K. H. OEDEKOVEN
KARL HEINZ OEDEKOVEN is regional forestry officer in the Near East Regional Office, Cairo, of the U.N. Food and Agriculture Organization.
This article is condensed from the UNESCO quarterly review, Impact of Science on Society, Volume XI, Number 1, 1961.
A "popular" article, which has appeared in the UNESCO periodical, Courier
AS FAR as the unknown origin of mankind, the path of human activity has been marked by the thoughtless destruction of forest and vegetation. In the course of history, civilizations have flourished and disappeared with a resultant depletion of trees and plants, leaving only steppe and desert behind. Only in recent centuries has man begun to realize that he was cutting off the branch that he was sitting on.
Man is becoming more aware today of nature's vengeance and, at the same time, of the challenge which confronts him in preserving his dwindling natural assets while endeavoring to extend the fertile earth which is the very basis of his existence. The demands of an ever-increasing population make his task more and more insistent.
The forest, our largest and most durable soil cover, was once regarded as only an obstacle to settlement, agriculture and communications. It was recklessly burned or exploited until it suddenly became a focus of intense human interest.
Man has come to learn that the two most important elements of his existence - soil and water - owe their stability and availability to the presence of sufficient forest cover. In many countries this knowledge has not been confined only to a few informed specialists, but is today appreciated by a majority of the citizens.
After visiting the denuded mountains of Natal, the former Prime Minister of South Africa, Jan Smuts, declared in Parliament: "This is the vital problem of our people, it is more important than all politics!"
In some distant future, this change of mind, this great turning back from the destruction of forests to reafforestation, may perhaps appear to the historian as a more important landmark in the development of mankind than all the great wars of our age.
But awareness alone does not solve problems. Ministers of agriculture in most countries are deeply perplexed. World population increases by more than 50,000 people daily but the available area of productive land steadily declines.
Three-quarters of the world's population are undernourished. There is only about one acre of land per head for food production and no less than twice this area is needed to ensure satisfactory nutrition. The true Enemy No. I in the world is not a political or military opponent, but the deterioration of the soil, the dryness, the irresistible progress of semideserts and deserts.
In some countries, like the United States of America and the Union of Soviet Socialist Republics, soil conservation has become almost a "state religion." In southern America, all over Africa, Asia and Australia there is great concern over the manifold dangers which threaten the soil.
While international rivalries change, while political leaders come and go, this destructive process of soil deterioration remains a permanent menace. Each government inherits this problem from its predecessor. Yet, even today, the efforts of many countries to remedy the situation are merely in their infancy.
Only a few years ago the streets of Swakopmund in South-West Africa were swept over by a sandstorm that piled up sand dunes 20 feet high. We know from the experience of 500 years that the Sahara desert progresses toward the south at the rate of over three feet a year on a wide front of 2,000 miles. Lake Chad, which some decades ago was still an ideal refuge for migrating birds from Europe, is steadily diminishing in surface area and depth and its shores are fuming from fertile green to steppe brown. All far-reaching plans for the development of Africa as the "continent of the future," all plans for water use and industrialization will fail unless the necessary attention is paid to the importance of trees and forests.
In classifying the great list of lost or endangered productive lands we find first that two desert belts have developed along both sides of the equator The one in the south reaches from Australia to South Africa and South America. The one in the northern hemisphere spreads north from China, all across Asia, North America and Mexico.
The northern belt includes those nations which, as we learned in our history classes at school, were once rulers of the world. We were puzzled to hear in geography class that large areas of these once powerful nations arc now sterile. The truth is, of course, that in ancient times they were not so.
Ctesiphon and Baghdad, once centers of concentrated power, were described by Herodotus mole than two thousand years ago: Of all the countries we know this is the most suitable for growing grain. It is so well favored that it yields two hundredfold and, where conditions are best, even three hundredfold. The cars of wheat and barley grow to the width of four fingers. But to the height of what tree millet and barley grow I shall not disclose, though I know it exactly. No one who has not seen Babylon would believe me.
