BARE SLOPES

Hawke's Bay Tribune, Volume XXIII, Issue 275, 3 November 1933, Page 11

BARE SLOPES

RAIN ON THE RIDGES

SOIL WASHED INTO THE SEA. LEAVE NATURE ALONE. (By Will Lawson). Every time it rains on the ridges, some more of New Zealand is washed towards the sea. There was a time when this did not happen, but that was before Man stripped the ridges of their forest covering, made them as bare as roofs, so that the top soil became dry in d loose, all ready to be blown or washed away. New Zealand is not the only country where this process is going on. There have been plenty of examples in history and in recent days to warn tier people. For example, the countries bordering the Mediterranean, north and south, once had forests on their hilltops, where now bare hills offer no reward for any effort of husbandry by man. China, too, is a glaring example of what deforestation will do. Millions of tons of soil are washed down from the hills into the valleys every year; i millions of tons go out to sea in the streams of her great rivers. Thirty miles off-shore, the Yellow river, the mighty Yangtsc-kiang, discolours the sea with mud, torn from the ridges in the interior. Tn the mountain areas of the United States, 21,000,000 acres—an area exceeding the total area of arable land in Japan, have been rendered entirely useless because the ridges and slopes have been stripped of their forests and the forest plants and herbage which hold the water. Grass on the ridges is better than nothing, for it holds a little water long enough for it to evaporate and thus moisten the air. NATURE’S RESERVOIR. But the roots of the plants that compose the floor or carpet of a forest, carry the water into the earth where it is stored in Nature’s reservoirs, to ooze out slowly and keep the earth moist, and the hills verdant. The trees themselves catch a large percentage of the rain and mists, and by evaporation, this moistens the air, making it humid instead of dry and parching. When it rains on forested hills, the moisture passes slowly into the streams and rivulets, as it would from a sponge which is overcharged with moisture, and thus the streams pass the water to the rivers nnd so to the sea, carrying none of the soil or other valuable humus with it. But when there is no vegetation, the rain pours down the ridges as it would off a roof, carrying with it first the top soil, then the useless sub-soil and stones and debris, and these spread into the valleys, gradually covering their fertile lands, till they arc useless for grazing or agriculture. TWO INCHES IN 10 YEARS. This has been going on in many lands for hundreds, maybe thousands of years, because Man has cut the forests. The cedars of Lebanon, timber from which was used in building Solomon’s Temple are only a remnant to-day. It is going on in New Zealand now. “But,” someone says, “it will take a long time to strip the ridges of their soil.” Not so long! In 10 years nearly two inches of soil will go. If we look back 25 years we can recall the bush-felling operations which were going on all over New Zealand, to bare the land for grass, that sheep might be pastured.

To-day we see bare ridges everywhere, the bare slopes, too, where the rain has stripped the soil away. The hills of Queen Charlotte Sound are an instance; the hills around Wellington, too. There is a ridge on the track from South Makara to Terawhiti homestead, where 30 years ago there was a pretty grove of native bush. The slopes below were bare of trees but they were green from the water that oozed down from the forest patch above them. In the grove the track passed pools of water, often it was slippery with moisture. To get more grass, the trees were cut down, and today the ridges and the slopes below arc dry. This is merely an instance of what is happening all over New Zealand. HILL TOPS TABOO. The Swiss and the Japanese have learned and put their knowledge to good use. It is decreed in these countries that the forest on the ridges and higher slopes shall not be touched. It remains to hold the moisture and save the hill-tops from being stripped of soil. Our administrators ought to have known, but they let the greed for an immediate return in grass cloud their judgment. To actually demonstrate what effect deforestation has on streams, the Swiss Forest Research Institute, some 30 years ngn started to study two valleys, one of which was partly wooded, the other completely covered with forests. For over 30 years the falls of rain and snow were measured with special instruments; automatic installations noted continuously the volume of water which drained away, and in specially-built barriers, the stones and (Concluded on foot oi previous evluam)