BY WILLIAM VOGT
EVERY sector of the human race enjoys - or suffers from - its own superstitions. There are few superstitions as deeply grounded as the belief that Latin America is rich in timber resources. True the region between the Río Grande (Río Bravo) and Cape Horn includes one of the greatest remaining extensions of forest. It is equally true that much of this forest could be turned into marketable and usable timber; millions of hectares have already been cut and burned, with costly results to the Latin-American nations. Yet, continuation of the policy - or lack of policy - that has characterized cutting, down to the present, may well prove to be a disaster. It is important that the belief concerning Latin America's timber endowment be critically examined.
Development of ecological understanding, in this fifth decade of the twentieth century, has brought us to an increasing realization that we may only rarely, 'with justification, think of a stand of trees merely in terms of timber. While we may consider the trees as timber, we must also, in most parts of the world, evaluate their relationship to the total environment - as watershed protection, wildlife habitat, stabilizers of soil, etc.; and in a world of mounting population pressures, where new uses for wood are constantly being discovered, consideration of forest resources is meaningless except in terms of their relationship to human societies. The tendency, characteristic not only of Latin America but of most of the world, to look at an area of trees and think of it in terms of one of these isolated factors is, in the light of modern science, indefensible. Both theoretically and in actuality, the significance of any tree is a function (in-the mathematical sense) of its environment. Its commercial value may be determined by transportation facilities, inflation 10,000 miles away, or a war on another continent; its social value - not only distinct from, but at times opposed to, its cash value - will certainly be governed by slope, rainfall, soils, the total supply of trees, esthetic considerations, the human beings using it directly or indirectly, etc.1
1 Alfred Korzybski, Science and Sanity (second edition, Lancaster, Pennsylvania: Science Press, 1941).
These are not philosophical or academic "verbalizations." They are harsh facts that affect the well-being and even the survival probabilities of millions of men, women, and children around the earth.
Most environments are complex; that of Latin America is almost infinitely so. Through the intricacy that is the Latin-American forest, there run three brilliantly colored strands.
The first of these is a dynamic, and often violent, geography. Most of Latin America lies within the tropics. This immediately implies high temperatures, intense rainfall, and nearly as intense desiccation. Destruction of the forest cover, with exposure of the v soil to the open sky, raises the average maximum temperature by as much as 17° C.2 and to the full impact, of rains that, in Costa Rica, reach 2,800 millimeters a month.3 The intense heat of the sun accelerates oxidation to such a point that land that once supported a rich tropical forest may, within a decade, lose its capacity to support more than an impoverished scrub. Concentrated rains leach out minerals and, though the accumulation of humus may produce fine crops for a few years, exposure to rainfall rapidly destroys the productive capacity.
2 Jean-Paul Harroy, Afrique, terre qui meurt (Brussels: Marcel Hayez, 1944)
3 Personal communication from Carlos Lankester.
High temperatures and driving rains, in part be cause of their maleficent influence on agriculture and in part because of the fact that they create ideal conditions for the existence of such human diseases as dysenteries, malaria, schistosomiasis, etc., raise the environmental resistance against human occupation. This tends to concentrate human beings above the 700-meter altitude. Here the farmer is usually forced to cultivate slopes (often in excess of 45 degrees) and soil erosion rapidly gains control.
Except for the Argentine pampas, unexcelled in richness, Latin America possesses little level land within the temperate zone, except in high, intermontane valleys, which are of course sharply limited in extent. Level, noneroding lands, apart from these areas, consist almost entirely of areas with deficient precipitation, as in Patagonia and northeastern Brazil, or expanses such as the Amazon Valley and Venezuela's llanos, which suffer tropical climatic limitations. For most of Latin America's land there is no crop so well suited as trees.