For Herodotus, Babylon was the essence of fertility He also accorded the same honor to Cinyps, a region in North Africa: "This country produces grain equal to the best I have seen, for it has black soil and springs water it The yield is equal to that of Babylon, three hundredfold under the best conditions."
Soldiers in the sand and torrid conditions of this region (part of modern Cyrenaica) during the last war would have had difficulty in imagining that a now desolate desert was the richest of farming land two millennia ago.
Mankind has lost a considerable part of its cultivable soil during the course of recorded history and, throught this process, nations which once ruled the world have gone down to poverty and misery.
There are three zones on the globe which successively were homes of dominating civilizations but where the soil became progressively devastated in proportion to the age of their settlement
The first zone is the desert of North Africa. In the Sahara, hundreds of archaeological finds anti cave paintings indicate that this was once a flourishing country of many lakes and rivers. One cave painting shows men swimming. Imagine swimmers in the Sahara desert today!
A second zone is the continuous range of stone, salt and sand deserts which spreads from west China, across Turkestan, Afghanistan, Iran, Iraq, Jordan, Sinai and up to north Africa. In ancient times these latitudes were inhabited by Sumerians, Babylonians, Persians, Macedonians, and Phoenicians - names which are all connected with world power and wealth.
The third zone covers Palestine, Syria, Asia Minor, Greece, Italy and Spain. It is true that the southern European states, Greece, Italy and Spain, are neither steppes nor deserts, but their deforested mountains justify the statement once made by Henry C. Wallace, former United States Minister of Agriculture: "Nations live as long as their humus!''
These countries to which for centuries numerous foreigners came in search of fertile land, nowadays see their own inhabitants emigrating to all parts of the world to find better living conditions.
Zones of depleted land extend slowly from the south to the north, and this epidemic of devastated soil seems to be a contagious one. Attempts at reafforestation in Spain, Italy and Greece would certainly have been more successful had the opposite shores of the Mediterranean still been covered With a wide belt of fertile land as once they were. Rut the terrible desert has already reached the shore of the Mediterranean on a wide front and sends out its drying winds to the European countries.
The ever-blue sky of Italy has not always been as blue. Some 2,000 years ago it was just as grey and cloudy as in northern parts of Europe and the complaints of the old Romans about frost and snowfall - which seem so strange to those who know Italy today - were probably justified.
Much of the world's population (except in east and south Asia) has left its earlier home and shifted more and more to the north. What caused this change from paradise to desert? Is this dreadful development unavoidable, or is man himself to blame?
While once it took millennia, or at least centuries, to deplete fertile land, modern history offers a striking example of how man can start and complete this disastrous chain-reaction in only a few decades. Hardly a hundred years ago, the American farmer moved into the Middle West, full of initiative and energy.
At first, the existing forests seemed inexhaustible. The! were cut down, houses and bridges were built, the wood was burned in locomotives, on ships and in stoves. Great quantities were felled and burned on the spot to make large areas of ash-fertilized farming land. A little later, monocultures and tractors cleared away those clumps of trees and hedges which had survived.
The result was that water ran off the land too rapidly, soil was eroded, floods occurred and drought appeared between rainy periods. This process was accelerated during the first world war when large areas of what remained of tree-covered prairie were plowed up for more intensive wheat production.
After the war, part of this land was left idle, but there was no longer any deep-rooting grass or other soil cover to conserve the moisture and stabilize the soil. Storms swept the land from the Mexican Gulf and Canada unchecked, for there were no forests to break their force. The wind carried away the fertile topsoil leaving only sterile layers and rocks.
The same thing happened to former forest areas. Without the protection of the trees, without the firm grip of their roots, without humus, the soil was carried away. In the south, where the frost which usually stabilizes the soil during winter seldom occurs, and where there is seldom snow cover to prevent the damage, soil and wind erosion had the same detrimental effect.
