Duncan Poore
DUNCAN POORE is Senior Ecologist with the International Union for the Conservation of Nature and Natural Resources Before that he was Director of the Nature Conservancy of Great Britain and Professor of Botany at the University of Malaya.
It is often tacitly assumed that environmental effects, consequences or impacts (all of which essentially mean the same thing) must, almost by definition, be harmful. If mosquitoes are sprayed with DDT, the harm caused to other insects, fish and wild birds is thought to be an environmental effect but the smaller number of human deaths from malaria is not. This is twisting the sense of words in a quite unjustifiable way; the price to be paid should be balanced as objectively as possible against the short and long-term benefits.
The environmental consequences of any action can be defined as the changes taking place in the environment because of that action and the environment can be defined as everything that surrounds us. In this same sense you are part of my environment and I am part of yours which leads to considerable difficulties in assessing costs and benefits, to which I shall return later.
Ideally it should be possible to measure all these changes; but in practice of course, this is not possible, nor indeed is it necessary. What is important is to measure changes that are of significant human concern.
EROSION CAUSED BY DEFORESTATION IN YOMASA, COLOMBIA underneath the forest floor
It is reasonable to assume that the criterion which should be used in evaluating or judging any action is whether, taken as a whole, its beneficial effects are greater than those that are harmful (Such judgements are always being made by society; stealing benefits the thief and harms the loser but the damage caused by theft to the fabric of society leads to laws by which the thief is punished, even though he may have good reasons to steal - like a starving man taking food, for example.) A wise government, in theory at least, decides on certain policies and actions because it deems that they are in the best interests of the lasting welfare of its people.
The difficulty in assessing environmental consequences lies in the evaluation of the changes that are likely to take place and in balancing the benefits against the costs.
Balancing benefits against costs is rarely an easy exercise. It becomes acutely difficult when they are unequally distributed, either in time or in space. For example, clearing an area of lowland tropical forest may bring immediate benefits for a relatively short period of time to a relatively small number of people. However, it may also deprive future generations of an irreplaceable genetic resource - and the cost to them may be regarded as outweighing the benefit to the smaller group. Conversely, not clearing that area might be regarded as a cost against the present generation. Evaluating short and long-term costs and benefits is often a matter less of economics than of politics and ethics.
The matter of scale is very important in assessing environmental consequences. The effects of the modification or transformation of forest may be confined to the actual area where the change takes place or they may be much wider. They may have a significance that is only local or their significance may be universal. Examples will help to make these distinctions clear.
The effect may be entirely confined to the area in which the operation is carried out. If one hectare of forest is cleared for agriculture, that particular piece of forest with everything in it has disappeared completely and been replaced by a totally different ecosystem. If the removal of forest also leads to the loss of two centimetres of top soil, of the organic matter and of the base exchange capacity, this is equally a localized effect.
On the other hand, the change of use may affect areas outside and results of this kind are common: soil erosion in the area of changed land use leading to siltation and scouring of river courses downstream; changes in the hydrological characteristics of an area altering the quality of the water delivered by it; the breaking of the migration path of wild elephants causing a change of habits and their passage through farming land; the settlement of people from outside leading to the spread of new diseases among the surrounding indigenous peoples.
The changes may be even more pervasive. The most often quoted are pollutants which are disseminated by air, water or living organisms and which have effects far from the point where the material was originally used. The deposition of DDT in the layers of snow and ice of the Arctic and Antarctic is a well known example. Such may indeed potentially affect the whole biosphere. It has been suggested, for example, that the removal of large areas of tropical moist forest might have far-reaching effects on the characteristics of the atmosphere and hence on world climate - by altering the balance of carbon dioxide or by modifying atmospheric circulation.
But there is another kind of effect that can well be called universal - the elimination of the last example of a forest type or the extinction of a species or gene pool. Such losses have a universal significance because they are irrevocable and irreversible and are of interest in a very special sense to the whole of mankind.
The normal approach to questions of land-use planning in tropical forest areas, as elsewhere, is dominated by economic considerations, softened and qualified by social constraints. The arguments have been well set out by Lee Peng Choong (1974). This approach generally leads to a simple hierarchy of uses, land being allocated to that which is likely to lead to the greatest return on investment. The market is generally considered to be the measure of what is desirable. Protection is generally considered as a restraint on development and the importance accorded to it depends on the value that society places on the characteristic to be protected, and these values are often not readily susceptible to market forces. It is interesting to examine how attitudes to this question have changed about the features that are important.
People have only recently come to realize and appreciate many of the values of areas which are natural or near natural. It is probably no coincidence that this growing awareness has come during a period when the natural in our surroundings has been replaced by the artificial at an unprecedented rate; and this awareness is probably strongest where there is least left. Nothing stimulates interest and concern like scarcity. The sense of appreciation is there, perhaps, when there is plenty, but it is latent, unperceived, inarticulate. It is only aroused by the threat of loss.
In 1962, FAO published a volume on forest influences, much of which was devoted to the effects of forest on water, soil and micro and meso-climate. Indeed, it is only in the last chapter on the "evaluation of the utility of forest influences" that there is any recognition of other values. Here influences are distinguished as (a) "...direct influences roughly corresponding to mechanical effects," e.g. protective influence of forest against falls of rocks or avalanches; (b) "...indirect influences, comprising those in which the physicochemical influence play the principal, though not the only, role. These are the influences which, through modifying the environment, let the forest affect soil retention and the water cycle;" and (c) "...psycho-physiological influences. These are the influences that directly interest man, since they provide him with a better environment, purified air, rest and recreation areas (green belts), tourism, sports, and so on."
SWIMMING TIGER, INDIA the basic dictum: conserve adequate habitat
The fact that the last of these receives very scant attention may surprise us now, but was natural at the time. For this was a period when people were particularly alert to the dangers of soil erosion, of floods and water shortage and were beginning to have the leisure and money to go away from home in search of pleasure grounds. Other aspects of concern for the environment were confined to a relatively small number of concerned individuals.
In contrast an FAO/ECE group in 1974 quoted in Grayson (1974) proposed the following classification:
- Influence of forests in climate, air, water and soil.
- Conservation of the biological heritage represented by forest ecosystems.
- Role of forests in the landscape and for recreation.
This is a significant shift brought about essentially by changing public attitudes. It also holds an important lesson - that tastes and priorities do change, and that the change may be speedy. So it is important in planning land use to allow flexibility to meet the future needs of society; and it may be not altogether easy to predict these.
I put forth an alternative approach which, I believe, provides rather better for future flexibility and the varying requirements of societies and this has been used in a number of British planning studies (Poore, 1973). It would seem to be equally appropriate to the tropical moist forest.
This begins with identifying the main areas of public interest; it then examines the land in relation to their importance in each of these. The various values are then compared with one another. The result exposes conflicts between the various different aspects of the public interest and these can then be made compatible with one another. The success of the technique depends on the success with which the various aspects of the public interest are recognized or anticipated and the skill which is used in survey and ranking. The resolution of conflicts is then largely a matter of political judgement based on an assessment of socio-economic priorities. This is the philosophy which underlies the present consideration of the consequences of the removal of rain forest.