The stringently limiting factors of the tropical low lands and semiarid areas have had an influence on the distribution of human populations, the danger of which is only beginning to be realized. Latin America may be said to face the problem, within its own borders of at least 20 million and probably 40 million displaced persons, a dilemma that makes the solution of the European D. P. problem seem like child's play. These tens of millions are displaced not in a political sense, but in an ecological sense. They are concentrated on sloping lands, the cultivation of which, under our present economic system, can result only in rapid, and in many cases permanent, destruction of the means of subsistence. They are able to grow their own food, and fibers for clothing and other purposes, and to supply the needs of growing cities, only by a process of autophagy. Economists who exult in increased "production" from such lands are blind to the fact that the people living on them exist by a per version of the Prometheus myth: They may enjoy a rich meal, but it is on their own liver that they are feeding.
A second predominant strand in the tangled environment is rooted deep in the aboriginal past. It is the ancient custom of the milpa, or shifting agriculture. Utilized by primitive peoples throughout the world, especially in the tropics, it has served well under primitive conditions. The forest was cut and burned, cultivated for a brief period until its fertility fell below a productive level, and then abandoned - for periods as long as 30 or 40 years - while vegetation re-established itself, once more built up a humus cap, and in part restored fertility. The tropical forest is a closed system that, drawing carbon dioxide and water from the air, sustains itself; once the cycle is broken, it falls apart.
With the increase of populations throughout Latin America and with improved markets for foodstuffs, it is no longer possible to rest the land for a sufficiently long period to restore it. There is simply not enough land that can be farmed. As a result, the period of fallowing has been diminished, the ultimate tribute is wrung from the soil, and hillsides are falling into the rivers. Millions of hectares have been so devastated by this maltreatment that it is improbable they will be restored to productivity within the lifetime of men now living.
The means of adapting human use to the limitations imposed by natural laws, and of escaping from the abuse of the aboriginal pattern, lies of course within the province of modern science. But here we encounter a third dominant influence in the complex - the tradition of centralized government, brought to the New World from the Iberian peninsula. In most Latin American countries, which have to adjust themselves to the new economic patterns of a technological world, the interest of the government and the availability of its services are still in many cases directly proportional to the proximity to one or two large cities. " Back country " is often considered primarily in terms of exploitation. Road systems are developed for access to the capital, rather than for development of the provinces. Health, educational, and other facilities that build up a region and make it acceptable to settlers are again usually concentrated in the capital city and one or two satellites. Forest areas usually lie far from centers of governmental activity and as a result are not always at the forefront of attention.
This condition results in part from the low carrying capacity of much of Latin America's land. The Venezuelan llanos, the Ceará district of Brazil, the selva of Peru, the Guanacaste plains of Costa Rica, etc., like large areas of Arizona, New Mexico, and the western Dakotas in the United States, have such a low carrying capacity (are able to produce so little wealth) per square kilometer, that they are unable to support large enough aggregates of people to justify the maintenance of modern schools, hospitals, water and sewerage systems, roads, and motion picture theaters - the amenities that we consider part of the modern high standard of living. This explains, to a considerable extent, the concentration of populations in the large cities. Whereas roads have been built in some parts of the world to open up new territories, their effect in much if not most of Latin America has been to siphon people off the land into the large towns. A powerful contributing factor in bringing this about is the urban background of the Spanish culture, which attaches the highest value to activities concerned with existence in cities. The "hick" or country bumpkin, while he may be a social inferior in the Anglo-Saxon culture, is regarded with even less esteem in the Latin-American culture. Even the trained agronomist and forester are inclined to feel that, once they have graduated from a technical school, they should take on a desk job and spend most of their time in town.
What have these factors to do with the Latin-American forestry situation? They have combined with many other factors, such as the virtual absence of pure stands, to develop a social pattern-in relation to available forest areas that makes consideration of Latin-American forest resources, in a European or North American term of reference, completely invalid. Forest utilization in Latin America must be approached with a mind free from preconceptions.
