By M. VILLIÈRE, Inspector of Waters and Forests at the Central Timber Testing Laboratory, Paris
France has a long tradition of research in the field of wood technology. As long ago as 1707 Parent published a treatise entitled Expériences sur la résistance des bois de chêne et de sapin (Experiments on the qualities of oak and fir woods). A little later, in 1767, Duhamel du Monceau, Inspector-General of the Royal Navy, published his famous work, Du transport, de la conservation et de la force des bois (On the transport, preservation, and strength of wood), which is without doubt the first important book on these questions and marks the beginning of scientific study of wood as a raw material. In the nineteenth century we find the names of Dupin - Expériences sur la flexibilité, la force et l'élasticité des bois, 1815 (Experiments in the flexibility, strength, and elasticity of wood) - and Chevaudier and Wertheim - Mémoire sur les propriétés mécaniques des bois, 1846 (Report on the mechanical properties of wood).
It was not until the twentieth century, however, that wood research was organized on a national scale. In the time of Duhamel du Monceau research was directed to the use of wood for the Navy, but it was wood for aeronautics which was finally responsible for the creation of the first wood research laboratories in France. As an exceptionally light material with the maximum physical and mechanical toughness was necessary for this use, a systematic testing of all species was initiated. The name of Monnin is associated with these early studies, which took place during World War I, and the methods he established have become those universally accepted in France.
After this rapid glance into the past, we shall pass on to the present organization of wood research in France The Administration of Waters and Forests (Administration des Eaux et Forêts) was the first to develop research on a national scale; and though its initiative was followed by other official and private organizations, it is still the leader in this field and devotes a higher percentage of time and money to these studies than do other organizations.
We give below particulars on various existing organizations, distinguishing between those which fall under the General Directorate of Waters and Forests, and others which, under ' various titles, are occupied with wood or cellulose research.
ORGANIZATIONS UNDER THE GENERAL DIRECTORATE OF WATERS AND FORESTS
In 1920, at the instigation of its Director, M. Guinier, the National School of Waters and Forests (Ecole nationale des Eaux et Forêts) set up a wood-testing laboratory as an adjunct to the Forest Research and Experiment Station. This laboratory is devoted to the study of forest products in relation to conditions of growth.
In 1933 the Administration of Waters and Forests and the principal professional organizations, in collaboration with the Service of Technical Instruction (Enseignement technique), established a semi-official organization to promote research on wood and its utilization as well as technical instruction on wood. It is called the National Timber Institute (Institut national du bois).
A little later, in 1936, the Administration of Waters and Forests also set up the Central Timber Testing Laboratory (Laboratoire central d'essais des bois) and equipped it for the complete study of wood and its utilization possibilities.
This combination is now proving satisfactory.
The School for Advanced Study of Wood (Ecole supérieure du bois) in Paris is responsible for training technicians and engineers specializing in wood studies. Wood industries recruit many of its graduates as their need for technical specialists is steadily increasing, and at present about three hundred persons who have been trained here are scattered throughout French industry. The school has now about a hundred students who, during a two years' course, receive specialized instruction in the study of wood, its processing, and its application in industry.
The School for Wood at Mouchard in the Jura (Ecole du bois de Mouchard) trains skilled personnel for timber cutting and sawmill operations, clerks, and foremen who are experts in the maintenance of saws, the use of power (forestry) machinery, and the grading and cutting of timber, etc. It also provides special courses for the speedy training of saw filers.
The Central Timber Testing Laboratory (Laboratoire central d'essais des bois) in its three specialized sections - biological, mechanical and chemical - makes a general study of wood as a construction material and as a raw material. The Laboratory of the National Timber Institute (Laboratoire de l'Institut national du bois), which is attached to it has set up a Section of Industrial Applications (Section d'applications industrielles) which studies all problems of wood utilization; impregnation, drying and preservative treatment; glues and varnishes; machining of wood; testing of structural units and individual members, etc. The Laboratory conducts general research and also performs tests at the request of private industry.
