mathematical analyses that short-cut laborious and time-consuming tests of individual specimens. This information has been depended on widely by the wood-using industries in the selection of material and species for specific purposes, such as poles, structural timbers, aircraft, boxes, boats, and housing.

The development of Federal specifications for wood and fiberboard boxes has been almost entirely a responsibility of the Laboratory for the past 30 years. Although these specifications were designed for Government use, they have been widely adopted as the basis for improved commercial containers that have greatly reduced shipping costs. It has been estimated that the research on containers has effected annual peacetime savings of about 40 million dollars through reduced damage to merchandise, use of thinner lumber, and containers of lower weight and less volume.

The satisfactory service rendered by many wood products depends on the glue used as a binder for their parts. Skill in the gluing of wood has been improving for centuries, with the most striking advances taking place within recent years. Accepted standards for measuring the strength and durability of glue joints have been important in this development. To provide those standards, we devised two glue-test joints, a tension-test joint for plywood and a block-shear-test joint for heavier laminated woods, and standard methods of testing them that have been accepted by glue makers and users. The strength of new glues and their resistance to moisture, heat, and decay have been measured by their performance in these standard-type joints, both newly made and after exposure to severe conditions of service.

DURING THE SECOND WORLD WAR, more than 100 new commercial resin glues were tested for the Army and the Navy. The tests assisted the manufacturers in the elimination of poor glues and the rapid development of the more effective glues. These adhesives have made plywood and laminated wood joints highly durable for outdoor use. They have made practical, also, the gluing of wood to metal, plastics, and other materials that require adhesive properties not possessed by glues previously used for joining wood to wood.

In the field of wood preservation, the work here has contributed substantially to the development and to the standardization of preservatives and treating methods for a wide range of wood uses in which durability is important. An example is the work on pentachlorophenol, an oil-soluble chemical, which has come into increasing use as a wood preservative until now millions of pounds of it are produced annually for this purpose. One of its common applications is quick treatment of window sash to impart decay resistance. The development of this material as a wood preservative dates back to 1930, when we suggested to chemical manufacturers that, on the basis of observations and the theoretical poisoning effect of certain benzene compounds on decay organisms, chlorinated phenols would have special value as wood preservatives.

To broaden the source of raw materials for the pulp and paper industry, such species as the southern yellow pines and various hardwoods have been made usable by means of new pulping processes. Those species supplement the dwindling supplies of spruce and balsam that have been most favored by the industry. Research has opened the way to such new materials and processes. One entirely new process, semichemical pulping, was developed and first placed on a practical basis by the Laboratory in about 1924. This process, that is especially adapted to hardwoods, yields about 50 percent more pulp, with less costly plants, than some of the older processes. By it, nearly 500,000 tons of semichemical pulp are now being produced annually, and the amount is increasing. More recent investigations of its possibilities for the conversion of low-quality wood and wood residues are leading to increased utilization of those materials for many kinds of pulp and paper.

The painting of wood has been placed on a more scientific basis. The greater part of the knowledge on which this improvement is based has come from research and exposure tests at the Laboratory on the paint-holding capacity of American woods. As a result, the usefulness of paints for their effect on the appearance of woods (as distinguished from their protective properties) is now better understood. The common woods have been distinctly classified as to their paintability, and the causes of various types of paint failure have been determined. The disadvantages of using unlike paints in succession on the same surface, as in repainting, have become clear, and the use of special primers and control of two-coat work developed. Millions of dollars were saved by the armed forces during the war by applying the findings to the painting of military buildings.

It has been known for years that cellulose can be transformed into sugars. This knowledge was first applied in this country during the First World War and later more efficiently utilized by the Germans. In the last few years, the commercial possibilities of sugar production from wood have been developed further by reducing the treating time to one-half of that needed by the Germans and increasing the yield to about one-half ton of sugar from a ton of wood. These sugars show promise as molasses for animal feed and as the raw material for producing alcohol, yeast, and other products.

Although the Laboratory staff has been occupied largely by major research problems of the kind named, many minor problems, such as deal with a single type of use for a single species, have not been neglected. Some years ago, for example, certain western railroads were about to reject Engelmann spruce as a material for cross ties, although it was at hand in their territory, because it was difficult to treat with preservatives. The Laboratory found a means of reducing the difficulty and made possible the continued use of this wood. Similarly, a way was devised to cut southern water oak into veneer satisfactory for plywood for fruit and vegetable containers, by which a market was provided for this previously neglected species. Since then, one operator produced in 3 months a half million square feet of water oak plywood.

New wood products developed in recent years include moisture-resistant, dimensionally stable, resin-treated impreg and compreg used for aircraft propellers, knife handles, and for ship decking; the high-strength laminated paper plastic, papreg, used for table tops, truck floors, and ammunition boxes; and the dimensionally stable, resin-free, compressed wood, staypak, useful for textile spinning reels, shuttles, picker sticks, and mine guides. New uses for wood been suggested by the unusual moisture resistance, the freedom from shrinking and swelling, the hardness, and the beautiful appearance of some of these modified woods, although their applications to use have thus far been limited by their cost.

Practical developments, such as laminated wood for ships, highly moisture-resistant plywoods, new dry-kiln schedules as well as new paper-making processes, do not come of themselves, however. Scientific progress is not, as a rule, the fruit of accidental discoveries. It is rather the result of plodding analysis of facts unearthed by painstaking research methods. The information so uncovered is then applied to so-called practical developments. The Forest Products Laboratory, therefore, keeps its sights leveled on the fundamental aspects of research, pursuing developmental work as basic findings warrant.

Charles F. Brannan

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