IN THE SAHARA, PETRIFIED FORMATIONS OF VEGETAL ORIGIN; FROM ANCIENT TREE ROOTS? reminders
This approach has been carried further in a study made and published by the Scientific Committee on Problems of the Environment of the International Council of Scientific Unions. In this the principles and procedures which should be used in environmental impact assessment were considered. The chain of reasoning behind the recommendations is important to us, for it considered that the consequences of all actions should be judged by their impact on areas of human concern and that decisions should be made on the best possible assessment of the balance of advantage.
If the argument so far has been accepted two consequences flow from it:
- Physical and biological changes are only important if they affect human interests in some way.- The standard against which any action should be assessed is its lasting effect on human well-being.
This leads us immediately to two of the great difficulties which attend the assessment of environmental change, one concerned with time and the other with space.
1. Many of the adverse effects may take some time to become evident. An action that brings immediate advantages may carry in it the seeds of future deterioration. Moreover the value that people place on various features of the forest may change with the passage of time. Once the basic neccessities of life have been met (food, drink and shelter) preferences and priorities change from society to society and from time to time within a society.2. The effect of any change of land use or indeed any action, such as legislation, having a bearing on the use of land may have effects near to or far from its point of application. It may therefore affect few people or many people. Moreover those who benefit may be quite different from those who might suffer.
Thus it is important to assess any changes that may occur by the effect that they may have on different groups of people at different periods of time. The decisions that will be reached will, therefore, by their very nature be political decisions - but it is important to ensure that as many as possible of the significant elements are available to those who have to make the decisions.
It must generally be assumed that the intentions of those carrying out development are good (though unfortunately this is not always the case) and that they are directed at improving the health, nutrition or standard of living of the people. There is, therefore, necessarily a concentration in this article on the adverse or unintended consequences of development bearing in mind that these must always be balanced against the assumed benefits.
Areas covered by tropical moist forest have a number of values which are considered important. Some of these, such as their value as samples of undisturbed ecosystems, are inherent in the original forest and decrease if the forest is interfered with in any way. Others, the yield of timber or other forest produce for example, can only be realized if the forest is changed by taking a crop from it. Still other values are latent and advantage can only be taken of them if the forest is removed; no profit can be gained by the potential of a soil under forest for growing rubber or oil palm while the forest remains.
It may be helpful in this discussion to distinguish two kinds of change - modification and transformation.
This is a process by which the original structure, composition or dynamics of the forest is altered by human intervention. In its slightest form it may be merely a matter of extracting a few good trees or forest produce (fruit, rattan, gum for example); at the other extreme it can include forms of shifting cultivation which induce secondary succession in the forest. These processes can be called "modification" provided that continuity is maintained with the original forest ecosystem and that there is no permanent loss of potential (by soil erosion, extinction of species, etc.) so that, in theory at least, there is a possibility that the forest could return in a reasonable time to something like its original condition. (An exact return may be almost unattainable in some characteristics, for example, distribution of species and of age classes within species.)
This is a completely different kind of change by which the original or modified forest is totally removed and replaced by a man-made ecosystem or by inanimate structures.
As the forest is modified or transformed from its original state its values are also changed, some decrease or disappear, others increase. Looking at these changes and assessing them can start with a simple enumeration of those that seem at present to be important; but we should always remember that others may appear in future of which we have now no conception. The list which follows begins with the values of the original, unmodified forest and moves towards those of the transformed forest area. The order is not necessarily any measure of importance. It will be seen, in inspecting the list, that these values have different characteristics and that they overlap to some extent with one another.
Tropical moist forest areas may have importance because:
1. Certain parts of the forest are the living areas of indigenous peoples who also derive all their means of subsistence from it. In unmodified forest these are under gatherers who do not attempt to modify or control their environment but are part of it. Others modify it extensively (e.g. by shifting cultivation) but have attained in some instances a stable, dynamic balance with it (Lawson, 1975; Watters, 1975).2. They are the habitat of species and genotypes of plants and animals in which these can perpetuate themselves and can express their evolutionary potential. They serve as natural gene banks and areas where evolution can continue.
3. Certain areas represent undisturbed samples of the range of variation in the ecosystems of the tropical moist forest.
4. The forest covering a catchment area regulates the quality and quantity of water leaving the catchment and prevents erosion, thus maintaining the potential fertility of the area itself and checking siltation and other undesirable consequences downstream. Forest along rivers or streams often protects the banks from erosion.
5. They can serve as areas in which scientific research on natural processes can be carried out or may be places where there is a great amount of valuable scientific information resulting from previous research.
6. They may be used as standards against which changes in areas outside may be measured and evaluated.
7. They can provide monitoring stations for the measurement of regional or global changes in certain environmental measures, for example, atmospheric components and pollutants.
8. They are areas in which students and other members of the public can become educated in natural processes and therefore become aware of their importance.
9. They can be an important asset for recreation and enjoyment, especially in areas of great natural beauty and near centres of population.
10. By their physical presence they can act as a moderating influence on climate.
11. They may act as a buffer against epidemics of pests and diseases affecting both man and his domesticated plants and animals.
12. The forest contains timber and other forest produce, both plant and animal, which can be cropped to provide a continuing yield or which can be converted into capital for investment if it is, decided to remove the forest for other purposes.
13. The sites on which the forests occur may have value for transformation to other uses - agriculture, dam sites, mining, etc. The forest cover maintains the potential and integrity of these sites.
It will readily be seen that these values are very different in kind. Some are consistent with one another, others are not. Some represent capital assets that can only be realized by removing the forest and destroying any other contribution it might make. Some convey immediate benefits; in others the benefit is to be looked for in the future (for example those that provide facilities for research and education).
Against this conceptual background let us examine the possible effects of the removal of substantial areas of tropical moist forest.
The climate of the world is not constant It has changed in the past, is changing and will continue to change. A significant part of this is not caused by any human action, is beyond man's control and is very imperfectly understood. Although knowledge of the natural processes of global meteorology is growing rapidly, it is at present impossible to predict, except in a very rudimentary way, changes in continental or global weather patterns that are of fundamental importance for many human activities. This has, of course, great significance for both the development and the conservation of the tropical moist forest. At this stage in the argument it is important to point out that any humanly induced climatic modification may either cancel out or accentuate an underlying natural trend. For example, if the regional climate is naturally becoming wetter but a change in land use reduces the rainfall, there may appear to be no change. But if the trend in regional climate is reversed and it becomes drier, then the natural and man-induced changes will accentuate one another and the climate will rapidly become more arid. It is therefore most important to judge any possible changes caused by man against a background of the likely natural changes.