Finally, a Reference Center (Centre de documentation) has recently been established by the Institute and is at the disposal of all wood users. This Center has a large technical library and an extensive collection of reference material, both French and foreign. Inquiries are handled by personal consultation or by mail. It is now being equipped to supply upon request microfilms and photostatic copies of documents and pamphlets, etc.
Organization of the Central Timber Testing Laboratory (Laboratoire central d'essais des bois)
This laboratory is organized into the three following sections, each suitably equipped and specializing in a specific program of research:
1) Biological and Technological Section (Section de biologie et technologie). - The studies carried out here are, of course, the basis of all research on wood since they are concerned with the structure, properties, and compositional defects and variations of wood. Studies in wood anatomy permit the identification of different woods, so important from a commercial point of view, and the investigation of the different elements with a view to their industrial utilization (cellulose, chemical industry, etc.). Technology permits determination of defects, selection of the best varieties, listing of specifications, and determination of the essentials for different end uses. It also involves research on the characteristics of wood enemies such as insects and fungi and on the efficiency of products used for protecting wood from their action.For these studies the section possesses a micro graphic laboratory containing research microscopes, a polarizing microscope, binoculars, and various measuring instruments. For research on durability and on the value of antiseptic products and the measurement of their toxicity, it has a mycological laboratory equipped with incubators, autoclaves, and other special equipment used in this kind of research.
2) Physical and Mechanical Section (Section de physique et mécanique).
This branch carries out: (a) Fundamental research in which wood is considered from the point of view of the physicist simply as a material under scientific investigation, without consideration of immediate practical application. These tests are to determine the elastic properties of wood, its physical and mechanical characteristics, and the influence of certain factors' such as structure, on the physical and mechanical characteristics of each variety. (b) Practical tests from the point of view of the engineer in which problems relating to the strength of materials, as such, are investigated. The determination of safe loads, the influence of defects, and the strength of assemblies are a few of the important problems considered in this connection.
The section is well equipped. The mechanical testing room contains a screw-type Trayvou horizontal testing machine with a capacity of 50 metric tons. This is a very large machine especially constructed for wood testing. It permits bending tests up to a span of 2 meters and buckling tests on pieces up to 6 meters in length. It has variable speed and three loading ranges. It permits testing of full-size pieces such as built-up beams, columns, girders, etc., as well as small specimens or scale models. The laboratory also has a Malicet and Thin universal machine of 12 metric ton capacity, a special Amsler hand-powered machine for standard tests of wood; a torsion machine with chart-type recorder; a Monnin-type machine for tests of wood quality on standardized test pieces; a dynamometric ram of 10 kg./m capacity S.T.A.; a rotary ram for shock tests at various speeds; various dynamometers, balances, measuring apparatus' etc.
Research on wood seasoning is also conducted by this section. The prime necessity of producing seasoned wood is generally recognized and, owing to the economic difficulties attendant on natural drying, artificial drying has become of increasing importance. There is a whole field of physico-chemical research on humidity, absorption and retention of moisture by the cell walls, etc., which is as yet only in its elementary stages. The practical: value of this research is that it will lead to a knowledge of' the conditions of the passage of water through wood and of seasoning. It will thus be possible to establish seasoning tables and precise rules for use in industrial seasoning practices.
Studies of the main elements of seasoning are carried out in a group of kilns and compartments that permit all kinds of tests, ranging from small-scale laboratory tests up to semi-industrial practical tests. Special kilns provided with uniform longitudinal circulation and moisture injection make it possible to determine the characteristics of sample specimens Dry kilns of semi-industrial size, equipped with automatic balances and special regulating devices, make it possible to interpret the results obtained in terms of industrial operations and thus to reach conclusions which are valid for dry kilns of larger dimensions.
3) Chemical Section (Section de chimie). - In view of the importance of wood in the modern chemical industry and its adaptation to all kinds of uses, the program of this section is very extensive.
