ELECTRIC POWER TRANSMISSION POLES.

New Zealand Journal of Agriculture, Volume XXX, Issue 3, 20 March 1925, Page 157

ELECTRIC POWER TRANSMISSION POLES.

EUCALYPT SPECIES FOR NEW ZEALAND CONDITIONS.

J. H. SIMMONDS.

>, Takanini, Auckland.

New Zealand needs increasing thousands of supports for carrying electric wires. In theory, the supports may consist of reinforced ■concrete, or bolted steel bars, or wood. In practice, general preference is being given,. and seems likely to be given, to wood. The concrete pole is heavy and easily fractured. The steel tower may come into favour for main lines ; it may be best for very steep country where material can be delivered in sections more easily than in long lengths ; but for the rapidly expanding reticulations it apparently cannot compete in economy and convenience with the wood pole. The wood poles now being distributed, by our engineers for the new power though so crude and plain, bear impressive witness to the genius and progress of civilized man. They tell of learned research into, the secrets of nature, and of well-instructed planning to convert the energy of falling water into light and heat and mechanical movement. They tell of forests and skilled woodmen in far-off Australia. They tell of freighted ships crossing the Tasman Sea, and of strong-limbed men and powerful appliances doing the work of landing and distribution in our own country. A hundred .years ago British men were here gathering kauri spars for the masts and yards of ships ; to-day we are importing hardwood poles for the transmission of electricity. As we still look at these great shafts of wood and try to estimate their cost we find ourselves asking why they are being brought from Australia instead of being grown in our own forests. The. question is pertinent and must be competently answered. The botanical genus that yields these poles has been made known to the world under the strange Greek compound Eucalyptus. It is a genus unique and apart in the earth’s manifold flora. It belongs to the great myrtle family, but is easily distinguished from all other myrtles. In multitude of species it holds second place only to the genus Acacia. Though restricted in natural habitat to the island continent of Australia and adjacent islands, it is unsurpassed in climatic range by any single genus of the forests — indigenous and locally adapted species being found in every available climatic region from the southern capes of Tasmania to the tropical jungle of New Guinea, and from genial lowlands on the- seaboard to alpine heights above the winter snow-line. Some of the species are humble shrubs ; some are bushy mallees. At least one hundred are timber-yielders ■of medium to large dimensions, and of these twenty or more easily hold place in the first rank of forest giants. Many are very beautiful, .and from the foliage of a large number there may be extracted fragrant and valuable essential oil. As exotics distributed by the hand of man many of the species are showing wonderful capacity for , acclimatization. Planting was begun in countries outside of Australia over sixty years ago ; and, speaking generally, it has since then been continued with steadily increasing enthusiasm and success. Many countries have contributed