NESTING HERONS, KENYA such a delicate balance
During the last decade there has been a significant change in world weather patterns compared with the previous 2030 years (Lamb, 1974). Equatorial latitudes have become wetter and subtropical latitudes drier. But it is not known whether this is a temporary fluctuation or part of a more lasting trend. As it stands, however, it will exaggerate the environmental difficulties in those equatorial regions where the rainfall is already high and in the outer fringes of the tropical moist deciduous forest where seasonal drought can cause problems.
It is hardly surprising that there is still considerable doubt about the effect of large-scale changes in land use on regional or even global climate. Aspects of the subject have been reviewed by the Société malgache d'investissement et du crédit (SMIC, 1971) and Newell (1971). This is without doubt a subject in which further research and facts are needed.
Removal of forest or changes of land use affect the radiation balance (and hence possibly the temperature and rainfall regimes) by changing the albedo, the surface roughness and the apportionment of radiation between the sensible and the latent heating of the atmosphere. The most significant of these is the last. There are great differences between the Bowen ratio (balance between sensible and latent heat) in desert regions (and presumably bare soil) on the one hand, and tropical rain forests, swamps, rice-fields and oceans on the other. Discussion hinges, therefore, around the question whether changes in land use in the tropical moist forest region can produce cumulative changes by feed-back mechanisms of a magnitude to change these physical characteristics in a way that is either irreversible or difficult to reverse.
To quote from the SMIC report:
"Destruction of the Brazilian, Indonesian, or the African jungles might be expected to produce regional increases in Bowen ratio of almost the same order of magnitude. The replacement of such large latent heat sources by large sensible heat sources might have significant effect on the generation and dissipation of tropical easterly waves. This deforestation might also, as suggested by Newell (1971), affect the dynamics of the general circulation through a series of nonlinear interactions. We believe, therefore, that there is an urgent need for numerical experiments designed to test the sensitivities of the models to major changes in the reapportionment of sensible and latent heat fluxes in the tropics.""We should mention here that the destruction of a jungle is almost an irreversible process. Soil moisture is no longer retained and there are frequent flash floods during the rainy season. In addition, the soil dries rapidly and may release clouds of dust into the atmosphere, changing the regional balance. Bryson (1971), for example, has argued that the Rajputana Desert in western India is manmade. Noting that the vertically integrated water vapour content being comparable with that over some tropical forest regions, he suggests that the tropospheric dust loading has increased atmospheric subsidence, thus inhibiting precipitation. Archaeological and pollen studies indicate that the desert was indeed relatively fertile several centuries ago and that it contained a fresh-water lake that supported an early civilization. Bryson's studies remind us that numerical simulations of man-made changes in the tropics must include the effects on the tropospheric radiation balance induced by windblown dust."
It is clearly important to approach changes of land use with great caution
It must be questioned, however, whether it is legitimate to extrapolate from the Rajputana area to the majority of the surfaces covered by tropical moist forest. Under prevailing climate it seems likely that this area would lie in the more arid extreme of tropical dry deciduous forest and only be evergreen where the forest had access to sources of ground water. In the tropical rain forest areas high forest is usually replaced by secondary forest, plantation crops, irrigated agriculture or grassland all of which have physical characteristics which are more similar to the original forest than the example from Rajputana. The tendency to self-generating aridity could however be important in tropical rain forest areas where soil is very poor, in those areas of seasonal drought where fires could increase the dust in the atmosphere and erosion could lead to large areas of bare soil being exposed, in the deforestation of areas of ground water or gallery forest, and everywhere in the ecotone between tropical moist forest into drier forest types.
With this degree of uncertainty however it is clearly very important to approach changes of land use in such sensitive areas with great caution, and everywhere to try and replace forest, if it must be replaced, with systems of land use which reproduce as far as possible the most significant physical features of the vegetation that is being removed.
The question has also been raised about the possible effect of the removal of tropical moist forest on the carbon cycle of the biosphere and particularly on the carbon dioxide content of the atmosphere. It is now well known from observations at Mauna Loa and elsewhere (SCEP, 1970; Woodwell and Pecan, 1973) that the carbon dioxide in the atmosphere has been increasing since 1958 at 0.2%/year or 0.7 ppM/year and that the rate is now about 1.5 ppM/year. The increase is attributed to the use of fossil fuels.
The evidence having a bearing on the carbon cycle was reviewed in the Brookhaven Symposium (Woodwell and Pecan, 1973) and a summary was prepared under the auspices of the institute of Ecology. The following account leans heavily on SCEP and on the results of this symposium.
It is clear that too little is known about many of the main variables for confident predictions to be made about the effect of human action. There is a complex dynamic equilibrium between the four main compartments of the biosphere the atmosphere, the land, the surface and deep layers of the ocean and sediments.
Estimates of the amount of carbon in the main components are as follows:
Amount in metric tons × 109 carbon
|
ATMOSPHERE |
670 |
|
LAND |
|
|
Living organic |
833 |
|
Dead organic |
700 |
|
Freshwater |
330 |
|
OCEAN |
|
|
Living organic |
1.5 |
|
Dead organic |
1000 |
|
Inorganic |
40000 |
|
SEDIMENTS |
|
|
Fossil fuels |
10000 |
|
Diffuse carbon and inorganic carbon sediments |
20000000 |
These figures are at best estimates and subject to many qualifications; moreover the transfer rates between many of these pools are still largely unknown. It seems likely however that the most active transfer (and that of the most immediate interest to man) takes place in the land systems and between those and the atmosphere as a result of present rates of combustion of fossil fuel. An estimated 100 is fixed every year by gross photosynthesis and approximately the same amount is returned by respiration and other forms of oxidation.
Most of the organic matter on land is concentrated in forests. Whittaker and Likens (in Woodwell and Pecan, 1973) give the following estimates:
|
Tropical rain forest |
340 |
|
Tropical seasonal forest |
120 |
|
Temperate evergreen forest |
80 |
|
Temperate deciduous forest |
95 |
|
Boreal forest |
108 |
These compare with:
|
Cultivated land |
7 |
|
Total continental carbon |
827 |
By assigning "present agricultural lands to other ecosystem types and giving higher biomass values for climax conditions to the forests" they suggest that world biomass before the influence of civilized man was over 1000 × 109 metric tons of carbon.
It is clearly important in estimating the possible effects of deforestation on the carbon cycle to distinguish, as the SCEP study does, between carbon with a short residence time (including leaves, litter and short lived animals) and that with a long residence time (wood, large roots, upper soil humus). Upper soil humus in the tropical moist forest region is likely to have a short residence time. Removing the tropical rain forest will clearly bring about a reduction of biomass and will replace carbon with a relatively long residence time by that with a shorter life.
The total net effect of this is impossible to assess on present information but it might be noted in passing that the total plant biomass of the tropical rain forest (estimated by Whittaker and Likens at 340) were to be converted into carbon dioxide over the next 50 years and be replaced by no other stored carbon, it would release carbon dioxide to the atmosphere for that 50 years at double the present rate for fossil fuels. This is likely to be the maximum possible effect.
