MASSEY COLLEGE

Hawera Star, Volume LIV, 28 April 1934, Page 7

MASSEY COLLEGE

MONTHLY BULLETIN FARM SHELTER (By J. S. Yeatcs, M.Sc., Ph.D.) The tree-planting season is now. approaching and every farmer should consider whether additional planting will not be to his- advantage, There are Very few farms indeed on which more trees will not improve the returns and increase the value of the property. By taking up the matter early in. the season it is possible to be on the watch for pitfalls which have caught your neighbours, and to consult those who have a good knowledge of local conditions. A good local nurseryman can usually give excellent advice on the choice of suitable species. Above all, do not plant even one tree more than you can ,fence- and l tend until it. can look after itself.

The main purpose of setting out farm shelTer belts is, of to protect stock, • crops, and pastures from the effect of excessive wind. It is an ac-

cepted- faet that, cattle need 1 more food ,to maintain body temperature .when exposed' to cold .wind® than when adequately.' sheltered. The effect of shelter preventing damage to crops such

as oats or wheat is so obvious as to

hardly be worth mentioning. In con- - sidering the- effect of trees on pasture ■ it must be remembered !, that shelter

prevents excessive evaporation, of niois,ture from the soil./ Such evaporation has a very great cooling effect, as anyone who moistens a finger and- holds it in a breeze will know. By preventing such evaporation arid lowered temperature, shelter brings about a warmer soil and this in turn is followed by earlier spring growth. It may be objected that it is.desirable for moisture ,to be evaporated by the wind on extremely wet soils. The reply to thi9 ,would'be that the right way to deal with unwanted soil moisture is by drainage. Going to the other extreme of climate, shelter is almost equally necessary in summer as a protection from a tod fierce sun. The importance of shade is very much overlooked in most parts of ' this country. Hawke’s Bay with its popular willows is something of an exception and in times .of parched-up grass the willow, foliage, as green feed, is by no means to be despised. Native trees such as ngaio and karaka in warmer parts of the countrv are. both attractive and' use-i - iul shade trees-, though slower-grow-1 ing than, willows and. poplars. TIMBER AND FIREWOOD Although this article deals rnainly with the provision of farm shelter, it is natural that 'the provision of timber for. posts ..and firewood should be considered at .the same time. It needs - only a little thought to make one realise how great a saving both £n actual cost and in transport can be made by 1 having suitable fencing timber growling within convenient distance of each part of a farm. • This applies particularly to. hilly country where transport of posts is an expensive item. A further use for trees in many, dis- . tricts is the smothering of weeds such as gorse and blackberry on the steep sides of creeks'and gullies.- In counjtny liable to slips, trees should be freely used on steep, faces!, either to prevent slips or' to cover the ugliness' of old slips. The trees chosen should be those suitable also for posts and firewood. In arranging the layout of trees planted primarily for shelter, the direction of the most troublesome winds is the first consideration, but care should be taken that the trees do not cast unnecessary shade on good land. In some cases it may bo possible to arrange a shelter-belt among a. road boundary so that the shade falls mostly on the road, and yet the belt may be good protection against the worst Windst Care must, of course, be exercised that the shade and) moisture do not make the road liable to break up under traffic. A common method to prevent excessive shade from being cast is to uso a shelter-belt which is broad at ground level but runs to a point like a wellbuilt hay-stack. This shape may be obtained' either by using a. single row of conical trees such as Cupressus Lawsoniana where suitable, or by having three or more rows of trees in the belt, the centre row or rows being quicker growing and t aller than the outside . ones.

In planning the nature of windbreaks and their direction there are a number of factors to be considered. Amongst these are the cost of fencing an cl land, and whether a few wide belts or a number of small belts are to be ■used. Other considerations should be the suitability of various species for the district, the number of years for which they will continue to give good shelter 1 , the distance between the trees themselves and also between the trees a ndr the fences.

•PROTECTION BY FENCES Inadequate fencing is probably the most common fault in tree-planting cm the farm. A mistake almost as frequent is to put the fences too close to the trees and to plant the trees too close together. Ninety per cent, of the so-called windbreaks merely serve to concentrate a strong draught just where shelter is most needed’, because their lower branches are destroyed. l by unsuitable spacing. Trees such as pinus insi'gnis, P. Muricata, or macro-, earpa. should be at least ten feet from any fence and the trees eight to test feet apart. If they are close to a fence.the lower branches are damaged by stock, while if the trees are too close to one another the shade will cause the lower branches to die at an early age. Lawsoniana, which makes an ideal shelter in many of our dairying districts, should be spaced at least six feet from fences and four to six feet between the trees. Fencing is probably 'the most expensive single item in planting windbreaks, so that

