By THE STAFF OF THE DIVISION OF FORESTRY AND FOREST PRODUCTS
ALMOST every country in the world is seriously concerned about the insufficient production of wood and, particularly, of lumber. The shortage is one of the principal obstacles to reconstruction in countries devastated by war, and even in the United States it is hampering the progress of construction programs. In view of the seriousness of the present situation, one might wonder whether such a shortage is likely to continue and whether the potential production of the forests of the world is really insufficient to satisfy the needs of its peoples.
The following article undertakes to show that, contrary to the usual belief, it is possible to foresee a more satisfactory situation for future production of wood and lumber, even though we limit ourselves to forests which are now accessible. Current developments, including greater study of these forests, improvements in methods of silviculture, and better utilization of forest products are reassuring trends to support an optimistic outlook.
The report submitted to the Annual Conference in 1946 at Copenhagen and entitled Forestry and Forest Products - World Situation 1937-1946 presents in its early pages a table containing data of great interest, not only to the economist and the statistician. but also to the silviculturist.
The portion of this table of special significance in our present study is reproduced as Table 1.
TABLE 1. - DISTRIBUTION OF FORESTS, 1937
|
|
Europe other than U.S.S.R. |
U.S.S.R. |
Middle East and N. Africa |
North America |
Central and South America |
Africa other than North Africa |
Southern and Eastern Asia |
Pacific Area |
World Total |
|
Population in 1939 (millions) |
392 |
178 |
98 |
143 |
130 |
115 |
1,099 |
11 |
2,166 |
|
Forest Area (million hectares) |
132 |
960 |
41 |
635 |
815 |
512 |
500 |
54 |
3,650 |
|
Forest Area per caput (hectares) |
0.3 |
5.4 |
0.4 |
4.4 |
6.3 |
4.4 |
0.4 |
4.9 |
1.7 |
|
Annual Cut |
|||||||||
|
Total (million m³) |
308 |
262 |
5 |
392 |
178 |
65 |
300 |
10 |
1,500 |
|
per hectare (m³) |
2.3 |
0.3 |
0.1 |
0.6 |
0.2 |
0.1 |
0.6 |
0.2 |
0.4 |
|
per caput (m³) |
0.8 |
1.5 |
0.05 |
2.7 |
1.4 |
0.4 |
0.3 |
0.9 |
0.7 |
In spite of the inaccuracies inevitable in world-wide statistics of this sort, Table 1 shows that the average quantity of wood obtained annually by man from the total forest area at his disposal is about 0.4 m³ per hectare. If we omit Europe, where annual yield reaches 2.3 m³ per hectare, the average for the remainder of the world drops to 0.34 m³ and in no region except Europe does it exceed 0.6 m³. These figures are extremely low, even allowing for the fact that forest areas which are now inaccessible are included in the calculations. Nevertheless, we find that, in almost every country, competent forest authorities are constantly deploring the ill effects of the current exploitation of forests.
Fig. 1. Hill forest in India of Silver fir, Abies pindrow Spach.
In order to investigate the cause of this low production rate, it is worthwhile to examine the average rates at which the principal forest-producing countries of the world estimate the annual growth of their forests. Table 2 is based on information appearing in the appendix of the report cited above.
We have eliminated from Table 2 all countries for which statistics are lacking, and also all countries whose forests are chiefly of the equatorial or tropical type. Too little is known about tropical forests to permit the formulation of a sound opinion as to their actual rate of growth. Table 2 also covers most of the countries producing softwoods, and it is apparent that the major difficulties confronting the lumber trade throughout the world are caused by current shortages of softwoods. The most salient feature of the figures available for growth per hectare, both net or gross, is their diversity. Estimates of average gross increment vary from 0.35 m³ for the forests of Alaska to 6 m³ for those of Denmark.
It is evident that these disparities are caused in part by differences in natural conditions and in part by considerations of a statistical character. Figures stated in the "total" and "net" growth columns are based, in the case of some countries, on relatively precise knowledge. In regard to other countries, there have been various interpretations of the true state of affairs on the part of statisticians concerned.
FAO deems it to be one of its essential tasks to investigate this matter more thoroughly and to request each country to furnish detailed information as to its methods of computation. This task, however, will be long and difficult.
