DEFORESTATION

Nelson Evening Mail, Volume LXX, 22 June 1936, Page 8

DEFORESTATION

SOME OF THE EVILS AN INTERESTING REVIEW (By H. G. Kingsland) I do not claim that there is anything original in this article. The bulk of the facts have been culled from magazines, books and the daily newspapers. The functions of a forest are threefold. (1) To provide forest products. (2) The prevention of erosion. (3) The conservation of water and regulation of stream flow. The damage caused by the destruction of the bush may be divided into two classes. Deterioration of climate, and loss of soil through wind and water. Originally the greater part of this globe was covered with dense forests. Civilised man has always waged war on the forests, and the destruction of these upsets the balance of nature, and brings other evils in its train. In dealing with the first mentioned evil —the deterioration of climate. It does not always follow that when forests are destroyed the rainfall decreases. It frequently does, but not always. As far as New Zealand is concerned there is only 10 per cent, of our total area left in forest, and yet the rainfall over the greater part of the area is still sufficient and well distributed.

NELSON CLIMATE Dealing with the Nelson climate I have the records back to 1857. There appears to be wide variations over individual years, but taken in 35 year periods back for 70 years there is not much difference; our average is about the same or between 37 and 38 inches. There is no doubt that in districts well wooded the yearly rainfall is better distributed, the showers being more frequent. Leaving Nelson and New Zealand alone, there are many countries where the evidence is quite conclusive. The rain has disappeared with the forests. Mesopotamia once a forested and fertile country is now one of the most sterile lands in the East and the Euphrates is swallowed up in the desert. Asia Minor once densely peopled is now for the most part treeless, sterile and sparsely populated. In Palestine we have a better example: 2000 years ago this was a fertile country—a land flowing with milk and honey. With the destruction of its trees by the Turks the climate gradually deteriorated, and for a thousand years or more the country was largely depopulated and sterile, but in recent years the rains are returning. This is attributed to colonisation by the Jews and the large tree planting programme being carried out in connection with this. Whether the return of the rains is due to the planting of trees or not I cannot say, but certainly the rains are returning on an area that has been largely treeless and rainless for over a thousand years. Leaving this aspect of the question alone let us turn to the other clanger —erosion. On this point there is no doubt at all. The effects of the destruction of trees in this repect are immediately noticeable. Practically every civilised country in the world has suffered in this respect, some more than others.

| TREES AND MOISTURE I Trees by absorbing the moisture and releasing it gradually act as a brake and prevent erosion. When the hillI sides are stripped of‘their covering, ' the water rushing down quickly brings enormous quantities of gravel with

it, and by gradually raising the levels of the riverbeds will in course of time destroy the whole of the valley flats, stripping the hillsides of their soil at the same time. An apt illustration of this is to be had close at home. 1 refer to the Waihopai in Marlborough where a 60ft dam has filled up in a few years. The same tiling is happening in practically every riverbed in New Zealand. It is also occurring in every country where the hills feeding the rivers have been stripped of their forest covering. In the Appalachian mountains in U.S.A. several costly clams have had their water capacity reduced by threequarters. Also the Burrinjuck dam in southern N.S.W. The water capacity in eight years has been reduced by 12,000,000 cubic feet. The Chinese have ruined large parts of their Empire particularly in Northern China, where many hundreds of square miles have been totally ruined for the habitation of man. The periodical flooding of the Hwang-Ho has caused the loss of millions of lives and inestimable damage to property. Mr Emerson Hough in “Everybody’s Magazine” says “China is the best example of a country that never cared for forestry. She builds houses now of little poles, uses for fuel saplings, shrubs, herbage. Her children literally comb the hillsides for fuel and fodder. The land is bared to the bone. It is a land of floods. Villages are swept away, hard tilled fields ruined. Starvation always stalks in China. Alternate floods and water famines follow the waste of forests.” It is a discovery of hydraulic science that the erosive power of water varies as the square of its velocity. When the protective covering is stripped from hillsides, the water rushes off much more rapidly and docs an increasing amount of damage. Recent tests made in America showed that in a given time on cleared and uncleared hillsides, three times the quantity ran off the cleared hillside at a speed 30 times greater. Practically every European country has suffered severely at some time from the same cause,i but in most of these countries steps have been taken to minimise the effects' by huge replanting schemes. Sicily at one time the granary of Rome is now entirely deforested and is a poor agricultural country.

There are parts of Denmark, Yffgo Slavia, Austria, France, Italy, Spain, which have become valueless in modern times through deforestation. It has been said of Spain that the loss of her power and wealth, and the decay of her Empire were due more than anything to the empoverishment of her soil, following the destruction of forests on the central tablelands of the interior. The best illustration of the effects of deforestation are to be had in the meterological and topographical history of France during the past century. The excessive clearing of forests on the Lpwer Alps and Pyrenees and the floods and land slips which followed culminating in a record flood in 1875, forced the French to undertake an extensive system of reforestation which has minimised the dafinage.

