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The forest crop of the future - Quality or quantity?


Will quality or quantity be required in the forest crop of the future? This question is particularly important since a forest responds slowly to silvicultural treatment; a change in wood utilization trends in nature or degree therefore necessitates early action by the forester if advantage is to be taken of that change with the least delay.

In presenting one of the papers prepared by FAO for the Third World Forestry Congress at Helsinki, an FAO representative suggested at a plenary session that in the future forests may be required to produce quantity rather than quality. Several speakers supported that suggestion; the majority, however, deplored the idea, maintaining that the forester's aim will continue to be the production of crops of the highest quality. Since the matter was not pursued further at the Congress and was therefore left rather in the air, it may now be appropriate to elaborate the attitude of FAO's Division of Forestry and Forest Products in regard to this question.

The Helsinki Congress expressed the view that the primary task of the forester is to grow and produce both the amounts and kinds of forest products needed by industry and other consumers. It thereby implied that the requirements of the trade must be given first consideration in any attempt to lay down the general lines of a forest production policy.

Such a policy must be based on an appraisal of the long-term evolution of world needs. An appraisal of this nature can obviously only be made in very general terms. It can only consider industrial requirements on the world scale, whilst acknowledging that the development of these requirements will acquire varying emphasis in different parts of the world. Non-industrial requirements, such as firewood, must be largely ignored. No special weight can be given to the relative accessibility of various forests to factories manufacturing secondary products or to the extraction problems of different forest areas. Nor can consideration be given to any functions of the forest other than its production function.

The forester will be concerned with any trends revealed by the appraisal which will affect the object of management and therefore the treatment of forests. The extent to which forest management will be affected can similarly only be expressed in general terms, and this limitation may open certain loopholes, for objections owing to the fact that there will almost certainly be instances or circumstances which will not conform to the over-all general conclusions.

However, the major objection is likely to stem from alarm lest, in the fervor for chemical conversion and new methods of reconstituting wood, the old art of producing timber of high quality should lose its importance, and that henceforward it will be a question of crude mass production to feed these methods of utilization. We do not hold the view that for the future the forester's concept of "quality" is in danger. On the contrary, we are of the opinion that the need for "quality" as the forester sees it will remain secure, and in fact we think that the discernible trends will enhance the prospects for more intensive silviculture.

Apprehension seems to us to arise through a misconception of what is meant by "quality," and if that is so, it is desirable at once to attempt to clarify the meaning.

What is quality?

To answer this question, some definition of the term must first be attempted. Now the meaning of "quantity" is more or less self-evident, but unfortunately "quality" can mean one thing to the forester and something quite different to the trade.

When contemplating "quality" the forester thinks in terms of the forest stand, the tree, and the wood, and it is easy to imagine "quality" as embodying all three. The forester and the trade do not, however, always have the same outlook, and this is understandable. The forester naturally has what almost amounts to affection for a crop of trees he has nursed towards maturity, an affection that cannot be expected from the trade which views the forest mainly as a source of raw material, obtainable when its components - the trees - are felled at their due time. The forester cannot have quite the same regard for the wood as the trader does; the latter's main concern is with the wood and its conversion into manufactured or semi-manufactured commodities, a phase with which foresters, at least those who are essentially field officers, are not often intimately conversant.

Now quality may be judged by different criteria. First, "quality" may have reference to the wood it-self - the intrinsic properties or characters relative to the purpose for which it is required, such as density, hardness, strength, length of fibers, and figure.

Secondly, "quality" may refer not so much to the wood itself as to the tree which provides the wood. In such a case, diameter, length of bole, absence of knots, and grain will be the main features assessed. The forester may be able to influence the properties and characters in the group first mentioned, although the extent to which this is possible is not well understood and certainly not predictable. But in the case of this second group he can exert appreciable influence, subject naturally to local conditions of soil and climate. In particular, he can control diameter, but more of that later.

Thirdly, "quality" may also imply the general aesthetic appeal of a forest stand. To the forester a stand of high quality is one where the canopy is sufficiently dense, the soil good, and the trees tall and straight with well-balanced crowns. Certain of the properties and characters mentioned in the paragraphs above are of course inherent in these characteristics.

Fourthly, and finally, "quality" may be a general measure of the actual trade value of the wood or of the growing stock which produces it. A wood, tree, or stand is commonly assessed as of high quality because it is of high commercial value. But here one must be careful to distinguish between value relating to wood as raw material and the value in situ of a standing tree or a whole stand.

