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Tropical forestry - Some aspects of forest problems peculiar to the tropics

The Fourth World Forestry Congress will devote an important part of its discussions to tropical forestry, and will be probably the first truly world-wide forestry meeting to do so.

Why should tropical forestry be discussed as though it were a separate topic? Is it to be regarded as a separate science or merely as a special application to tropical conditions of the "forestry" that has hitherto been most highly developed in the temperate parts of the world? There has been much talk on this point which still continues, but the issue is more academic than practical. The basic principles of "forestry," whether relating purely to silviculture, policy or economics, are valid in all latitudes and for all work throughout the world. But admittedly the conditions in the tropics - physical, biological, social, economic and even political - and the ways and means of translating principles into practice are very different from elsewhere. It may be conceded, therefore, that tropical forestry, in the main, presents a series of special cases in each of the broad fields which together constitute what we call "forestry." This paper offers some premises in regard to such special cases as a basis for discussion. 1

1 Special features of coniferous forests, pure stands or almost homogeneous types growing in tropical areas are outside the scope of this paper. The problems involved are less complex than in the case of mixed tropical forest and they have already been the subject of much study.

The tropical forest in the local economy

Correct appraisal of the forest's role in the economy of individual countries or sections of a country is needed the world over. In the tropics a proper assessment is of special importance because on it may hinge all efforts towards economic development.

To the north and south of the tropical zones lie countries where economic development is, to generalize very broadly, well advanced and perhaps has already taken its final shape. In some instances the forest serves its proper place, even though elsewhere it has been too- much encroached upon. On the whole forestry is a matter of applying known practices and techniques to known conditions.

In the tropics, on the other hand, lie countries which for the most part are only on the verge of economic development - new countries, in an economic sense, where everything can be schemed in perspective. For the most part the climate, soil and vegetation are such that deliberate planning is necessary to assure the maintenance of a proper equilibrium between the natural conditions of a country and steady economic growth. But the problems to be faced in planning are novel and involved; particularly the forester is confronted by the difficulties arising from the mixed character of tropical forests and from the great lack of knowledge of the useful products that can be drawn from the forests.

In any planning for economic development, agricultural and industrial activities must be balanced. What makes the role of the forest so important in the tropics is that here, more than elsewhere, the forest is basic both to agriculture and industry. Therefore? it is necessary to decide:

1. the relative emphasis to be given to agricultural and industrial development;

2. the place of the forest (whether permanent or temporary) in relation to the picture of rural development and farming proper, keeping in mind not only soil conservation and land capability but also particular practices such as shifting cultivation;

3. the place of forest industries in the general industrial development. The forest, as a renewable natural resource, may on reflection prove of primary rather than secondary importance.

Before decisions can be made on these matters as a preliminary to full-scale planning, detailed area studies must be undertaken. And here we come to a first principle that must guide the forester in the tropics: forestry in tropical areas must not be regarded only in the absolute. Save in certain rich and densely populated areas, the possibilities for forestry must always be appraised against the local characteristics of soil, climate and vegetation, and against local customs, practices and rights of usage that are not abruptly to be changed or abolished. They must, in fact, be reconciled with:

(a) the general agrarian structure, and a comprehensive program of soil conservation and sound land use;

(b) the overall economic development possibilities of the area, and a program of balanced agricultural and industrial expansion.

Forest inventories

In speaking of a "program" we thereby postulate a thorough knowledge of all the local circumstances, which in turn means a prior resource survey. And in the tropics, a forest inventory is the most important part of any such survey. From our first principle, therefore, we infer that the basis of all planning must be the forest inventory. It is not possible in a paper of this sort to go into the technical details or special difficulties of making an inventory of tropical forests. These, it is hoped, will be treated in other papers presented to the Fourth World Forestry Congress. But we can say that such inventories are complicated matters which, whatever the degree of detail required, cannot be carried through without the active co-operation of foresters actually working in the forest. Whether it is for the purpose of quick surveys for delimiting areas of forest to be protected, or of detailed studies for drawing up individual working plans, aerial photography experts need to work in close collaboration not only with the men in the field carrying out ground sampling and mensuration, but also with the forest services invested with the responsibility of co-ordinating the various tasks involved and making the final analysis of the results.

