LINCOLN R. THIESMEYER
I THIS PAPER the author intends that the word "technology" be used in its broadest sense as meaning the application of the botanical, biological and physical sciences, mathematics, various disciplines of engineering and computers to the forests and to the manufacturing industries based on them. Today there is an increasing tendency to regard the operations of growing, protecting and harvesting trees and transporting wood from the forests to the manufacturing plants as integral parts of the total production activity. In this concept, the forest becomes a part of the "total manufacturing plant." Sound forest management must, therefore, include increasing use of technology, as here defined.
Protecting the trees from the ravages of fire, insects and disease becomes a plant maintenance activity for the forest end of the total manufacturing plant. Its cost can be regarded in the same way as the costs of maintaining the machine at the mills. In forest protection we can anticipate much wider use of aircraft. In Canada hydroplanes have been developed for multipurpose use - in mapping and inventory, in the water bombing of fires, in fire patrols to detect and locate incipient fires, both visually and with the use of infrared devices, in spraying of insecticides and herbicides and in aerial fertilization. In North America there is increasing use of helicopters for these purposes; and the use of helicopters and balloons to assist in logging under special conditions appears to be practical.
The practice of selecting the best-shaped and most vigorous trees in an existing stand - which are referred to as "plus trees" - is spreading. Deliberately to collect the seeds from such trees for nurseries, plantations and reforestation and to leave a few such trees to bring back the next crop in areas where natural regeneration will suffice are modern applications of the science of genetics to forestry. Elaborate cross-breeding of superior types practiced by the Italians to produce fast-growing hybrid poplars has produced spectacular results. These hybrids have been transplanted to other latitudes with considerable success. This work will have far-ranging consequences, just as has been the case in the induced breeding of beef and dairy cattle by genetically superior bulls thousands of miles away. We can confidently expect that the forest of the future will be much improved through the gradual weeding out of the weaker and less desirable trees and their replacement by much better ones provided through applications of genetics. Moreover, in plantations on lands at present unforested and in plantations on cut-over areas we have the opportunity to plan the spacing of the trees in such a manner as to encourage optimum growth and the easiest and least costly harvesting procedures when these trees reach the size for thinning or for final cutting to provide both the best yield per acre and the lowest logging cost.
In the boreal forests of Canada, parts of Scandinavia and much of the U.S.S.R., black spruce is prolific in swampy areas; but its growth is rather slow because of the cold climate and the thick accumulation of undecomposed humus in which its roots spread. This humus contains nitrogen in a form not readily used by the trees as it is released too slowly. Also, these trees are subject to blowdown because of their shallow root systems. These problems are being studied intensively by the Pulp and Paper Research Institute of Canada, from both chemical and microbiological points of view. A breakthrough in this research, applied across northern latitudes, could mean tremendous increases in growth rates and thereby large additions to the wood supply of highly desirable species for pulping and papermaking.
A paper presented to the Sixth World Forestry Congress by the president of the Pulp and Paper Research institute of Canada.
A few years ago, the executives of the lumbering and pulp and paper industries seemed to regard fertilization of forests as something which only governments could afford to do because it would take such a long time for the results to be useful industrially. However, in Sweden it has been established that fertilization of an existing stand creates an immediate response in increased growth, an effect which persists, in diminishing values, over a period of five to ten years from the time of application of the fertilizer. Fertilization of near-mature trees five years before cutting brings about a sufficient added increment in growth to pay for all the costs of fertilizing and, by increasing log diameter, reduces the cost of logging. Other research in fertilization has shown that it not only increases growth but also makes the trees more resistant to certain types of insect and bacterial or virus attack. Fertilized trees are bigger and healthier.
Rapid diagnosis of nutritional deficiencies through foliar analysis and speeded-up pot trials in greenhouses, together with improving knowledge concerning the optimum quantities of macronutrients, micronutrients and trace elements which particular species require for optimum growth and vigor, now make possible determination within a few months of what treatments should be applied and to what extent quantitatively. The benefits of forest fertilization can be seen immediately. Application of nutrients does not have to be made every year, as with agricultural crops; and the allowable cut in the year following fertilization can be increased because a step has been taken to improve the growth rate immediately and for several years ahead. Hence, the attitude toward aerial fertilization of forests has changed. Now many thousands of acres are being sprayed from the air with pellets of fertilizer. This practice will undoubtedly spread widely and have a tremendous impact on the available wood supply. However, there is much yet to be learned about the most suitable time for applying fertilizers to particular forest sites and species.
In North America, within the last 20 years, power saws have virtually replaced hand saws for cutting and delimbing operations, even with the very large trees of the West Coast. Now the power saw is being replaced by the hydraulic shear which can snip the tree off close to the ground, leaving very little or no stump. Along with this there has been rapid development of portable debarkers, and now of a machine which can square a log for lumber while at the same time producing chips from the semicircular slabs and edgings.