In conclusion the data on various aspects of the carbon cycle are so inadequate that it is impossible at present to make reliable predictions. It would, therefore, be prudent, pending more accurate models, to avoid aggravating the situation already caused by the burning of fossil fuels and to retain a high biomass on as large a proportion as possible of the tropical moist forest region either in forest or in tree crops. In the tropics the storage of carbon in peat or in surface humus layers is small and depends also on tree cover.
It is generally agreed now that the effect of changes of land use in the tropical moist forest area would have insignificant effects on the oxygen content of the atmosphere.
The most important consequence of the removal of tropical moist forest is perhaps so obvious that it is seldom stated: If the forest is removed, that kind of forest and all the species it contains will totally disappear.
In this characteristic the tropical moist forests differ from those in temperate or more arid regions. The arguments and evidence for this view are presented by Gómez-Pompa, Vázquez-Yanes and Guevara (1972) in their paper "The tropical rain forest a nonrenewable resource" and they would be generally accepted by most if not all workers who have close experience with the biology of these forests.
The reasons can be simply stated. If a forest is cleared, recovery depends on either the persistence of the species on the spot as adults, on regeneration from dormant seeds or on the possibility of recolonization from outside. In temperate and arid regions many of the tree species can continue to exist as isolated specimens, they have effective means of dispersal and the seeds can frequently remain dormant for long periods. Conditions therefor favour both persistence and recolonization provided that small refuges remain. The forest also contains fewer tree species (rarely more than five to ten in temperate Europe for example) and smaller areas are thus necessary to retain representative samples. The forest species of birds and insects can also persist in small refuges; and chains of these, such as are provided by the hedges in the European landscape, enable migration from one remnant of forest to another. In spite of the massive and regrettable destruction of forests in some parts of the temperate regions, the rate of extinction has been very small.
The position in the tropical moist forests is very different. Except where special limiting factors prevail (for example, the impoverished whitesands areas - though even these are richer than temperate forests), the forest is very rich in species of tree. In tropical America and Southeast Asia, one hectare of forest usually has more than 100 different species of tree over 10 cm in diameter, often more than 150. In Malaysia, Poore (1968) found 385 species of tree of over 25 cm diameter in 50 hectares. Many species are represented by very few individuals. Dispersal mechanisms are generally inefficient, so that possibilities of recolonization are slight. Individual, isolated trees do not persist; the period of viability of the seeds is short and successful regeneration only occurs under forest conditions.
The usual effect of removing forest on the flora is the total disappearance of forest species, except for a few "migratory" species (e.g., of the genera Mecaranga in Malaysia, Musanga in Africa, Cecropia, Ochroma and Jacaranda in tropical America) which occur very sparsely in temporary gaps in the climax forest and spread widely in secondary forest. The effect on the fauna appears to be similar. Harrison (1968) compares the 76 species of mammals recorded in 150 square miles of lowland forest in Selangor, Malaysia, over a period of 10 years with the 12-13 which are found in areas of rubber and oil palm converted from forest. Of these two were introduced species of rat and others may have depended on the nearness of remaining forest. McClure (1968) found, similarly, that less than five percent of the local species of birds could adjust to the change from forest to non-forest conditions. The extent to which this reduction occurs is likely to depend on how far the species is bound to a particular niche and specialized in its habitat. Less mobile species such as many invertebrates are likely to disappear completely once the forest habitat is destroyed. Harrison also points out that the pests of cultivated areas are seldom truly forest species but immigrants from different habitats; though there are cases of severe depredations, for example by elephants where their habitats have been disrupted by development.
The effect of widespread destruction might therefore be the complete elimination of the various types of the tropical moist forest and the species they contain.
To quote Whitmore (1975): "Conserve adequate habitat is the basic dictum. If this simple plan is followed the future existence of rain forest animals and plants is assured, and rain forest will continue to help sustain and enrich the life of man. The habitat is conserved if sufficient and representative samples of virgin tropical rain forest be set aside as national parks, inviolate in perpetuity. Such national parks are the forest areas in which adequate populations will be retained to maintain the full genetic diversity of animal and plant species, especially those which occur at very low density, such as hornbill, tapir and tiger or have large territories, such as gaur and elephant...
"A large proportion of the mammals and birds occur only at low elevations as do the majority of the plants with greatest potential for human use. It is essential therefore to conserve lowland evergreen rain forest, (the most valuable kind for logging) and other lowland formations, and totally inadequate solely to conserve montane formations."
If one examines this problem on a world scale there is little ground for complacency. Some indication is given by the UN List of National Parks and Protected Areas.
The total areas in national parks and equivalent reserves are:
|
Tropical rain forest |
13650000 ha |
|
Tropical areas of high altitudes |
1500000 ha |
|
Monsoon forest |
608000 ha |
of which nearly six million hectares are in Zaire, none in Brazilian Amazonia and little in lowland forest where the need is greatest. This compares with a world area of tropical moist forest which is certainly over ten million square kilometres (data from Persson, 1974).
If the forest is removed, that kind of forest and all the species it contains will disappear
However, these figures should be treated with caution. For instance, it is not always clear from descriptions how much of an area is rain forest and how much is covered by other formations.
This situation is even less encouraging if we look at the distribution according to biotic provinces which gives some indication of the extent to which these areas provide protection for characteristic regional types o tropical moist forest with their district animals and plants.
Analysis of the UN List shows that of the 42 biotic provinces that are wholly or in part (e.g. mountains and island provinces) occupied by tropical moist forest, five contain three-five, fifteen contain one-two and thirteen contain none.
It is clear that a much more comprehensive coverage is required if the genetic resources of tropical moist forest are to be preserved in situ. This is one of the main fields of action of the International Union for the Conservation of Nature and Natural Resources in which it collaborates with the new efforts of Unesco to promote the establishment of biosphere reserves.
Little is known about the size of areas which are needed to enable rain forest species to survive. Whitmore (1975) quotes the example of the Taman Negara in West Malaysia. "It has been estimated that Taman Negara (4340 km2) contains 60 percent of the local specialized endemic mammals of the Sunda shelf region, 142 of the 198 species being dependent on forest for their existence, and a major proportion of them living below 330 m elevation (Medway, 1971); 172 of the 241 known lowland forest birds and 52 of the 76 known mountain species which breed in Malaysia have also been recorded within this park (Wells, 1971). The most valuable lowland forest, covering perhaps 30 percent of Taman Negara, contains timber valued in 1971 at about one million Malaysian dollars per square mile (2.6 km2). The pressures in the future to extract this timber can be expected to be powerful indeed, but if Taman Negara is to serve its function they will have to be resisted (Ho et al., 1971)."
Terborgh (1974) has attempted to estimate extinction rates of bird species based on analogies with island faunas. Alternatively Whitmore (1975) has argued from known densities and the number of individuals that are thought to provide an adequate gene pool. "Wild fruit trees occur in the Malaysian lowland rain forest at very low density. In a survey of 676 ha of Ulu Kelantan few species exceeded 24 trees/100 ha and 11 out of 18 had fewer than 13 trees/100 ha (Whitmore, 1971). It can be seen that as is likely, for each species at least 10000 trees are needed to provide an adequate gene pool (Toda, in Richardson, 1970) huge tracts must be conserved."