It is now proposed to investigate the different factors which have caused the diversity among the figures reported and, after analyzing these factors, to determine in what way the estimates could be adjusted to make them represent the real state of affairs; also, to determine in what way and under what conditions actual growth could be increased through improvements in silviculture.
Thus, our study will deal with two problems which at first sight, seem widely different. On the one hand, we will attempt to show how statistical information may be improved in order that the true situation in all countries may be set forth on a comparable basis. On the other hand:' the question of statistics being disposed of, we will inquire whether it would be possible, through the application of appropriate silvicultural methods, to provide in the future an actual increase in the world's forest growth.
In the course of the present study, we recognize that these two problems are, in fact, closely linked. This is true because any improvement from a statistical point of view can be achieved only through a more thorough study of forests. But completion of our study is merely the first essential step toward the rational treatment of the forest and the adoption of silvicultural methods able to improve rates of growth. This article undertakes to show that progress toward solutions of both problems lies in the adoption of correct forest management - the word "management" being used here in its widest sense.
TABLE: 2. - FOREST AREAS, GROWTH, AND CUT
|
Country |
Forest Area |
Growth |
Growth per hectare |
Volume of Annual Cut |
||
|
Total |
Net |
Total |
Net |
|||
|
million hectares |
million m³ |
m³ |
million m³ |
|||
|
British Isles |
1.3 |
1.5 |
1.3 |
1.15 |
1.00 |
1.5 |
|
France |
10.5 |
26.8 |
26.8 |
2.55 |
2.55 |
20.2 |
|
Belgium and Luxembourg |
0.6 |
2.0 |
1.8 |
3.33 |
3.00 |
1.8 |
|
Netherlands |
0.2 |
0.6 |
0.6 |
3.00 |
3.00 |
0.6 |
|
Denmark |
0.4 |
2.4 |
2.4 |
6.00 |
6.00 |
2.1 |
|
Germany |
12.6 |
41.7 |
41.7 |
3.31 |
3.31 |
56.0 |
|
Switzerland |
0.9 |
3.1 |
3.1 |
3.44 |
3.44 |
3.2 |
|
Hungary |
1.2 |
3.0 |
3.0 |
2.50 |
2.50 |
3.1 |
|
Spain |
4.9 |
4.0 |
4.0 |
0.82 |
0.82 |
4.0 |
|
Italy |
5.8 |
12.5 |
12.0 |
2.16 |
2.07 |
12.0 |
|
Norway |
7.7 |
11.7 |
10.6 |
1.52 |
1.32 |
11.7 |
|
Sweden |
23.1 |
41.6 |
42.0 |
2.06 |
1.82 |
45.0 |
|
Finland |
38.3 |
45.7 |
39.7 |
1.19 |
1.04 |
47.6 |
|
Poland |
8.5 |
18.0 |
16.4 |
2.12 |
1.93 |
17.7 |
|
Czechoslovakia |
4.6 |
13.4 |
12.9 |
2.91 |
2.80 |
12.9 |
|
Austria |
3.2 |
9.2 |
9.2 |
2.87 |
2.87 |
10.5 |
|
Portugal |
2.3 |
9.0 |
9.0 |
3.91 |
3.91 |
9.0 |
|
Yugoslavia |
8.1 |
16.0 |
16.0 |
1.98 |
1.98 |
22.6 |
|
Bulgaria |
2.6 |
3.0 |
3.0 |
1.15 |
1.15 |
3.0 |
|
Rumania |
6.5 |
25.0 |
18.0 |
3.85 |
2.77 |
18.6 |
|
Canada |
334.5 |
154.0 |
80.0 |
0.46 |
0.24 |
67.0 |
|
Newfoundland |
11.6 |
12.5 |
4.0 |
1.08 |
0.34 |
2.4 |
|
United States |
255.2 |
319.8 |
248.3 |
1.25 |
0.97 |
322.0 |
|
Alaska |
40.5 |
14.0 |
0.2 |
0.35 |
0.00 |
0.4 |
|
China |
66.0 |
200.0 |
20.0 |
3.03 |
0.304 |
15.5 |
|
Japan |
25.9 |
90.0 |
90.0 |
3.47 |
3.47 |
75.0 |
|
U. S. S. R. |
960.0 |
630.0 |
262.0 |
0.66 |
0.27 |
262.0 |
|
New Zealand |
5.3 |
3.1 |
2.3 |
0.58 |
0.43 |
2.3 |
To begin with, it appears certain that most of the available figures on gross increment per hectare, that is to say, on total wood production, are nothing more than approximate estimates and are not based on complete measurements.
