by Prof. Dr. J. WECK, and Prof. F. KOLLMANN
both of the Federal Institute of Forest and Wood Economics, Reinbek
It is the tradition in Germany that scientific research work should be linked, whenever possible, with university studies. This explains why even today most forestry institutes in the Federal Republic are headed by scientists who are also university teachers. A course of study of a minimum of 8 semesters, leading to a forestry degree ("Diplom-Forstwirt"), can be followed at the universities of Freiburg-im-Breisgau, Göttingen (Hann.-Münden) and Munich. We shall first describe the operation of the forestry institutes of these three universities.
UNIVERSITY RESEARCH INSTITUTE
University of Freiburg-im-Breisgau. The faculty of Natural Sciences and Mathematics here has a forestry section consisting of 8 institutes, covering:
Forest Management and Economics,
Forest Yield and Wood Science, which incorporates
the Baden Forestry Experiment Institute,
The Institute of Forest Management and Economics is at present primarily studying the improvement of the generally unsatisfactory farm wood lot productivity in Germany, on the basis of a survey made in 1946-51 in Baden. The following research projects are under way: on the relation between small farm forest management and the management of the farm itself; on the practicability of the beech selection system in farm wood lots; on the status of coppice and the possibility of its conversion into high forest; on problems of farm land and pastures in the Black Forest. The Director of the Institute of Forest Yield and Wood Science is also the head of the Baden Forestry Experiment Institute, where recently priority has been given to studies of differences in rate of growth of the main wood species in various types of forest. At the Institute of Forest Policy, the following research work is at present under way: reform of forest legislation; comparison of types of government assistance to private forest owners; development of forest management statistics and the bases for forest economy statistics; setting up of timber balances for the Federal domain. The Institute of Forest History considers the old established forest economy, the scientific basis of which was (laid over 150 years ago, as a unique major experiment, the conditions, successes and failures of which it seeks to investigate in search of lessons for the present and future. An attempt is being made to determine the changes in species in individual forest areas in the course of history.
University of Göttingen. The Faculty of Forestry at Hann.-Münden has 10 research institutes, and, in addition, a "Training Center for Forest Work". The institutes cover:
Forest Botany and Mycology,
Forest Law and History,
Forest Policy and Economics,
Forest Management and Production,
The Institute of Forest Botany and Mycology is at present studying the basic problems of forest genetics. At the Institute of Soil Science, since 1945, results have been achieved mainly in the matters of fertilizers, humus, and stand surveying and mapping. Plant sociology findings at the Institute of Pure Silviculture have been used particulary for the diagnosis of conditions and for planning. The head of the Institute of Applied Silviculture is also in charge of a 2,200 ha. demonstration forest in the Weserbergland, where on a 500 ha. plot an experiment on the transformation of extensive, even-aged high forest into mixed unevenaged stands is under way. In the Institute, attention is focused on ecological conditions, economic pre-requisites and the effects upon the stand of type of treatment. The Institute of Forest Law and History is continuing its researches in the realm of forest history on the changes in tree species in the beach stands of northwest Germany, as well as on the evolution of forest land tenure and the forest police and ranger corps. In forest law, special research is being done on forest legislation and penal law.
'The Director of the Institute of Forest Management and Scientific Production is also the head of Section A (Production Research) of the Forest Experiment Institute of Lower Saxony. The Institute is working out volume tables for individual trees and stands. The Section has under observation those experimental plots of the former Prussian Forest Research Institute at Eberswalde to which it still has access and parts of which have been the subject of accurate observation for 70 years. Particular stress has lately been laid on ascertaining and evaluating the properties of individual trees in these areas under various treatments, and on research into the structure, increment and biological characteristics of mixed stands. Section B of this Experiment Institute (Control of Forest Pests) in Sieber/Harz is not a university institute. At present, research is being conducted on the control of the larvae of Melolontha vulgaris and the large brown snout weevil, as well as on such pests as the oak-leaf roller and the small spruce sawfly. Special research is being done on infestation causes, prophylaxes and direct and indirect control measures. Work is also being done on the dieback of beech trees, with particular reference to the beech aphis and Buprestidae. A regular job of the Institute is the testing of insecticides. The Institute of Forest Utilization is investigating primarily the properties of unprocessed wood and the effect of climate, soil and forest treatment upon timber qualities and defects. Studies are also being made on quality changes between felling and processing. The Institute is also studying the expansion of Central European wood extraction techniques and the improvement of logging methods in permanent forests.