The extent of logging mechanization in major wood-producing countries during the past 20 years is nothing short of astounding. In vast areas the horse has been replaced by the tracked or wheeled vehicle. In this activity there are two well-defined trends. One is toward vehicles which approach the tree and carry out a sequence of processing operations such as felling, delimbing, perhaps debarking, cutting to log lengths and placing these aboard the back of the vehicle, or bunching and piling them for forwarding to a loading by yet another vehicle. Mechanized logging involves the development of a family of mechanized equipment to operate between the stump and the transportation system. Perhaps in the not too distant future, present-day systems will be replaced by a large, stable moving platform which has on it all of the equipment necessary to reduce a tree to chips which can then be blown, or otherwise transported rapidly, to the head of a chip pipeline transportation network.
The other system of mechanized logging involves felling the trees and dragging them with crowns attached to a platform on which the subsequent operations of delimbing, debarking, cutting to log length and perhaps even chipping can be carried out. This full-tree logging brings to one location all of the branches and foliage which would otherwise be left as slash in the cutover area - as a fire hazard on the one hand and as a protection for seedlings and a source of returned nutrients on the other. Something must be done with this slash at these central processing plants. Either it must be spread back on the land to provide protection for the next generation of seedlings and nutrition when it decomposes, or it must be suitably processed and sent to the mill for use in the manufacture of other products. Thus full-tree logging has inherent in it the possibility of full-tree utilization. U.S.S.R. scientists and logging engineers obviously had this possibility in mind when they sent batches of chips made from stem wood, followed by batches of chips made from branches, followed by batches of chopped bark, followed by batches of needles through their experimental chip pipeline. Today, there is much discussion as to whether removal of whole trees in full-tree logging will carry away substantial quantities of the necessary nutrients for the next generation and thereby deplete the soil so that subsequent fertilization will be required. Exceedingly painstaking and detailed research will be needed to answer the question. In any event, perhaps the economic advantages of full-tree logging and full-tree utilization will more than compensate for any required fertilization afterward.
The effects of mechanized logging on the site, particularly with reference to damage to the second growth, are not yet known. This matter is being studied on a systematic basis in Canada. Again, it seems likely that the economics of mechanization may be more than adequate to pay for remedial treatments. In areas which do not normally require planting, moderate scarification to expose mineral soil to the fall from seed trees may be sufficient to compensate for damage to seedlings produced by tracked and wheeled vehicles.
Pioneering studies have been made in Canada as to the possibility of transporting wood in the form of chips in a water slurry overland through pipelines from the forests to the mills. This is also now being studied in the United States, the U.S.S.R. and Japan. The technical feasibility of this form of transportation has been well established by the Canadian work, and there is talk of hydraulic chip pipelines in many countries. In general, it can be said that chip pipelines will only come into use where there is the possibility of accumulating at the head of a pipeline a sufficient quantity of wood chips (say 250,000 cords per year) to keep the pipeline operating 24 hours a day all year round. There well may be exceptions to this, of course, in situations where climate, terrain, profile, mill size, etc., would make the pipeline an attractive proposition. Negotiations are currently under way to build the first commercial prototype of a chip pipeline in western Canada. Clearly, the economics of the use of this form of wood transportation will only become known from the operation of such a commercial prototype. Thereafter the economics of each proposed installation will have to be studied as an individual matter. The number of variables to be taken into account in each case will be large. The potential advantages which can accrue from the use of chip pipelines have been well documented in papers published by our research institute at Montreal. Collectively they represent such large possible savings in costs as to warrant careful study of the matter by each company in the industry.
This brings us to a consideration of what is going on at the mills which may have an impact on what is practiced in the forests. There are strong efforts to establish correlation between the morphological characteristics of the wood in different species and from different sites with the end properties of the pulps and papers which can be produced from those woods by the various mechanical and chemical treatments of mill practice. This is tedious and time-consuming research. Success in it may, however, make possible the hand-tailoring of pulps for particular products from selected species or mixtures of species, or from selected sites, or from mixtures of wood from several sites. Such studies of wood quality or wood characteristics can lead to much more scientific selection of the raw materials for processing. These studies also bring in the* train investigations as to the manner in which the wood characteristics are modified by fertilization at various stages during the growth of the tree from a seedling until it is eventually cut.
In the mechanical or chemical processing of pulp in paper manufacture, changes are coming which are nothing short of revolutionary. One of these is the making of superior groundwood with refiners. This has spread so rapidly in recent years that, today, over a million tons of such superior groundwood is being made on a world basis. And new newsprint mills are being designed with nothing but refiners, in place of grinders. Thus, newsprint manufacturers are becoming interested in having a supply of chips delivered to their mills, perhaps by pipeline in some cases, rather than building huge blockpiles of logs.