In my view there can be no single answer to this question. If it is desired to protect these areas in perpetuity, success will depend not only on size but on the range of conditions in the protected area in relation to the changes of climate that may reasonably be expected to occur. Any estimate of the last would be highly speculative. In the absence of more accurate guidance it would seem prudent:
1. To select areas that are large and have as wide a range of conditions in them as possible - from wet to dry soils for example, and from low to high altitudes.2. To supplement these with smaller reserves (The Virgin Jungle Reserves, by Wyatt-Smith, 1950) chosen to represent samples of as wide a range of conditions and to include as many species as possible.
3. To monitor changes in these so that the system can be constantly improved.
A few words should perhaps be added here about two other characteristics of tropical moist forests which are often mentioned in the literature in the defence of retaining land under forest. These are the "biological productivity" of the forest and the relation between diversity and stability.
Measurement of the rate of net production of dry matter in tropical moist forests is a very difficult matter and data are very scarce. Whittaker and Likens (Woodwell and Pecan, 1973) estimate that of tropical rain forest to be 900 grams of carbon/m2/year, (20 metric tons dry matter/hectare/year). But in a climax forest, as tropical moist forest is presumed to be, the biomass is constant and so this rate of production is balanced by the same rate of oxidation (via herbivores, fungi, bacteria, etc.). This rate of production is greatly surpassed by some agricultural crops (e.g., sugar-cane) by oil palm and rubber under favourable conditions (Wycherley, 1969) and by tropical tree plantations (Dawkins, 1967). This is hardly surprising for the climax tropical moist forest represents a steady state with trees of all ages while the others are mainly in the logarithmic phase of growth.
Similar misconceptions surround the "diversity" of the tropical moist forests and the relation between this and its stability. Certain types of tropical moist forests certainly have as great diversity as any communities in the world (Poore, 1968). This diversity confers on them stability in relation to those kinds of natural changes of the environment in which they have evolved (small and gradual changes of climate, geomorphological processes, etc.) and would appear to provide mechanisms protect them from pests or diseases of epidemic proportions. It did not, however, evolve in response to destruction by man and the diversity of the forest, far from providing stability in the face of these new threats, makes the tropical forest exceptionally fragile and vulnerable (Gómez-Pompa, Vásquez-Yánes and Guevara, 1972).
During the period 1965-1971 a total 17.56 million gallons of herbicides were used on forest and crops in Viet-Nam in mixtures containing 2,4-D, 2,4,5-T, Pictoram and Cacodylic acid. Inland forests and mangroves were subjected to treatments of various severity.
The effects have been very extensively reviewed in publications of the National Academy of Sciences and the Summary and Conclusions are presented in NAS (1974).
The effect on inland forest depended largely on the number and severity of application. A single application did little but defoliate the canopy trees; the result of more applications was more serious. It is estimated that about one sixth of the timber has been lost and that the damage "was undoubtedly extensive and serious." Rehabilitation should, however, be possible after detailed inventory. No evidence was found of laterization or loss of fertility in the soils.
The consequences for the mangrove were more serious. About a third of the total area of mangrove (260000 out of 720000 ha) were sprayed. No recolonization or regeneration is to be found in these areas, probably because of the viviparous habit of most of the mangrove species. The evidence about the effect on mangrove fisheries was inconclusive; and removal of mangrove by spraying appeared to have the same effect on the incidence of malaria as removal by cutting.
Tropical forest peoples are here defined as those peoples whose way of life appears to be adjusted to the tropical forest environment. Generally there is a food-collecting (hunting, gathering, fishing) component in their economy, and when it is exclusive (as with hunter-gatherers) or dominant (as with hunter-gardeners) it is not difficult to appreciate that this should be so. But there are also peoples who are almost entirely agricultural, yet who, because of their particular farming systems, co-exist with the forest rather than replace it.
None of these peoples is alike. They range from small nomadic bands, through varying degrees of semi-nomadism and semi-sedentism, to large settled tribes. This enormous cultural variety makes it difficult to generalize about "tropical forest peoples," but in this context it may be assumed that we refer throughout to those forest dwellers who, because of their mobility (nomadism) and/or because of their lack of experience of cultures with entirely different value-systems, are ill-equipped to cope with the pressures of development.
The most severe effect of development on forest peoples is to kill them. Forest peoples generally have no resistance to such diseases as influenza, measles, smallpox and tuberculosis. These have decimated populations much more often than the rare attempts at genocide. It should be pointed out, however, that few peoples have been totally extinguished thereby, at least genetically. The remnants either are absorbed into the dominant culture, usually at the lowest level as mixed-blood peasants, or are absorbed into another forest people to whom they flee for protection, or they recover.
First contact invariably results in epidemics, which often reoccur periodically for some time afterwards. Peoples who traditionally moved around their country in small groups for all or part of each year, when settled (usually in larger groups) are especially prone to infection.
Their vulnerability to imported diseases makes forest peoples dependent on outside medicines and medical help, when formerly they were not. Paradoxically, this can lead to an increase in incurable disease. Once they have been fully exposed to modern medicine, they begin to lose faith in their own curing techniques, particularly as these are rarely if ever effective against measles, smallpox and the like. Unfortunately traditional ailments, especially psychosomatic ones, can persist for some time after the religio-medical practices that could have cured them have died out. The Western medicine that has replaced them is, not surprisingly, ill-equipped to treat a complaint that is the expression of a very different culture, and the ailment remains uncured.
This phenomenon is symptomatic of the severe post-contact demoralization which often occurs among forest peoples. This demoralization has various causes, besides the enormous shock of diseases of which they have had no previous experience and cannot possibly control. One is the discovery that even the most respected and competent adults in the group cannot cope any longer. The rules of life have mysteriously changed, and it is not enough now to be a skilled hunter, fisher or gardener. The forest peoples we are concerned with have no experience of money, and are easily cheated by more sophisticated peoples who would think it perverse not to get as good a bargain as they are able.
The dominant culture often makes no secret of its contempt or pity for the customs and manners of the forest tribe. Visitors stare at nakedness, are patronizing, and laugh at rituals they do not understand. These reactions reinforce the loss of confidence the forest peoples succumb to when they find their most valued institutions are useless in the face of the changes imposed by the dominant culture. The effect of this demoralization should not be underestimated, for to be deprived of faith in all that a person values can be as devastating as being deprived of the means of subsistence.
Apparently benign acts by the dominant culture can also be demoralizing, as when reserves are created for the protection of the forest people and an official is stationed to prevent contacts with undesirables, provide simple medical aid, and so on. In such circumstances, full-grown, highly experienced adults find themselves treated as minors, and eventually they themselves come to be convinced that they are not equal to the pressures of the outside world.