to useful and progressive experiment. Selecting from the long list,, we may perhaps especially mention Algeria, South Africa, California, and our own New Zealand. LIMITATION OF RANGE. Like the now greatly appreciated Pinus radiata and Cupressus macrocarpa, the eucalypts have had to win their way against lack of knowledge and much prejudice. For a long time it was commonly assumed that there were only a few sorts of. “ gum-trees,” as they were called, and that “ gum-tree ” seed collected anywhere in Australia, could be propagated anywhere in New Zealand. We know now that the genus Eucalyptus has during its long history branched and evolved into over three hundred and fifty quite distinct specific forms. We further know to-day that each species has a climatic and geographical range within which it finds its optimum or best development, and beyond which it declines in vigour and ultimately dies out. For onespecies the range may be narrow, for another very wide, but for each there are limits. Even now the eucalypts are not nearly well enough understood for winning best results in cultivation on a large scale. If we are to avoid the errors of the past and to put the growing of these trees on a footing of practical. certainty we must begin by competently studying the problem of climatic adaptation. No economic merits of a species will count if we plant/that species where naturehas predetermined that it shall not flourish. Much the most important and restrictive factor in the limitation of the range of eucalypts is temperature. Exceptional extremes of heat or cold may inflict serious injury, but they are followed by recovery. It is the mean annual temperature that constitutes the insuperable barrier, and so imperious is nature in this matter that the cold-country tree and the warm-country tree cannot under any circumstances changeplaces without serious loss of vigour and possible extinction to both. The number of days per annum upon which the sun shines through a. clear sky, though less understood, is also very important for some of the species. The second master factor in the limitation of range israinfall. All the large-growing species require from 30 in. to 60 in. of rain per annum for their -best development. Inland species of smaller dimensions can survive and yield valuable poles, fencing-posts, and fuel with as little as 20 in. or even 15 in. of fall. Chemical constitution and physical condition of the soil and subsoil are very important, but these are repeated in different climatic zones and must be separately considered for each species. In studying climatic conditions we must always remember how theproblem is affected by both latitude and altitude. The general law is that as a species extends its range to higher latitude or away from the Equator it must descend to lower altitude, and, reversely, that asit extends its range to lower latitude , or towards the Equator it must or may ascend to higher altitude. Thus, if we find a species flourishing at an altitude of 1,000 ft. to , 1,500 ft. in Central North Island weshall not expect to find it in .a. similar, condition at that altitude in Otago, and Southland, but somewhere within a hundred feet of sealevel, and • vice versa. Species that, find , their optimum on warm lowlands north of about , latitude 38 - will be barred from extending

southward at all unless at the cost of vigour and size. Apparent exceptions to the general law arise from local contour., of the land. In nearly all groups of low foothills there are limited areas where at night the cold air falls to the lower levels and forces the warm air up to the knolls and small plateaux. Many such relatively warm patches may be found in both the South and the North Islands. They slightly extend the possible range of tender species, but do not negative the general law. Sea-breezes modify temperature ; but, unless they are first arrested by screens of hardy conifers, they are usually too saline and too persistent for the young foliage of Eucalyptus trees. SUCCESSES AND FAILURES IN NEW ZEALAND. Power Boards, local bodies, and private owners of land intending now to make plantations of eucalypts must accept the climatic conditions imposed by nature upon these and all other trees. Conflict with nature does not pay. If a Power Board wished to plant, say, 500 acres of pole-timber trees as a source of supply for its future necessities, what is to be the procedure ? Choice lies between the haphazard practice of. the past and a practice based upon sound deductions from all available sources of information and guidance. Two generations of people in this country have planted eucalypts or have seen them planted. In a large number of cases the results have been splendid and wonderful. The trees have grown as if by magic and have in an incredibly short period of time reached very large dimensions. In both Islands heavy crops have already been reaped and utilized. Poles, fence - posts, sawn timber, and fuel in great quantities have been derived from relatively very small areas of land. Had all the eucalypts planted in this country during the last fifty years done equally well there would have been no need now to import poles from Australia. But in every region of the Dominion there' have been failures, the total sum of which has amounted to a great national loss. If we are to put the enterprise on a sounder footing for the future the causes of failure must be candidly and fearlessly laid bare. It is an ungracious task to chide dead men, but it must be said here that in earlier years seed-collectors, seed-vendors, and nurserymen were too often not reliable in the matter of Eucalyptus seeds and plants. Charity will say that they lacked knowledge for this particular branch of their work, and will further excuse them by saying that in those times even botanists were not always sure of their ground. We are concerned, just now with what happened to the tree-planting interest. Seeds were often collected from relatively useless trees and sold under wrong names. The enthusiast who sowed these seeds in anticipation of becoming the proud owner of a noble patch of forest found himself instead, after twenty years of waiting, in possession of a promiscuous collection of shrubs and low-branching trees with crooked stems. In other cases the seed was right, but the localities chosen for the planting were wrong. Catalogues. made an eloquent story about the merits of jarrah, spotted gum, and broad-leaved ironbark, but failed altogether to inform the planter that these and some other valuable species were exceedingly exacting in respect to climatic conditions. One gentleman planted about thirty valuable but tender species at a