The laboratory acts as a liaison agent between the different specialized French laboratories. It comprises a general chemical laboratory for analysis, research on wood constituents, quantitative analysis, determination of chemical properties, extraction of component elements, etc.
Attached to this laboratory is an impregnation room, equipped with an experimental autoclave three meters in length with an upper autoclave for impregnation by the Rüping process and two smaller autoclaves for special impregnations (antiseptics, synthetic resins, etc.). This equipment naturally includes a steam boiler, a compressor unit, and liquid storage vats, as well as the customary measuring instruments such as thermometers, manometers, vacuum gauges, etc. An idea of the possibilities of the installation may be had from the feet that it permits the use of temperatures up to 180° C. in the autoclaves (steam-heated by external jacketing) and pressures up to 35 kilograms per square centimeter.
Basic Research and Industrial Application
Most of the investigation and research is conducted both on the theoretical level, to improve the general knowledge of wood, and on the practical level with regard to its application to construction and industry. The Laboratory is therefore divided into two main sections, one concerned primarily with basic research, the other with industrial applications; but the line of demarcation between these two types of research is not always clearly defined and the two fields very often overlap.
In addition to its research of a general nature, the Laboratory undertakes studies, tests, and analyses on behalf of individuals or various organizations. A nominal fee covering only the time of the technicians and workers and the costs of materials is charged. All requests for information are answered, either by the Laboratory or by the Reference Center.
The Laboratory is thus in direct contact or in constant correspondence with numerous manufacturers or users of wood, as well as with numerous government or private agencies. Among these may be mentioned the Ministry of Reconstruction and City Planning (Ministère de la Reconstruction et de l'Urbanisme) for technical consultation on documents and specifications; the Postal and Telegraphic Service (Administration des Postes et Télégraphes), the National Electric Power Administration (Electricité de France), the National Railway Company (Société nationale des chemins de fer) for all matters concerning wood impregnation and preservation; the Ministry of Air and of the Navy, and the Renault Administration (Régie Renault) for matters pertaining to the use of wood in construction; and the Paper Industry Technical Association (Association technique papetière) for those pertaining to the use of wood in paper manufacture, etc. Often special studies have been carried out for these organizations.
To give some idea of the number of these consultations and tests and the extent of the Laboratory's service to other agencies, a few figures will be cited.
Identifying wood specimens at the Central Timber Testing Laboratory.
During 1948 the Laboratory handled more than 1,000 incoming letters and more than 1,300 outgoing. Detailed replies were made to more than 350 requests for information on a great variety of subjects concerning the properties of wood and its industrial utilization. Approximately 150 paid tests were made for a total of over 360,000 francs The number of callers in search of information and advice during the same period amounted to more than 500. These figures show the great number of services performed, in spite of a reduction in personnel and the fact that the staff was occupied primarily with the general research functions of the Laboratory.
Several methods are employed to make available the results obtained in the Laboratory. Reports have been made on all studies as soon as they produced results. These may be consulted under the appropriate heading in the Reference Center, which is open to the public. Numerous articles have been published in the documentary and technical section of La Revue du Bois (The Wood Review), sponsored by the National Timber Institute, and in professional journals or technical reviews. Special bulletins on the use of wood in construction have been published through the Annales de l'Institut technique du bâtiment et des travaux publics (Annals of the Technical Institute of Building and Public Works).
Finally, pamphlets have been published directly by the Laboratory and sold at a price sufficient to cover the cost of printing. An edition of 4,000 copies of a manual on saw filing was sold out within a few months of publication. Seven hundred copies of pamphlets put out by the Laboratory were sold during the year 1948.