University of Munich
In the Department of National Economy of this University there is a Forest Research Section comprising 10 institutes covering the following subjects:
Forest Seed and Plant-breeding,
Soil and Habitat,
Forest Economic Policy and Management,
Wood Science and Forest Utilization.
The Munich research establishments have not yet had war-damage completely restored so that research work is still greatly impeded. The Institute of Forest Botany is well known for its long and comprehensive study of tree-ring chronology in Central Europe. The Forest Seed and Plant-breeding Institute is concentrating on forest tree seed problems. The Soil and Habitat Institute devotes attention, in addition to soil science and ecological problems, to the systematic improvement of methods of surveying and to the organization of work in forest site determination, combining with work on geology, soil analysis, vegetation, and forest history. At the Meteorological Institute, valuable research has for years been carried out on the extent to which the microclimate is affected by silvicultural measures and on the specific weather conditions which may cause forest fires in Central Europe. The silviculture tradition at the University of Munich, which, since 1878, has become famous with the names of Carl Gayer, Heinrich Mayer and Ludwig Fabricius, molds the present and future work of the Institute of Silviculture. The latter is concerned mainly with problems of mixed stands, the intensification of forest care, forest sociology in the broader sense, and forest geography in the form of forest site surveys. In the scientific work on these problems, particular emphasis is laid on the review of practical silvicultural results. The Institute of Wood Science and Forest Utilization is primarily interested in biological research.
THE FEDERAL INSTITUTE AT REINBEK
As a result of World War II and its aftermath, all the Reich institutes dealing with the forestry and wood economy sectors were rendered ineffective and it was not until 1947 that the Federal Institute of Forest and Wood Economy was developed at Reinbek near Hamburg out of the former Reich Institute of Foreign and Colonial Forest Economy. It includes the Institutes of Forest Economy and of Wood Economy and Research, which are also branches of the University of Hamburg, where the Department of Mathematics and Natural Sciences offers an 8-semester course for foresters (this was given at Eberswalde up to 1945). In addition, there are at Reinbek post-graduate study facilities consisting of lectures, seminars and practical work in world forest economy and exploitation. The work of the Institute of Forest Economy, with its 5 research sections, is concentrated on the following subjects: analyses of the forest products economic situation in the world following World War II; evolving reliable scientific methods of analysis and forecast, especially for appraising the industrial potential of economic forest management units; technological and regeneration methods for reconstituting woodland and increasing production in existing commercial forests. Furthermore, it is one of the tasks of the Institute to evaluate foreign 'literature on silviculture and make it available to German foresters and to promote and strengthen ties with foreign forestry institutes.
The work of the Forest and Wood Economy Policy Section centers on the collection and processing of home and foreign statistical data and their compilation in documents, statistical card indices and a world forest 'atlas. Work is also being done on inventory procedures on a sampling basis. The main current work in the Forest Ecology and Soil Science Section concerns comparative studies on ecological aspects of growing domestic and exotic tree species, with particular attention to the poor diluvial soils of northwestern Germany. In the Forestry, Silviculture and Forest Protection Section, research is under way on the technique and prospects of afforestation of wasteland, the application of laws of growth to the diagnosis and forecast of increment, seed physiology and the root system of forest trees. For practical purposes, tree diseases and the biology of forest pests, particularly in exotic tree species grown in northwest Germany are being observed. The Forest Engineering and Utilization Section, still in the process of being built up, has started research on the improvement of extraction and transport. The Forest Genetics and Forest Plant Breeding Section with its 20 hectare Tannenhoft arboretum has been very intensively developed since 1948. Furthermore, it is to be expanded into a very much bigger institute, because in this field Germany has to make up for much lost time. An inventory of parent stock and grafted plantations is being established. Progress has been made with hybridization of Larix, Pinus and Picea, and the breeding of Populus and Betula. The Institute of Applied Mycology and Wood Protection in Hann.-Münden is, a federal agency conducting official tests on forest protection measures under the auspices of the Federal Biological Institute of Agriculture and Forest Economy at Brunswick. Of its work a recent investigation on the cause of the misnamed "beech dieback" is particularly worth noting.