Shifting cultivation

Before leaving this section on the fitting of forests into planning for economic development, some words should be said on a particular aspect, namely shifting cultivation.

In a predominantly agricultural economy, the next step after the resource survey and analysis of the results will be a land classification into three major types, whether or not any particular land was originally under forest:

1. lands to be permanently dedicated to forest, whether at present forested or to be restored to forest as the climax vegetation;

2. lands to be dedicated permanently to agriculture;

3. intermediate lands, suited to multiple use, and whose precise functions would be settled on economic grounds as the overall development plan was worked out. The allocation of such intermediary type lands is always a delicate matter, complicated in the tropics because of the common practice of shifting cultivation.

Some people regard shifting cultivation merely as a traditional form of forest use by the autochthonous population and a problem that the forester can be expected to solve either by total prohibition of the practice or by restricting it to specified areas. Others, on the contrary, only concerned with the agricultural aspects, wish to see the native farmers weaned from shifting cultivation to permanent settlement. The matter is far less simple and must be looked at against the background of the entire agrarian structure in a given tropical area.

Shifting cultivation, as traditionally practiced by native inhabitants before the arrival of settlers from other areas, for instance by the Britons in what is now England before the arrival of the Romans, is not particularly dangerous. In the wet tropics a state of equilibrium is commonly reached, first, because tillage is restricted to soils of suitable structure and chemical composition which, however, contrary to general belief, are limited in extent in forest zones and, second, because the forest clearing is part of a true crop rotation system which includes a forest fallow of sufficient duration to permit restoration of the tree cover and the regaining of soil fertility. Primitive communities who practiced shifting cultivation customarily set self-imposed rules:

(a) use of suitable soils which did not deteriorate too rapidly after having been cleared of cover;

(b) crop rotation, which did not leave the soil too long exposed and which included a sufficiently long forest fallow to permit both the restoration of the tree cover and of the humus;

(c) choice of an area where the climatic conditions made possible a rapid and dense regrowth of trees to form a stable forest canopy.

With the arrival of new settlers and increasing populations, this equilibrium was upset for various reasons - changes in the types of food crops grown, larger food requirements as living standards rose, the introduction of cash crops. It became necessary to produce more and, since the villager was not able to increase his yields, he had to enlarge the area that he cultivated.

First he tried to use more fully such suitable soils as were still available for shifting cultivation. But generally there was not enough such land which was not at the same time too far from the community center, so the alternative was to cultivate poorer soils or to return more frequently to the same areas and reduce the period of forest fallow.

The outcome in either case was gradual soil degradation, with a decrease in crop productivity, and because of the disappearance or impoverishment of the original type of forest cover, unfortunate direct or indirect effects on the forest.

Shifting cultivation may be said to become dangerous as soon as it loses its nomadic characteristics without any compensating features - when in fact it becomes nothing more than regular cultivation on forest soils.

To obviate the bad results of malpractices in shifting cultivation, two courses are necessary:

1. measures must be stipulated (change of cultivation methods, still utilizing shifting cultivation practices if need be) that will maintain or increase crop output without causing soil deterioration;

2. the reservation of minimum areas of high forest in any given locality where shifting cultivation is totally prohibited so as:

(a) to effect soil conservation and maintain streamflow;

(b) to meet local needs for timber and fuelwood and in other ways to provide for a balanced economy.

This oversimplified sketch of the problem of shifting cultivation is sufficient to indicate the solution to be sought and the forester's responsibility. Improvement of shifting cultivation practices must be based on planned use of soils and forests. It is thus contingent on forest inventories, and depends on local circumstances, the possibilities of introducing various agricultural and silvicultural techniques, and present or prospective social and political conditions.

Wherever shifting cultivation is practiced, forest policy cannot properly be formulated or implemented, either for protection or to promote development, without taking all the various factors involved into account. It is because of its bearing on our first principle of tropical forestry that the topic of shifting cultivation has been included in the program of the Fourth World Forestry Congress.

Management and treatment of the forest

Planning is not possible without some understanding of the relative value of the elements involved. In the tropics, with few exceptions (pure stands or forest types with few associated dominants) the present and even more so the future value of the forest capital is hard to assess. Any development scheme based on forestry, which must perforce long-term, must therefore be drawn up on the forester's appraisal of the forest, how he wants to treat and manage it, and on his assessment of the type and quantities of products that he expects to obtain.