high altitude in Canterbury and lost them all. Had this planting been. done in the Marlborough Sounds or oil warm lowlands of the North Island most , of the species would now have been yielding poles' for carrying wires and logs for the sawmill. .' SPECIES FOR WIRE-CARRYING POLES. There are at least sixty timber-yielding species of Eucalyptus that can be grown somewhere and to .some extent in New Zealand. To the timber list there may. be added a large number of ornamental species of smaller dimensions. In a handbook which the writer hopes soon to publish all the most important of these species will be given detailed description, with notes on climatic requirements and uses of the trees. The purpose of the present article is to meet an urgent demand for information; that will enable local bodies, syndicates, or private owners of land to start plantations for the production of wire-carrying poles. • ; The task of selection will be made easier if we place the several available species in groups. For those who are not botanists the most convenient basis for grouping is bark. The living bark of Eucalyptus trees, like that of many other trees, is always gradually changing into dead bark. The dead bark may cling to the tree, or it may fall away, leaving the living bark bare ; it may be stringy, fibrous,’ sub-fibrous, or entirely non-fibrous : it may be soft or hard. On this'bark basis we easily form five groups, as follows : . (i) Stringy-barks, (2) gums, (3) woolly-butts, (4) ironbarks, (5) boxes. The order in which the groups are here placed is determined by value of the crop they can return to us in New Zealand. Two factors enter into the value of a timber-tree (a) Quality and durability of the mature wood, (&) rapidity and abundance of its production. The best tree is that which most completely combines both, factors, and the best, group is that which includes the largest number of such trees. The stringy-barks and gums are placed first because they are the groups that can produce the largest quantity of good timber in the shortest period of time ; the ironbarks and boxes come last because, although their mature wood is of exceedingly high merit, their prospective productivity is low. STRINGY-BARKS. • The term “ stringy-bark ” is here used in the widest sense, so as to include all the eucalypts whose dead bark is distinctly fibrous or stringy. So numerous and so generally valuable are the members of this group that it would be easy to write' a pamphlet about them. In this article on trees .for electric power transmission poles we . must be content to mention a few. Eucalyptus pilularis. This species has dead bark persistent on the stem only, fibrous but not stringy ; leaves in juvenile stage sessile (without stalks), lance-shaped, richly coloured, on adult trees deep green and shiny on upper surface; seed-cups about f in. in width; mature wood pale, easily worked, strong, durable in the ground. The species has its native home in warm parts of eastern Australia. It was introduced into New Zealand about fifty years ago, and is now represented by vigorous millable specimens on the Auckland Isthmus, in three separate plantations near Papakura, and in two localities in the Hawke's Bay District. The trees grow rapidly to a large size, and, if intended for power-line poles, must be matured in close stands. In the seedling stage