There is no easy solution to these problems. When a laissez-faire altitude would lead to their destruction, it is difficult not to treat as minors people who do not speak the national language, do not understand individual ownership of land or the value of money, have no experience of a work economy, and have no means or experience of political representation.
Culture change is never uniform; a loss is not always balanced by a gain
The introduction of money and of technologies alien to the tribe's social system frequently undermine that system without providing a replacement. Where the exchange of goods and labour is based on kinship relations, the arrival of the money economy weakens those relations, often severely, and the tribal order gives way to an unstructured set of impersonal non-familial associations.
The tribal technologies, although well-adapted to the economy of the tribe, cannot compete with manufactured goods. An influx of these goods eliminates local technologies before people have had time to learn how to earn enough to buy the alternatives and to adjust to a work economy. Often tribal technologies do much more for the society than could be inferred from their functions as artefacts. The long-house of the Motilone of Colombia, for example, as much determines as it is determined by Motilone social structure. The replacement of traditional housing by "modern" forms has led to a collapse of Motilone social structure, just as the organization of the Bororo of Brazil was undermined when missionaries forced them to build their houses in rows rather than in the traditional circle.
Probably the most destructive impact of development on forest peoples is loss of land. Without land, they cannot support themselves, and a once-self-sufficient people ceases to be so. With land, the forest people retains both its dignity in being able to support itself and the option of returning to its original economy (fully or partly) during the long and difficult experiment of adjusting to an entirely different way of life. It should go without saying that each forest people should be guaranteed under the law the full extent of its traditional lands, and that ownership should be vested in the people as a whole. If the tribe is restricted to an area too small for it to practice its traditional subsistence economy, it cannot support itself. Nor can it if it is moved to an area the same size but dissimilar ecologically. If ownership is vested in the individual rather than the group, it will be easy for others to take advantage of the forest peoples' ignorance of individual ownership to buy up their land at knockdown prices, leaving them with money that would be inadequate even if they knew how to use it.
Culture change is never uniform. Too often, the changes that occur are not matched by compensating changes. An artefact is no longer made, a mode of behaviour atrophies, but the forces that displace them cannot fill the functional gap they leave behind them. So it is that throughout the world indigenous minorities have lost much if not all that is positive about their cultures without gaining much if anything that is positive in the dominant ones. They still feel different, but they are no longer confident of themselves in their difference. Development does not transpose a forest people into the mainstream of national society into a cultural limbo where it is neither one thing nor the other.
The profound and detailed knowledge of their environment that is a particular strength of forest peoples, being orally recorded, is one of the first and most positive aspects of their culture to disappear, especially with loss of land and livelihood. This is singularly unfortunate, because this knowledge could provide an effective link between the forest and the dominant national cultures as it is of the greatest utility to them both. Properly exploited, it could restore the pride and confidence of the forest people and could contribute significantly to the sustainable development of tropical forest lands to the benefit of the nation as a whole.
A number of other potentially harmful consequences of tropical moist forest removal have been investigated very little, and indeed their investigation would not be easy. Nevertheless, some of them could be considerable.
By now this has become something of a catch phrase, easily uttered and as quickly forgotten. Its consequences are likely to be profound:
· Loss of germ plasm of food-plants valued both globally (e.g., banana, cocoa) and locally (e.g., rambutan, mangosteen).· Loss of germ plasm of medicinal and other essential non-food-plants (e.g., Rauwolfia).
Beyond a certain point, cultivation of these plants would become more difficult, with breeding programmes progressively less able to combat outbreaks of pests and (especially) diseases. Experience suggests that keeping plasm "artificially" in seed banks is not in itself insurance of genetic variety. Until we are able to guarantee, virtually indefinitely, the survival of germ plasm in man-controlled environments, as well as predict the innumerable circumstances for which geneticists may be required to breed new hybrids, both static banks and evolving "natural" reserves are likely to be essential.
· A third serious consequence of the reduction of genetic diversity is the loss of products yet to be developed This is a tricky area of speculation, in which one is likely to hear the mocking laughter of the British economist Wilfred Beckerman, who has suggested that nobody regrets the failure of his grandfather to invent the invaluable substance "Beckermonium" (Beckerman, 1974). There is a strong possibility, however, that Beckermonium = prudence.
The range of chemical compounds found in tropical moist forest vegetation is unmatched elsewhere, yet scarcely investigated - a source-book of potential foods, drinks, medicines, contraceptives, abortifacients, gums, resins, scents, colourants, specific pesticides, and so on, of which we have scarcely turned the pages. Not knowing precisely what is in this source-book, we could not claim, strictly speaking, to - miss anything if we burned it. Just as we would not "miss" wheat if it had been exterminated before man had domesticated it. However, it would be imprudent thus to circumscribe the economic options of nations fortunate enough still to contain areas of tropical moist forest. It is also worth bearing in mind that the chemical clues leading to the development of a great many synthetics-from aspirin to the oral contraceptive-were not "invented," but were discovered from plants.
Besides the obviously adverse effects of loss of genetic diversity, it is possible that removal of tropical moist forest could reduce the efficiency of local agriculture. Sustainable food production in tropical moist forest areas may be facilitated by, even if it does not depend on, the continued presence of forest tracts as refuges, breeding sites, and carryover feeding grounds for pollinators, the predators and parasites of pests.
Little study appears to have been made of beneficial species exchange (the movement of pollinators and of the predators and parasites of pests) between areas of tropical moist forest and farms, gardens or other cultivated land. Some work has been done in temperate regions, where conditions are clearly different, but with results that suggest that thorough investigation in the tropics would be worthwhile. In the meantime, the possibly benign role of tropical moist forest as a reservoir of species useful, even if not essential, for reliable and economical food production should not be ended by its removal.
Some strains of virus, normally confined to the forest canopy, may be obliged to migrate to a lower level, where they may affect large numbers of human beings, if too great an area of the canopy is removed. This seems to have occurred in the case of recent outbreaks of haemorrhagic dengue fever in Malaysia.
There may be other consequences of tropical moist forest removal, which by their nature are impossible to assess, and accordingly are rarely referred to in discussions of this kind. Yet for all their apparent amorphousness, they are not the less real or important.
Man's progress is in large measure due to his ability to learn all he can of his environment, and to use this knowledge to shape it for his own purposes. Tropical moist forests are among the world's least well-known environments, yet they are central to an understanding of fundamental problems of evolution and ecology, including the efficient use of nutrients and energy and the evolutionary development of species interrelationships. It is possible that to some extent the continued progress of technology and civilization, especially in the tropics, depends on our leaving untouched areas of tropical moist forest to serve as living laboratories.
This is not the appropriate place for a detailed review of the effects of deforestation on tropical soils or on the water regime of tropical catchment areas. General accounts and references can be found, for example, in Pereira (1973) and Russell (1973).
As with other effects of the removal of forest, no simple generalizations are possible. What happens depends upon where the forest is removed, how it is removed and how the land is managed afterwards.