It is noteworthy. however, that the countries showing the highest figures are precisely those in which carefully controlled silvicultural methods have already been established for a long time; Denmark, 6 m³; Japan, 3.7 m³; Switzerland, 3.44 ma; and Portugal, 3.91 m³.
Actually, there is but one positive way of ascertaining the true production of wood in a forest and that is the method of repeated surveys or inventories at regular intervals. Actual production is then determined either by comparing volumes at the beginning and end of each period (making due allowance for trees cut down during the period) or by numerous increment borings.
It is true that a 100 percent inventory of large forests, such as is or should be commonly practiced in western Europe, is impracticable in the vast forest expanses of North America, or at best can be considered only as an ideal which might be reached in the remote future.
Sampling methods, based on the measurement of strips or plots, have been widely developed in North America during the last 30 years. These methods have been improved to a point where the composition of a forest by diameter classes can be determined as accurately as may be desired. The best results are obtained when sampling methods on the ground are used in conjunction with modern air photography. With these inventories as a starting point, actual production is usually determined by numerous increment borings or by repeated re-measurement of selected sample plots at regular intervals.
It will easily be realized that the accuracy obtained from these methods depends primarily on the intensity of sampling and on the suitable location of the samples measured; hence, accuracy depends on the amount of existing knowledge as to the nature of the forests.
The more detailed the study of forests, the more accurate will be the estimate of their rate of growth; and it is interesting to note that, as survey methods have developed and been perfected, increasingly higher estimates of growth in the forests of the United States have been obtained. In 1931 the area of commercial forests was estimated by the United States Forest Service at 461.7 million acres (187 million hectares) and the standing timber at 519,000 million cubic feet (13,700 million m³) - 1,000 cubic feet per acre (70 m³ per ha.) - while their annual growth was estimated at 8.900 million cubic feet (252 million m³) - 19 cubic feet per acre (1.37 m³ per ha.). The annual rate of increase was, therefore, 1.83 percent. In 1945, on an area of 439 million acres (184 million ha.), the standing timber was estimated at 469,500 million cubic feet (13,000 million m³) - 1,044 cubic feet per acre (73 m³ per ha.) - and annual growth was estimated at 13,300 million cubic feet (378 million m³) - 29 cubic feet per acre (2.05 m³ per ha.) - giving a rate of increase of 2.8 percent.
A survey of the forest area and an inventory of the volume of standing timber should normally constitute the first step in the management of a forest. A complete survey and inventory, however, are not always made, and a great many forests are managed entirely on an area control basis and without any records of changes in volume from time to time. Except in the case of even-aged forests in which one compartment is clear-felled each year - and such cases are rare - the actual growth is unknown. As a matter of fact, serious mistakes have occurred through the rigid application of systems of management based solely on area control. This is most likely the reason why France, where there are a great many privately owned and unmanaged forests, shows a comparatively low estimate for average annual growth per hectare.
The facts we have just noted are particularly encouraging since we are justified in believing that the more we know about the forests and the more intensively they are managed, the higher will the estimates of their actual growth become. There is no doubt that forestry experts tend to underestimate annual growth, and for this they can hardly be blamed by anyone who realizes the danger of excessive felling which overevaluation would entail. We are certain, however, that, even in the case of countries already showing substantial figures for total growth per hectare, still larger estimates may be expected to arise from a more careful study of the forests.
Fig. 2. Tree sampling in the United States.
In Table 2 the estimated figures for total growth were divided by the total areas of the forests in order to determine average growth per hectare. It is known, however, that the total forest area reported, representing 27.6 percent of the land area of the world includes areas that are forests in name only. For example, some areas in the dry southern regions and on mountain slopes in Europe and America bear only scrubby trees which cannot even be used for fuel because of their remoteness from inhabited centers. Others, in the northern regions, bear only-deformed and extremely small trees whose development is limited by the shortness of the growing season. These areas are very extensive and their production of wood, while not absolutely nonexistent, is very low. Because the wood they do produce has little or no value, they will always remain useless to man as a source of forest products. Even if they should become accessible in the future, through development of transportation systems, their net growth is negligible and will probably remain so.