THE FOREST EXPERIMENT STATIONS
German Länder without forestry schools have forest experiment stations responsible directly and solely to the forest administration. They continue the work of decades in existing experimental plots, and tackle current problems of urgent interest to the forest administration of the particular Land. Certain priority has recently been given to the evaluation of old experiments and the starting of new ones on fertilizer application, techniques, costs and the consequences of new growth care.
This group of research establishments comprises:
The Hessian Forestry Experiment Station at Giessen, Brandplatz;
the Wuerttemberg Forestry Experiment Station at Stuttgart and Tübingen;
the North Rhine-Westphalia Forestry Research Institute with the Institute of Silviculture at Bonn and the Institute of Growth Research at Lintorf near Düsseldorf.
The last of these has begun operations that go beyond the present scope of work of the forest research stations, as outlined above. The work being done there includes the measurement of respiration and transpiration of the most important European and North American trees to be introduced in the near future, in order to determine the intensity and economy of their metabolism their reaction to the lack of light, drought, waterlogging, soil acidification and lack of certain nutrients in addition, research is being conducted on heat generation of various trees.
PRIVATE RESEARCH STATIONS
There are at present only two non-governmental institutes, in the Federal Republic.
The Institute of Logging at Reinbek near Hamburg, formerly at Eberswalde, which this year celebrates its 25th anniversary, has greatly influenced work methods in logging industries and the training of forest workers. Priority is given to the study of the effect of various conditions of work on the physical well-being of the workers.
The Scientific Institute of the German Poplar Association at Brühl near Cologne is working out the basis for as broad an expansion as possible of poplar cultivation outside the forest proper, particularly in commercial plantations. The study of these problems is of particular interest to the German pulp and paper industry which is suffering from a shortage of raw material.
To sum up, the University Institute and the Länder Experiment Station are working mainly on regional forestry problems of their respective Länder, and particularly on site appraisal, silviculture and forest management, while the Federal and non-governmental institutes handle supra-regional matters. However, this division of labor is not clear-cut or absolute, for all research, workers are allowed, after having fulfilled their assigned duties, the time and the means to pursue research work of their own choosing. In this manner the most important problems are being investigated by various institutes and often by different methods. This undoubtedly shows the possible advantage of spreading German forestry research over a large number of relatively independent institutes. A notable disadvantage of such -an arrangement is, however, that as a result of splitting up the generally limited research funds, certain unavoidably expensive research work can only be inadequately dealt with, if indeed at all. Research institutes doing this type of work will therefore have to be provided with funds for the specific purpose. Thus, for example, the following activities might be promoted: the development of rational statistical methods for assessing stock, growing increment and forest output; the working out of practical, effective methods for improving degraded stands (farm-forests) and for the afforestation of wastelands; work on genetics and breeding of forest plants.
The results of the research of German institutes are published in several professional journals. The teaching staff of the Freiburg and (Hann.-Münden) have collaborated for 123 years in the publication of the "Allgemeine Forst- und Jadzeitung"; "Forstwissenschaftliche Centralblatt" (Central Forest Science Journal), has been for the past 71 years, the organ of the Munich Institutes. Both publications carry original articles on problems and results of research in various German forest areas. The "Forstarchiv" prints, in addition to short articles covering the latest scientific and technical achievements, a very careful and comprehensive abstracts section; the "Zeitschrift für Welforstwirtschaft" is the organ of the Federal Forestry Institute at Reinbek. It prints original papers particularly those dealing with the world-wide interdependence of forestry and wood-using industries. The very exhaustive abstracts section is also world-wide in scope. A new paper, "Zeitschrift für Forstgenetik und Forstpflanzenzüchtung", edited by the Forest Genetic Section of the Federal Forestry Institute is in its first year.
To the above list should be added the following publications, which do not appear regularly but only when valuable original contributions are to be published: "Schriftenreihe der forstlichen Fakultät der Universität Göttingen"; "Mitteilungen aus der Staatsforstverwaltung Bayerns"; "Schriftenreihe der badischen forstlichen Versuchsanstalt"; "Mitteilungen und Merkblätter der Bundesanstalt für Forst- und Holzwirtschaft" including the supplement ''Bibliographie des ausländischen forst- und holzwirtschaftlichen Schrifttums". Finally, we should mention the "Allgemeine Forstzeitschrift" and "Forst und Holz", which endeavor to inform the broad group of forestry workers, including those in the middle and lower grades, of advances in the field of forest economy.
