The Chronicle. PUBLISHED DAILY MONDAY, JANUARY 30, 1911 INFLUENCE OF FORESTS ON RAINFALL.

Horowhenua Chronicle, 30 January 1911, Page 2

The Chronicle. PUBLISHED DAILY MONDAY, JANUARY 30, 1911 INFLUENCE OF FORESTS ON RAINFALL.

Komk two months ago this newspaper dealt editorially with the importance of preserving—in a pastoral and agricultural tract of country such a.s ours—those natural features willic:li contribute to the almodfe unparalleled rainfall —in point of equable distribution and sufficiency— with which the county of Horowlienua. is endowed and blessed. One of the greatest proofs of the beneficence with which Nature has treated us in this regard is afforded by tilie present disposition of local settlers 'to complain because around Levin and Shannon there has been a. period of about two weeks without a shower of rain. This very minor trouble lias resulted in the local pastures taking on an unusual brownnoss of colour, and in a noticeable shrinkage of the milk yields, but apart from these disabilities tihere are no present pastoral troubles. In sun-parched Hawke's Bay, stripped by man of the natural inducements which Nature sets up for a country's protection against drought, the pastoral conditions iliave been serious for a long time past, and Itihe fields had become so dry and barren—before last week's welcome and long-delayed rains fell in tliat ■province—that tiho older sorts of sheep were being sold at the ruinously low rates of 2s per ihead. As to 'the main question of rain-induc-ing characteristics, this journal remains firmly of opinion that forest reserves are one of the finest protections against drought that any district can be endowed with. AY as tilie comparatively droughty Dannevii'ke district of to-day ever troubled with anything but excessive rainfall in the times when virgin bush surrounded it on all sides? Let someone answer that query! AVe will not multiply instances indefinitely, especially when it is our intention to give publicity to another aspect of the case. There are many who disagree entirely with the theories as to forest and lake tract influences to which we ourselves subscribe ; and we hold it but fair to give to such philosophers all the pubj licitv we can. Then the wise man may weigh the evidence of 'both sides, and decide for (himself a.s to the relative merits. It is a

poor case indeed that can only ho maintained by smothering the arguments of its antagonists. The particular philosopher whom we have in mind to-day signs himself "Bushman," and he writes as follows in the latest issue of The Farmers' Union Advocate:-7-

"An extremely interesting statement by Professor Willis Moore, of the United States Bureau, was published by you in your issue of 7th January. It completely revolutionises the idea usually expressed' on the subject of the effect of hush on rainfall and floods. I happen to have lived: on rivers most of my life, and in New Zealand have spent thirty years on a rapid river, which for long I had to cross every day on horseback, so that I had to observe tho river very closely. .1

need not say that amongst those living on the river, especially amongst the Maoris, it formed a subject for a great deal of discussion. The question of busih affecting the rainfall has,l fancy, long been discarded. The mountains and hills are really i'r.e cause, and the hush only an incident. It is the case, however, that wherever the original country was open fern or scrub land, to this day there is a. less rainfall than amongst the hills which were clothed by nature with •bush. No doubt the foush grew where nature provided a rainfall sufficient to grow it. On the east coast of the North Island the whole of the open, fern la ml is subject to droughts, and the country burns up in summer, and in summer there is a dried, parched feeling in the air whiciln one loses the moment the bush district is readied, and at Woodvilie and Pahiatua. there is often a mist, and in certain .portions (now that the bush is down) the rainfall still continues heavy. Through on the west coast, Palmerston frequently gets a shower in summer when the whole of what was open country is quite dry. Again, the country which got most rainfall still gets it, and: it .frequently rains at "\\ a nganui, HunterviJle and round by Feikling and Palmerston and Marton gets none. Marton again gets more summer rain than the lower country. Up at Taihape and around there the grass is quite green at the present moment, whereas in the lower district is has its regular dry summer brown appearance. lanuiaki is another example. The plains and coast are dried up, but round about the mountain where it was bush, it is quite green. Therefor© it is quite reasonable to say that the bush is tihe effect and not the cause of rain.

"When, however, we come to 'floods, it has always been accepted that a flood comes down quicker where the bush, has been cleared.Although accepting this in theory, I have never seen it proved', and! for several years past. I have been doubting it- During the last thirty year, l ?

the whole of the bush at tho_ head waters of the Turakina,Rangitikei, Oroua and Manawatu rivers have lieon foiled, and. the land is now in grass; at least five-sixths of the whole area is now in grass that was hush originally. Tlio higgost flood in the Manawatu was in 1882, though scarcely any rain fell on the west coast. The height of the flood marked on the trees shows an incredible amount of water covering a huge area of lniid all round the swamp country on the viroua aw j Manawatu. The railway line from Foxton was several feeb under water. Yet this was certainly before- much of the hush was down on the headwaters of the Pohangina or Manawatu. The biggest flood in the other rivers occurred at the same time (in April, 1897), when the whole of the west coast rivers were in high flood, but the Oroua and Rungitikei particularly so. The Manawatu not being so high, there was not the same area- of country covered as in 1882. Around Oroua and at Foxton there was considerable less watei. This 1807 flood was caused by the extraordinary rainfall in the country at tilic head of the Pangitikei beyond Erewhon, where it was almost a water-spout, which must have hugged the hills, and also fallen at the head-waters of the Oroua. The next high flood was in 1902. five years later, but this was not nearly so high as that of ISO<. All this of course proves nothing, vet I ain convinced that the rivers, if they were measured as Professor Moore has done would show that less water comes down in the course of a year than used to be the case. The freshes that come are fewer, and the height of the river is less, at least that is the impression left on my mind, although nothing can

prove it now. "I tliink it stands to reason that with grass covering the soil instead of bush, a much greater amount of moisture will he absorbed. Watch rain falling on grass, and on a road. The road will he standing in puddles, and the grass land quite dry to walk over. Look at it on ploughed land, how nmoih more wet it boconies than grassland, especially in summer. Even grass canr-it absorb the excess of water that falls .sometimes in winter, but judging by summer effects it must take up a great deal. A water-spout would of course alter the whole effect. Exceptionally heavy rains, thunder storms and the like, if they fall at a, great rate fill the creeks in no time, simply because the soil will not absorb it quickly enough ; the soil could perhaps absorb one inch of rain if it fell in six hours. Initit could not do so if it fell in twenty minutes. But thunder storms are generally so local that they have no real effect- upon the river 'beyond making it muddy. It would not be difficult to measure the various rivers 011 the west coast and record tho heights for comparison. Nearly all of them could be recorded by the Railway Department without any extra expense, and the weather people might make an application itjhrough their Minister, wjlio is I believe also Minister for Railways, to have this done. Sailors have always an interest in the weather and floods and gales, and perhaps Mr Millar, the Minister for Marino, might lend a sympathetic oar to such a request."