The inclusion in the total forest area of such tree-covered lands as are described in the preceding paragraph, is obviously the main reason why production per hectare in many countries, and particularly in the northern countries, appears so low. This is certainly true in the cases of Russia, Canada, Newfoundland, and Alaska.
Real difficulties are entailed by the inclusion of these nonproductive forests in calculations of growth per hectare, because the low figures derived are apt to make forestry experts unduly cautious with regard to the real growth of productive forests.
It would be preferable to place these areas in the category to which they really belong, that is, unproductive lands. In a sense, their broad classification would be the same as that of the polar regions or of high mountain tops. The only difference is that some of the nonproductive forests might eventually be transformed to a productive condition. This, however, would be a slow process and would probably be impossible in the case of large areas.
At any rate, a more accurate determination of the area of these unproductive forest lands will permit a more precise determination of the average rate of growth of productive forests. The new averages would be higher than the figures we now possess, even though more accurate measurement will not, in itself, increase growth rates. What is needed is simply more reconnaissance work in those countries where it is not yet complete, as well as improved statistical evaluations on which FAO is already working.
Fig. 3. Virgin stand of Douglas fir, Pseudolsuga taxifolia Britt., in the United States
In densely populated countries where forests are intensively managed and in which available means of transportation give easy access for the removal of timber by tractors, cable systems, etc., all the wood which falls in the forest, whether it is felled or falls as a result of wind, insects, fire, disease, or old age, is ordinarily considered as part of the production of a forest and is used in some manner by man. The only limiting condition is that the market value or utility of the wood, when transported to the place where it is to be used, must be sufficiently high to cover the costs of stumpage, felling, and transportation. In countries such as are described. above, this condition is usually fulfilled, although exceptions occur when the fallen trees are rendered worthless by rot or by fire, or when they happen to lie in places from which removal is too costly. Under normal conditions the total wood production in the forest can be acquired by man. It may happen that for various reasons a volume either greater or smaller than the actual growth is felled but, in any case, the whole of the volume harvested becomes available for man's use.
Under the conditions outlined in the previous paragraph we consider that net growth is equal to total growth, which is the reason why, for most of the countries of western Europe, the tabulated figures for both types of growth are identical. It is somewhat surprising to find that in the case of certain countries such as the United Kingdom, Belgium, and Poland, there are considerable differences between these figures, while there is absolute agreement for other countries. It is evident that here we have certain anomalies in estimating net growth which are of a purely statistical nature and which can readily be rectified. The necessary corrections would in no way affect the figures for total production per hectare.
If, on the other hand, we consider virgin forests, we may find that they too show an actual growth of wood. Such net growth does not accumulate indefinitely. This is proved by referring to certain inventories carried out in virgin forests, particularly in virgin forests of fir in the Balkans; moreover, common sense shows that the composition and the volume of a virgin forest must necessarily remain relatively constant, except for minor variations.
Fig. 4. Virgin forest of redwoods, Sequoia sempervirens Endl., in the United States
Actual growth is offset by an equal volume of trees which die or fall in the forests and which, although they may be fit for man's use at the time of their fall, will in fact remain untouched because that forest is inaccessible and their removal is economically impracticable. Such a forest, therefore, has a gross increment but its net increment is nil.
Virgin forests extend over considerable areas in North America, Russia, and in the Scandinavian countries. Tropical countries, of course, have vast expanses of such forests.
In our present figures on growth, two different methods of computation are found to be in use. In the first instance, the countries concerned may not have included growth in virgin forests in their estimates of total increment. As in the case of the unproductive forests previously considered, total growth per hectare, as well as net growth, obviously stands at very low figures; but the situation is different here because these inaccessible forests form a potentially productive reserve. When compelled by necessity or when the means at his disposal have become adequate, man will be able to extract from these forests a volume of timber equal to their potential net growth. For a while he may be able to cut even more than the net annual growth because of accumulated reserves of large timber. Total growth for the country will thus show an increase and so will net growth and, of course, the estimated average growth per unit of area for the country as a whole will be increased.