The value of wood is directly related to its usefulness for specific purposes, to the range of such purposes, and to quantities available. Its usefulness depends on its intrinsic properties, particularly the mechanical properties and sometimes the physical characters referred to earlier. A wood whose utility will serve a large number of different purposes is obviously of greater value than one whose utility is more limited. Relative abundance also affects the value: inadequate supplies may make for lower value but in certain cases and especially with ornamental timbers, the absence of a plentiful supply usually helps to keep up the value - a luxury value. A case in point is the timber from certain oak forests of Central and Western Europe. This timber is scarce but is naturally suited for high-class veneer, cabinet work, and so on, and on that account demands a high price. If, however, the special luxury markets should disappear, or if plentiful new sources of the same quality wood should be developed, the price of the wood would obviously drop, for in both cases the luxury value would be gone.

Value owed to a special supply and demand situation may fluctuate considerably, and often with suddenness. During the war, timber suitable for use only as fuelwood became very valuable because other sources of fuel were shut off. A more striking example is that of the "true firs" and hemlocks of the forests of the west coast of North America. The wood of these trees, which occur in mixed forests with Douglas fi, was formerly regarded as useless and there was no demand for it. However, the general shortage of timber during the war led to a search for new supplies, and it was found that with suitable treatment the wood of these species could be adapted to a great variety of uses. As a result, they acquired a value in their own right on the timber markets of this region.

The value of a tree or stand will vary with the market value of the timber, but the relationship between these two values will differ according to accessibility and relative difficulties of extraction. For instance, a forest which provides only a harvest of pitprops has naturally a higher value the nearer it is located to the minehead.

Trade "quality" and the forester's "quality"

In view of the varied interpretations which can be attached to the word. "quality," it is not surprising that the trade and the forester often tend to think in different terms.

For the trade the prime factor is the value of the timber, based on suitability for the purpose for which it is required. The user is not interested in the vigor, health, or appearance of the stand from which the timber has come. He assesses value according to utility and the extent to which the raw material measures up to the particular requirements of an industry.

But different industries demand different qualities in timber. There are two main categories of industrial users: one breaks down wood in its solid form, and sawmill operators are most numerous in this group; the other processes wood by mechanical or chemical means into a so-called "disintegrated" form, and here pulp manufacturers are clearly the most important class. (This classification excludes those who only deal in wood as potential fuel.)

For the first category of users, the quality of the timber is determined by those basic properties or characters of the wood or of the tree which we have already mentioned. The actual properties or characters favored depend on the uses to which the wood is put. The second category is less demanding and is not much concerned with characters of the tree itself; the only things that matter are certain properties or characters of the wood - for instance, density and nature of fiber walls in the case of pulp manufacture.

To the forester, "quality" is a subtle mixture of fine appearance and value. As regards value, he is more concerned with the value of the standing trees than with the value of the harvested timber. But, generally, the forester cannot help associating value with the general aspect of the forest crop.

It is to a great extent common sense, since pleasing appearance in itself presupposes certain basic characters, and an assurance that the individual trees will yield valuable products. But where there are no close working contacts between the forester and those who have to use the timber which he produces, the forester perhaps appears inclined to attach more-weight to the fine appearance of his forest than to the value of its products. Such an attitude cannot be justified today. The forester must adapt his methods of management so as to produce the amounts and finds of forest products needed by industry. The "beautiful forest" can no longer suffice as an end in itself; the forest must be capable of yielding the raw material most useful to the industries which depend upon it.

Diameter quality

Of all the factors which help to determine the value of the products of a tree, diameter is the one which can be appreciably modified by the forester.

Diameter has always been considered as a fundamental characteristic of quality. Apart from special cases, it still remains a basic element of forest management, in that a certain diameter is usually prescribed up to which trees are to be allowed to grow before being felled. Although under certain methods of management no fixed rotation or exploitable size is prescribed, it is nevertheless implicit that the aim of management of productive forest is to grow trees of the most economic size from the commercial standpoint.

The importance of diameter is easily explained. Once the species or several species required for a particular use have been selected, and so long as the timber is to be used in solid form, the principal element still remaining to be decided is the diameter limit, minimum or maximum or sometimes both, to be laid down for the trees destined for this use.