In terms of slope, climate, favorable temperatures, soils, etc., only about 5 percent4 of South America's land can, in the terms of modern western civilization, be considered arable. (Were lowland areas, particularly along river bottoms, to be opened to a water-buffalo and rice culture such as obtains in Asia, and such as is being advocated by Asiatic leaders faced with the problem of excessive populations, the problem of arable land would be entirely different.) A very high proportion of this 5 percent is adjacent to rivers. In few parts of the world is agriculture, the basis of existence of the vast majority of the Latin-American people, so immediately associated with the hydrologic regime, and in no part of the world is the hydrologic regime balanced on so delicate an equilibbrium, so vulnerable to disturbance. The ecology of Latin America, like that of Africa and tropical Asia, is peculiarly difficult to live with. Latin America, from Mexico to southern Chile, has been gravely wounded by disturbance of the hydrologic regime, primarily as a result of deforestation. Poverty has been extended, living standards lowered, and some countries brought to the brink of starvation, through lack of proper use of forests. Nine years of study of Latin-American ecology have convinced me that there is no factor more important to the future well-being of this great area with its rapidly increasing population of 150 million people than a healthy relationship among human populations, forests, and water.
4 Frank A. Pearson and Floyd A. Harper, The World's Hunger (Ithaca, New York: Cornell University Press, 1945).
Let us consider what this relationship has been, in some sample countries:
Deforestation for purposes of mining had become such an obvious threat in the 1540's that the native Mexicans in the region of Taxco petitioned Viceroy Mendoza to protect their lands and their wood supply by forest regulation. The earliest forestry laws of the New World were promulgated in a decree by the Viceroy in February 1550;5 many features of them could still be considered sound forestry. One has only to look at the landscape around Taxco today, seamed and pitted like the face of a dissipated old man, to realize that whatever may have been done in 1550, the Viceroy's wisdom had little effect. Hillsides have been stripped not only of their forests but of their soil. Streams that once ran steadily throughout the year are now intermittent, alternating between flood and disappearance. Springs have vanished. Much of the land has been turned into a virtually unproductive waste.
5 Boletín del Archivo General de la Nación (Mexico), Vol. II, pp. 260-263.
What is true of the Taxco region is more painfully true of many other parts of the Mexican uplands. Here, over hundreds of thousands of square kilometers, land that once produced rich coniferous forests - and that today could be the source of an enormous income to Mexico - has lost not only its trees but its topsoil. Where it once produced great pines, it can now scarcely support the maguey cactus.
Obviously this soil has had to go somewhere. It has washed into hundreds of lakes, hydroelectric and other reservoirs, stock ponds, and rivers Infertile silt has covered valuable lands downstream. River beds have been elevated by silt, and rivers forced to seek new courses. Coastal swamps have been extended.
Without the forest to break the fall of the rain and without its roots to hold the soil in place, erosion has been accelerated probably more than 100 times. Without the humus layer to absorb the rain and let it sink into the water table, the rate of run-off has been speeded up. No survey is available, but it is certain that thousands of springs that once fed human populations and contributed their slow clear trickle to the streams have disappeared. Man has turned hundreds of thousands of square kilometers into an ecological desert, for the sake of a quick and profitable crop of trees, a few years of corn and potato production, and grazing. He has reduced the productive capacity of this land to the vanishing point. Even in the time of Cortés, there were protests over his wanton cutting of trees for urban construction.6 The destruction has continued, at least into 1947, when President Alemán sharply restricted the cutting of timber on state-owned lands.
6 Lesley B. Simpson, Many Mexicos (second edition, New York: G. P. Putnam's Sons, 1946).
Many of the remaining Mexican upland forests are in an unhealthy condition. Virtually uncontrolled fires and grazing have destroyed the forest complex and replaced the normal, reproductive understory by park-like expanses of grass, of low carrying capacity. In some areas, such as the national parks near Mexico City, where I estimated the age of the trees to be 60 to 80 years, there is literally no reproduction. Were all grazing to be excluded immediately, and were 100 percent-effective fire protection organized, there is in these forests no possible way in which Mexico can close the gap between maturing trees and replacement.
Largely as a result of de-vegetation, water tables are falling in Mexico (as they are in many countries) and there are few towns of any size that are not faced with the threat, or the actuality, of water shortage. Like the North Americans, the Mexicans are trying to go farther and farther afield, at increasing cost, for their water supplies. They are not aware of the fallacy of the position in the United States and of the failure to realize that subsurface water is limited and can be replaced only by infiltration of water that falls from the sky. Indeed, the North American destruction of watershed capacity is being generally repeated throughout Latin America.