Seven years after the end of World War II, there are again 40 institutes of varying sizes doing fruitful forest research work. As yet, not all the ravages of the war have been made good and several institutes are not working to capacity through lack of adequate equipment and working capital. The reorganization of German forest research, however, has probably now in fact been completed.
A Central National Institute of Wood Research, replacing the Prussian Wood Research Institute set up in 1934, was established before World War II at Eberwalde. On the collapse and partition of Germany, it ceased to exist, and the revival of timber research in West Germany has been slow and difficult; but important results have been obtained and this paper is an attempt to survey some of these achievements.
BIOLOGICAL WOOD RESEARCH
H. von Pechmann is in charge of the Institute of Wood Science and Forest Utilization at Munich. He recently issued a short bulletin on the "Basic problems of growing commercially valuable timber", a subject which is the prime concern of biological wood research. Besides correct seed selection, care of the stand is a decisive factor. From investigations of stem growth in pine, it would appear that timely thinning of young stands is essential to produce the best quality logs and prevent decreasing width of annual rings if crown development is hindered, permanent loss in increment results. This applies equally to larch. Broader annual rings characterize the better quality and tougher woods of ash, oak, and elm and inadequate crown development detracts from wood quality. Quick grown broadringed wood is desirable in beech, and only ash veneer wood should be fine-ringed. Von Pechmann's studies have been carried out in collaboration with the Institute of Silviculture; the effect of natural phenomena and weather, hail storms for example, on increment and the quality of wood are also being investigated.
Von Pechmann, together with O. Schaile, has further improved the impact bending method for testing the natural durability of woods and evaluating the consequences of fungus infestation and the effectiveness of wood preservatives. In this process, wood specimens measuring 8.5 X 8.5 X 120 mm are enclosed in a Kolle container with pure cultures of wood-destructive fungi; the test takes from 10 to 60 days. It was found that within a few weeks, dry rot almost entirely destroyed the strength of the wood. A loss of weight of only 5 percent corresponded to a 60 percent loss in impact and fracture resistance. Chemical analyses showed that alkali solubility was the best measure of the reduction of chain molecular structure. Further and more extensive series of experiments and additional field work are planned. Von Pechmann has also carried out impact and stress tests, as well as additional microscopic and chemical investigations on infected and non-infected sections of individual wood specimens, with a view to determining more accurately the effect of "red stripiness" on the properties of spruce and fir.
Work at Hann-Münden
A particularly interesting piece of work has been done by Mayer-Wegelin at the Hann-Münden Institute of Forest Utilization. Great variations in thickness and hardness inside the annual ring seriously affect wood quality, but it has not been easy to assess these features by testing methods hitherto used. There is, however, an easily-made instrument, the "Härtetaster", with which variations in the quality of the wood along the radius of the stem can be determined by the depth to which a thin needle penetrates at a number of adjacent points. The boundaries between spring and autumn wood, that can otherwise scarcely be determined, are clearly distinguishable. Mayer-Wegelin has also worked on the special properties of poplars, the problem of removing bark from beech, and the effect of hardening on the properties of beech.
R. Schober, at the Institute of Forest Management and Production, Hann.-Münden, has published a basic treatise on the formation of the annual ring structure, and has also written on the effect of drought on wood formation. His institute has also been working for some time on the preparation of grading rules for timber used for pitprops and for European larch.
Closely associated with wood research are technological investigations into the best designs for woodcutting tools. In this connection, G. Reissinger and H. Gläser (Research Station for Lumbering and Logging Machinery, Hann.-Münden) have done research on the most suitable shapes of axes, bringing out the effect of wood moisture content, angle of strike, cross-section and annual ring growth in the test material, and the best chip thickness.
At the Institute of Forest Botany at Munich, B. Huber and his students have made some remarkable contributions to biological wood research. They have further developed a system of annual ring chronology, based on the supposition that the width of the annual ring can in all probability serve as a direct measure of rainfall during the growing period. This is of value not only in meteorology for ascertaining climatic changes in the past, but also to forest history. Mention may also be made of work on the physiology of bark peeling in spruce and oak, on the structure of pine wood, on domestic sources of tannin supply, and the pathology of Armillaria mellea.