OTHER ORGANIZATIONS
Colonial Wood Laboratory - Technical Section for Forestry of the: Ministry of Overseas France. (Laboratoire des bois coloniaux - Section technique forestière du Ministère de la France d'Outre-Mer)
The Technical Section for Forestry of the of Overseas France is an administrative research organization attached from the technical point of view, to the Service of Waters and Forests of the Ministry of Overseas France (Service des eaux et forêts du Ministère de la France d'Outre-Mer, 27, rue Oudinot, Paris) and, from the administrative point of view, to the Technical Section for Tropical Agriculture (Section technique d'agriculture tropicale, 45 bis, avenue de la Belle Gabrielle, Nogent-sur-Marne).
The tropical forests, which constitute the world's last untapped source of wood, contain a very large number of species whose properties are as yet unknown. The Technical Section for Forestry is concerned with the study of the wood of these species with a view to determining the possibilities and methods of their use. It at present includes: (1) an administrative organization, comprised of a section chief and a secretarial staff; (2) a library (for the time being not open to the public) and a museum of colonial woods (which may be visited by the public), and (3) three research divisions, the Divisions of Technology, Anatomy, and Chemistry.
The Division of Technology includes: (a) A laboratory for physical and mechanical tests of wood in which the physical and mechanical properties of tropical woods are studied and determined; (b) a sawmill and a wood-working shop in which systematic tests are made to determine the tool or machine appropriate for each wood and the best methods of using such equipment.
The Division of Anatomy laboratory is devoted to the examination of woods with a view to determining, on the one hand, positive methods of identifying various species from samples and, on the other hand, the relationships that may exist between the structure of different woods and their possible uses. The principal activities of this laboratory are: (a) Obtaining specimens of native growth,: some with herbarium material so that a positive botanical identification can be made; examination of wood with the naked eye and by means of the magnifying glass and the microscope; and systematic description of sections and photomicrographs and preparation of identification keys; (b) comparative studies of the structural characteristics of various woods in relation to their mechanical and physico-chemical properties.
The Division of Chemistry studies: (1) In a general way the relations which can exist between the chemical composition of woods and their possible uses; (2) special methods of wood treatment involving the study of wood as a chemical raw material in order to derive from wood the wide range of extremely varied products which it can provide. Research is also conducted on the secondary components of wood and its by-products, such as tannins, substances extractible with neutral solvents, gums, resins, etc. Among the various methods of treatment, dry distillation and wood hydrolysis are the subject of special investigation.
The Pine Institute laboratory (Laboratoire de l'Institut du pin)
The laboratories of the Pine Institute, housed in the Science School of the University of Bordeaux (Faculté des Sciences de Bordeaux), focus their attention upon problems relating to Maritime pine:(Pinus pinaster) and especially upon improvements and investigations necessary to the pine resin industry in the forests of southwestern France.
In addition to its administrative section, the fine Institute includes the following laboratories and services:
1) Research laboratories on the chemistry and use of resinous products and their derivatives. - This service, which is the largest, has a staff of eighteen persons, including the laboratory head and eight chemical engineers. Various studies on resins of both a theoretical and a practical nature are now under way. In particular, much attention is being turned to the question of the incorporation of resinous products in copolymers, so that these may benefit from the enormous and extremely rapid development of synthetic resins and plastics, a development which would endanger the resinous products industry unless proper steps were taken to participate in this field. Mention might also be made of tests on a semi-industrial scale of the hydrogenation of rosins, the preparation of dextropimaric acid, etc.2) Physical Research Laboratory. - This laboratory possesses the necessary apparatus for polarimetric measurements, observation by means of Raman, ultraviolet and infra-red spectrography, X-ray photography, etc., which are indispensable for research on the: composition and utilization of the products studied in this Institute.
3) Laboratory of Forest Biology. - This laboratory studies the diverse problems relating to the forests the Landes region: propagation of Maritime pine by cuttings, seed germination, destruction of under-growth with chemical agents, etc. It also subsidizes research on insect enemies of the Maritime pine, particularly on the bark beetle, which is the cause of great damage in the forest.