As one might expect, with the increased rate of run-off, flood hazards mount. In the latter part of 1944, some 300 people were drowned in the Mexican low lands in floods that for the most part originated on deforested slopes.7
7 William Vogt, Mexican Natural Resources - Their past, Present, and Future. Report on Activities of the Conservation Section, Division of Agricultural Co-operation, Pan American Union, 1943-1946 (Washington: Pan American Union June 1946).
Mexico's great wealth of pure or nearly pure stand of conifers, found in the uplands, has been at the same time Mexico's liability. Clear-cutting has been profitable in the absence of an adequately developed forest management policy, and not only forests but the tote land complex and social environment have suffered Mexico's lowland forests in Yucatan, Tehuantepec, etc., have been largely protected from exploitation up to the present time, by their mixed character. True certain valuable woods have been cut over wide areas and the milpa, driven forward by increasing population pressures, has caused large tracts to be burned Conversations with lumbermen indicate that a new danger is arising - that of clear-cutting. As large areas of tropical forest are cut off, particularly where they grow on the porous soils of Yucatan, we must expect a profound ecological change that will once more turn great areas into desert or near-desert. Here, as in so much of tropical America, we may see in operation the land degeneration so vividly described by Harroy for Africa.8
8 Harroy, op. cit.
As we move south into Guatemala, we find an even more serious situation than that found in Mexico. The population pressure, relative to areas of arable land, is far higher in this beautiful republic. Cornfields have been pushed up such steep hillsides that they are commonly said to be planted with shotguns! In many parts of the highlands one may see areas where the cutting of the vegetation has brought about such a change in the angle of repose of the soil that entire hillsides have collapsed into the valley below. The milpa system is again dominant here. As a result, at the end of the dry season of 1945 smoke was so thick, in the region of Atitlán, that photography was impossible. Standley9 reports that some Indian communities in Guatemala, for want of fuel, cannot cook their unleavened corncakes (tortillas) but must content themselves with a thick cornmeal mush.
9 Paul B. Standley, "The Forests of Guatemala," Tropical Woods, 67, 1941
This raises one of the major forestry problems of Latin America: how to supply sufficient cordwood and charcoal. At least 75 million people depend on these fuels for all their cooking, heating, and in many cases industrial, purposes. Railroads depending on wood from mountainsides through which they run, have spread devastation over thousands of square kilometers. In the Urubamba Valley of Peru, for example, the railroad has been largely responsible for tearing down the mountainsides. In Brazil, firewood for the locomotives is in some cases trucked as many as- 152 kilometers, because of extensive deforestation.10 Smelting is still carried on with charcoal in a number of countries, as it was in the sixteenth century.
10 M. L. Cooke, Brazil on the March (New York: Whittlesey House, 1944).
It is probable that no single crop in Latin America is as important as firewood. Yet it is probably safe to say that no Latin-American country produces it on a sustained-yield basis, i.e., grows as much as it cuts. If only to repair the damage caused by charcoal burners, whose ovens are one of the chief causes of forest fires, the maintenance of extensive research programs and forestry schools would be justified in both human and monetary terms. Such facilities will have to be created.
El Salvador, without coal or petroleum, with little to export except coffee (with an annual value of $15 to $20 [U. S.] per capita), and with barely adequate hydroelectric resources in the rainy season and a serious lack of electric power in the dry season, is rapidly approaching the fuel-less condition of the Guatemalans described by Standley. Two million people, in creasing at the rate of 40,000 per year, are crowded into 13,000 square kilometers, with only about a mil lion hectares of arable land at their disposal.