Except for certain special uses, such as pitprops, poles, or piling, trees of greater diameter are generally considered to be of higher quality. A tree of large diameter lends itself to a much greater variety of uses than a small-size tree. On the saw bench, in particular, large trees convert to greater advantage than small trees. Taking a combination of both chemical and mechanical utilization, the range of end products obtainable from a large tree is obviously greater than from a small tree.

Moreover, limiting the argument to mechanical utilization alone-and especially the production of sawn lumber, the proportion of wastage is less from big trees than from small. Other things being equal, then, the tree of larger diameter is generally considered of better quality.

The forester must obviously limit the diameter of the trees which he grows, either because the interest earned on the capital value of his crop declines after a certain age, or because he fears that overmature trees will decay, or because of the physical difficulties entailed in logging and extracting big logs. It is none the less true that at the mill large logs are generally graded as higher quality than small-diameter logs.

Future requirements of the wood-using industries

The purpose of the paper submitted by FAO to the Helsinki Congress was to try to evaluate the probable nature of the future requirements of the wood-using industries. Its conclusions were corroborated in a similar paper submitted by Professor Streyffert, of Sweden.

Both papers supported their arguments with statistics, although it may be safer to base forecasts of future trends on laboratory and industrial research and other experimental work. The conclusions of these two papers can hardly be disputed in the light of what is happening in the research world.

These conclusions may be briefly summarized as follows: While the volume of wood required from our forests by industries processing timber in solid form remains constant or increases only gradually, industries based on "disintegration" processes (mechanical or chemical) will be wanting an ever larger quantity of raw material. In other words, the proportion of the annual world forest output utilized in a "disintegrated" form will progressively increase over the next decades.

The additional quantities of raw material required by the "disintegration" industries will not be secured at the expense of the other wood-using industries they will mainly be obtained by increased exploitation of species hitherto of no economic value and of trees and logs now abandoned in the forest, and by utilization of conversion waste which is at present discarded or used as fuel. In other words, what was "waste" will in future have value.

More wood, formerly treated as waste, and more species not hitherto marketable, are already in demand for a large variety of industries, and their value is rising. In fact, there is a definite tendency in some places for the value of so-called "waste" species and wood waste to approach the value of the supposedly principal products. This is inevitable when the requirements of the industries using wood for "disintegration" processes are increasing proportionately more rapidly than the requirements of the industries converting solid timber. It is already clearly manifest in many parts of the world where pulp factories and sawmills must obtain their raw material supplies on the same markets. The raw material for industries based on disintegration processes generally represents a relatively small portion of the cost of the final manufactured product; these industries can therefore pay high prices in competition with other wood-using industries.

A fine stand of oaks (Quercus robur), 180 years old, in a French forest.

(Photo by courtesy of French National Forest School)

The significance of these trends for the forester

How will the changing requirements of the wood-using industries affect the forester? There are two principal conclusions.

First, the greater possibilities for the utilization of material and species not hitherto extracted will lead the forester to revise his ideas on the growing stock to be included in the composition of his forest stands. This more intensive utilization is not at present significant in terms of volume, but it may soon become so. For instance, there is the progress made in the utilization of soft wooded broadleaved species and even of hard wooded species in pulp manufacture. Experiments carried out in using mixtures of tropical woods for pulp manufacture, as described at the Montreal Pulp Conference in May 1949, cannot be ignored. Furthermore, it is not only the industries using disintegration processes which may extend the range of their raw materials; the instance of the "true firs" and hemlocks of the west coast of North America proves that this may also happen in the case of lumber. It only awaits new methods of drying, storage, and preservative treatment. Many tropical species may also become better appreciated so as to give real value to additional large quantities of wood on local, regional or world markets.

Second, the greater utility and value accorded to so-called "waste" will make foresters tolerate a greater proportion of small-size trees in their stands, and lead them to lower felling limits This will probably become normal practice. In fact, self-interest in forest management will make it inevitable. The greater quantities of smaller trees will find a ready outlet even if the sawmills do not use them; and there will be no need to continue to grow trees as largess before because there will be a ready sale for conversion waste.

Both these conclusions are in keeping with the declared aim of the member governments of FAO - to secure a more efficient and complete utilization of the raw material which the forest provides, and thereby to ease the world shortage of wood.

