EROSION: New Zealand’s Urgent Problem

Forest and Bird, Issue 57, 1 August 1940, Page 6

EROSION: New Zealand’s Urgent Problem

(Major J. R. Kirk, M.8.E.)

“Erosion has, indeed, been one of the most potent factors causing the downfall of former civilisations and empires, whose ruined cities now lie amid barren wastes that once were the world’s most fertile lands.” —Dr. G. V. Jacks —“The Rape of the Earth.”

LIFE for most is such a hurried thing to-day, and its interests so complex, that evident facts, such as that grass is green, that rain causes floods, if observed at all, are hardly given a thought. For life goes pleasantly on, and legislators have been appointed to do all the necessary thinking to keep it so! Indifference is thus engendered, and it is usually not until the dire effects of some calamity of nature which overtakes a district are observed and perhaps felt, that indignation displaces indifference and the necessity for greater thought for the future is clearly seen. It is principally for those who have little time or inclination to read long articles or a scientific

symposium that the following facts have been marshalled.

Life depends absolutely upon the top layer, and the top layer only, of the earth’s surfacesoil. Remove that, and desert conditions result; nothing can grow, nothing live. It has been estimated that one inch of top soil was laid down every 500 years —in some places it took 1,000 years. Yet water and wind can take in a single day all the top soil from land which fire or mechanical process has first laid bare!

The natural vegetation, comprising trees hundreds of years old, tussock and other native grasses, protected and fed the soil. When the rain descended, its damage as floods was

minimised, these protective features of nature retaining and detaining it. Birds nested in the forest and in turn protected the trees from the ravages of insects. Nature kept its equilibrium until Man, to whom the beautiful green land was given as a trust for all time, applied the fire stick, the axe, the saw, and the gun! Forests were fired and cut, birds in their millions were destroyed, the land was laid bare, and floods swept away the precious top-soil and buried it in the ocean.

Have you time for just a few of many instances? Then read on! Three billion tons of solid material, washed out of the fields and pastures of America every year by water erosion, contain forty million tons of phosphorus, potassium and nitrogen. To haul this incomprehensible bulk of rich farm soil would require a train of freight trucks 475,000 miles longenough to girdle this planet at the equator nineteen times! Approximately 400 million tons of solid earth are annually dumped into the Gulf of Mexico by the Mississippi River alone—greater part of it super-soil, richer than that of the Nile!

Farms in America in what is known as the “Dust Bowl” Western Oklahoma, Western Kansas, Eastern Colorado, parts of Texas and Wyoming blew clear out to the Atlantic Ocean 2,000 miles away. On a single day 300 million tons of rich top soil were lifted from the Great Plains, never to return. More than nine million acres of good land have been virtually destroyed by wind erosion, and serious damage is reported on nearly 80 million acres! Birds are the chief enemies of insects, and

without their protection, plant and animal life are thrown out of balance, while life for man speedily becomes unendurable. Yet listen! The last Passenger Pigeon, the most abundant and most beautiful of all American game birds, died in the Cincinnati Zoo in 1914. Towards the end a single season’s slaughter in Michigan alone accounted for five millions of these unfortunate creatures! Thus the beauty of the bird, and the brightness of its flight, have followed the natural vegetation into oblivion, with billions of acres of life-sustaining soil; almost incomprehensible material and financial loss has been suffered,

and an environment lovely to the eye sacrificed. The foregoing are facts relative to only part of the United States of America, but in my travels I have seen with despair the good soil being carried down the great rivers of China and Africa as well, and being blown away in Australia, the primary cause being man’s unwise interference with those features of nature which were meant to be of a protective character.

And what of New Zealand? We have , the example of these other countries to guide and warn us, but on we go, gaily throwing cigarette butts and matches along the bush-lined roads, firing natural cover, hacking down trees from mountain sides and hill-tops and ruining for ever a natural beauty with no compensating result whatever, dissipating a capital fund, of the interest of which we are wickedly or carelessly depriving posteritythe only effect the ruination of the hillside and the plains below! For the most part these areas are not replanted, but we spend thousands in straightening watercourses to give the floods which now follow quicker run to sea with their valuable cargoes of life-giving soil! New Zealanders, awake! It is not too late to save what remains and possibly to rehabili-

tate much that has been despoiled. Europe has learned the lesson, and Denmark, much in the news to-day, has now twice as many forest trees as she had 75 years ago; Sweden began to preserve her forests in 1600, and adopts a wise policy of cutting and replanting; while in Asia, Japan over 50 years ago initiated an erosion-prevention policy with results that are the joy of all who visit that land. And America is not asleep!

The State must have the co-operation of the people, and landowners especially must be prepared to helpthemselves. It will be costly, but, as has been wisely remarked, further delay will be more so.

From “Rich Land, Poor Land,” a study of waste in the natural resources of America, by Stuart Chase, and published by Whittlesey House, New York and London, I have used the main material for this article. I recommend this book, and hope it will be widely read. Applying its final paragraph to this country, I conclude: “The strength of New Zealanders is due to these islands. They have moulded us, nourished us, fed their abundant vitality into our veins. We are their children, lost and homeless without their strong arms about us. Shall we destroy them?”