E. pilularis is very sensitive to frost, and it is a bad transplantery Wherever practicable, therefore, seed should be sown on thoroughly cultivated ground where the trees . are to grow,, a very sprinkling of Italian rye-grass being sown with it to protect the plants against frost in their first winter. For unploughable country the. plants must be so prepared in boxes or pots that they may be transferred to the per-, manent ground with soil about their roots. ' ... ■..... . .■ .... ... 1 - (2.) E. eugenioides.— Has dead bark distinctly stringy, persistent from ground to small branches ; leaves in juvenile stage brown, hairy, creased, on older trees smooth and somewhat shiny ; seed-cups in. to in. in diameter, on-short stalklets, in crowded heads ; mature wood pale or pinkish, straight in grain, easily .split, excellent for sawing into boards, much. valued for posts’ and poles, resistant to fire, The species has its native habitat in eastern Australia, from south to north through Victoria, New South Wales, and southern Queensland ; from east to west over , the lowlands, tablelands, - and mountains. It has found a congenial home in New. Zealand, as witnessed by numerous specimens of millable size in the Papakura-Clevedon district near Auckland, in the State forests at. Whakarewarewa, in the Waikato near Cambridge, and in the Wairau Valley, Marlborough. Many trees have been, felled and utilized with results that well sustain the Australian reputation of the timber for durability in the ground. Grown in close stands E. eugenioides sheds its side branches and forms long, straight, stems in every way suited for carrying electric wires. Seed for future plantings should be obtained. either from our own acclimatized trees; or from certified and approved trees in cold parts of the natural habitat. The species is one of those that give their best results when seed is sown on quite clean, well-cultivated land where the trees are " to grow. For propagation by transplanting the plants must’ be prepared as recommended for E. pilularis. In the young stage seedlings of these species require especial care to prevent overtopping and suppression by weeds and grass. A little blood-and-bone manure. mixed with the soil near each plant will promote a rapid start and greatly reduce the risk of failure. (3.) E. Muelleriana and E. laevopinea are two species similar- in botanical characters and in’ economic merits to E. eugenioides. E. Muelleriana is represented by vigorous specimens of pole-timber size in the State plantations near Rotorua, and by younger specimens in a few localities. E. laevopineaXiSS only recently been introduced. Both species are worthy of experimental plantings in medium’climatic conditions, but, until further tested, neither, can be recommended for cultivation on a very large scale in this country. ■ . (4.) E. gigantea (syn. E. delegatensis') is a mountain stringy-bark that should be given trial in small plantings where climatic conditions, become too severe for E. eugenioides. ' . . . GUMS. Eucalypts- were first called “ gums ” in reference to the gum-like kino that exudes from the stems and large branches of many species. Later the term was restricted by Australian woodmen to those specie,s that shed their dead bark and present a more or less smooth surface. , ; (1.) E. nocalyx (syn. E. cladocalyx). — dead bark comes off in scales ; : leaves in juvenile stage round or oval, on adult trees narrow

with oily lustre ; seed-cups about | in. long by f in. wide, barrel-shaped, striped ; mature wood brown to dull .yellow, hard, and very lasting. The species is cultivated as a pole-yielder in South Australia and Victoria. Many scattered specimens are doing well in warm parts of New Zealand. At a place called Fern Glen, near the. coast in northern Wairarapa, there is a stand of about 9 acres, many units of which are now large enough for carrying wires. The species merits persistent experiment in similar situations. Sowings should be made in situ on well-prepared land with seed from best acclimatized trees. (2.) E. saligna.— dead bark is deciduous from branches and stem, newly exposed living bark greenish or bluish ; leaves deep green, shiny on upper surface; seed-cups about jin., long, much narrower at the base than at rim; mature wood red, clean in grain, easily. worked, excellent for building-construction, durable in contact with the ground. The natural habitat is the coastal belt and gullies of the tablelands in New South Wales and Queensland. As an exotic in our country E. saligna is proving hardier than the conditions of its native home would -have led us to expect. Healthy and vigorous specimens have been noted by the writer in many North Island plantations. In the Waikato, near Cambridge, and Upper Tutaenui, near Marton, there are large millable trees. Seedlings are now reported to have survived their first winter at Taihape. It is a fair inference to assume that this beautiful. and valuable tree would flourish in sheltered parts of the Marlborough Sounds and in Nelson. Grown in close plantations it rapidly develops long, clean poles that will be fit for cutting in thirty years. . . (3.) E. globulus. This is the Tasmanian “ blue-gum,” and is too familiar in New Zealand to need description. It is a tree that has suffered in reputation through bad treatment and consequent prejudice. Properly understood and in its proper place it is very valuable. It requires a climate that is cold without alpine severity, and a soil that is deep and moist without being wet. We erred when we planted this tree on warm lowlands of the North Island ; we also erred when we planted it on dry uplands. Our error exposed the tree to disease ; and' then, instead of blaming ourselves, we discredited the tree. The optimum of the species in New Zealand has-been found at low altitudes on alluvial flats in the South Island. Planted there in close stands it grows with great vigour, and soon develops heavy crops of tall, straight poles of great , value. When quite mature, felled in. the winter, and properly seasoned the poles may be expected to last sixteen years ; treated with preservatives they should last much longer. But there are good and bad strains of E. globulus. The best trees have large single flowers, vigorous foliage, and straight smooth-barked stems. Seed, should be collected only from the best and most blight-resistant trees ; and in no case should the species be further planted where it has already failed. E. globulus has the merit of being able to grow and flourish in southern localities where the number of eucalypts available for cultivation is greatly reduced by climatic conditions. : (4.) E. viminalis.—The dead bark is usually deciduous from branches and stem, -but may persist for a few feet near the ground ; leaves in juvenile stage sessile, lance-shaped, on adult trees rather narrow and long;- seed-cups up to in. in diameter, usually in threes; mature wood pale, rather .coarse in texture, strong, .known to. have lasted