In the second instance, the countries concerned, while including gross increment of virgin forests in their figures for total growth, naturally do not incorporate it in their net growth. This would explain the wide disparity noted between total and net growth for certain countries such as the U. S. S. R. But, even in this case, the method by which these virgin forests were evaluated is not quite clear. In the case-of such forests, sample plots are of very little help, since the comparative stability of the stand, to which we have previously referred, may be observed only over wide areas exceeding at least 100 hectares. In any case, if only as a measure of caution, their growth was probably estimated most conservatively. Even if the figure arrived at should be accurate, this evaluation would, no doubt, increase soon after the forest was put under systematic management. Well-managed cuts, while singling out choice specimens and promoting regeneration, would, at the same time, bring about a higher rate of growth even though the growing stock was reduced.
Consequently, we believe that in all cases the opening up of virgin forests will, if ruthless and excessive fellings are avoided, lead to an increase in estimates of average growth per hectare.
It is true that changing conditions which lead man to investigate the opening up of new forests do not all operate in one direction and that, given certain economic conditions, it may become necessary to withdraw from other forests. This happened before the Second World War in western European countries which had large coppice forests whose products no longer had a market because of the competition of coal. These forests were undoubtedly in danger of reverting to a "virgin" state. In any ease, we are dealing here with a temporary phenomenon of relatively small importance which could, even though repeated, have no more than a slight influence on wood statistics.
Between the systematically managed forest and the virgin forest, all intermediate stages are possible. In one region, with sparse population, one may find a forest in which normal fellings are regularly carried out but where the incidental products, distributed for the most part over wide areas, are not extracted or are only partially extracted from the forests.
In other regions, the remoteness of the forest and the necessity for providing expensive means of extraction for each partial cutting make it necessary to concentrate the fellings within small areas and, consequently, to work on a program of long felling cycles with the removal of large volumes at each felling. Between fellings the incidental products are not extracted; and, even when the fellings are made, inferior specimens, the market value of which would be less than the cost of removal and transportation, are left behind. In certain forests of the Karst; for instance, although systematic management is in force, economic necessity compels the adoption of felling cycles of some 22 to 25 years in the better forests where the rate of increase may be about 2 percent, so that 40 to 50 percent of the growing stock may be felled in one operation. In other cases, economic pressure may compel almost wholesale clear-felling. In such cases, there is likely to be a loss of productive capacity of the soil because regeneration may take a long time.
From a statistical point of view, the wastage of wood tends to increase the difference between estimated total growth and net growth. It is obviously for this reason that the difference is most marked in the countries which are still rich in virgin forests: Canada, the U.S.S.R., and the United States. But the phenomena under discussion undoubtedly influence both total production and growth per hectare. In most, if not all, eases the greatest yield is obtainable from a forest through light fellings repeated at short intervals, although the regeneration of some species may require small clear-fellings at the end of a rotation. The silviculturist is thus given the opportunity to act at the right time to ensure the extraction of the best trees and to hasten regeneration; furthermore, if he is adequately equipped to estimate growth accurately, he may concentrate the greater part of his operations in the way best suited to further the interest of the stand.
It is a foregone conclusion that as the conditions of accessibility of a forest improve - particularly when its products become increasingly easy to reach - it will become possible to apply silvicultural methods, which will increase growth per hectare and. at the same time, the difference between total and net growth will decrease to a point where it will eventually disappear.
As a rule, in moving from south to north within the North Temperate Zone, the average annual growth per hectare decreases. There are, however, notable exceptions, such as Denmark, in which a very high average growth per hectare is obtained partly, perhaps, because the forests are growing on rich agricultural sails.
This tendency toward lower production in the higher latitudes results from an increasing severity of the climate, and it is evidently useless to hope that the production per hectare of the Scandinavian forests will ever reach the figure attained, for example, in Switzerland.
The Swiss Alps and the French Alps, however, contain many forests situated at high altitudes where climatic conditions are comparable to those of the northern countries. A great many identical species are to be found in the forests of both Switzerland and Scandinavia, although there may be differences in strains. On the other hand, the appearance and the production of these forests differ so widely that one might inquire, at a time when the most intensive cultivation of presently accessible forest lands is imperatively needed, whether the degree of perfection of silvicultural methods in use is not in itself a most important factor in accounting for the variations noted in production per hectare between different parts of the world.
In comparing the northern forests - and, for that matter, the forests of many other countries enjoying more favorable climatic conditions - with those of Switzerland, we find that the former have only fair to low stands per hectare (at times less than 60 m³) and trees of very small average diameter.