Silvicultural consequences

In the first place, the trend towards "quantity" production, as reflected in the increase in the number of species which industry can utilize, will make it easier for foresters to adapt their crops to local environmental conditions.

At the Helsinki Congress, the need to plant pure forests of coniferous species was often stressed, mainly by foresters of Mediterranean and Western European countries, on the grounds that only such uniform crops can properly fulfill industrial requirements when the species occurring naturally, are to all intents and purposes unusable. It is well understood that the establishment of such plantations entails certain risks; the way to obviate these is in many eases through the introduction of other species either to create a mixed growing stock or to provide a soil-enriching under-story under the main coniferous crop. These supplementary species at present may not have a market value, even though they have a recognized silvicultural value, and the normal objection to such a course is that it requires an investment of capital without any appreciable financial return. However, if the new species can be turned into a cash crop, then this type of operation may more readily be applied.

Where silviculture is designed to favor the growth of individual trees. A mixed broadleaved stand in a Michigan forest, U.S.A.

(Photo by courtesy of U.S. Forest Service)

Pursuing the same line of thought, the day may come when financial considerations will no longer prevent the forester from growing crops which are properly in harmony with the ecological environment of the locality. A forest of such a type would naturally be easier to grow and be less subject to many natural hazards than purely exotic stands. It might possibly, however, be less productive, in terms of quantity, and it is not safe to predict how silviculture would develop under such circumstances; no doubt practices would vary from one locality to another.

In any case, far from resulting in the demise of the art of silviculture, the trend toward "quantity" production should promote sound silvicultural methods and favor the growing of good types of forest stands.

Another consequence of the trend towards "quantity" production will probably be a lowering of the diameter limits at which trees are felled. This, again, should be conducive to the practice of better silvicultural methods and the establishment of high quality stands.

For instance, the chief obstacle at present to the carrying out of regular thinnings, which are necessary as a means of promoting both quantity and maximum quality in the final crop, is the feet that it is often impossible to dispose profitably of the smaller trees taken out during the thinning operations. Should these trees, however, command a ready sale, this obstacle would be removed, and the practice, which is now practically unknown over wide forested areas of the world, could become economically feasible. The value of the produce extracted would justify the maintenance of road networks and the organization of the necessary cutting operations.

The volume of pulpwood cut in Canada rose from about 1¼ million m³ in 1900 to around 29 million m³ in 1946, when it constituted 32 percent of the total annual cut. The percentage is still rising.

(Photo by courtesy of National Film Board of Canada)

This is not all. Under present circumstances, the forester is often obliged to maintain an even-aged crop beyond the point of culmination of the current annual growth, at which stage a progressive diminution in current increment sets in. In other words, with a lengthened rotation he has to be satisfied with a smaller mean annual growth than could be obtained if the crop were cut at the most advantageous age and immediately replaced by young trees. Due to the special value attached to diameter quality, the rotation affording the greatest average net annual money yield is longer, and for some species much than the rotation for maximum current annual growth.

Obviously, therefore, any trend in wood utilization which enhances the value of smaller diameter trees encourages the application of sounder silvicultural practices and the growing of better stands. The stands will be better not merely because they will reach the maximum point of increment and go no further, but because they will be less susceptible to disease, insect attack, and wind damage, if felled before they are on the decline.

It is a moot question whether the crops of the future will be any the less excellent or less beautiful than the forests of today merely because they contain fewer large trees. In general, an abundance of large trees does not in itself contribute to the so-called "beauty" of a forest unless these large trees really are of peculiar value because of their size; this does not imply that they should be systematically eliminated.

It seems fairly well established that we shall rarely again find "quality" such as is represented by the enormous trees now being exploited in the last virgin forests of the western coast of North America. The kind of lumber or plywood derived from Douglas firs or Sequoias several hundreds or thousands of years old will probably never be seen again, because it seems unlikely that anyone would attempt to maintain standing timber in a managed forest until it had reached such an advanced age, save in the most exceptional cases.