The need for more land is acute; this drives people up the hillsides, where they plant corn on 100-percent slopes. Under such conditions and without control measures such as the expensive stone terraces of the ancient Incas or the modern Javanese, it is literally impossible to hold the soil in place. The need for fuel under such conditions is inevitably becoming more acute. Here, also, springs are disappearing. For some years there has been under consideration a plan to develop a counterpart of the Tennessee Valley Authority (TVA) on the Río Lempa, which rises in Guatemala and crosses El Salvador. This would require complete de-population of the precipitous slopes above the river, and it raises the problem as to where the population could be resettled. So much silt is dumped into the river from the nearly vertical cornfields that any dams constructed would be turned into silt traps within a very short time. On 28 August 1946, the
Lempa was carrying a silt load equivalent to 170,208 metric tons per day!11
11 W. C. Bourne, T. W. McKinley, O. P. Stevens, and U. Pacheco Preliminary Survey of Conservation Possibilities in El Salvador (San Salvador: Servicio Cooperativo Interamericano de Salud Pública, 1947)
The northern border of El Salvador, adjacent to Honduras, where the town of Ocotepeque was wiped out a few years ago by a flood resulting from deforestation, is dissected with hundreds of eroded gullies that are often 15 or 20 meters deep. They are dumping their sterile subsoil into the country's short rivers, whose Hash floods, spreading this sand on the good lands downstream, are a cause of great national concern. One of the cardinal needs in El Salvador today is a vast reforestation program that will restore the country's lands to the use to which they are best suited, that will stop gullying, and that will bring under control the waters which, when unregulated, are one of man's most dangerous enemies.
Costa Rica possesses the considerable advantage of a small population in relation to its productive area. Nevertheless, as in Mexico, it has concentrated its people in the salubrious and productive highlands, where lands that should never have been de-vegetated have been planted to corn and coffee - with the expected result. Costa Rica possesses some extremely interesting forestry problems and, in a sense, epitomizes some of the difficulties of Latin-American forestry. She possesses, for example, magnificent stands of the copeyi oak. This appears to have been unknown to foresters and lumber dealers alike until a route was sought for the Inter-American Highway. Since the opening up of the forest, destruction has been almost without limits.12 Steep slopes are being stripped; some areas have been burned - though fortunately the humidity keeps down forest fires - and much of the area looks as though Panzers had passed over it.
12 William Vogt, The Population of Costa Rica and Its Natural-Resources (Washington: Pan American Union, July 1946).
This oak forest, one of the most magnificent stands of trees left in the Western Hemisphere, has been recommended as a national park, in order that its beauty and its scientific interest might be preserved, at least in part, for generations to come. Not only will unbridled destruction of the trees destroy a great cultural value; it will rapidly destroy the land. The rainfall in this area is about four meters per year. Soils are thin and sloping and cannot possibly produce many crops. Nearby areas, reported to have been cleared within 25 years, have degenerated into low-grade pastures in which bracken, Pteris sp., is the dominating plant. Much of the control of the waters that flow across the El General Valley, into which Costa Rica hopes to extend its agriculture, lies in this oak forest.
An uncomfortable object lesson in what destruction of this watershed may do, can be found on Costa Rica's Pacific coast and in the Province of Guanacaste. On the Pacific slope, most of the area occupied by man has degenerated into such low-grade pasture as was mentioned above. Here, rivers that might be an important source of hydroelectric power vary as much as 100 to 1 between the wet and dry seasons, largely as a result of deforestation. On the plains of Guanacaste, formerly covered at least in the southern extensions by tropical forest, rivers are so laden with silt that it has been necessary several times to move entire ports downstream, in order that they might continue accessible to boats. The rush of waters from the uplands floods so much of southern Guanacaste that cattle must be removed if they are not to drown. In the same regions, when attempts have been made to replace the forests with grassland, in the dry season the cattle die of thirst.
This disturbance of the hydrologic regime has taken place under relatively primitive conditions. The head waters of the Guanacaste rivers have scarcely felt the lumberman's ax and the farmer's torch. As the Inter-American Highway is opened up across these watersheds and, in the absence of controls, the forest is wiped out, much of Guanacaste, the seat of Costa Rica's important cattle industry, will be made uninhabitable.