The chemical pulping process has not changed materially since it was introduced about 100 years ago. The chemicals used for the dissolution of the lignin have varied in both the acid and alkaline types of pulping. But the cycles have remained long, the cooking being carried out while the chips were steeped in an excess of the cooking liquor for hours. Until the late 1940s or early 1950s, pulping was accomplished on a batch basis. Now there have been introduced a number of types of equipment for cooking on a continuous basis. During the current half-century the kraft process has spread to dominate the chemical pulping industry, both because of the stronger pulp it produces and because a recovery of the chemicals was made possible by the introduction of the Tomlinson furnace. More recently, the neutral semichemical process has spread because it makes possible the utilization of hardwoods. This year marked the introduction at a mill scale of a new continuous, rapid, vapor-phase kraft pulping process developed by the Pulp and Paper Research Institute of Canada. At the Red Rock, Ontario, mill of Domtar Limited, conventional kraft pulp of high quality is being made in a 150-ton-per-day continuous digester. The cycle is less than one hour, in contrast to the conventional cycle of 3 to 3½ hours. This could start a trend toward smaller equipment operating under closer control, better uniformity of product, lower consumption of chemicals and smaller capital cost.
In North America the customers of our industry have been demanding brighter and whiter papers and boards for printing their advertising in color. This has forced the industry to add more stages to its bleaching operations, almost to the point of no return. Extracting the last bit of residual lignin and making the product a few points higher in brightness is decidedly costly. It has led to more than six or seven stages in the bleaching sequence, each of which is carried out with the pulp at low density and requires hours and large capital-costly equipment. It is now said that the cost of the bleach plant alone of a modern kraft pulp mill is as much as the cost of everything which precedes it in the sequence of pulping to papermaking (half of the total mill cost for bleaching alone). This trend must be reversed.
Professor Howard Rapson and his associates at the University of Toronto in Canada have done excellent pioneering work in finding improved procedures for the brightening of groundwood and for bleaching paper on the machine rather than bleaching the pulp before it is formed into a sheet. The Pulp and Paper Research Institute of Canada and others have been studying a sequence of bleaching in the vapor-phase with pulp at high density, taking advantage of all of the specific surface of the pulp when it is in turbulent suspension in gases. We have developed a three-stage sequence which will bring a kraft pulp to an 80 G.E. (General Electric) brightness in a few minutes, rather than in several hours. This is now being studied on a pilot scale also by one of our supporting member companies, and we are planning to take it to a pilot scale. Here again, the speed and simplicity of operations may mean large reductions in capital-plant and operating costs.
The Fourdrinier paper machine has not changed materially since it was introduced over a century ago. It has become wider and longer and operates far more rapidly. A few improvements such as vacuum pick-up and the substitution of foils for table rolls have improved its operation. But in recent years it has been found that, when a sheet is formed between two wires with drainage in opposite directions, rather than in only one direction as in the standard Fourdrinier, much faster operation is possible and there are other improvements in paper structure and quality. Such operation was first tried at the Thames Board Mill in the United Kingdom. The name Inverform was given to this modification of the conventional Fourdrinier wet end. Subsequently, Time, Inc. in the United States made modifications to this design; and the Beloit Corporation of the United States acquired the rights and is marketing such a machine under the name Twinverform. The first version of this has been in operation satisfactorily at a mill of the Kimberly Clark Corporation at Niagara, Wisconsin and a second one is scheduled for production at a mill of the Crown Zellerbach Corporation of Florida.
A different configuration of the two-wire machine is that produced by the Black Clawson part of the Parsons & Whittemore organization of New York. This is known as the Verti-forma because in this machine the stock comes down vertically between two wires which have opposing foils and vacuum boxes to remove the water in two directions. It is understood that this machine is about to go to the first commercial prototype at a mill in the near future. Obviously, such a machine will produce a paper which has no two-sidedness, as does paper produced on the conventional Fourdrinier which has drainage in only one direction.
