RECLAMATION OF SAND WASTES.

Shannon News, 10 July 1923, Page 4

RECLAMATION OF SAND WASTES.

FORESTRY-IN NEW ZEALAND. DEPARTMENT'S-WORK AT RANGITIKEI RIVER. (By our Special Reporter). Recently through the courtesy of the New Zealand Forestry Department; a"Chronicle”* representative had the opportunity of inspecting the work, mainly experimental as yet, which is being carried out by that. Department with a view to the ultimate afforestation of the sand-dunes, approximating 300,000 laicires, lying along the New* Zealand coasts. The area selected for the present work lies south from the Rangitikei River to Lake Puki Phiki, a distance of .about three miles, by miles in; depth, and is part of Run .24, leased from the Government by Mr J. Me-: Kelvie. This area, 3000 acres in extent, which, being practically (Valueless as. grazing country, Iras been resumed by the Government, is reached from Bal4 merston North via Oroua-Downs;- after which four, miles by road and a fur-, ther three miles * across country/ one to the camp where seven men under Mr H. D. Stride,- an officer of the. Forestry Department,, are engaged in the work.

i, The present operations owe their in-; ji ception to experiments commenced, j some years ago by the Lands Depart-’ it ment, when miles of the foreshore.! i! by a. depth of 5 chains wa,s planted) it with miairram 1 graiss in an attempt to i|) stop the drift from the sea. The work, i) was abandoned! in 1916. Two years. '} ago, during the slump, it was decided ] to continue this work, partly as | means of providing work for unem--1 ployed. , i j A MARRAM-GRASS NURSERY. ! The original intention, wais to emj ploy about 200 m,en, but on investiga--1 tion it was found that sufficient sup-; j! plies of marram-grass were not availj: able to provide work for this number, j the graiss which had, been planted bell, ing mostly too old to provide good: j; plants. 4 |l It. was found necessary to establish ; what might be called nurseries to, ' provide plants for future operations, ; and'3o men were put on planting, 60 t acres being put in that winter, about, ; ten acres of which could be used to \ provide new plants. The remaining 50, j aicres were planted'in order to save i Lake Puki' Puki, which was being encroached on from, the seaward (side by, Wandering dunes, the water being; forced out over the adjacent land. In passing it maty be mentioned that, - as an indication of the rapidity with, which a “wandering dune”—one moving- inland under the action of the; wind—can encroach Mr, Stride pointed out that lia.st year; when owing to the i light, winds prevailing the progress would not be most rapid, in one. sUch i dune with a frontage of. 12 chains, i under observation, the progress had i been three chains resulting, in- a loss ,of 3£ acre/3 of grass lands.-in that short frontage. Further it., must be remembered that besides • the grass actually submerged by the dune, a considerable extent of grass inside this strip, has been*partly covered by the flying, piairticles.of sand. This year ai further 100 acres will be; planted from five- acres of established - marram, and by 1925 sufficient plants, will 'be obtainable to plant the l whole > 3000 acres. It must be remembered, also, that although these 'areas laire being planted primarily for th©.purpose, of providing plants ' for - future, use; they 'a,re at, the Same time binding the, : sand, so that the work is of; perm an-, j est value. Again the work provides a;n, admirable opportunity for, experiments' of various kindb snicih a.s the .best- formlaitioni to.a dout. when planting/ number of plants to the/scruiare yard, etc., all of Which will be invaluable later When a| comnrehenisive scheme for* dealing with the drifting sand is inaugurated on a. natioml-basis.

FIRST STEP TO AFFORESTATION.