In central Costa Rica, the region around San Ramon is approaching that of the maguey lands of Mexico, as a result of deforestation and subsequent soil erosion. The hydroelectric reservoir of the town of Heredia has lost approximately 75 percent of its storage capacity - despite constant attempts to clean out the silt - because of the destruction of forests and the sowing of corn on its watersheds.
Costa Rica still possesses large areas of forests. As one considers them and the potential wealth locked up in them, one cannot help asking whether they are more important to this richly endowed little country as a source of immediate wealth, in the form of marketable timber, or as regulators of the waters on Costa Rica's hillsides. A policy and techniques of sustained-yield lumbering will have to be developed for this country, since it would not be worth while, for the money a single crop of trees will bring, to turn thousands of kilometers into a desert.
A forester of broad experience in Venezuela is the authority for the statement that approximately half of its trees of high timber value have already been cut. Whether or not this estimate is sound, Venezuela's hydrologic regime - it is no exaggeration to say - has been wrecked by de-vegetation of the Andean slopes that dominate the country. In some of the other more heavily populated nations, destruction of the land is more widespread; in no country that I know are the dynamics of land destruction more violent.
Here, once more, we find the familiar pattern, with 70 percent of the country's population crowded into 13 percent of its area that comprises highlands. A clue to the effect of this concentration is given by what might be called alluvial peneplains, which still survive in some of the highland valleys. These indicate that alluvial soil, once available for farming, formerly lay some hundred meters deep and provided broad, nearly level fields for food production. The slopes of the mountains, according to early travelers, were heavily forested. Deforestation subsequent to the arrival of the Spaniards accelerated run-off of rainwater (in some areas totalling about four meters a year), cut down through the alluvial deposits, and over an area of hundreds of kilometers carried the rich soil to the sea. Cornfields that were once a thousand or more meters across are now down to 20 or 30 meters. So much soil has been stripped from the slopes themselves that broad areas can no longer be cultivated. Some fields are producing no more than 0.1 to 0.2 quintals of wheat per hectare.13
13 William Vogt, The Population of Venezuela and Its Natural Resources (Washington: Pan American Union, December 1946).
Rivers in Costa Rica are accumulating so much silt that ports have to be moved. or abandoned.
Venezuelans now talk of the "anarchic" regime of their rivers, ignoring the fact that it is man, and not the rivers, that is anarchic. Soil brought down from the uplands has covered wide expanses of level lowland and has raised river beds. Streams, the flow of which was once regulated by the tropical forest, now alternate between flash floods and periods of near-dryness. As river beds are raised by upland soil, they must seek new outlets. They lash slowly to and from, like the tail of an angry tiger. The town of Garcitas, on Lake Maracaibo, has already been destroyed by the Río Chama. The important port town of Santa Barbara is threatened with inundation by the Chama and the Río Zulia, which are slowly drawing together.
Across the Andes, hundreds of rivers dump millions of tons of rainwater onto the llanos, which are alternately flooded and desiccated. It is reported that 15,000 cattle were drowned year before last in the region of San Fernando de Apure alone. This important state capital is every year isolated for weeks or months by the uncontrolled floods from the uplands.
A clue to the destructiveness of these unleashed waters is given by hydroelectric stations. That at Valera has a settling tank 2.5 x 15 x 20 meters, with an intake of 2.5 x 1.5 meters. So much silt enters this tank in the rainy season that it must be cleaned out daily. Despite this, so much silt passes into the penstocks that turbine blades must be replaced every few months. Heroic attempts are made to clear detritus out of one of the power reservoirs of the city of San Cristóbal; but erosion on its watershed is so violent that the reservoir is sometimes filled almost to capacity with rocks and sand after a single storm.