Russel (1973) has summarized the important general characteristics of tropical soils. These, very simplified, are as follows:
1. There are very great differences between juvenile soils which may contain abundant nutrients and the deeply weathered soils on old and stable land surfaces. This is the result of the intensity of weathering.2. The decomposition of dead plant and animal material and its uptake by the vegetation is very rapid, so that a high proportion of nutrients at any time are in the living crop. Biological activity is confined to a shallow surface layer.
3. Water-holding capacity and base exchange capacity are generally low.
It follows that many sites in the tropical moist forest appear to be more fertile than they really are. Change of use should therefore be based on knowledge of the characteristics of the different soils and on adequate soil survey. Many soils such as the tropical podzols (Brunig, 1969) acid peats and all soils on steep slopes should be maintained under perennial tree cover that protects them from the direct radiation of the sun and the damaging effects of the impact of rain drops.
Much is now available about the development of productive, sustained agriculture in this zone. Success depends on careful assessment of land capability, choice of crops, methods of clearing, erosion control and cultivation. It therefore requires a sustained application of skill and a continued investment in fertilizer and in pest control. Given all these conditions a high level of sustained production is possible in certain areas with clear benefits in nutrition and economic wealth. When all these conditions are not met, however, the potential which has been maintained unimpaired under forest cover can be rapidly dissipated with all the well known consequences of erosion, siltation of rivers flooding and colonization with useless secondary vegetation or at the best the continuance of agriculture on a soil that has lost its fertility through leaching and destruction of soil structure.
Sufficient data are not available to me to estimate what proportion of the land in the tropical moist forest is suitable for conversion to sustained agriculture but a high proportion is likely to have limitations imposed by slope, unsuitable soil or excessive rainfall. The tertiary and quaternary sediments of the Amazon basin are likely to prove largely unsuitable. By contrast an area of nearly 100000 ha in the eastern part of the Malay peninsula gave the following figures (FENCO, 1972): Unsuitable for agriculture or forestry with present technology 28.5%, of which over one fifth (4.6% of the whole) is recommended for park and conservation areas. An additional 10.9% has some future logging potential (peat, swamp and peat land) but no agricultural potential. Although 60.4% is suitable for agriculture, only 28.2% is Class I or II land free from any constraints on use.
It should be borne in mind that these proportions are relatively high and that Southeast Asia is something of a special case compared with Asia or America. For example, proportions of as low as one percent have been advanced for Amazonia. Broadly speaking prospects of substantially increasing agricultural output (including the production of grass) lie more with the improvement of existing production methods in areas already opened than with clearing new land.
Little is known about the long-term effects of cropping or the rate of production on leached tropical soils, but a considerable input of fertilizers is necessary to maintain this in rubber and oil palm and is likely also to prove necessary for other tree crops; (Wycherley, 1969) unless systems of combined plant and animal cropping can be used that rely on an internal circulation of nutrients.
The conversion of humid forests to open grasslands for the grazing of ruminant livestock should be approached with caution. These pastures have sometimes proved productive, particularly where they have been developed on fertile soils, but more often they have failed, resulting in degradation of the areas and low productivity of the livestock. Large areas of Amazonia have been cleared and put under grass for livestock production. Often, the soil becomes compacted very quickly, and serious weed invasion occurs within a few years. In some parts, such extensive deforestation has increased the risk of floods.
This subject has been thoroughly reviewed by Pereira (1973). The disastrous consequences of bad land use in tropical catchment areas is well documented, resulting in high peak flows and droughts, erosion leading to the rise of land level in alluvial plains and consequent flooding, etc. Land clearance without proper attention to conservation measures produces the most serious results but due attention has to be paid also in silvicultural operations, the siting of extraction roads and in the management of plantation tree crops. Details of effects are given in Reynolds and Wood (1975).
In the tropical moist forests maintaining original tree cover is likely to be the cheapest effective way of protecting catchment areas. Freise (1934) has shown that forested soils have a greater pore volume and water holding capacity than cleared soils. Thus at a Brazilian site he found that pore volume declined from 51 percent in virgin soil to 12 percent in degraded soil, rising after a year's protection by reafforestation to 35 percent. Pereira (1973) gives an example from Kenya of slopes of four degrees at an altitude of 2200 m and under: rainfall of 1500-2500 mm which was subjected to 90 mm of rainfall (75 mm in one hour) falling on soil already thoroughly wet from ten days of rain. The maximum streamflow measured from 540 ha of forested catchment was 0.6 m3/sec/km2, contrasted with a flow of 27 m3/sec/km2 from 240 ha of land recently cleared and laid out as a tea estate with great attention to soil and water conservation.
Within 10 years however this tea estate had attained the same hydrological characteristics as the forest in, for example, total water use and control of discharge. Pereira's conclusions are worth quoting in full:
"Thus the critical stages in the development of land from protective forest to the cover of a tree crop have been shown to be possible without permanent deterioration in water resources either in quantity or in behaviour. High capital input and the professional skill required to achieve this degree of hydrological control, almost equal to that exerted by the forest, is in sharp contrast to the unplanned invasion of forested catchment areas by peasant cultivators, which has destroyed most of East Africa's forests outside the boundaries of the forest reserves. It is important that the hydrology of this land-use change should be correctly interpreted. Mountain watersheds which are the source areas of important rivers need careful protection.Natural forest, preserved against fire, felling and grazing, gives excellent protection. Tea estates planned and developed with full soil conservation at a professional engineering level, have so far, over the first ten years, proved to be a hydrologically effective substitute."
We have seen so far the kind of adverse changes that can be brought about by removing the forest and transforming it to other uses, if this is badly planned or badly executed. Let us for a moment take the blackest view of the future and imagine what the worst consequences might be.
A YOUNG TROPICAL FERN among the oldest survivors
In a century we might see 10-15 million square kilometres of the surface of the Earth reduced to unproductive waste. Good agriculture might persist on those fortunate areas which possessed stable volcanic soils completely resistant to misuse; even if these had been abandoned they could be reclaimed for productive use. But the picture of the remainder would be very different; barren, infertile, deeply eroded soils would be the rule, covered with scrub, fire-climax grassland and the barest subsistence farming. The possibility of this recovering to forest by natural succession would have gone forever, for the forest trees would no longer exist. Instead any vegetational change would take the form of colonization by ubiquitous, fire-resistant and usually useless shrubs and grasses. The total natural capital, in soil fertility, in variety of organisms, in capacity to recover would have been lost. To use a phrase first applied in the Middle East, the land would be "in a stable state of completed erosion."
The means to obtain capital for restoration would have gone too: the original forest which had been used so prodigally and unwisely in the last century. There might be minerals, but they too might be a waning asset.
Like the trees and animals, the people who once lived in these regions would have disappeared with their knowledge, skills and culture. At best they would be completely absorbed in an urban economy; at worst they would have largely succumbed to imported disease or be living a miserable existence on marginal soils or in slum settlements on the edge of cities.