Two questions naturally occur at this- 'Stage to the man unacquainted : with sand reclamation. The first is: Wih'ait has the planting of manram- !. grass got to do with afforeistation of ; sand areas? 'and. the second: why is it { necessary to- go in for experimental i work when the reclamation of such country hiais been carried! out successfully ini other countries on iai. wellrecognised plan? The answer to the first question is I feimply that trees cannot be establish-, i ed in shifting, sand, some means of I stabilising the surface 'being .. neces- ! sa;ry, and , to the second that it is ' necessairy to. discover the, modifications I to the usual procedure necessitated by ; local-conditions. For instance, on the I coasts of France where extensive oper- , ations have, been carried out, the I strongest winds, which are, however, '■not'of such high velocity as those bb- , talning in New Zealand, usually qccur in the winter time when the sand , is wet. and therefore does not shift much. Tn New Zealand the windy season is in the summer and autumn when the sand is at its dryest, and having no cohesion is in continual motion on the surface, and it was necessary. : to discover, if treatment found sufficient in France,would also suffice under our . more exacting conditions. To understand the work necessary for,sand-fixation, without a knowledge of which it. is impossible to follow the work . that, is being done at Oroua Downs, it is necessary to understand the formation of the country bordering the coast. The area, at present, being dealt with, which is typical of the whole of this country consists of »a quarter of'a mile in depth of what- is technically known as the “dune-com-plex,” which is a tumbled mass of sand-hillocks, partly wandering ,and nartly hound with a, growth of the native pingao, a reed-like, grass with strong ropy roots forming, a net work hoinw the",surface. This dune-complex is constantly augmented bv the arrivab of fresh'supplier-- of sand blowing up from the sea, and,is pierced in every direction by wind-channels, up which the winds, confined in their action rush with nearly doubled vel'oc- < ity. The smallest obstacle is sufficient

to cause oneuot.these* wimbchannels—two tufts of -grass-growing close together may cause/ a - scour.: 'between, which will deepen, with -astonishing rapidity, and before long, cut a gully through a sand-hill. The wind coming through this, will in- turn attack, a hillocki.further: inland and so the perpetual change goes on.. On. these, hillocks of. thet'dune-Gomplex .'all stages of. the work of. sand-hill ;-formation-and; disintegration may vjje .observed. In one place a wind-channel-is in process of .formation on the fore-front of a dune ; in-another, place,, a wandering dune is gradually , moving destroying as- it goeis the pingao which ha,s bound the sand in, front ; whilst:in yet another the wind coming.throuigh one of the channels, has attacked the edge of a -neighbouring: pin,gao-bound dune and is gradually .eating .it. away. . Immediately behind -the dune com-plex-extensive bare sand flats, many of which are in winter ■ with water, occur, between more defined sand ridges, most of. which < a,re wan .-dering,- and-further, inland still, are sand flats roughly oovered with grass, rashes and iscrub, lying/-between wan deringi dunes, which extend as far mlandLas three .andi a,-half miles. _ It. Will be understood: from this that in?the-work (which the . Department has undertaken + two things, are pHmar,Snf «“to total'Mready , blowing ui:Snd.,»n4 S 6 i wandering 'dunes: from en .proachingf further- on Ibe adjacent land/ /The;-latter,:.ist- done simply by : planting with .marram .grass,. but the • former is. more- complicated.

PROBLEM OP, THE WIND CHANNEL

As has- been explained the cou* y immediately bordering the ocean presents:* the appearance of a collection of -tumbled hillocks with wind channels’.between, and mat tnese channels , are, the principal means ot keeping the \ system im When the- Lands did us planting some years ago, no-attempt was made- -to . -artificially, alter J^ 1 ® conformation. - The shore was ptooted just as- it was, with* the result that these channels/, speedily -destroyed a considerable extent of the work. Upon the Forestry/ Depairtment taking over the scheme, an attempt was made to fill up the wind-channels >by erecting driftwood fences - which it was hoped would; danse the sand to build up, and in this Way; to" gradually- form a continuo-uisi fore-dune to;-protect tne country further inland.; It was found, ■however, that the velocity of the wind amounting at times, in the confined space; to -80 miles per-; hour, precluded this being done satisfactorily, and it-was then -decided to do as Was been done in; France and; elsewnere--estab-lish a- fore or littoral; dun© by totally artificial means, injront of-any, formation? which might) exist. - This is naturally a.- more ’ expensive hut'the value .of the-experiment- lies in the fact, that ■ the more - economical scheme-was- found; impracticable.