We may be sure that, except in the case of purely protective forest, no forester wants to leave the heterogeneous growing stock of tropical forests to nature. The complex composition of the stands and the poor quality of most of the timber make extraction and utilization difficult, both from the point of view of methods and economics. But the forester has to set the need to convert the forest against the danger that conversion may upset the particularly delicate ecological balance.

There is no intention of presenting here a thesis on tropical forestry, but some words would be in place on the schools of thought that have arisen in this field. Commercial exploitation of tropical forests has in general been restricted to a small number of merchantable species; foresters have tried to increase the proportion of these valuable species in the growing stock, either artificially or by improvement fellings, sometimes both together. To do so they devised and perfected a variety of methods.

Gradually the number of merchantable species accepted on international markets grew, domestic demand rose appreciably and wood-working industries able to absorb many more species of mixed forest types became established right in the zones of tropical forest. All this gave rise to the admirable concept of total utilization of tropical forests.

Although this was theoretically the goal, in practice total utilization remained impractical or prohibitively expensive, even with the help of certain chemical industries which were not dependent on particular species but could use wood of any kind. The aim was therefore modified to optimum use of the products of the tropical forest, and in some cases it became possible to set the number of economically usable species at a high figure. Silviculturists tried to devise methods permitting optimum use of the maximum number of species and economic conversion of the growing stock into less heterogeneous, and hence more fully utilizable, types.

The difficulties encountered in introducing the various silvicultural and utilization techniques required to this end have led many experts to advocate the eradication of virgin tropical forest and its replacement by pure stands. This attitude, which until recently had few proponents, seems today to be gaining ground, chiefly as a result of recent surveys made with a view to establishing new pulp mills in the tropics; a series of studies undertaken by FAO and UNESCO suggest greatly increased demand for paper in future and a trend to decentralize the pulp and paper industry. 2 Because of the rapidity of growth of certain species under tropical conditions and the technical advantages of working pure stands, many people recommend the creation of pure softwood or hardwood stands as the only solution to the problem of continuous supply to proposed new pulp mills.

2 The prospects are summed up in the FAO report World Pulp and Paper Resources and Prospects to be published shortly.

Broadly speaking, then, three schools of thought have emerged in tropical forestry:

1. improvement of existing stands;
2. gradual conversion of mixed forest into less heterogeneous types;
3. transformation of mixed growing stock into pure stands.

This is no place to make any pronouncement on the relative merits of these processes but perhaps some general principles can be drawn. It seems reasonable to infer that:

1. it is essential to alter the composition of heterogeneous virgin forest;
2. conversion should render easier the economic extraction and utilization of forest products;
3. some methods of conversion may be dangerous both to the forest and the soil.

Therefore we may say that tropical forestry must, wherever possible, seek to convert a heterogeneous growing stock into more readily and economically usable types, but conversion techniques must have due regard to climatic, soil, and vegetation conditions so that the new stands to be formed shall be stable and without hazard.

In many cases, this principle will most properly lead to gradual conversion of stands through improvement by normal silvicultural methods. However, it does not preclude making radical changes under proper safeguards, such as artificially introducing native or exotic species, even in the case of protective forests, though here the concept of stability is of cardinal importance and must be the prime concern of the forester.

This principle also holds good for reforestation in arid regions, where the forests are ordinarily of no great economic value and serve principally a protective role. It is common experience that cash yields are the best argument for the protection of a forest. Even here, then, a cautious enhancement of the commercial value of the forest is advisable.

In considering our second principle economic considerations are always to the fore. A third which we will try to formulate rests purely on economic factors. We have said that in converting tropical forests, their stability must be maintained. This raises a series of technical problems to which foresters have devoted much study.

All experience shows that large-scale forestry operations cannot be undertaken purely on technical grounds. To be practicable they must eventually be able to pay their way, preferably tangibly in hard cash.

It is always technically possible to reforest an arid area or convert a mixed tropical forest into a stand of more desirable composition. The crux of the matter is whether such an undertaking is financially sound. Tropical forestry needs in most cases to get beyond the purely silvicultural research stage, however desirable this may be in itself, and to have regard more to economic considerations. We would, in fact, suggest a third principle of tropical forestry to the effect that forestry must especially be orientated toward perfecting techniques and practices that are sound financial propositions, given the difficult local conditions, the forest types, the social structure of the country, and, above all, the uncertainty of future requirement trends, so much less easy to predict than in the temperate zones. Techniques and practices must be appraised not only on the basis of the cost of initial work required but also on the probable cost of subsequent operations that will become necessary in the light of the long-term purpose of each operation, whether it be for protection or straight profit.