Interest in Poplars and Willows
Poplars, on which much interest is focussed in German forestry, has been dealt with in two publications, "Pappeljahrbuch 1947" (Poplar Yearbook) and "Pappelbuch" published by H. Hesmer. In these publications, well-known experts have dealt with the biological properties, culture, and utilization of poplars. The mechanical and chemical properties of poplar wood and their improvement are also discussed, as well as the economic significance of poplar growing and its relation to agriculture.
Special attention has been devoted by the Institute of Logging at Reinbek to the willow as another quick-growing, soft, deciduous species. This Institute is working on the rationalization of logging operations, studying the utilization of previously disregarded material useful in agriculture, for instance as supports in market gardens. Since knowledge of true solid content is essential for accurate time-studies, volume determinations on a number of commodities (logs, poles, pulpwood, and pitprops) have been made.
Wood preservation has always been regarded as essential to the economic use of commercial timbers, and has been increasingly studied in Germany since 1945. The Berlin-Dahlem Materials Testing Laboratory has produced no less than 46 publications on wood preservation since 1946. The Wood Preservation Section now has seven laboratories, three fully automatic air-conditioned rooms, some experimental cells, and roughly 2,000 m3 of land for field experiments.
Some of the many research problems dealt with by the research staff are the testing of woods for resistance to white ants; the reaction of woods to salt impregnation; the effect of coal-tar oil preparations on insects and fungi; the ecology of the beetle Hylotrupes bajulus; new tests and experiments with wood preservatives.
H. Seekamp has been working on the prevention and combatting of fire. A particularly important piece of research has been carried out on iron corrosion caused by wood preservatives, and a considerably simplified form of the vat-dipping process for the preservation of woods has also been tested.
W. Bavendamm, at the Federal Institute of Forest and Wood Economy in Reinbek, has conducted systematic investigations on the effect of the chemicals used in wood preservatives on fungi, and his conclusions are that the hitherto customary practice of evaluating wood preservatives only on the basis of the degree of penetration achieved is unsatisfactory, since there is no uniformity in results. This explains discrepancies between experimental results and practical experience. The test should rather be the concentration of the "preservative liquid" on penetration. Many other activities connected with testing the natural durability of woods, termite-resistance, deep impregnation, and the collating of all relevant literature are carried on at Reinbek. W. Sandermann and his colleagues in the Wood Chemistry Section have also concerned themselves with the chemistry of wood preservation. Wood preservation has in the past tended to be a subject for the pathologist and entomologist, and from this point of view, research had probably been carried as far as it could go. There is no doubt that many problems can still be clarified with the help of the chemist and his more perfected techniques. A first report by W. Sandermann, E. Schärfe and O. Froede relates to the depth of impregnation of corrosive sublimate in ordinary and improved cyanization. By means of a new calorimetric mercury determination, it has been possible to show that the true depth of impregnation of spruce by the sublimate is some 15 mm. more than that shown by darkening with ammonium sulphide. With a mixture of 66 percent sublimate and 6.6 percent salt, impregnation by the vat-dipping process can be increased 4 to 5 times. When steamed to 100° and 120° C., a spruce log 12 cm. thick is almost completely impregnated.
W. Liese, at the Institute of Applied Mycology and Wood Protection at Hann.-Münden, which is under the direction of H. Zycha, has carried out investigations on impregnation with oily wood preservatives. He found that the poor absorption capacity of spruce is due to an irreversible closing of the tracheids. In air-dried wood the closing of the tracheids can he arrested or relaxed by various treatments. In green wood, preliminary alcohol or acetone applications, keep the tracheids open, and the timber can be fully impregnated with oil.
An important piece of research by H. Zycha concerns "red heart" in beech. The theory has been evolved that impregnation of the tracheal cavities with oxygen is sufficient to cause tylosis. Investigation of water distribution in standing beech stems shows that red heart always penetrates to the point where the water content reaches some 60 percent, in relation to dry wood. All the capillaries remain free of water while the conducting cells still retain their turgor. Since culture experiments show that red heart only occasionally contains fungal hypae, its formation cannot be a reaction to fungus irritation but must be physiological. "Frostheart" or dieback due to frost is a particularly severe form of red heart, caused by excessive air penetration of the trunk. Hardening in beech wood is a matter of localized change from sapwood to hardwood. Preventive treatment promises results only if the air and water conditions are taken into account. Zycha has also established a procedure for testing recently developed chemical preservatives against blue stain, which according to recent results, gives quick and reliable figures.