MODERN TIMES Coming down to more modern times America is going through exactly similar experiences. Last summer U.S.A. was visited by»a series of duststorms, the magnitude and intensity of which it is hard to realise. The dust stopped trains, and motor traffic, choked animals and human life was almost insupportable. Again only a month or two ago the country was swept by floods of a severity unparalleled in the history of the country. Over 25 per cent of the total land area was under water, and the damage ran into hundreds of millions of dollars. During the dust storms the top soil was blown off an area equal to the states of California and Massachusetts. I Mr Morris L. Cooke, Rural Electrification Administrator asserted. “If things go on as they are now, in 50 years we will have a total area of fertile land not much more than three times the size of Nebraska. Unless there is a marked improvement in our present methods of agriculture, we as a nation have less than a hundred years to go. As a nation we are in the position of an individual far gone with such disease as tuberculosis or cancer.” Realising the seriousness of the position the Roosevelt Administration has launched a vast soil conservation scheme in which tree planting ranks as the first line of defence. Amongst other things farmers are to be paid five dollars for every acre planted in forest trees. NEW ZEALAND’S POSITION

Reverting to New Zealand our position is worse than that of U.S.A. though the process is not so far advanced. Exclusive of Alaska they still have 25 per cent, of their land area still in forest. New Zealand only has 19 per cent. When the'Maori came to New Zealand it is estimated 95 per cent of our land area was in forest, when the white man followed several hundred years later there was left about 45 per cent, still in forest. Now after less than 100 years of settlement our area of native forest is down to 18 per cent. It is true that six or seven hundred thousand acres of exotics have been planted but these only amount to about 1 per cent of our area bringing the total up to 19 per cent., which is far too low for safety. The destruction started by the Maori has been carried on by the white man with fire and axe and now the'declare completing the destruction of our forests. Always the deer are bringing death nearer to our forests by eating out the undergrowth and preventing' regeneration. Nature pronounces a curse of sterility and desolation on lands denuded of their forGStS. In a mountainous country like New Zealand it is necessary to retain a considerable portion of the total land area in forest if the valleys and flats are not to become gravel beds. The destruction of . forests generally becomes a veritable disaster to countiics and results in the decadence and ruin of the farming industry. China with between 8 and 9 per cent, of her area in forests is a land of floods and famines. Germany has a well organised forest service with 25 per cent, of her area under l'oiest. France with 20 per cent is not far short of Germany but has suffered severely from flood damage. U.S.A. with 25 per cent is on the edge of! disaster and has embarked on a bold nation wide soil conservation scheme. New Zealand with only 19 per cent is well below the safety mark for a mountainous country, and this should j be substantially increased if the ex-

periences of older countries are to be avoided. DISASTROUS FLOODS During the month of February last New Zealand was again swept with a series of disastrous floods, and the total damage must have run into millions. In Canterbury alone the estimated damage to the wheat crop was £500,000. In New Zealand we have a great number of river boards, and without exception they are all concentrating on the protection of the river banks and course. Mr J. H. Blackwell, chairman of the Waimakariri River Trust has just returned from America. The engineers with whom he conferred there were surprised to learn that in no case in New Zealand had the River Boards any jurisdicition or control over the watersheds feeding the streams they controlled. Spending money on river control without similar attention to the water shed is simply throwing money away. There is no gain saying the fact that floods in New Zealand are increasing both in frequency and intensity. We are fast following in the footsteps of older countries. The only remedy is to stop grazing on mountain areas and reserve these areas for stream control.

' The history of the prosperity or lack of it is based on that country’s forest wealth. To tackle the reafforestation of our denuded areas seems an insuperable task, but it is not. For stream control purposes the densely planted, immaculately manicured forests as existing in New Zealand to-day are unnecessary. All that is required is to establish seed or mother trees, keep the fire and the stock out, and nature will do the rest. In some localities possibly this can be affected with the native trees but over the bulk of the area this is not practicable, for two reasons. Firstly they are too slow, and secondly the deer eat out the young trees as fast as they appear. Everywhere in New Zealand the deer are destroying the young trees, by which regeneration is effected, but this does not apply the same to exotics, they are more able to withstand the presence of imported animals. If the deer were destroyed in New Zealand it would be possible to regenerate with natives, but even then the process would be very slow and the extermination of the deer is a very difficult task. Natural regeneration is followed in most timber producing countries and is practicable here alright.

DEER AND FIRE The point I want to make however is that the maintenance of our mountain areas for stream control purposes are incompatible with their occupation for grazing in any form. The grazier must use fire and fire is the stone end of natural regeneration. New Zealand native forests to-day are in the position of a nation which is killing off the babies. The young trees cannot withstand the presence of deer. New Zealand is in exactly the same position as most other countries where the forests have been destroyed. The hill lands or mountain areas which I suggest should be withdrawn .from grazing, are fast deteriorating anyway. Take the whole of the hill country in Nelson province, right from the Sounds to Murchison. Jt- is all deteriorating fast, a great deal of it has already reached a stage . from a grazier’s viowpoint where the production is practically nil. The purpose of this paper is two fold. To point out the effects of deforestation, and the Remedy.' There is nothing controversial or new in anything I have written. Perhaps it is not generally realised how serious the position is. What an enormous amount of damage is done annually in New Zealand how that damage is continually on the increase, and how it can be alleviated or checked, provided we act in time. Finally let me say New Zealand has to work out her own forest problems with very little assistance from American or European sources. The mistakes made in New Zealand up to the present have arisen through slavishly following principles laid down in text books which may apply in other countries but certainly do not here. In New Zealand we have conditions unparalleled anywhere in the world and these call for the intelligent application of initiative in the solving of our own problems.