This principle seems particularly important because it lays stress on local circumstances, economic and social. For instance, desirable silvicultural practices such as improvement thinnings in heterogeneous forests may be practicable in densely populated countries like Puerto Rico or Java where the products have an appreciable market value and the proceeds can help defray the costs of the operations. In the Amazon or parts of Africa, on the contrary, the products are just so much waste. So are the intermediate yields from artificial plantations established either for protection or timber production when there are as yet no local markets. Such forestry undertakings are, therefore, risky and of value only over the long-term.

Foresters must be sure what finally they want to achieve before choosing their silvicultural methods and assessing the probable results. This is perhaps their most delicate problem because it needs a brave man indeed to predict the course that industrial technology will take or the future requirements of local or foreign markets. It is axiomatic to say that the forester works for future generations, but he must not jealously guard to himself the right to look into the future. We go back to our first principle and the need for long-term integration of forestry into a wider planning.

Industrial aspects of tropical forestry

At this stage we may attempt to clarify established principles underlying industrial developments in tropical areas, planned or already under way, though this lies somewhat apart from forestry proper. There are two principles which should govern how the forest shall be managed, the one a corollary of the other. First, total utilization of the tropical forest, and second, integration of forest industries. Recent experience in underdeveloped countries has shown how difficult it is to put either fully into practice, however the ideas may be subscribed to in theory. Total utilization and integration remain the best means of attaining the desired objectives; but they are not, in themselves, objectives to be achieved at any price in the first stages of industrialization.

During the early development of a country, it is not financially practicable to establish a series of properly integrated forest industries or special industries that can utilize all available products of a forest. Planning must be on a practical business basis and the initial start must be made with industries that are both technically easy to establish and sufficiently profitable to amortize the capital investment. It is a question, above all, of markets, although even the initial industries should be designed with a view to their ultimately fitting into a pattern of fully integrated use of the forest as markets and finance permit. The principles remain valid, but they must be realized slowly.

This digression into the field of industrial development is important so far as forestry as a science and art is concerned because a more gradual evolution of forest industries than was advocated a few years ago will make it the more practicable to adapt forestry techniques to commercial needs, which is inherently one of the most difficult problems of tropical forestry.

Special protection problems in arid zones

So far our discussion on tropical forests has related primarily to the humid tropics. But the forester in the inter-tropical zone may also be confronted with dry, semi-arid and arid, and even desert, areas.

Without wishing to raise arguments as to the origin and evolution of the special climatic conditions in such regions, we are on safe ground in saying that many parts of the globe, now barren, were still comparatively densely forested within historical times. While climatic changes may have initiated the disappearance of the forest, man by persistent deforestation has certainly aggravated matters.

Foresters and conservationists are well aware of this fact, but it still needs to be repeated to prevent mistakes by those laymen in such matters who, however, as officials, must yet judge and decide on high-level forest policy.

Perhaps we may put it as follows: although certain extreme climatic conditions leading, in some regions, to the formation of actual deserts, cannot be considered as being initially caused by man, the aggravation and advance of these conditions is certainly to be attributed to him. While it may not be prudent to envisage radically changing such conditions through forestry measures alone, it is essential for the forester to counteract directly the actions by man that have conduced and still are conducing to the encroachment of the desert

In this way we limit the scope of the forester's responsibility; to define it more accurately we may run over the many services rendered by the forest, or rather that can be rendered by new forests, in arid zones.

Their value from the protection standpoint is discussed in another paper in this issue of Unasylva. The main interest lies in the part they play in protecting the soil, particularly against dessication and intensive wind erosion. The effect on moisture exchange between air and soil is also far from negligible, particularly when the plantations form a compact extensive block rather than scattered units, although admittedly such influence is local.