The smallness of the stands of timber per hectare in the north is due chiefly to the small diameters of the trees which the sites, conditioned by soil and climate, are capable of producing. It hardly seems possible to modify to any considerable extent the limits imposed by nature on the productive capacity of the soil. Recent studies, however, on selection and hybridization now in progress in the United States, the Scandinavian countries, and Portugal give rise to many hopes. Although at the outset certain silviculturists feared that the quantity of timber could be increased only at the expense of quality, these apprehensions are today proving unjustified, especially because wood utilization techniques are undergoing great alterations and may, in the future, require precisely the qualities that accompany rapid growth. But, leaving aside the possibilities of applying the findings of this new research work, the question may still be put as to whether the small number of trees per hectare found in some of these stands is not due to deficiencies of natural regeneration. In considering this aspect of the question, we can exclude the most northerly forests which form a necessary transition between the true productive forests and the unproductive lands. wrongly called forests, to which we have referred above.
Where natural regeneration is insufficient, conditions could be improved either through a better adaptation of silvicultural methods to local conditions or by having recourse to planting. It must be remembered, however, that application of either of these remedies requires that the forests concerned should be at least reasonably accessible. Extreme remoteness of forests and difficult conditions of transportation inevitably give rise to wholesale felling, which makes regeneration difficult if the species in question does not naturally happen to react favorably. Furthermore, the establishment of new plantings, which require much manpower not only for the planting operation, but also for the upkeep of nurseries in the vicinity, is difficult, if not impossible, in very remote areas.
In any ease, failure to obtain adequate forest regeneration cannot be charged merely to certain particular countries. Even in the most carefully developed forests. there are lands exposed by openings, caused by windfall or by badly planned fellings, where natural regeneration was too heavily depended upon for rehabilitation. The nature of the various species suitable for use in reforestation is now sufficiently well known, and the choice of varieties is usually large enough to prevent hesitation as to the advisability of having recourse to artificial regeneration because of fear of failure. The above should not be construed to mean that artificial regeneration should always be the rule, because, apart from difficulties of cultivation, it might impose upon the forest an expenditure which it would not always be in a position to bear. But, in principle, it should be considered abnormal for recently logged forest land to remain unproductive for several years, and, when this occurs, artificial regeneration should be undertaken.
There is also the question as to the ideal average diameter of the trees composing a forest. There has been much discussion of this question, but not enough practical and accurate research upon it. At least, research has too often been directed toward the study of regular stands; while the possibilities of the even-aged forest, which, through an intelligently planned arrangement, allows the maximum possible production to be extracted from each tree, have too often been neglected.
Insofar as softwoods are concerned, there is at present a tendency toward the harvesting of trees of small diameter due to the development of a market for this class of material. Forests which are managed entirely for the production of small diameter material and therefore on a short rotation, are attractive to forest owners because they yield a comparatively high rate of interest on the investment, a feet which will facilitate reforestation.
Japan is probably the country where one finds the most typical ease of limitation of exploitable diameter. In managed forests the average tree does not exceed 30 to 35 cm. and the rotation is 80 years at the most and nave generally, 50 to 60 years. On the other hand, the average volume per hectare is usually much lower than 200 m³. This limitation is possibly due in part to the feet that logging operations are mostly conducted by hand; it is, however, also based on yield tables which at first sight appear conclusive and tend to show that, at the above ages, a noticeable reduction in the annual growth per hectare actually takes place.
Nevertheless, such yield tables, drawn up under very special conditions, seem to call for some reservation, and in the forests of western Europe it seems that the forests which are the richest in material and particularly in large timber provide the largest growth per hectare, attaining or exceeding 10 m³ annually. Of course, the volume of such stands increases at a relatively low rate and the method involves the immobilization of a considerable capital, but the soil produces at its maximum capacity.
We have to choose between two different policies but in the present period of shortage it would seem desirable to extract from every hectare of forest land the highest rate of growth attainable; always providing, of course, that this is compatible with economic conditions, good quality of the products, and the proper maintenance of the forests.
In our estimation silvicultural research has not been pursued far enough in the different countries to determine finally the best forest policy for each one. On the other hand, current research on selection of species, hybridization, reproduction by sprouts. the action of mycorrhiza, etc., may well alter conclusions which have already been reached.
