Art. X.—The Building Materials of Otago.
[Read before the Otago Institute, 31st October, 1876.]
Properties of Timbers.
Although the properties of timbers generally are better known than those of the other building materials that have already been discussed, it is necessary for the proper investigation of our subject to consider the leading characteristics that bear on their economic value, and in doing so I shall trace the timber through the various stages of its existence.
Structure.—As you are probably aware, the structure of ordinary timber is, to all intents and purposes, identical with that of a brick wall: it is composed of vertical and horizontal layers, breaking joints, and cemented together in much the same way. The vertical joints, consisting of the annual rings and medullary rays, are quite clear and distinct; but the horizontal ones, made from the interlacing of bundles of woody fibre of irregular lengths, are only visible to the microscopist. It is this difference in the length of the scarf, or joint, that makes splitting timber so much easier than cutting it across the grain. The concentric rings represent the growth in a year or season; they are generally very distinct in timber grown in a cold climate, where there is a decided period of repose in the the vegetation; but in many tropical trees the rings are scarcely discernable, and some botanists allege that occasionally so many as four rings are formed in one year. The medullary rays are thin plates of woody matter that radiate from the pith to the bark, and form the weft which interlaces with the warp of the annual rings. Although believed to exist in all timbers, these rays cannot be traced in the firs and pines of the old country, but are very conspicuous in oak, beech, and other hard woods; this rule does not hold good in Otago, for there are few timbers hard or soft in which they do not appear. These medullary rays are what give the peculiar watered figure called silver grain, which is so much prized by cabinet-makers and other manufacturers of fancy wood-work.
Growth.—The principal agent in the formation and development of woody fibre and tissue is the sap, which performs the same functions in plants that blood does in animals. After being extracted by the roots from the soil, it rises through the trunk to the leaves, and is there subjected to certain chemical changes that fit it for the formation of timber. In saplings, the fluid permeates and rises through the whole trunk; but in old trees with solid heart-wood, it is confined to the sap-wood and the bark. At this stage the heart-wood contributes nothing to the other parts of the tree
except in supporting them. The leaves are the lungs of the plant, but, instead of making the original fluid thinner, and purifying it by the extraction of carbonic acid and the addition of oxygen as in animals, they make the sap thicker, and add carbonic acid, which is the food of plants. The precise nature of the chemical process carried on in the leaves, and the exact constituents of its product, are imperfectly understood. After the sap has acquired the necessary ingredients, it returns through the outer layer of the wood and the inner layer of the bark, leaving in its course a deposit of ligneous matter on each, and permeating to a greater or less extent all the rings of sap-wood. The deposits made on the bark and wood harden into rings of timber and bark, the former to increase the size of the tree, and the latter to replace the scales that are continually falling off the outer surface. The conversion of sap into heart-wood is attributed to the combined action of the juices and the compressive force exercised by the shrinkage of the outer rings and bark; but against this idea we have the fact of the change being generally sudden: one ring may be perfect heart, and the next sapwood of a very inferior quality. Whatever be the cause of this ripening of the timber, the process is not simultaneous with its growth, for the rings of sapwood always decrease in number as the tree approaches maturity, and there are frequently fewer rings on one side than the other.
Climate, situation, and soil, exercise a great influence on the character of timber. Among different treès the best timber is obtained from tropical countries, but in the same species the product of cold climates is found to be the strongest and most durable. Most authorities, ancient and modern, pronounce in favor of slow growth in timber trees as essential to perfection; but I observe that Mr. Laslett, Inspector of Timber to the Admiralty, entertains an opposite opinion formed from observations on oak and fir trees. I can easily understand the possibility of rapid growth being conducive to strength and durability, as it proves that the plant is well fed and in vigorous health. Although the wood may be soft and porous in the young tree, it does not follow that the old one will inherit these qualities; the energy that puts forth strong shoots is in all probability sufficient to provide them with a proportionate supply of woody fibre and the other essentials of strength.
Timber grown in open ground is stronger and more durable than that from the dark forest, but, on the other hand, it is more subject to twists, shakes, and irregularity of composition, and the trees are often stunted and crooked. The effect of the weather is well shown on the southern side of the Otago Peninsula, where the trees are blown into shapes as grotesque as could be seen in a Dutch garden.