Some other activities connected with wood preservation which may be mentioned are research by K. Gösswald, Institute of Applied Zoology, University of Würzburg, on the protection of standing timber against insects; by W. Zwölfer, Institute of Applied Zoology, University of Munich, on the control of bark beetle pests of oak; H. Stolley, Institute of Wood Research, Brunswick-Querum, on the protection of synthetic wood products, particularly chipboards, against, wood-destroying fungi and termites; H. Schmidt, Reinbek, on the protection of industrial timbers against termites, Teredinidae, and noxious beetles.
Wood chemistry research extends far beyond the province of forest and timber economy and cannot be dealt with at length in this paper. It should be remembered, however, that without knowledge of wood constituents, their formation and association in the cell-wall, it is impossible to assess many -physical and mechanical wood problems. For example, the chemical structure of wood and of cellulose explains swelling and shrinkage, elasticity, and other physical properties. The correction of collapse, which is of major interest to the mechanical wood industry, is a chemical problem; and the majority of wood discolorations can be explained mainly on chemical grounds.
Much important work has been done in West Germany in these and similar fields. There is, first of all, the work of H. Staudinger, who celebrated his 70th birthday in March 1951. Staudinger is the founder of macro-molecullar chemistry and the creator of the empirical viscosity equation which has made it possible to determine the average chain length of substances like cellulose and their associated carbohydrates. He has also investigated and demonstrated the connection between physical properties and degree of polymerization of celluloses, and found that the cellulose filamentary molecules can undergo a series of stages of crystallization. His work since 1945 and that of his school would alone fill a separate article.
K. Freudenberg and his school, at the Chemical Institute of the University of Heidelberg, have been doing basic research on lignin, the second most important constituent of wood. Publications have recently been issued on the bio-chemical synthesis of lignin-like substances, on spruce lignin and its synthetic production, on soluble lignin from spruce and beech, and on infra-red spectra of lignin and lignin-soluble substances. It has been possible to separate out lignin from wood in an apparently unchanged state, so that it can now be compared with synthetic lignin. It has also recently been possible to synthesize sinapin alcohol, the basic element in hardwood lignin.
,Much significant work has been done since 1945 by G. Jayme and his colleagues at the Institute of Cellulose Chemistry, Darmstad Technical University. Jayme and M. Harders-Steinhäuser have been studying a new method for microscopic detection of proto-lignin in plant cell-walls, and its application in beech. The problems of the chemical definition and utilization of quick growing poplar wood have also been studied. One investigation dealt with the influence of variety and site on the chemical composition and suitability of poplar woods for cellulose manufacture; other studies dealt with the determination of cellulose content and other chemical research on poplar woods.
At the Institute of Papermaking, W. Brecht has been exploring the multiple problems of papermaking technology, ranging from chemical and structural comparison of cellulose through bleaching to infra-red drying. Mention may also be made of W. Klauditz's work on the chemical composition of beech and poplar wood and many similar subjects.
Finally, recognition must be accorded to the wood chemistry work carried out in the sections concerned at Reinbek. R.O.H. Runker has devoted attention to the dissolving of wood with sodium chloride, the utilization of eucalyptus wood for cellulose production, and, above all, to wood molding by the application of heat. Besides his work on wood preservation, W. Sandermann has been working on the chemical utilization of tree stumps, the transformation of lignin and wood with anhydrids of dicarboxylic acid, and the effect of chemical factors on the strength of cement-bound fiberboards.
MECHANICAL WOOD TECHNOLOGY
In view of the present need for rapid application of the findings of research in mechanical wood technology, attention has been focussed on the following points: wood seasoning with its basic physical laws; the elasticity and strength of wood and wood-derived materials; improving the economic status of wood, that is to say, creating new and valuable wood products; glued woods; wood processing; and the economical use of wood in construction. F. Kollmann and R. Keylwerth, at Reinbek, have published a bulletin "Beiträge zur Kraft-und Wärmewirtschaft in der Holzindustrie" (The use of power and heat in the timber industry), which is the first of a series entitled "Holzfragen der Gegenwart" (Present-day timber problems). The second volume in this series comprises several reports by Kollmann on the wood economy, research and timber industry of Sweden where he worked for some years On many problems. Continuing the work he started in 1932, Kollmann has devoted further attention to the properties, testing and grading of fiberboards and chipboards.