FIXING THE SAND THE ’ FIRST TASK A stretch, of coiast aobut (half a mile long was selected for the' experiment, the points on . which it .-was desired to obtain information - being—'the most economical means of establishing the dune;, the time it would taMtb form a, dune of sufficient height (33ft is considered sufficient in'. France, but Mr Stride is of opinion; that, a greater height is desirable in, New Zealand); fixation of the dune so formed, etc. A start, wlais made; by erecting, two fences of driftwood, which is very plentiful a,t this spot, with a space of 1 about' 14 feet between. This, although satisfactory ’a's a sand , harrier, was expensive, as the laboulr necessairy 16 erect it was considerable, and •when ■it ‘ is understood ' that a twenty-four hours heavy.- wind. in dry weather is sufficient to submerge a four foot fence, it will be. seen, why this form of fence was abandoned. EARLY: EXPERIMENTS. The next, kindexperimented with was of flax-blades. Stakes: were driven; in the sand .above the; former, fence, now submerged, to which two wires were attached. The flax-blade wias knotted to the top. wire, the butt end resting; against the; lower, one. Spaces of about an inch were left, to, enable the sand to filter through, to form the 'rear of: the dune. -i The efficacy of this fence and also the amount of sand drffting; in from the ocean is indicated by the fact that the fore-dune although only started in October, of last year, is now about 12ft high, by roughly two chain,si wide at’the base. The fence had the; disadvantage, however, of being too open, .so. that a considerable amount, of sand blew inland; it required considerable labour to erect; and the lower: wire was invariably lost as the fence became submerged. In France, pine; boards of about Ift, in width are used to, form' fence, Ihese. being;; lifted! a,s they became covered. Flax; however.*; would not stand lifting and the-practise was to build one fence on top of another. MANUKA FENCES, NOW: USED.

The latest and most successful fence is made of manuka. Stakes are driven into the sand with one wire stapled to them at a height of about 3ft. The manuka is then stuck butt end into Ihe sand along this fence and the tops rested against the wire, which prevents the wind blowing it over. As the fence submerges the stakes will be lifted'together with the, wire and 1 another fence erected: In places where tlm tyne m. sand fence is erected for a short. di c ta,nce in a long stretch of flax-fence the difference in the height of the dime” is noticeable. Satisfactory arrangements have been made to obtain the necessary supplies of manuka which will be generally used for the purpose in future. When Jho dune is mised-to the desired height it will be ‘fixed’ bv planting with marram' grass, which has,the property, a fact, tn be remembered, of lasting permanently only where fre-h supplies of sand are ennstanitlv arriving, so that it is here ideally situated. PREPARING FOR TREE PLANTING. With the supply of sand stopped at its source, the process of preparing the country further inland for treeplanting can be proceeded with. As

has been , explained tibe first thing necessary is to fix the surface by some means, and here the planting of marram grass is being largely used. It must be pointed out that owing to the formation of the country, in which ex-* tensive flats are in places protected by ridges, it is not necessary to plant the ■ whole a,rea in order to obtain stability. ■ Mr Stride estimates that, on the piece at present being- experimented' with. : one third only will have to be planted, a fact which will have a decided; • bearing on the cost of the work. As was- previously explained the planting at present being done, is jo a, large extent meant to provide plants for a continuance of the work, but even in. their arrangement considerable useful experimental work is being done. Roughly they are put'in in rows at a distance of 2ft, 6in between plants. Experiments -are being conducted with a view to discovering the least expensive process of planting, number of - plants necessary on exposed and less exposed faces, etc., the most important of these experiments being probably tests conducted with a view, to discovering the possibility of lowering, some of the dunes, and distributing the sand across the low-lying waterlogged flats, by planting the dune for a certain distance up from its ba-e and allowing the wind to blow the ton off. If this can be done successfully —and there is no reason to doubt its nossibility—it is going to have astwofold effect: by doing away with the channels between dunes it will greatly reduce the difficulties of fixation, and it will ; provide a. level floor for the forest to be established later, thus greatly facilitating its working.