Control of erosion, provided human beings can be controlled, may be possible in the Venezuelan Andes by means of grasses. Destruction of humus, with its power of water retention, is, however, so widespread and so complete that restoration of forests as a means of flood control may well require decades. When the imperative of slow rebuilding through inevitable plant successions is set against a social background in which shifting agriculture and burning are commonplace and in which human populations are rapidly increasing, it is possible to gain some idea of the difficulty of the task that lies before the forester. It is an unfortunate, unpalatable, and inevitable fact that most of Venezuela's uplands should have been kept under forest and never cultivated. Venezuela faces no problem more difficult or immediate than the resettlement of 1 to 2 million people, whose disregard of limiting factors on the uplands is making survival on the lowlands difficult, if not impossible. Not all of the Andean forest in Venezuela has been cut; but the exploitation is proceeding rapidly, as roads make the forests available. Much of the area should never have been logged, even on the basis of selective cutting. Here is another environment in which the felling of a single tree may so disturb the angle of repose of the soil that a landslide will follow.
The coastal region of Peru consists of almost unbroken desert. The eastern slope of its mountain chain again characterized by rain forest with level land almost nonexistent, is again subject to the limitations we have described. Until recently, it has been cheaper for residents of Lima to purchase Oregon pine than the products of their forests. If no adequate forest policy is developed, it may still be preferable - in terms of Peru's survival - to import lumber from abroad.
As we move southward into Chile, we escape from the limiting high temperatures of the tropics. But as we travel south of Santiago into the famous zone of the "Roaring Forties," we must again face the problem of driving rainstorms. Forest exploitation in south central Chile has already taken tragic toll. Thousands of hectares that should have been maintained in trees have been cleared and the land planted to wheat. Soil exhaustion, erosion, and a fall in yields (see table) is a tendency that is all too widespread. A sample will suffice to show the situation.14
14 Manuel Elgueta G. and Juan Jirkal H., "Erosión de los Suelos de Chile." Boletín Técnico Núm. 4 (Santiago de Chile: Departamento de Genética y Fitotecnia, Ministerio de Agricultura, Enero 1943).
Osorno, the principal city of south Chile, was formerly a port, but siltation resulting from forest destruction has long since isolated it from the sea. Corral, at present the outstanding port in the south of Chile, is threatened with a similar fate. Aysen, on Chile's frontier fringe, is nearly isolated by silt washed into the fjord by which it is approached.
Chile has actively enlarged its program of timber cutting and foresters are wont to refer to this as an increase of "production." If the cutting, however, is not being done on a selective, sustained-yield basis and there is no adequate provision for reforestation, it would seem more accurate to translate "production" into "destruction." Many of south Chile's forests grow on such thin soil and such sloping land that a single cutting results in erosion that strips the soil bedrock. Over much of the Huaitecas archipelago, for example, there is little probability of more than one crop of trees. The same situation obtains, of course, in the Northern Hemisphere, on the Archean shield, where a single cutting, especially if it be followed by fire, leaves the hilltops naked.
|
Period |
Yield of Wheat |
|||||||
|
Cauquenes |
Chanco |
Quirihue |
Florida |
Mulchén |
Traiguén |
Imperial |
Collipulli |
|
|
(...quintals per hectare*...) |
||||||||
|
1911-1917 |
8.7 |
9.7 |
7.7 |
11.2 |
10.3 |
11.3 |
12.0 |
13.4 |
|
1918-1924 |
8.6 |
7.2 |
... |
... |
9.9 |
11.1 |
126 |
9.9 |
|
1925-1931 |
8.0 |
6.8 |
7.3 |
7.3 |
8.0 |
10.1 |
10.9 |
8.8 |
|
1932-1939 |
5.9 |
4.7 |
4.8 |
6.7 |
7.7 |
10.2 |
9.9 |
7.2 |
*A quintal equals one hundred-weight.
Not all the forests of Latin America occur on vulnerable slopes. Millions of hectares, particularly in the Amazon Basin and coastal plains, are-distributed over level or near-level land. These forests, of course, do not exist in pure stands and relatively little is known about the utility of most of the trees in them. Exploitation that will be both economically and ecologically sound will require far more research than has yet been undertaken. That vast riches are locked within these forests - riches that can be safely harvested only on the basis of rational exploitation - seems highly probable. Here lies a great frontier, intellectual as well as geographic. A co-ordinated research program, internationally financed, would seem to be one of the most promising investments for the governments of the wood-hungry world.