4) Reference Center. - This service maintains a large technical library, with French and foreign reference material, specializing in the: subject of resinous products
Laboratory of the French School of Papermaking at Grenoble (Laboratoire de l'Ecole française de papeterie de Grenoble)
The Paper Laboratory at Grenoble (Isère), located in the French School of Papermaking, is concerned with studies, research, and experiments to further the development of the pulp, paper, and paperboard industries and to improve manufacturing processes. It comprises:
An experimental papermaking plant. - This is installed in a large room equipped with a papermaking machine having an effective width of one meter, rotating spherical digester rated at 6 kilos, a combination beater and bleacher, a beater, a calender, and a trimmer. The auxiliary services (motive power, electric boiler, etc.) are housed in the basement, this equipment-it is possible to run tests on the utilization of raw materials, and research is conducted with a view to adaptation of results for use in industry.
A laboratory for physical, chemical, and micrographic tests on pulp, paper, and paperboard - A number of rooms are assigned to this service; they are provided with entirely new equipment, quite distinct from used in: instruction.
The physical testing laboratory consists of a constant-temperature chamber conditioned to 21° C. and 65 percent relative humidity by means of an automatically controlled machine comprising a cold-air intake, a ventilator, a heater, a water-spray cabinet and a refrigerating machine.
There is a darkroom for micrographic photography for studying the effects of aging paper by the Wood light method and for observation of colorfastness.
The laboratory for chemical analysis is in a spacious room, completely equipped for day-to-day problems of analysis. It is supplemented by two additional rooms in which long-range and detailed research is carried on.
The micrographic laboratory occupies extensive quarters on the fourth floor; it is thus assured the strong light which is essential for microscopic examination. The laboratory possesses a considerable collection of raw materials, pulps, papers, paperboards, prepared microscopic slides, photographs, and drawings to facilitate identification of the different types of paper fibers.
A laboratory for the manufacture and testing of paper and pulp. - The equipment consists of small beaters of various types, equipment for the preparation of bleaching solutions such as calcium hypochlorite and sodium hypochlorite, and a small machine for making round test sheets.
For the preparation of paper pulps, this laboratory has two digesters built of acid-resistant steel, heated by induction, and rated at 15 kilos, with which it is possible to conduct experiments on all processes of cooking raw materials under pressure using calcium bisulfite, soda, sulfate, monosulfite, etc., with a charge of from 100 grams to 1 kg. 500 grams of raw materials; a laboratory-type disintegrator for fiberizing and separating the material after cooking; and a bleaching apparatus.
For pulp testing, the equipment consists of a Lampen mill, a Schopper-Riegler apparatus, a disintegrator, a sheet former, a hydraulic press, and drying rolls. With this equipment it is possible to reproduce very precisely the stages of pulping for the purpose of studying the effect of various factors on the strength of the pulp.
Equipment for the preparation of standard sheets is also employed for research on sizing, coloring, etc.
Reference Bureau. - This bureau was set up at the request of manufacturers, who wished to have a complete reference center for use by their industry attached to the School. It consists of a collection of the principal works on papermaking and especially files of technical journals'.
The Paper Laboratory makes studies of all vegetable fibers, particularly domestic woods, with a view to their better utilization in papermaking. A particularly broad program of research is being carried on at present in conjunction with the Laboratories of the National Chemical Services (Laboratoires des services chimiques de l'Etat) for improved utilization of coppice woods; such as beech, elm, poplar, basswood, and birch..
Central Laboratory of the National Chemical Services (Laboratoire central des services chimiques de l'Etat)
This is the only organization for research; study, and supervision under the Directorate of Chemical Industries (Direction des industries chimiques) of the Department of Commerce and Industry (Ministère du Commerce et de l'Industrie). It has two establishments, presided over by one director: (1) the main laboratory in Paris, and (2) an annex at Bouchet-par-Vert-le-Petit (Seine-et-Oise). Its general research activity is mainly devoted to the study of the large molecules (cellulose, rubber, etc.) and to related problems.