twenty years in the ground. For New Zealand the species has the immense advantage of being adapted to a climate with cold winters. It is easily propagated and a great cropper. Splendid plantations of it may be seen in the Waikato, at Rotorua, in Marlborough, and in northern Canterbury. For poles it must be matured in close stands to prevent excess in diameter. A noble species closely similar to E. viminalis, and believed to be still more resistant to cold, has recently been made known to science under the name of E. Dalrymple Both are inland trees, and must be protected by screens of pines when planted near the sea. E. Dalrympleana should be introduced and tested in cold localities without delay. (5.) E. Gunnii. — The dead bark is scaly and deciduous; leaves in juvenile stage round, sessile, on adult trees narrow, short; seed-cups in threes, long, narrow ; mature wood pale, hard, said to be durable in the ground. The native home of the species is in the mountains of Tasmania. Away from the reach of frost and snow E. Gunnii remains small and feeble ; at altitudes between 1,000 ft. and 2,000 ft. in the North Island, and on the lowlands of Southland, it becomes a vigorous and beautiful tree of medium dimensions. We cannot yet say that this tree will yield satisfactory poles ; but the promise is fair and experiments well worth while. " WOOLLY-BUTTS. The dead bark in this group is sub-fibrous or wholly non-fibrous ; usually thick ; on some species spongy, on others hard. It clings to the stem and in some cases also to the large branches. ' (1.) E. hotry aides. — The dead bark on old trees is very coarse and thick ; leaves broad, shiny on upper surface ; seed-cups | in. to J- in. long, angular at base, sessile ; mature wood red, coarse in texture, very durable in ground. In its native home—eastern Australiait is a warm-country species, and at its best in localities not very remote from the sea. As an exotic in our North Island it is showing wonderful capacity for acclimatization. Near the coast and as far inland as Piako and Cambridge it has endured the frosts and attained a good poletimber size in twenty-five to thirty-five years. It is a very beautiful tree and strongly resistant to insect enemies. (2.) E. longifolia.— The dead bark on saplings is finely divided, on older trees coarse and thick ; leaves on vigorous young trees long, on old . trees medium; seed-cups in threes, up to | in. long and | in wide mature wood dark -red, very durable. The species comes from coastal regions in south-eastern Australia. From Auckland southward as far as Papakura it has grown to a pole-timber size in about thirty years. ’ '' - ' (3.) E. Macarthuri. — The dead bark is thick and brittle leaves in juvenile stage,sessile and lance-shaped, on adult trees narrow; seedcups very small, less than | in. in diameter ; mature wood pale,, coarse in grain, liable to crack radially, very strong, long-lasting in ground. The native home of the species extends from eastern New South Whies' westwards up the mountains. It is strongly resistant to frost and easily propagated. In the' Waikato it' has yielded very heavy crops and supplied many thousands of lasting fence-posts. ' It is a fair inference to expect that it will do well in Nelson, Marlborough,' and