The influence of situation and soil on the growth of trees is very re-
markable, as the following table, compiled from the “Forester,” will show. It gives the diameter in inches at eight feet from the ground, of various kinds grown in favorable and unfavorable situations:—
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|Favourable Situations.||Unfavourable Situations.|
|Oak, 80 years old||31 ½ inches||11 ½ inches|
|Scots Pine, 50 "||17 "||7 ¼ "|
|Larch, 35 "||17 "||8 "|
|Spruce Fir, 35 "||15 "||6 "|
Felling.—One of the most important considerations in the cultivation of timber for building purposes, is the time at which it should be cut—first, the age of the tree, and, next, the season of the year. The desideratum in the first instance is the zenith of growth—when maturity has been reached, and the decline not begun; and, in the second, when the tree contains the minimum of sap. Unripe timber is soft, sappy, and liable to decay; and, when too ripe, it is brittle, and the decay has already commenced at the heart. There is comparatively little difficulty in judging as to the ripeness of timber: when the top shoots cease to grow vigorously, and the branches become stunted and thick, it is ready for the axe. The following are given in various works as the ascertained ages of the common English trees:—
|Yew||1,214 to 2,820 years.|
|Oak||810 to 1,500 "|
As a further indication of their ages, Mr. Laslett gives a very complete list of the known timber trees throughout the world, with the number of concentric layers in an inch of an ordinary-sized specimen. I subjoin a few of the more common varieties:—
|English Oak, fast grown||1.50|
|Blue Gum, Australia||3.30|
|Iron Bark, Australia||4.00|
|White American Oak||4.70|
|Pine, Yellow, Canadian||5.22|
|Kauri, New Zealand||6.70|
There is a considerable difference of opinion as to the proper season for felling timber; while all authorities are agreed in considering it the time
when there is least sap in the tree, the time itself is not decided. One party argues that as vegetation is suspended during winter, there must be little sap in the timber. But the other maintains that midsummer is the best season for felling, as all the juices that rise in spring are then expended in forming leaves. With deciduous trees, and in a cold climate, the chances are greatly in favour of winter felling, but, with evergreens and in a warm climate, there seems little choice between summer and winter. Of course there is a very marked difference in the quality of timber felled in winter and spring, and in summer and autumn. Experiments made in Germany to settle this point gave the following results. Timber cut in December was impervious to water end-wise; in January, a few drops percolated through in 48 hour; in February, two quarts went through in that time; and the March cut timber allowed two quarts to run through in two and a half hours. It is to be regretted that these experiments were not carried over the whole year, as the result would go a long way towards deciding the relative merits of winter and summer felling. Notwithstanding the fact that spring is admitted on all sides to be the worst season of the year for felling timber, it is the one in which the “indestructable” English oak is cut; this is in consequence of the bark, which is used for tanning, being more valuable when the sap is rising. Summer is considered the best time for cutting alder and beech in England; it is also the season in which oak is felled in Italy and pines in Germany.
The ancients believed that the moon had a ripening influence on timber, consequently it was felled during her last quarter. The same belief was embodied in the Code Napoleon, and prevails to this day in the forests of Germany and Central America. It has a commercial significance in the latter place, for mahogany that is guaranteed to have been cut during the proper phase of the moon commands a higher price than any other. This lunar influence is probably quite imaginary, but when we consider the effect of the planets' attraction on the ocean, it is not unreasonable to suppose that vegetable juices may be attracted in a similar manner, at the same time we would expect a manifestation twice a month, as in the tides, instead of once only.
Qualities of Timber.—The chief attributes of good timber are—a minimum amount of sapwood, compactness of texture, and depth of colour where colour exists. The proportion of sap-wood varies in trees of different ages and kinds—chestnut, fifteen and half inches in diameter, has three-eighths of an inch of sap all round; oak, seventeen inches diameter, has one and quarter inch of sap; and Scotch fir, twenty-four inches diameter, two and half inches of sap. The ordinary defects in growing timber are the shakes, or cracks and hollows that appear in the heart of full grown and
over ripe trees. A small straight crack in the centre of a log does little harm, but when it is of a star shape, and has a twist in the length of the timber, its strength as a beam is seriously impaired, and it cannot be cut into planks. Another defect, known as the cup shake, consists in want of cohesion between the annual rings; it is less common but more serious than the one just described. The heart cavity is caused entirely by over ripeness in the trees, and its extent is in direct proportion to the time they have been allowed to stand after maturity. The cup shake is rare in Otago, but the other two defects occur in several kinds— a straight heart crack filled with gum or resin is very common in rimu, and the hollow heart is always met with in aged totara and cedar.