Logs of tropical species are tested at the Colonial Wood Laboratory.
In addition to the resources provided by the establishment's laboratory of pure science, which places at its disposal such ultra-modern apparatus as the electronic microscope, spectrographs, furnaces for microanalysis, the ultra-centrifuge, osmometers, etc., which it may find occasionally useful, the Cellulose Technical Branch of the Central Laboratory possesses the following equipment of its own at Paris and at Bouchet: all the chemical equipment needed for ordinary analyses and preparations; microscopic and micrographic equipment; viscosimetric equipment; an air-conditioned room (temperature 20° C., relative humidity 65 percent), capable of accommodating four working personnel and apparatus for measuring paper characteristics; the necessary equipment for pulp-cooking (digesters and autoclaves); standardized English equipment for "picking" the sheets and checking mechanical properties.
Monthly meetings of the "Cellulose Commission," composed of representatives from various governments or private laboratories and organizations, are held in this laboratory. The Commission' subdivided into technical subcommittees on pulp analysis, wood analysis, beating, etc., serves to co-ordinate the activities and projects of the various participating bodies in the direction of topics of general interest which are proposed either by members of the Commission or by manufacturers in the paper and artificial textile industries.
At present, the main lines of wood research are the following:
1) In conjunction with the Cellulose Commission, laying down approved methods of analyzing various woods and cellulose pulps in line with the proposal to AFNOR (Association française de Normalisation) for standardizing operating techniques as, for instance, calculating the proportions of alpha cellulose, lignon, pentosans, ash, extract of organic solvents; determining index figures for copper and iodine; measuring the nitro-acetonic concentration; estimating the amounts of polysaccharides readily obtainable by hydrolysis from wood; determining microscopically the fibrous composition, the effect of methods of division used in the preparation of samples, etc.2) Measurement of paper characteristics. - Research on the improvement of more or less standardized apparatus now used for testing paper pulps. Checking of paper pulps submitted for approval. Expert appraisal of pulps, papers, and paperboards upon the request of manufacturers.
3) Chemical studies on wood sugars. - Research and perfecting of methods of characterization, extraction, and analysis of glucosides and saccharides contained in vegetable substances.
4) Theoretical and practical study of the beating of cellulose pulps. - The influence of various physical and chemical factors on the speed and efficacy of different types of beating equipment. Investigation to determine a satisfactory theoretical explanation of the beating phenomenon. Accelerating agents. The effect of beating on the mechanical, physical, and chemical properties of the fibers treated.
5) Research on the manufacture of cellulose pulps. - (a) Paper pulps. An extensive research program has just been undertaken, in collaboration with the laboratories of the School of Papermaking at Grenoble and the laboratory of the National Wood Institute, for the study of the use of wood of broadleaved trees in papermaking: a study of the various chemical and semichemical processings of various species of coppice woods, beech, elm, basswood, and birch. In addition, a comparative study of the different processes of preparing pulp from straw is now under way. Finally, studies of a general nature on the various reactions that occur during cooking will be given consideration in the very near future. (b) Pulps for artificial textiles. Perfection of the preparation of pulps for viscose, derived from annuals of the vegetable class such as wheat straw and alfalfa and from deciduous trees (beech, poplar, etc.).
CO-ORDINATION OF RESEARCH
Liaisons exist between these various organizations and those of the General Directorate of Waters and Forests (Direction générale des Eaux et Forêts), and in some cases the latter subsidizes research of general interest (papermaking, hydrolysis, utilization of broadleaved trees, etc.) from funds which it has available for research purposes. In such eases, the Diretorate participates in working out the programs and follows the development of subsequent operations.: Actually, the wood resources of France are the responsibility of the Ministry of Agriculture; thus all questions concerning the use of wood and the technical development of its possibilities of utilization are of the utmost concern to the Ministry.
Photographs accompanyinng this article supplied by courtesy of the authors