parts 'of northern Canterbury. For. poles it must be planted close to check diameter growth, and near the sea it' requires protection against the saline winds. ' . (4.) E. aCervula (syn. E. ovata). — This species is not recommended for- extensive planting, but where stands of it already exist they will supply strong poles of good medium ■ durability. The species grows rapidly to pole-timber size up to altitudes of about 1,000 ft. all over the North' Island. ■ ' irone ARKS. The dead bark in this group persists on stem and large branches; it is very firm, entirely non-fibrous, and on ' older specimens . deeply furrowed. The ironbarks known to the timber trade are as follows :— . . (1.) E.- crebra. —-The dead bark on young trees is pale', on older trees dark ; leaves very narrow ; seed-cups very small, about. | in. in diameter; mature wood dark with.tinge of red, hard, strong, and very lasting. ' (2.) E. . panic ulata. — Dead bark pale ; leaves rather narrow, bright green seed-cups small, under in. in diameter mature wood pale, unsurpassed for strength and durability, much in demand for railwaysleepers, posts, and wire-poles. (3.) E. siderophloia. — bark at first flaky, later very hard, with, deep furrows and wide ridges ; leaves broad, especially in seedling and sapling stages; seed-cups up to in. in length; mature wood, dull red, dense, strong, in first grade for wire-poles and other work in contact with the ground. ' (4.) E. sideroxylon.—Dead bark very dark and hard ; leaves rather narrow, leathery, dull green; seed-cups often-over f in. in depth, urn-shaped ; mature wood red, very durable in any situation. . These four ironbarks are all indigenous to eastern Australia. All are warm-country' trees, though E. crebra and E. sideroxylon extend their range westward over the cooler uplands. In New Zealand scattered specimens of E. sideroxylon have grown in forty years to a large pole-timber diameter in the North Island as far inland as Cambridge and as far south. as Hawke’s Bay ; but their stems are neither very long nor quite straight. E. paniculata, favourably situated on the Auckland Isthmus, has grown to a small pole-timber size in thirty years; in other localities it has not done so well. E. crebra and E. siderophloia are represented by a few trees in genial situations, all still under pole-timber size. There is nothing yet in our New Zealand experience to warrant extensive planting of ironbarks ; but there is good reason to make small experimental plantings of all the species in warm northern localities. BOXES. ■ .The name “ box ” came to be applied to the. trees of this groupbecause their bark somewhat resembled that . of the European boxtree (Buxus sempervirens). The two most important eucalypts of the box group are E. Bosistoana and E. hemiphloia. They may be briefly described as follows :— (1.) E. Bosistoana.— -Dead bark short-fibred (or, as the botanists say,, sub-fibrous), deciduous from branches, persistent on stem to a less or greater height; leaves in juvenile stage round or oval, on adult trees, rather’ narrow ; ripe seed-cups in. or more in diameter ; mature wood

reddish-yellow, / strong, and very durable in any. situation. The species appears to be at its' best oh. limestone formations in Gippsland, Victoria, where the trees present long branchless boles of the type required for carrying wires. E. Bosistoana has not yet been successively cultivated in New Zealand, but, reasoning from natural habitat, we might expect it to flourish on limestone country a little inland from our northern coasts. ; - - ■' ’ -. (2.) E. hemiphloia. — Dead bark flaky, sub-fibrous; leaves very broad on seedlings and saplings, oval to very narrow on older trees ; ripe seed-cups .•& in. long by > in. wide, or sometimes much smaller ; mature wood pale, dense, strong, and very lasting. The species has a wide- distribution oh lowlands and uplands in eastern Australia. The trees as the traveller usually see them in Victoria and New South Wales are short, with spreading branches, and valuable only for fence-posts and fuel. In sheltered valleys they run up to a good pole-height. The best specimens known to the writer in New Zealand grew at “Trecarne,” near Cambridge. They belonged to a small-fruited variety of the species. When first noted by the writer they were about thirty years old; In diameter they were then large enough for telegraphpoles, but some of them were deficient in length. ■ E. eugenioides in the same plantation and of the same age more than equalled them in diameter and greatly exceeded., them in length of clean stem. E. Macarthuri, also in the same plantation and of the same age,: had already been yielding posts and poles of quite good durability. The boxes are thus in a similar position to the ironbarks. They must be still treated experimentally. E. hemiphloia varies greatly in merit under natural conditions in Australia. If we are to succeed with it as a cultivated timber-yield in New Zealand competent steps must be taken to obtain supplies of seed from certified and approved parent trees where the species is at its best in cool parts of its native home. We have wasted much time and money , in this country through breeding from inferior parent trees. ’ . 1 SPECIES IN ORDER OF RESISTANCE TO LOW TEMPERATURES. ' It will further help the planter in selection of species for his particular district if our list is now presented in the order of resistance to low temperatures, as follows : —