Quality and quantity in forest stands

The probable trends in wood utilization need not make the forester alter his concept of the forest of pleasing appearance; they will rather stimulate the growing of excellent forests

We said earlier that the forester was apt to couple the outward appearance of the forest with the concept of the value of the products of the forest. It must: be conceded that "beauty" of a forest is generally more an index of high productivity than of utility. Leaving aside any question of felling diameter, which the forester is usually free to decide for himself, the selection of the single or several species to constitute the growing stock determines to a great extent the uses of the products. We have already said that there is no precise knowledge as to the effect silvicultural operations may have on the basic properties of wood itself. Therefore the forester's object must be to achieve, within the limitations imposed by nature, the highest possible output and he will direct his silvicultural operations to this end. For the forester, the elite tree is obviously one which supplies useful products; but it is primarily the one which will yield an above average quantity of these products.

"Diameter quality" has been left out of consideration in the preceding argument, and it might be objected that large trees are often conserved, despite a slowing down in the increment rate, so as to get a better quality of product rather than a greater quantity. It is true that in such cases the concept of enhancement of value replaces that of greater quantity. But at the same time such methods of silviculture are difficult. If the rotations to attain both maximum quantity and value could be made to coincide, management of the forest would be greatly facilitated without either "beauty" or "quality" being sacrificed. On the global scale, it is precisely this trend which appears to be developing.

The ideal forest crop

Before considering the world market, the forester must consider the demand in his own locality. It may therefore be asked whether in the event that he decides to lower felling limits, he will not run the risk of limiting the size and grade of product which he can offer on this market.

Will this not lead to local upsets, which could be avoided by more progressive local action, even though the global trend is inescapable? In other: words, is there not a danger, even if we again stress we are generalizing, that the mere statement that there is this trend will lead foresters to try to establish more uniform types of crop, whose output will furnish supplies for some industries but fail to satisfy the raw material needs of others? Is it not contradictory to foster the idea of integrated forest industries while recommending steps which might render it difficult to supply certain industries that should constitute an integral part of such a set-up?

The paper submitted by FAO to the Helsinki Congress attempted to obviate just such a reproach by suggesting that present trends in the requirements of wood-using industries made it advisable, whenever possible, to cultivate mixed uneven-aged forests rather than uniform, even-aged types. Preference was expressed for what might be termed a silviculture looking towards the growth of individual trees rather than the growth of the stand as a whole.

Even where this kind of silviculture is possible - and it cannot always be possible - it is assuredly the more difficult to carry out successfully. It involves complex methods of management and continuous control of the forest, which is not practicable without a large staff, an adequate network of roads and paths, an effective fire-fighting system, and a grouping of industries capable of absorbing all the produce of the forest. However, as an ideal, it is the most flexible means of adapting forest production, not only to the special needs of industries, but also to changes in their requirements.

When a certain industry needs particular species or very large diameter trees from a forest managed in this way, the desired species can be favored or selected trees left to grow to the required diameter. When the demand from this particular industry falls off, the proportion of the particular species in the growing stock can be changed or the maximum felling limit reduced. This can be done without drastic treatment of the forest or any serious modification in the working plan, and without any interruption in the supplies to other industries.

Were such a system of silviculture universally adopted, it might be virtually unnecessary to worry further about trends in wood-using industries, because the adaptation of forest production to industrial requirements would be practically automatic. Unfortunately, we are still very far indeed from such an ideal state of affairs, and, as we have just stated such a system presupposes a harmonious development, both of silvicultural methods and forest industries, which cannot be expected to come about quickly. It is nevertheless true that the present trend in wood requirements logically favors such a development.


The conclusion of this paper is that, from the silvicultural standpoint, there are no valid grounds for an assumption that quantity production will displace quality production. For the future, as in the past, a fine-looking tree and a fine stand will have to measure up to certain standards which are a sign of high raw material output of the desired quality. Although on the global scale the requirements of the wood-using industries appear to be for "quantity" rather than "quality," this does not in any way lessen the need for effective and improved silviculture. The trend may, and probably will, necessitate more or less extensive local adjustments. But such adjustments need not cause the forester to alter his ideal of a high-quality forest. Rather, quantity and quality production will go together as a means towards wood abundance and economical silviculture.

No strict rules can, of course, be laid down for foresters as to the course which they should follow in view of probable wood utilization trends. Not only is there room for much latitude in the light of local conditions, but naturally each country will define its own policy, coordinating this policy with that of other countries of the world through the medium of FAO and its regional bodies.

The Division of Forestry and Forest Products seeks to point out the trends as they emerge from statistics and general thinking, and to deduce from them consequences of world-wide import. That is what was attempted in the paper presented to the Third World Forestry Congress, and what is again attempted here.

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