About one tenth of all plant and animal species on the Earth would be extinct or in dire danger of extinction. A few would persist - those that were adapted to the extreme conditions in areas too inaccessible or unpleasant to be reached by man. Many of these would be gone forever before their utility to man or the pleasure that they might give to him were ever experienced or even understood.
The eroded soils would have lost most of their capacity to absorb and retain water, so that the dower parts of catchment areas would be subjected to a succession of floods and droughts; and the water would be so laden with silt that it would be entirely unsuitable, without expensive treatment, for domestic or even industrial use. Impoundments would rapidly fill with silt and many dam sites would be lost which might have been used for power, or the regulation of water for irrigation or other uses. Over most of the land there would be effective drought because of rapid run-off and lowered water tables, even if there were not climatic change induced by the catastrophic loss of vegetation cover. But, probably before all of this came to pass there would also be widespread famine, epidemic disease and civil strife.
This is fanciful perhaps; but so may have seemed the warning in Plato two millennia ago - a warning that was not taken, with consequences that are all too clear today. This passage (Criteas, cat 400 B.C.) bears quoting once again because its message is so topical:
"There are mountains in Attica which can now keep nothing but bees, but which were clothed not so long ago with fine trees, producing timber suitable for roofing the largest buildings; the roofs hewn from this timber are still in existence. There were also many lofty cultivated trees, while the country produced bountiful pastures for cattle. The annual supply of rainfall was not then lost, as it is at present, through being allowed to flow over a denuded surface to the sea. It was received by the country in all its abundance, stored in impervious potter's earth, and so was able to discharge the drainage of the hills into the hollows in the form of springs or rivers with an abundant volume and wide distribution. The shrines that survive to the present day on the extinct water supplies are evidence for the correctness of my hypothesis."
This process of denudation and impoverishment has gone on to the present day almost unchecked, though more slowly because there is less to lose. It is now so complete that it is almost impossible to persuade those who live there that it was ever any different. Yet because many of the species of plant have long-lived seeds and efficient dispersal, extinctions may have been relatively few. The building stones are there which could be the foundation of recovery. In the tropics, especially in the area of rain forest, it would be different.
Unfortunately it is all too easy to find somewhere in the tropical moist forest region, examples of every one of the processes that I have described above. Massive timber concessions have been granted in the Philippines, Indonesia and Sabah before the ultimate allocation of the land is known. Latin America abounds with examples of land settlement without previous survey of land capability, often on soils where sustained agriculture has no chance of success. In almost all regions there is logging before the silvicultural knowledge is available on which management for sustained yield might be based. The last remaining areas of unique types of forest are being cleared or logged without appreciation of their other values. Indigenous peoples are being displaced to make way for other uses of the land. Even in countries where development is being carried out after careful assessment of land capability, there is inadequate provision for the safeguarding of natural areas and genetic resources. Everywhere development is proceeding without making use of the experience of the past.
But none of this need happen. There is another possible picture. Adequate and carefully selected areas for the protection of flora and fauna and of ecosystems; other areas of natural land, especially perhaps those of high scenic value, set aside for recreation and enjoyment; the gathering grounds of water and the banks of rivers under natural forest cover; lands not suitable for agriculture managed, wherever this is consistent with other conservation objectives, for a sustained yield of timber or other forest produce; intensively managed plantations of tree crops in suitable sites; and, allowing for the needs of protection, all soils of high potential fertility and few limitations under intensive farming.
In much of the tropical moist forest area this choice is still available. A high proportion of the land surface is still under forest and the climate is favourable for plant growth. But in some areas pressure of population makes it necessary to resort to the slow process of land restoration.
The true course of events is likely to lie somewhere between the two. It is unfortunately unlikely that governments will undertake and sustain the high level of long-term planning that would be needed to bring about the second, utopian, picture; and even if they did, mistakes are bound to occur. An additional difficulty concerns the needs of intensive systems for energy and fertilizers. The realization of the type of landscape that has been sketched above depends on the zonation of land. Some parts are protected from modification by intensification of use on the others. This intensification can be brought about either by investment in machinery, fertilizers and pesticides (to simplify somewhat) or by more intensive human involvement in more self-contained systems. Both are possible means of attaining the same objective and both are consistent with the kind of zonation proposed. They will, however, lead to very different kinds of life for the people concerned. The choice will no doubt depend on political preferences and on future trends in costs of energy, the cost and availability of imported fertilizers and the future demand for the kind of raw materials that can be produced in the tropical moist forest region. The point to emphasize here is that good zonation and land management will leave this choice open; bad planning and management will close it inexorably
What, then, is the conclusion? It is simple and in no way new. If the greatest benefit is to be derived from the tropical moist forests and the undesirable consequences avoided, three things are necessary: good planning for the allocation and use of land., high standards in the conversion from one use to another, and good management. This requires vigorous government action, above all, as well as much greater public understanding. Although I have from time to time emphasized the lack of information, there is already available in the world the knowledge and experience to implement the great majority of the measures that would ensure the smooth and satisfactory development of the tropical moist forest region. The main barriers are in attitudes and in institutions. A failure to appreciate the really vital importance of choosing the right course; a tendency to sacrifice long-term benefits for immediate gains, however untoward the consequences may be; a lack of political will to act; a failure of those who need advice to get in contact with those who can give it; the shortage of trained personnel to carry out operations to the required standards; and a reluctance to obtain information in the fields where lack of information is the main barrier to action. Finally there is the lack of public appreciation of the importance of the issues and that what may appear to be an unnecessary immediate sacrifice is for the sake of a great and lasting benefit.
Wise use of the tropical moist forests in future requires a revolution of attitudes. We should treat the world as we would treat our garden or a valuable work of art. It should be as unthinkable to destroy a unique area of forest as to break up the Taj Mahal for road metal or to burn a canvas of Raphael to keep warm for an hour.
In practice this means that the onus of proving their case should lie with those who wish to remove the forest rather than those who wish to retain it. They should be obliged to demonstrate that the changes they propose are genuinely for the lasting benefit of the community.
· Finally, a plea for more action. Nothing that I have said is new. Certainly there are gaps in knowledge; these are being identified in the State of Knowledge reports that are being prepared by Unesco as a basis for Project 1 of the Man and the Biosphere Programme. But it needs to be said again and again that a great deal of the knowledge, skill and experience needed to conserve the resources of tropical moist forests is already known and that conservation of these resources need not interfere with the wise development of the region.
SUDANESE CHILDREN CARRYING BANNERS IN PRAISE OF TREES they care
What is required is the political will to apply this knowledge and action in each of the countries which contain these forests to conserve in the process of development. The guidelines for this are set out briefly and clearly in the International Union for the Conservation of Nature and Natural Resources Guidelines for development of tropical forest regions. A sound land-use policy and adequate planning based on long-term ecological considerations are essential. Changes of land use should seek, as far as possible, to keep the nation's options open; and of course each use should employ the highest standards of management, based on continuing research.
· Wise allocation to various uses;
· High standards of changing from one use to another;
· High standards of management. These are the simple, cardinal rules.