Climatic Conditions.

Species.

Winters with severe and prolonged frosts and heavy. falls of snow Winters with frequent severe frosts .. and occasional falls of snow Winters with, many frosty nights usually followed by clear days Winters with mild. frosts usually followed by clear days ’ ’ Winters without or almost without frost, with many hot days in summer

E. Gunnii, E. gigantea, E. Dalrympleana (probably). E. viminalis, E. gigantea. E. globulus (seaboard), E. Mdcarthwi ‘(inland), E. acervula, E. eugenioides . E. eugenioides, ' E. sdligna, E. botryoides, E. hemiphloia, E. Muelleriana, E. sideroxylon, E. laevopinea (probably), E. Bosistoana (probably), E. pilularis. E. longifolia, E. corynocalyx, E. crebva, E. paniculate, E. siderophloia. ■

In all ~ cases . where practicable information conveyed in printed articles should be supplemented by inspection, of the planting-ground by some. one who knows the species . and has' studied their behaviour in various localities. GENERAL CONSIDERATIONS. • The demand generally will be for heavy crops in short rotation. Very few people will be found who will be content to plant slowgrowing and light-cropping trees for the sake of greater durability in the timber. Choice will fall upon the best and most adapted of the rapid growers. We must look at the question in the light of what is happening in Australia. The natural forests of ironbark and box are heavily depleted. Regeneration is good in many localities, but insufficient for prospective requirements. Timbers of less durability are coming increasingly into use. Power Boards are having their poles treated with creosote and tar or other preservatives. . In ten to twenty years’ time poles imported from Australia may be no better than those we can abundantly produce in our own country. Preservative methods will have to be adopted here as elsewhere. Properly and efficiently treated, our own best poles may thus be expected to last quite as long as those we shall ultimately be able to obtain from our neighbours across the water, and when our home-grown poles decay the cheapest remedy will be renewal from adjacent plantations. The importance of insect enemies as a factor in the selection of eucalypt species for New Zealand conditions is well recognized by the writer. It is proposed to treat this aspect of the subject more specifically in a later article.

PROLONGED GESTATION PERIOD IN COW.

A case of extraordinarily prolonged gestation in a cow has been reported by Mr. W. J. Price, of, Hawera. The cow,- an aged animal belonging to Mr. Price, was served on 14th November, 1923, and was milked right through the season, never returning to the bull. Mr. Price does not allow his bull to run with the cows until the winter months and after he has culled his herd. In the ordinary course this cow should have calved about 25th August, 1924. On 26th November of that year, states Mr. Price, he noticed her in trouble with calving, a and yarded her for assistance. The calf —a heifer— got away, but it died in the process. It had an extremely large frame and was very thin ; it weighed 108 lb., the skin alone scaling 14 lb. The average weight of a calf at birth is about 70 lb. According to “ Fleming’s Obstetrics,” the longest known , period for which a cow has carried her calf is 353 days. Mr. Price’s cow, it will be seen, exceeded this record by twentyfour days. The facts as given by Mr. Price are supported by his neighbour, Mr. H. Steffert.

E. E. Elphick, M.R.C.V.S., D.V.H.,

Livestock Division.

Noxious Weeds Orders. — Woolly nightshade has been declared by Bay of Islands County ; broom, foxglove, and gorse by Waitomo County ; and hemlock by Greytown Borough.. .