Whatever the findings of research may be, they are likely to show the necessity for major reforms. For example, it may be demonstrated that the timber or pulp industries should direct their attention to the utilization of wood of a smaller or a larger average diameter, with corresponding changes in present manufacturing methods. It may be shown that nations should take all possible measures to improve their silviculture and to extend the benefits of new methods to privately owned forests. It is also likely that inquiry will show the advisability of adopting different policies to suit different countries, according to their relative degrees of forest wealth.
In any ease, the question is of the utmost importance and there is no doubt that, whatever the reaction to it in various countries, increased growth per hectare is bound to result from an improvement in silvicultural methods.
In general, it has been shown that higher figures for average yield per hectare should result from increased knowledge of the existing forests, the adoption of more intensive silvicultural methods, and the more skillful use of forest products.
Even today, true yields per hectare are probably higher than is generally indicated by statistics which are often based on mere estimates or on methods of computation which are themselves in the course of development.
Finally, increased net yield depends to a large extent on man, who has it in his power to increase the forest output sufficiently to meet all his needs and at the same time to maintain the forests in good condition. The unique feature of forest management is the feet that the obtaining of a harvest implies the removal of a part of the growing stock. The task of the silviculturist, therefore, consists in seeing to it that the extracted material is duly replaced, that annual growth occurs in the required quantity on a reduced number of stems, and lastly, that both these objectives are attained at the same time.
All the measures which have been suggested in the preceding paragraph for improving existing figures of production per hectare, either statistically or in fact, may be summed up in a single requirement, namely, improved management of the forest. The word "management," however, should be used in its broad sense and not restricted to mean merely that the rate of fellings and their distribution by areas should be subjected to regulation. Regulation of fellings is indeed necessary, but there are many other factors which must be taken into consideration if any plan of regulation is to be made practicable.
Since the term "forest management" appears to be used in different senses in different parts of the world' it appears worthwhile to discuss briefly its broader and narrower meanings, and the way in which they ought to be combined if we are to reach the objective of increased total and net yields per hectare.
It is the object of forest management to give to man full possession and control of the forest. Its first stage is logically the full and careful study of all such forests as are likely to produce wood and the precise limitation of their boundaries. In many countries of the world, this stage is very far from being attained.
The second stage is the protection of the forest against its enemies. This means chiefly protection against fire, since protection against injurious outbreaks of forest insects and tree diseases must depend chiefly on silvicultural measures.
It is true that adequate control of fire requires a network of roads, giving ready access to the forest area, but developments in recent years have shown that, even in the ease of so-called inaccessible forests, man now has at his disposal means which enable him to organize some degree of fire control. In this stage of forest management, the United States has reached a position of leadership. Through the adoption of modern methods, including aircraft, radio, and automotive equipment for the prevention and suppression of fires, and through painstaking attention to the small details of organization and equipment, American forestry experts have made remarkable progress in the control of forest fires. In certain parts of the United States, fire has even been used as a positive element in applied silviculture, and may yet prove to be more important in this respect than has previously been recognized.
The third stage of management, which has not yet been fully attained even in some of those countries where intensive silviculture has been practiced for a long time, aims to put the products of the forest within economic reach of the user. This stage consists in the provision of means of communication and transportation required for the economic development of the whole forest area.
The fourth and last stage consists in finding adequate markets for the products of the forest and, so far as possible, for all of the products. This stage is, of course, closely related to the third, because the building of transportation systems, involving large capital expenditures, cannot be undertaken unless it can be shown that the value of the products to be obtained will justify the investment. In many eases, a forest cannot be rationally developed unless man creates new industries - sawmills, pulp mills, etc. - for the conversion of its products. In general, it is desirable to have converting industries near the forest, because raw wood is heavy, bulky, and of relatively low value so that it cannot bear very high transportation costs. Once the timber is converted to lighter and more valuable products, transportation costs can more easily be supported. Although, in general, it seems desirable to have-conversion plants near the forest, an exception exists where logs can easily be floated down rivers for long distances at very low cost. This fourth stage of management may even include efforts to organize new local or world-wide markets which will be able to absorb all or part of the products of the newly developed forest. Therefore it calls for a wide knowledge of trade requirements for forest products, and from this point of view it may be expected that an international organization such as FAO will in the future be called upon to play a leading role.
