EROSION AND HISTORY

Grey River Argus, 19 September 1945, Page 3

EROSION AND HISTORY

Writing in the “New Zealand Science Review”, ,W. A. Jacques says:—• Western civilization had its beginning in the alluvial plains of the Nile Valley and of Mesopotamia. Early tillers of the soil, by primitive methods of irrigation and by the selection of food plants, were, if undisturbed by Nomadic tribes, able to produce more food tljari they themselves required. Division of labour thus began, and with it came progress in civilization and an increase in the command over nature. From these lands of the Near East our civilization moved westward, and in its path found cultivated land. The urge was ever westward for more and more such land, until the vanguard reached the■ Pacific Ocean waters that wash the western sands of the Americas. For the first time in the history of the human race there are no more continents to discover, to colonize and to exploit. The nations of the Americas occupy the last frontier of civilization. A survey of land use during this westward march discloses the genius of peoples and institutions on the one hand, and the complete disregard of any consequences following upon exploitation on the other. About 5,300 years ago, the Phoenicians migrated from the desert and settled along the eastern shore of the Mediterranean Sea, establishing the harbour towns of Tyre, Sidon, Beyrouth and Byblos. They found this land mountainous and heavily covered with forest, the greatest extent of which were the famous cedars of Lebanon. This forest became the timber supply for the treeless alluvial plains of the Nile and Mesopotamia. The growing population doubtless, soon exceeded the carrying capacity of the restricted flat lands, and was faced with several alternatives, one of which was further colonization, and another the cultivation of slopes. As these slopes were cleared of forests and were cultivated, they were subject to soil erosion under heavy winter rains. The great area of terrace wal’/S across the slopes in Various states of repair testify to the efforts of the slope farmer to retard or to control erosion 40 or possibly 50 centuries ago. To-day the forest has disappeared and on the mountains of ancient Phoenicia one may find' bare limestone slopes strewn with remnants of former terrace walls. Lowdermilk has estimated that the cost in human labour to level terrace slopes of 50 to 70 per cent., as were found in Beit Eddiner, Lebanon, works out at modern wage scales at 2 000 to 4,000 U.S. dollars per acre. Such ‘costs are not justified when more suitable land is available, but they represent what may, and sometimes must be paid in an economy, of survival. Such examples wiarn us to find ‘ ways of saving good land before necessity drives a people to such extremes in cost of human effort. Lands of the Old World display a indelible record' written across the landscape by resident, populations. The longer the occupation the deeper is the record written and the easier if is to read the story of a man’s stewardship' of the earth. Thus in Syria there are to be found the grandest ruins in the ancient world at Baalbeck and Jorash. But, to a soil conservationist, the most striking ruins are those of the “Dead Cities.” An area of about one million acres in North Syria lying between Aleppo. Antioch and Hama exhibits soil erosion at its worst. Here are ruins of villages and towns resting on a skeleton rock of limestone from which three to six feet of soil have been irretrievably lost, leaving the door-sills of the stone houses perched high above the hare rock. These cities are dead, with no hope of resurrection, for the basis of their prosperity is gone. The cities were not buried, but have been left high and stark by the irreversible process of erosion. The land which in the heyday of the Roman Empire provided olive oil and wine for Rome is to-day inhabited by semi-nomads, who find precarious shelter in the ruins of the former cities. This area contains the remains of convents, cathedrals, stores, public baths, hotels and tombs. The Persian and Arab invasions in 614 and 630 decimated the inhabitants, blotted out their culture, their cities, and even the traditions of agriculture, while the subsequent avarice of the Turks made recovery impossible. After 13 centuries of neglect, erosion has completed the destruction started by the invader, and created a desert generally devoid of vegetation, water and soil. The Promised Land of 3,000 years ago, “flowing with milk and honey,” has been so devastated by soil erosion that half the hill land is now barren. The finer soils washed into the Mediterranean turn it from a glorious blue to a dingy brown for miles along its shores. The marshes caused by the erosional debris and coastal river channels have had no small part in this work of destruction, for they brought malaria and depopulation. Erosion in the hills, marshy lowlands and malaria, have been sufficient to reduce the population of the Promised Land to one-third of the Roman and Byzantine period. North Africa, too, bristles with amazing ruins of prosperous cities and thousands of villages and works of the Roman epoch. The Roman city of Thydrus, now El Jem, was located in the midst of the great coastal plain of Tunisia. It had a coliseum to seat 60,000 spectators, second in size only to that in Rome. Now a wretched village stands on its site. Instead of green fields and olive orchards, there is sparse wild vegetation and isolated olive groves overrun by herds of grazing animals. The Roman city of Timgad in Algeria was once the proud centre of Roman culture and power. After the Arab invasion of the 7th century it was lost for over a thousand years, buried from sight by eroded dust. Only a few columns and a portion of Trajan’s arch reached above the earth, like tombstones to marl: the burial of a once great city. The surrounding land has been devastated by wind and water as a memorial to man’s folly. The striking contrast between the populous past and the present, decadence of North Africa led early students to believe that an adverse change of climate was responsible. This is to-day mainly discounted, as successful plantations of olive trees are to be found on the sites of ruined stone olive-presses, while an extensive experimental plantation at Sfax in Tunisia discounts ah adverse change of climate since Roman times. There still remain, in the vicinity of Sousse a few Roman olive orchards which ’ escaped the destructive invasion of the 7th century, to point to causes other than change of climate for the astounding decline. China and Peru can offer striding examples of successful slope-cultiva-tion methods developed independently, and probably predating those of the Phoenicians, for which they deserve equal praise for a marvellous achievement. The history of the Pontine Marshes in Italy is one of eroded hills, choked streams, and the conversion of coastal plains into marshes. Thus the story of Phoenicia is re-told in Rome. Emperors, from Appius Claudius in the 4th century 8.C., and the Popes, especially Pope Pius VI, have vainly attempted to dram the pestilential marshes. Only in 1931 were they brought under control by Mussolini, a feat, which will forever stand as a counter to the subsequent treachery of the once proud dictator. High population pressures in Italy

and France have made necessary the cultivation of slopes and also elaborate and comprehensive works to meet the increasing hazards of floods. The high cost, of control: is considered justified by the protection of valle.v lands from damage and prevention of loss of life and property. These are but a few lessons from history: but man has been slow to learn. His hunger for land, end still more land, has blinded his ej r es to the fundamentals of land use. We in New Zealand cannot point the accusing finger at any country, for ours is placed high on the list of lands where erosion is most evident. We cannot point with pride at achievements to save the soil. Indeed, we evince a prodigality hard to'match in the whole wide world, and one day we shall look with regret at those wasted years, when the rivers carried a perpetual load of good soil to the sea, when we were too indolent to stop it. ‘