elvery, possible method of saving, it should be used. Some hedges, including boxthorn and* barberry, need' no fencing. The former grows well’ on windy coastal land where many other good- shelter plants such as Lawsonrana are injured by wind, but boxthorn is a vigorous plant which must rob the soil of much plant food, and to keep it trimmed is an expensiveand thorny problcim | One method by which economy in I fen'eing can be effected was stressed by I speaking at the sheep fanners’ meet- { Mr C. H. Williams, of Gisborne, when i ing held last year in Palmerston North. I This is to use large cuttings of Lomi bardv. poplars as the outside row of | a shelter belt and to make them serve i also as posts. The wire should 1 not be I stapled directly to the- poplar, but | a batten should be nailed to the popJ lar and the wire stapled 1 to the batten. Large poplar cuttings of this sort will- have their leaves above the reach of cattle right from the start. Horses- alone are liable to injure them. Usually, of course, trees are planted along an existing fence line, so that at most- one new fence is needed. EFFECT ON PASTURE The value- of the- land) occupied by trees may be considerable, but, since) it involves no fresh outlay of capital,, does not cause so much -concern as fencing. On broken land, of course, the trees can be planted along the banks of small streams-, making use of laud which has- little value. It must be remembered that the land occupied by the trees is not only the strip directly underneath them. Their roots spread far and wide, robbing the soil of'moisture and ; plant foods-. This is often shown by the poor growth of pasture or . crops near trees 1 , especially os dry soils. It may in some cases prove a sound policy to use the landj alongside a windbreak as a farm-road, or cattle race, since this land is! partly spoiled for other purposes by the tree roots. It is assumed', Of course, that, the cattle are separated from the trees by a;f encc. Another point which is often overlooked is the effect of tree roots ou mole-drains or tile-drains. The roots of grasses and most crop, plants donot harm these drains, but the roots of trees ufld hedge plants- will enter and form tight plugs of roots which effectively block the drain. If a tiledrain must pass through or near a windbreak the- tiles should l be securely jointed with concrete to prevent- roots from entering. ( The decision whether to plant a few' wide shelter-belts or many "hedges or single rows of trees should depend on various considerations such as climate, size of pad-docks-, and whether or not the country is broken up by useless land! best suited to trees. The tendency on small farms, such as most dairy farms, is to depend’ chiefly on large: hedges or single rows for protecting! most of the paddocks., but to grow) larger shelter belts near the house and) farm building®. The latter trees will in due course provide firewood and fencing timber. ' On large farms the paddocks are usually also large and' windbreaks which are both higher and wider are more necessary. It must be remembered that a row of trees will give full protection from wind for a distance equal to five times the height of the trees, and- partial protection for a further distance equal to ten time® their height. LOW LEVEL SHELTER ' When high tree® are to be grown as windbreaks it is almost essential to grow more than one row. By .the time most trees have grown really tall they have ceased- to be an effective windbreak near the ground level. It is therefore necessary to have also' one or more low-growing rows of trees which wild provide shelter at this level.

When a definite shelter-belt consisting of several rows of trees is decided upon the selection and' spacing of the plants is the next consideration. In all parts of the North Island at less than 2500 feet elevation, and at the same elevation in all but the extreme south of the South Island 1 , pinu® insignis will probably be chosen as the most suitable tree for rapid growth of tall shelter and production of firewood. When a belt of three or more rows of trees is to be planted', this tree will nearly always be chosen- for one or more rows.

Pinus muricata, which grows especially well in coastal and lowland' districts of both islands, is another very useful shelter tree, though its timber is not large enough te bo of much use. Its growth is about one half as fast as that of P. insignis, but P. muricata is a more bushy plant which retains its lower branches to a greater age and provides a more dense windbreak. When’ planting either of these species for shelter, the trees should be at least twelve feet apart, and not less than ten feet from a fence. Trees: planted too closely soon lose their lower branches on account of the over-crowd-ing and consequent shading. This is desirable if clean trunks are needed' for timber (in which case plant not more than eight feet ajjart), but is most undesirable in a shelter belt. When planted too near a fence, projecting branches are damaged 1 by stock with the same result. Along road boundaries in particular abundant room for spread of the upper branches should be allowed'. A well grown tree of P. insignis often has branches more than twenty feet in length, and l the trees are likely to be ruined by being cut back to avoid electric wires. CHOICE OF VARIETIES The choice of the shorter growing species for the sides of the windbreaks is the next consideration.. Cupressus Lawsoniana is a most. suitable tree where soil, climate and: exposure to wind's are suited to it. Trees of it should be planted about six feet apart in the row, and about ten feet from the row of P. insigni'S. Some seedling plants of Lawsoniana are straggly in growth and care should l be taken to reject these, else the hedge tvilil not be uniform.

When a slow-growing hedge such as barberry is being used' to provide ground level shelter on the edge of a windbreak of pinus care is necessary

lest the 'shade from the pines should prevent good growth of the barberry. It is preferable in such eases to have a deciduous tree such as Lombardy poplar between the barberry andl the pine. The poplar casts little shade, and being without leaves in winter, inflicts little damage on the barberry. It should be noted that the barberry requires good drainage, and it is often desirable to plant it on a, tli rown-up bank to ensure this. A scheme which is being tested out, with some variations on the College farm, is a windbreak 33 feet across. The centre row is of Lombardy poplars, six feet apart. Ten feet to one side of the poplars is a row of P. insignia or P. muricata spaced twelve feet apart, while on the other side of the poplars and eight feet away is a barberry hedge. The outside fences are five feet from the barberry hedge on one side, and ten' feet' from .the pincS on the other side. The pines should be on the side facing the most troublesome wind, so that th.c barberry hedge is available to, provide snug shelter at ground 'level on the Ice side. It is impossible in a short article such as this to mention all the trees and methods of planting which arc suited to different parts of the country. The goneral tendency in the more thickly settled parts of the country appears to be one of using large hedgs snch as Lawsoniana or boxthorn with som large windbreaks. It is for each man to form his own: requirements. A little observation- as to the types of windbreak and their success in his.own locality is probably the soundest method of arriving at a decision. The hints given above will indicate the main points to be considered.