To-Day and To-Morrow?

New Zealand Graphic, Volume XLII, Issue 25, 23 June 1909, Page 20

To-Day and To-Morrow?

The Evils of Deforestation. (Concluded.) (By J. P. GROSSMANN. M.A.. Director of School of Commerce. A.l’.C.) ‘ Matter In the Wrong Place." THERE is one phase of this question that 1 must not altogether ignore, thought it will be impossible in a general sketch of this kind to treat it in full detail. I refer to the effects produced upon river and harbour navigation by the tloods which result from the clearing away of the bush. New Zealand is not. of course, the only country in which this evil has manifested itself. If we turn to America we find

an impressive mass of evidence already collected under this head, In an article entitled "A Continent Despoiled" Mr R. Cronau shows how at least a billion tons of soil are swept away every year from American hillsides into the rivers and harbour mouths, not only robbing the country, but depositing the silt and spoil where it does permanent and irreparable harm. "Year in. year out, our Government spends millions upon millions to dredge river channels and harbours that become clogged with gravel, snags, and mud. deposited there by the tloods.” In almost the same terms, Mr. M. G. Seckendorff. in an article on •■The Elimination of Waste." in a recent issue of "Munsey’s Magazine.’’ drew attention to the appalling waste of money that is one of the in-

direct effects of soil-erosion. “The soilmatter annually carried into lower rivers and harbours.” he tells us, "is computed at 780.000.000 tons. Soil-wash reduces by ten or twenty per cent the productivity of upland farms and increases

channel-cutting and bar-building on the rivers. The annual loss to the farms alone is fullv 500.000,000 dollars”; and

he proceeds to point out that the fertile soil thus irretrievably lost to the country involves its people in still heavier loss when, accumulated in rivers and harbours, it compels them to remove it at enormous expense.

The Cost of Silt. And in New Zealand, as I have already indicated, needless and burdensome sacrifices are constantly entailed upon us all by similar causes producing like effects. Everybody who has lived near the mouth of any of our rivers knows what a bar is. and how seriously it impedes navigation and trade. The silting up of our bar-harbours and the blocking of river-mouths along our coasts have already cost this country untold wealth, and' the evil is steadily intensifying itself with the progressive destruction of the bush. It would, indeed, be interesting to get a return of all expenditure incurred in the Wel-lington-Taranaki district alone in the attempt to dredge and keep open the Patea and the Wanganui and other streams. And within a short time some systematic attempt to cope with this danger will become absolutely imperative. I can hardly sum up this portion of my argument better than by quoting from an article on this subject which appeared some time ago in the Wellington "Evening Post.” The writer deals first with the silting evil in general terms. "In all parts of the Wairarapa, and, indeed, throughout New Zealand, farmers and local bodies are faced with the trouble of the silting up of the lirer beds. Gravel and debris are brought down the streams in flood time. The lifting up of the river-beds forces the streams to deviate all over the country- by their own natural law. The result is that in the progress of years a river covers an area miles in width." But this erosion process is not bv any means the worst of the storv; a'nd he goes on to refer to the destructive effect of the deposition of silt at the river mouths. “Should there be any appreciable silting up of the Ruamahanga

near its mouth, the consequences will be most disastrous to the whole of the Wairarapa in Hood time.” And if we add to the damage thus done by banking up the flood-waters, the injury inflicted everywhere on our coastal trade by the choking of otherwise navigable rivers, we must agree that “what is wanted is a comprehensive scheme for river conservation all over New Zealand, outlined by Government engineers especially appointed for the purpose.” But these articles have been written to little purpose if I have not by this time convinced my readers that no scheme of soil protection or river conservation can be of any value which does not take into account the devastating effects of the destruction of the natural bush along the banks of our streams.

Denudation and Erosion. But the prevalence of floods and the silting up of rivers and bar-har-bours is not by any means the only evil effect of deforestation, of which New Zealand has already had practical experience. I have spoken earlier in these articles of the terrible consequences of erosion and denudation on hillsides where forests have be?n cut away: and though our country has been too recently settled and cleared to exhibit the worst effects of these changes, it is no exaggeration to say that there is not a single district in the Dominion from the Bluff to the North Cape that does not in some way illustrate my argument. Travelling recently from Wellington to

Auckland by the Main Trunk line. 1 looked out on mile after mile of hillside where th? bush had been cut out. and where great gashes and clefts and channels had already been torn by landslips or scoured by rain. Everywhere these infallible signs show that the soil, no longer kept in place by trees and brushwood. is lx‘ing washed down into th? valleys, and it is only a matter of time before the hills will be stripped bare and the flats at their base will themselves be overlaid with the clay and shingle that will pour down as the process of erosion goes on. What all this may ultimately mean to the country, it is. as one of the greatest authorities on the subject has said, very difficult to convey in words. Marsh has traced in detail with impressive eloquence the transformation of

“forest-crowned hills, luxuriant pasture grounds, and abundant cornfields and vineyards well watered by springs and fertilising rivulets to bald mountain ridges, rocky declivities and steep earth banks furrowed by deep ravines with beds now dry. now filled by torrents of fluid mud and gravel hurrying down to spread themselves over the plain and dooming to everlasting barrenness the once productive fields. In traversing such scenes,” adds this distinguished observer. “it is difficult to resist the impression that Nature pronounced th? curse of perpetual sterility and desolation upon these sublime but fearful wastes, difficult to believe that they once and but for the folly of man might still be. blessed with all the natural advant-

ag?s which Providence has bestowed upon the most-favoured climes.” This is nu imaginative or fanciful description. It is absolutely realistic in its accuracy, and

it depicts only too clearly the terrible fat? that may overtake New Zealand, as