After several years' work, the first volume of the completely revised and greatly expanded second edition of the book "Technologie des Holzes und der Holzwerkstoffe" (Technology of timbers and wood materials) was brougth out in 1951. The periodical "Holz als Roh- und Werkstoff" (Wood as raw and industrial material) began to be re-issued in 1951.
R. Keylwerth has dealt with the mechanics of wood shrinkage, the simultaneous drying and impregnation of wood with hot oils, the relation between cleavage, shear resistance and lateral strength of woods, stress distribution in the traction joints with varying profiles or sections, the anisotropic elasticity of wood, and veneer drying. Courses at Reinbek devoted to special problems of wood technology have been greatly appreciated by the timber industry and trade, and have made it possible to demonstrate the equipment of the Institute to a wide public.
The wood physics and technology section has, in addition to strength-testing apparatus, an experimental drier with an infra-red chamber, high-frequency generator and the necessary optical and physical instruments.
The Institute of Technical Wood Research at the Stuttgart (under O. Graf and his deputy K. Egner) is mainly concerned with testing and research in organic or related building materials. In addition to determining the mechanical properties of woods, and of building and industrial materials containing wood, investigations are carried out on glueing, wood seasoning and heat drying; the behavior of wood-bonding materials, and of building and construction parts; injuries of all sorts to wood, and the behavior of wood in the event of fire. Vapor condensation in building materials and building parts is being studied, and research is also being carried out on the thermal properties of wooden floors as compared with other types of flooring.
Testing timbers and materials
The Stuttgart Institute has at its disposal wood-processing machinery a great variety of apparatus for testing static and dynamic stresses, a high-frequency plant, two wood-drying kilns, three air-conditioning plants, one tropical chamber, refrigerators, and a great variety of measuring instruments. The Berlin-Dahelm Materials Testing Laboratory is studying tensile strength problems of construction of timbers. A. Troche, professor of building techniques and timber construction at the Hannover Technical College, has been carrying out research on frame building designs.
In the Organic Materials Section of the North Rhine-Westphalia National Materials Testing Laboratory, the whole range of fuel and accessory material.,; and of solid building and industrial materials, is being worked on. A chemical laboratory analyses glues, paints and impregnating substances; there is also a fully equipped technical laboratory where wood and wood materials are tested, including a resistance-testing machine for loads of from 6 kg. to 100 tons. Another laboratory has been fitted out for research on wood preservatives, where research being carried Out included protection of poplar timbers, the interaction of glues and wood preservatives, and of wood preservatives and paints. W. Küch, the director of the section, is studying the durability of artificial rosin glues and has reported on his wartime experiments on producing improved wood by compression.
Research is also being undertaken on wood materials at the Wood Technological Laboratory, under A. Dosoudil, of the Bavarian Forest Research Institute. Material has been published on the durability of compressed woods and other subjects. Attention is drawn also to the work of H. Winter at the Machine-making and Light Construction Work Institute of the Hannover Technical College. Based on his wartime work on the principles of wooden airplane construction, he has compiled a useful book on construction with wood, with an abundance of figures, facts and diagrams. This Institute is also busy with the testing and utilization of semi-finished products and other non-metallic materials used in machine-making. H. Fahlbusch has produced a thesis on the bearing strength of bolts in wood under static loads.
This paper cannot be concluded without some reference to research work and publications relating to wood processing. In the Machine Tools Department at Hannover Technical College, work has been done under the guidance of O. Kienzle on wood screws, and the processes leading to chipping in milling machines. G. Pahlitzsch, head of the Department and Research Section on Machine Tools and Factory Management of the Brunswick Technical College, has issued a series of publications describing the latest position in wood-processing machine construction, Finally, mention must be made of the Experiment and Advisory Institute of Chemico-technical Wood Utilization at Hohenpeissenberg, the head of which, J. Rautnig, is an authority in this field.