Forest management, in its broad sense, is thus a long and exacting process which as a rule involves the investment of considerable amounts of capital. Very often, it implies national or even international action, either direct or indirect. Direct action may consist of organization of surveying expeditions into unexplored forests; of construction of communication and transportation systems, and the establishment of industries or the provision of financial assistance for them; of supplying adequate technical personnel capable of planning and carrying out the necessary operations; and of analyzing and securing the markets necessary to the disposal of products. Nations may act indirectly by drawing up forestry laws, which should be as inclusive as possible and properly adapted to actual conditions existing in each country. Those nations whose forests boast the highest yields per hectare are also those whose forest legislation is the oldest and the most comprehensive.
The more limited aspect of forest management applies to the individual forest owner rather than to the nations themselves. It should be noted, however, that in most countries the government is a major forest owner and that it can and must play an extremely important part even in private forestry by means of demonstration, public education, and perhaps control
The principles upon which proper management should be based are not always, nor everywhere, definitely laid down. Silvicultural research takes time and patience. It also implies government participation and even co-operation between governments. An example furnished in this article was the possible choice between the policies of producing small timber on short rotations or large timber on long rotations.
In any ease, management in the restricted sense consists of determining the permissible annual yield of the forest and in calculating the proper intensity and distribution of the fellings required to produce that yield, including necessary operations for forest improvement. It consists also in regulation of the timing of these fellings in such a way as to safeguard the best interests both of the forest and its owner. It implies the carrying out, at regular intervals, of accurate inventories of the forest in order to detect fluctuations of growth and to note progress or regression of the growing stock. Periodic expenditures for inventories should normally be regarded as an ordinary part of forest management expenditures, because this measure, which every forest owner should look upon as an obligation, is essential to the proper maintenance of the forest.
We have already shown that management in the narrow sense is possible only when the requisite conditions have been established through application of the principles implied by management in its broader sense. It would be purely an academic exercise to attempt to regulate fellings in a forest where the boundaries were not determined, in one whose very existence was constantly threatened by fire, in a forest where no fellings were possible because there would be no means for removing the products, or in one for whose products no market exists.
There are, no doubt, forests that are being managed in spite of the feet that some of the above conditions exist. Management under such conditions, however, must depart more or less from the principles of silviculture upon which it should be based. This is inevitable because of economic difficulties. Thus, the management of a forest lacking permanent transportation systems must necessarily be based on such long cutting cycles that silvicultural operations cannot be undertaken with any hope of success. We may say that management under these circumstances means a compromise between cultural and economic necessities and, unfortunately, too many operations, even in the more advanced countries, must be placed in this class.
Fig. 6. Plantation of teak, Tectona grandis L. f.
However, the gap between economic and cultural necessities tends to become smaller. Progress will, no doubt, be slow in countries where vast forest areas are still out of man's reach, and where management in the broad sense is just commencing. But, under the pressure of ever increasing requirements for wood implicit in the progress of civilization, man will be forced to have recourse to those resources which are as yet undeveloped. Furthermore, under the same pressure, and particularly if the initiative is taken by governments, he will strive everywhere to derive the maximum possible production from the forest lands already at his disposal. The improvement of silvicultural methods will be of tremendous help. In the field of forestry, progress is on the march, and it is up to the forestry experts of all nations to contribute their knowledge and enthusiasm. Their reward will come when world statistics show increases in the low figures for average yields per hectare which today are characteristic of the great majority of the world's forests.
The cause at stake is well worth whatever efforts are needed. Forest lands are not, in fact, merely poor relatives of agricultural lands, as is so often believed. The usefulness of their products cannot, of course, be compared directly with that of food, but, in a different sense, this usefulness is as great as that of agricultural lands whose value and ability to produce of ten depend, to a large extent, on the protection the forest affords them.
Insofar as production is concerned, the output-of forest lands, though it requires far less effort and expenditure, yet compares favorably with that of agricultural lands. One hectare of forest land in good condition can produce annually 10 m³ of timber, or, in terms of seasoned wood, 5,000 kg. of material suitable for lands use. On the other hand, one hectare of corn produces a yearly crop of about 1,800 kg. of food products, and a hectare of cotton may produce only 300 kg. The forest then, while assuring the protection essential to agricultural land, is itself a source of such wealth that no effort should be spared to increase its productive power.
Photographs accompanying this article are reproduced by courtesy of the following: Figs. 1, 5, and 6 - F. R. I. Dehra Dun, India Figs. 2, 3, and 4 - U. S. Forest Service.