Like a network of veins the first small gullies appeared in the soil, gradually deepening to real gorges. The process was repeated a million times all over the country until finally only the naked rock was left in some regions.
Even today American rivers carry away so much fertile soil that an old Indian once said: "Our country is a new Atlantis; one day it will disappear in the ocean!" It is significant that the Americans, aware of their responsibility for this destruction of their productive land, call their deserts "man-made."
If we were to summarize the direct repercussions of the destruction of forest land on human society the list of wasteful and harmful effects would be a long one. They would include soil deterioration, increased difficulty of watershed management, climatic deteriorations, lack of wood for many purposes which it fills in man's daily life, heavy expenditure for imported timber for countries whose supply has disappeared, loss of employment and income which forests and forest industries naturally provide, shortage of recreation areas, loss of additional incomes from small woods which help small farmers make ends meet, lack of shade for livestock and animals, to mention only a few. These effects in turn set off a whole chain of other negative reactions far too numerous to set down in detail.
But, to state the problem in general terms, all measures and efforts must be combined and incorporated in a sound forest policy. Each country must define for itself the role which forests, primary forests, forest and ancillary activities must play in relation to the physical, economic and social environment. Physical environments alter little with time, but economic and social conditions, on the contrary, change as a country seeks to improve the living standard of its people. Hence, forest policy must be a continued creation. This makes it all the more difficult since the objectives set are for the future. It always takes a long time for any action on the forest to show appreciable results.
The protective and indirect influences which forests provide is a comparatively young branch of study, greatly neglected by our technical age. It is true in many places that schoolchildren can identify almost any type of automobile at a glance but are often unable to distinguish an oak tree from a beech. It is thus all the more necessary to inform the public of the beneficial functions of trees in nature.
The forest has many indirect effects upon the economy, the prosperity and the well-being of a country and its people. One of its most important actions is the prevention of reduction of soil erosion. This protective action results from the fact that forest cover increases the degree of precipitation and checks run-off. Even small forest plants like shrub and bush in hot arid regions offer valuable defense if they are reasonably dense.
In many parts of the world where forests have been destroyed or depleted, all the fertile humus and topsoil has been washed away and only sterile rock has been left on the slopes. Not only these slopes are thereby condemned to sterility, but also vast areas in valleys and plains are overlaid with sterile sediment, not to speak of damage to roads, buildings, etc. The cost of such losses and outlays involved in repairing the damage done by erosion in the world reaches a figure of incredible size.
FIGURE 3. - Traditional tree of the Lebanon, the cedar has been replaced (above) near Beirut by these umbrella pines, descendants of those planted a century ago by a farseeing emir, to prevent the encroachment of sand dunes. In ancient times cedar wood was used in the building of Solomon's temple (a cedar still figures in the flag of the Republic of Lebanon). But many forests that once flourished in the Middle East and North Africa have disappeared - victims of man's improvidence - and are replaced by invading sands. (Photo, UNESCO - Kesting)
Erosion is only the first phase of a serious chain reaction which starts with the regression or disappearance of forests. Sediment deposited in reservoirs, water-courses, fields and cities is an important part of the total damage. This damage seldom comes to public attention because it is often invisible. Sediment increases the total volume and weight of flow in watercourses thus raising the height of flood peaks and their destructive power. In drainage basins and reservoirs, sediment can reduce water capacity in a short time.
Investigations made into the effect of silting on the capacity of dams in Algeria show several dams lost 100 percent of their original capacity in a period of 74 to 96 years. Similar findings in the United States with respect to annual storage depletion in numerous dams indicate that from 0.09 to 31.53 percent of the original storage capacity is lost as a result of silting. Recently a monograph on the Arno river basin in Italy revealed that 2,670,000 tons of solid material are carried away annually by the water flow, thus causing an average lowering of land surface of almost one inch (2.6 centimeters) a year.
Silting is almost always associated with deforestation. Dams fed from completely wooded watersheds practically never silt up. Experiments carried out by the Tennessee Valley Authority in 1955 showed that after reafforestation and protection works had been completed, the volume of sediment carried down by the river was reduced by 90 percent.