Not all the forests on the sloping lands should be left intact - not by any means. However, any plan for their exploitation should give full weight to the many influential and' complex factors involved, some of which were mentioned above. It does not seem unreasonable to insist that any program of timber utilization on sloping lands be weighed in the balance of its effect on the land itself - and on the well-being not only of downstream populations but those that, in this expanding world, may be expected to occupy the lower reaches of the watersheds within the next hundred years.
Drawn from the Preceding Article by the Staff of FAO's Forestry and Forest Products Division
A widespread process,. such as that so vividly described by Mr. Vogt, clearly calls for thorough study and the strict application of remedial and curative measures.
Responsibility lies, of course, with individual governments, who should accept this as being in their own national interests.
It is well to emphasize that broadly similar critical problems of forest and water-shed deterioration have occurred elsewhere and that, by aggressive planned action, they have been controlled. A simple outline of the kinds of measures which have been effective elsewhere may serve to indicate that the job ahead in Latin America, though formidable, is not incapable of solution.
(1) In the first place, a policy to halt the further spread of shifting cultivation on erodable, sloping land must be formally adopted. Whether control is to be exerted through establishing reserve forests, through zoning, or in some other way, is immaterial. Control in the general interest is the cardinal point. Similarly, deciding what types of administrative mechanism should be set up is far less important than that there should immediately be an authority to reach and enforce decisions, after proper study of the facts in each particular situation. Experience has shown that a decisive policy and an effective administrative authority can halt the process of degradation. To check any further increase in avoidable damage is clearly the first step.
(2) The complex task of restoring damaged and destroyed forests and water-sheds next needs attention. It seems clear that fire must be controlled. Whether resulting from land clearing, as a supposed aid to grazing, from lumbering, or from accident, fire aggravates the ill effects of shifting cultivation and sets back the natural processes of regeneration. A clear-cut policy and adequate legislation must be made operative by a field organization with the requisite authority to check traditional practices. Experience in many lands has shown that, given determination, such a program can be carried out.
(3) It is essential that felling of timber should be carried out with caution so that cut-over areas may still support forests and will not suffer from erosion. Methods will vary with different types of forest. The main objective is to halt the spread of barren land. Especially for public forest land, this implies an active field force of trained foresters for applying proper forestry practices. Such à body must have adequate legal powers and administrative authority.
(4) Once shifting cultivation and fire have been brought under control' positive action must be taken to encourage and accelerate restoration of the forest cover. Where natural restocking by useful species is likely to be long delayed, planting of suitable species will often be indicated.
In any event, extensive and costly reforestation programs are desirable only after substantial control of primary destructive forces has been achieved. The same applies to various direct methods of controlling active erosion and floods through soil conservation practices, combining engineering and forestry. Although these methods are expensive, a number of Latin-American countries will have to use them, in view of the situation described by Mr. Vogt. In fact, when a stage has been reached where slopes can no longer retain top soil, the establishment of vegetation is impossible until stability has been restored to the soil. Specialists must determine where these costly projects, which include drainage, trenching, dams, and retaining walls, should be carried out so as to obtain the best results. In most cases, this will be up in the watersheds as this is where streams and torrents gather momentum to cause floods and from where eroded soils are carried down to silt rivers and cause deltas.
Two very important and difficult programs must parallel the positive action suggested above. The first entails informing and educating the people directly concerned as to why they should change their traditional ways of using land and as to the benefits they will derive. Public support is always essential when such changes are planned. Methods of reaching the people are well-known but, of course, must be adapted to particular populations.
The second program entails creating a solid basis for the practice of forestry, proper land use, soil conservation, and flood control through a great deal of research and experiment. General principles and effective methods nearly always need to be adapted to local forest and soil conditions. Local research is therefore necessary.
In sum, then, Mr. Vogt's article points to the proper development of land use, forestry, and soil and water conservation as being major problems for Latin America. They present, however, a great opportunity and challenge to the determination of Latin-American governments and peoples.
Photos accompanying this article were furnished by courtesy of Marjorie W. Vogt and William Vogt.