The interplay between the forest and the rural communities is just as great as in the humid tropical regions. Forest clearance is, as we have seen, one of the chief ways in which man aggravates the extreme climatic conditions to make agriculture difficult and to favor the spread of desert conditions. The forests in the parts of the dry zone with relatively good rainfall, which are the areas best for agriculture, are those most gravely threatened; the pace of shifting cultivation tends to quicken and very soon natural regeneration of the existing forest becomes impossible. It is here that thorough investigations of remedial action suitable locally must be made and protective measures taken to halt or limit malpractices in the very interests of the local inhabitants. It may in many cases be necessary to change entirely the local economy if total ruin of the still existing forest areas is to be averted.

The wetter regions merge into the dry, arid and pre-desert zones with their special steppe type vegetation and these are the domain especially of graziers and nomadic herds of livestock. The use of these typical forest range areas confronts the forester with technical social and often even political problems.

Finally, the open woodlands or savanna forest in arid areas have always some kind of economic value which in itself is an incentive to their thoughtless destruction. The forester must arrange to meet local needs for timber and fuelwood without risking the disappearance of the trees.

Perhaps we may sum up as follows. Forest and woodlands in dry, arid and sub-desert regions must be resistant to extreme climate and to the action of man. It is precisely this which is technically very difficult and in terms of money very expensive. Remedial measures should always be on a large scale and in accord with long-term policy framed with due regard to the many potential services of the forest. The effect of forest on local climate is limited; therefore, in improvement works one must, near areas of permanent cultivation, deal in very extensive areas according to preconceived plans for sound land and natural resource use; and the agricultural economy must, if necessary, be reshaped to permit proper protection of forest and range.

In view of the technical difficulties and the costs involved, the various operations required must be performed as economically as possible - they should take the form of broad protection measures or very elementary silviculture. In afforestation, inexpensive methods adapted to extremely dry regions must be employed; methods commonly used in temperate climates, with or without irrigation, can only be practiced in special circumstances, chiefly to meet particular industrial needs.

Forest research in the tropics

Whether in the wet or dry tropics there are two types of problem with which forestry is confronted, technical and economic.

The object of forest research is to solve the technical problems and this is comparatively easy to do with good organization, well-planned programs, and able technicians and research workers, although there is a difficulty in seeing that research relates directly to practical problems and specific local conditions and does not wander off into the abstract. As already shown, the goal of forest policy and management is still in many cases not yet defined so that it is not always easy to set the tasks for research. Some research must of course precede and help in planning but most research is needed to gauge future possibilities. It must relate, therefore, to properly formulated programs. Here we see the need for a definite tie between planning and research.

Tropical forestry raises new, vast and complex aspects of science. The diversity of the problems to be solved by research has led to advocation of world co-ordination and centralization of research in order to eliminate duplication of effort, and expedite and improve the quality of the work. This idea, which is an application on a world scale of the now accepted principle of the utility of regional research, is certainly attractive and should not be rejected outright, but there are serious drawbacks to directed research.

The value of regional research lies in the fact that some courses of investigation relating to a specific "subject" or "site" can readily be centered for any given region; for instance, a central poplar experimental station for the Near East would not be difficult to envisage nor a forest experiment station for the Tropical Andes in South America. For the tropics as a whole, however, even where conditions of soil, climate and altitude are comparable, different economic, social and political backgrounds completely distort the picture. Forest research can hardly be conducted in Puerto Rico for application in parts of New Guinea because the whole concept of forestry is different in the two environments. Such difficulties are not insuperable, but they do lessen the degree of world centralization possible, bringing us back to the regional approach, although not altering the need for world-wide and co-ordinated exchange of information which remains an indisputable necessity from a purely technical point of view.

Highlights of tropical forestry

This paper in no way attempted to be a scientific analysis of the difficult problems facing tropical foresters. Its purpose is to "think out loud," and give some order to certain facts and principles. If these principles are deemed acceptable by the Fourth World Forestry Congress, discussion on the urgent features of the technical problems underlying the principles may profitably be resumed.

A forester not conversant with tropical conditions may regard what we have said as neither particularly original nor apt only to the tropics. This is, indeed, correct and goes some way towards answering the question raised right at the beginning as to whether tropical forestry should be regarded as a separate discipline. But the points and principles we have raised bear reiteration because they stand out as highlights in the experience of all whom FAO has consulted on the subject of tropical forestry. Tropical forestry should be seen not as some strange and awesome subject but as a matter to which all foresters can make common-sense contributions.

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