The Pulp and Paper Research Institute at Montreal has under active development a third version of a two-wire machine which is called the Papriformer. In this machine, the stock comes in from a specially designed new headbox, produced by Dominion Engineering Limited of Montreal, horizontally between two wires, tangentially to the bottom of a lower forming roll. The sheet is formed instantly and then carried up over a second roll to complete the water removal operation to a degree corresponding to the couch roll section of the wet end of a Fourdrinier machine. Newsprint has been successfully made on this experimental machine at 1,200 meters (4,000 feet) per minute and a sulfite bond sheet at 518 meters (1,700 feet) per minute. It is not yet possible to get an undistorted sample of this sheet at speeds higher than about 550 meters (1,800 feet) per minute. Hence, a conventional press section and a conventional drier section are being installed so that it will be possible to check out the properties of the sheet after it has been given conventional pressing and drying treatment. On the basis of Canadian experience in this type of work, it is believed that the information necessary to design and develop the first commercial prototype of the Papriformer is only about one year away
Each of these new machines has its advantages and its limitations. They will be discovered from operation of the first commercial prototypes. We do not regard any of them, including our own, as the last word in sheet formation. During the next few years "better mousetraps" may be devised by other workers. In any case, these two-wire machines mark decided advances over the conventional Fourdrinier. In the Verti-forma and the Papriformer there is a marked reduction in the length of the wires required, a complete elimination of table rolls and flat boxes, provision for a completely different structure of the sheet and a major potential reduction in capital cost. Moreover, because the flat boxes have been eliminated and the two wires are traveling at the same speed, there should be substantially increased wire life. This means reduced downtime for changing wires and the lost production which occurs during such changes. It is not yet known what the outside limits in speed of these two-wire machines really are. This will only be determined from operations at a mill scale. Speeds of 1,500 meters (5,000 feet) per minute are discussed with respect to the production of newsprint.
It would not make very good sense to speed up the production of newsprint and other grades of paper with these new paper-forming devices, if it is then necessary to add whirling tons of steam-heated metal at the drier section and to lengthen the building to accommodate the total, faster paper machine. Hence, new technology is urgently needed in the drying of paper. The research institute at Montreal is aware of this, and a new way of drying paper has been invented at a much faster rate (ten times that of conventional practice). This is at an earlier stage of development than the Papriformer and details are not yet available for publication. This combination of faster forming and faster drying should mean paper machines which are more compact and which cost a good deal less to build. They should be accommodated in buildings of much shorter length than those which characterize present-day operations.
The field of by-products recovery from both solid and liquid wastes of the pulp and paper industry has been slow in developing. This is because the quantities of material are so large, the processes for recovery are so expensive and the potential markets for recovery products are so small. Nevertheless, during this half-century there have been significant advances in this field. Today, tonnage quantities of such materials as turpentine, tall oil, vanillin, levulinic acid, dimethylsulfoxide, and lignosol chemicals and dispersants have been produced. Chemists have listed a whole range of products which could be produced from pulp mill spent liquors, if the markets for them were sufficient to justify the capital-plant installations.
One day, a situation will exist which the chemists have long predicted when the values recovered from the currently wasted raw materials will exceed in value the moneys now received from the cellulose fiber. In this field, the research institute at Montreal has been working to develop a new process (AST) which would recover the inorganic materials in pulping spent liquors plus some heat and, possibly, other chemicals. It has begun to study the possibility of producing tonnage quantities of gases from the organics in these liquors which might be used for synthesis of a range of exotic chemicals and plastics by the chemicals and petrochemicals industries. Such studies aimed at the reduction or elimination of pollution are becoming more and more significant in an environment in which legislatures are proposing more and more stringent standards for the treatment of the effluents from pulp and paper mills, both gaseous and liquid.
The burning of bark is, at best, only marginal in value. It is a spongy material, and when it goes through the bark presses it springs back to about 50 percent moisture. Burning at that moisture content is not very rewarding. Yet, bark contains useful fiber and chemical constituents which could be put to greater use. Much more research in this area is needed.
Techniques for technological forecasting have not yet been developed to the stage where one can quantify the forecasts: this is now being studied by the Organization for Economic Co-operation and Development (OECD). It is therefore not possible at the moment to provide a dollars-and-cents estimate of the impact of the technological changes described in this paper. Yet it will be appreciated that they could be substantial. Our industry needs: greatly improved raw materials from the forests; cheaper methods of transportation to the mills; more efficient, cheaper and faster processing at the mills; greater diversity of the product mix; increased utilization of more species and of more of the tree; and the recovery from wastes of even residual values, let alone new products. Better communications between the woodlands people of the lumbering and the pulp and paper and other forest products industries and the producing and research people at the mills are needed, and a greater willingness on the part of top management to experiment and to have a hard look at any new technology proposed.
From what has been said one can conclude that technology will not only keep the forest products industries viable but will improve them in many ways so that they can remain competitive with those other industries which are currently making inroads on their products with films, foils, and plastics. Developments in the pulp, paper and paperboard sector of the forest products industries certainly suggest that the forest-based industries will continue to be healthy for some time to come. If, eventually, our forests should be replaced by synthetic fibers, it may then be necessary to turn to the production of chemicals from a renewable resource available in large quantities. The oil industry, which is aware of the expansion of nuclear power, is currently spending millions of dollars on research aimed at the production of materials from petroleum and natural gas. Nuclear power is on the way in, and the burning of petroleum and gas and wood is on the way out. This change could take many years, or it could be accomplished in a generation or two.
Although it has not been possible to produce quantitative or dollar figures for the technological revolutions described here, it can be seen that the promise of technology to the pulp and paper, lumber and other wood-using industries is very great indeed.