The forest also plays an important part in protecting the soil against wind erosion and sand encroachment. Dune stabilization by tree planting is a well-known practice in many parts of the world. It is true that almost any vegetation cover will stabilize loose soil and prevent it from being eroded by wind and rain, but forests are probably more effective because of their height, density, deep-reaching roots and permanency.
It is a keenly debated question whether or not the forest can bring about increased rainfall or, at least, make for its better distribution. There are indications that the presence of forests may increase local rainfall, though effects on a regional or continental scale have not been demonstrated.
The denser the forest, the greater will be its power to reduce wind velocity. One authority has proved this protective effect and noted reductions in velocity of over 85 percent. In Italy, tests have shown that the Cecina forest reduced wind velocity by 56 percent anti a hard-wood coppice in the same region was responsible for a reduction of 89 percent.
The importance of such protection against wind erosion can hardly be exaggerated. In dry periods and on bare land the particles of certain types of soil become so severed from each other that a strong wind can easily carry them away. The finer particles form clouds and the coarser particles, whipped by the wind, roll and bounce over the surface of the soil. Their movement is halted whenever the wind slackens and they bank up in pits, ditches, canals and sunken roads, or in the neighborhood of sheltering objects where they may suffocate crops. This is only one of the perils of strong winds. Drying out of soil, direct damage to delicate products like fruit, and the distortion and stunting of exposed trees can all be traced to this cause.
In countries where forests have to be restored, reafforestation offers an excellent opportunity to provide transitional employment for workers who may find their ultimate destination in forest industries which do not yet exist. In Greece, for example, the proposed reafforestation program could absorb several thousands of people, mainly from mountain districts where work its often hard to get. In Spain, the government's forestry program employed between 30,000 and 100,000 men, according to the season, in 1956. A bold reafforestation program for the eastern Mediterranean would provide employment for some 145,000 to 200,000 men annually over the next 10 to 20 years.
It is a striking fact that a number of countries have never formulated a forest policy or passed a forest law, in spite of evident symptoms of soil deterioration and in spite of repeated warnings about the results of a further decline.
One of them comes from Professor Flatscher, scientist of the Academy for Soil Cultivation in Vienna. He has estimated that the world's forests produce about 1,600 million cubic meters of timber a year whereas the volume cut annually amounts to between 2,200 and 2,600 million cubic meters. This indicates that the annual fellings are about 50 percent above the allowable cut.
Any private individual who sanctioned such improvidence would be held responsible for bad management and would certainly be heavily penalized. But mankind as a whole, it seems, can indulge in prodigal waste of this kind without being in conflict with any law. The only explanation is perhaps that the inevitable results of violence against the laws of nature seldom fall directly on those who commit the offense.
Though forest areas and timber reserves are still decreasing, there are a few blight spots where we may confidently expect steady progress. The total forested area of the world ix estimated to be about 10,000 million acres (4,000 million hectares) and these forests should be capable of providing reasonably adequate supplies for a population larger than now exists. But the provision of such supplies will entail the treatment of all productive forests as renewable crops, the opening up of forests which are not yet accessible and the cessation of the widespread devastation of forests which still continues.
Of the 4,000 million acres (1,600 million hectares) of the earth's original forest area which man has destroyed, 1,000 million acres (400 million hectares) might well be replanted especially since much of this land is to be found in places where the population ix in greatest need of the products of the forest.
The cost per day of the second world war was a little over $500 million. The cost of one day of this war would reafforest at least 20 million acres (8 million hectares) and the cost of 50 days would be sufficient to reclothe the entire 1,000 million devastated acres with proper tree cover. Of course, no one is so naive as to believe we are on the verge of any such undertaking. But we are in possession of scientific knowledge, industrial skill, and technical equipment which could be used to spread the potential benefits of the forest to the uttermost ends of the inhabited earth.