FORESTRY DEPARTMENT’S OBJEC TIVE.

The idea qf the Forestry Department is,, naturally, the ultimate clothing of the whole of this area, and later the whole system of sand-dunes along the coast, with forest. The providing of a protective screen in order to turn thp country further inland into pasture is outside their scheme altogether, although plossibly, finances may demand something of the sort being done, at least temporarily- The Forestry Department recognises that with the depletion of our natural timber resources the country will before long, he faced with a serious shortage of timber, and is anxious to provide a sunply, utilising for its raising, land which is, at present, a. menace to the adioining country. That, these dunes will grow trees satisfactorily bias been amply demonstrated in New Zealand, where-in the Ashburton district from similar country. 35 year old pine trees have been milled. The sand Of the New Zealand coasts contains a. considerably higher percentage of plantfood than does that of Europe and whereas in France, pine-woods are worked on an 180-yea.r cv'cle. it is considered that. with, our better climate, etc., a similar tree can he ■ produced in New Zealand in 35 years. The immense differen'-c in the-economic values of the two forests will be readilv appreciated, 'and yet the French forests are said to pay interest on the capital invested.

TREE PLANTING ALREADY DONE. Three thousand trees have already , been planted, 'among which are pinus insignis. macrocarpa, Oregon pine, and several varieties of scrub trees for planting close to the shore.where good timber could not be obtained because of the wind, and for the purpose of nroviding. a wind break to the < timber varieties further, inland. These , include tawhini, Chatham' Island a ke ake. Australian s'and-stay, matip.o, and* pittisporum orassifolium. The pinetrees are doing exceptionally well, 4-year-old trees being now 4ft in height. Macrocarpa and practically all the other varieties look well,'and oregon pine where it is w6ll sheltered seems to; be healthy and making good growth. Where it is exposed to the wind, however, it is stunted and unthrifty. Seven try-five thousand trees are being obtained from the Government nuirseries at Rotorua this winder, and will be bedded out in preparation for planting next year on areas already; ‘fixed.’ PLANS FOR THE FUTURE..

Mr Stride, who .had had extensive experience in the. tree-planting .■ -areas iat Rotorua, is strongly in favour of planting trees and not sowing the dunes with pine seed under a covering of boughs,, etc., as. was done hi France, claiming that much more satisfactory results are to be obtained from the former method. Nevertheless, experiments in sowing are being made. An area, of 3£ acres has been covered with cut rushes, held down by “sanding”—.shovelfuls of sand thrown on at intervals— and this area sown with a mixture of lOlbs of marram, graS9, lOlbs blue lupin, 51 bs broom, and five lbs pine-seed, half being pinus insignia and half pmus pinesta, the marram-grass, lupin and broom being solely for the purpose of sheltering the growing pines. These plants are now. showing up through the rushes and the experiment is being watched with, considerable interggf.. The, principle which it is proposed to work on in afforestation will be -as follows, although it is admitted that experience may: suggest modifications—first 20 chains of marram-grass inside the littoral dune, then a further 20 chains of scrub, trees, etc., mainly for the purpose of forming a wind break, and inside that again the forest proper.- The cost of the whole work of fixing and afforestation is expected to average about. £7 per acre. over the whole aPea, hut it will be! readily' understood that these figures | are by no-means definite. I

It is a big work which has been started in a small-way- in this out of the way comer of the coastr-a work which ‘in the not distant future 'is hound to assume large proportion®. Here quietly and. unostentatiously, the necessary preliminary work, which will, probably save tens of thousands of pounds) when the scheme is undertaken on. a national basis, is being done. In Mr Stride,.-the Department'.has an enthusiast who recognises the national value of the. work ■ being done, and * who has the vision to see -what its ultimate re-

suit will be, and in the light of his enthusiasm our representative too, as he rode out towards civilisation again, saw, not the tumbled hillocks of drift ing sand interspersed, with bare water covered flats, but a stately forest forming one of the largest assets of the Dominion. . S.