Seasoning.—There is no operation connected with the utilizing of timber on which so much depends as seasoning, at the same time there is no subject that receives so little attention from practical men, particularly in new countries. When it is considered that proper seasoning doubles the strength of timber, and increases its durability to an indefinite extent, the folly of using it in a green state is too apparent to need comment. Barking the trees a few months before felling, which is a very old custom, assists materially in draining the sap, and if to this is added the cutting through of the sap-wood all round, it makes the process very complete. Barking as a means of seasoning, is practised to some extent in the North Island, but I never heard of its being resorted to for this purpose in Otago. After felling, timber is seasoned naturally by the weather, or artificially by steeping in water, smoking, boiling, steaming or drying in a warm atmosphere. The object in all cases is to abstract such portions of the sap as are calculated to cause decay, but in doing so there is a danger of going too far: the juices that give elasticity, toughness, and durability may be abstracted along with those of a pernicious kind. It is found that natural seasoning is the best, and next it that by steeping the timber in running water, but both are very much slower than any of the other methods named. According to Laslett the time required for seasoning timber in open sheds is as follows:—
Pieces 12 to 16 inches, Oak 14 months, Fir 7 months.
" 8 " 12 " do 10 " do 5 "
" 4 " 8 " do 6 " do 3 "
" 2 " 4 " do 4 " do 2 "
The same sizes of timber would be equally well seasoned by steeping for ten days in running water, and afterwards drying under cover for a month. The other methods of seasoning complete the work in a few hours and upwards, but what is gained in time is frequently lost in strength and durability; the only real benefit they bestow is the saving of shrinkage.
The amount of moisture contained in the ordinary English timbers is shewn by the following table:
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|In pounds weight per cubic foot. Green.||In pounds weight per cubic foot, when seasoned.|
|Fir||54 to 74||31 to 41|
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The ultimate transverse shrinkage in the seasoning of boards twelve inches square and half an inch thick, is found to be for oak, 1/12 the breadth; Riga fir, 1/32; Virginia pine, 1/27; larch, 1/27; elm, 1/24; kauri, 1/64.
Decay and Preservation.—The causes of decay in timber are of three kinds:—1st. Chemical decay—a natural decomposition by the action of the air and moisture; 2nd. Vegetable decay or dry rot, a decomposition that takes place through the growth of fungi; and 3rd. Animal decay, waste by the destruction caused by worms and insects. The first of these is to all intents and purposes a slow combustion effected by the acids of the atmosphere, and greatly accelerated by changes from wet to dry. Most timbers will last a long time if kept constantly wet or constantly dry in an equable temperature, but the best only will stand exposure to severe alternations from wet to dry; the most trying situation for timber in this respect is in posts in the ground, decay always attacks it first at the surface, between wet and dry. I am not aware of any cure for this natural decay; charring, painting or tarring will retard its progress, but the only safe course is the use of a durable timber well seasoned. In connection with this I may notice a practice that exists among our settlers of inverting posts when putting them in the ground to increase their durability; like the lunar influence already noticed this was long thought to be only an imaginary benefit, but lately the matter has become an established fact. Experiments made in England on oak posts from the same tree showed those put in the ground with the top upwards as they grew, to be rotten in twelve years, while their neighbours that were inverted showed no symptoms of decay in sixteen years. This is explained by assuming that the capillary tubes are provided with valves which open upwards, on inverting the post these valves oppose the rising of moisture.
The relative durability of the timbers in common use in England has been ascertained by inserting pieces 2 ⅝ inches square into the ground; they decayed in the following order:—
|Lime, American Birch, Alder, and Aspen||3years.|
|Willow, Horse Chestnut, and Plane||4 "|
|Elm, Ash, Hornbeam, and Lombardy Poplars||7 "|
Oak, Scotch Fir, Weymouth Pine, and Silver Fir, were only affected to a depth of half an inch in seven years, and Larch, Juniper, and Arbor Vitœ were not touched at all in that time.
Vegetable decay or dry rot, is a regular disease induced, in unseasoned timber by defective ventilation. In most parts of the world this is the worst enemy that timber has; we hear of ships being destroyed, and houses being made uninhabitable in an incredibly short time through its ravages and even cargoes of timber are seriously affected on the voyage from America to England. Hitherto this disease has been little known in Otago, not because any precautions are taken against it, but simply on account of the defects in our wooden buildings which give ample ventilation. I have seen several instances of dry rot in brick and stone buildings in Dunedin, but few in wooden ones; it is however very common in the timber work of mines.
The third cause of decay in timber, that by animals, is also of minor importance in Otago: the marine animals have caused some little trouble, but the land ones are scarcely known as destroyers in material that has been used. The latter class consist of a small beetle supposed to be much the same as the English one, and the large white worm that used to be eaten by the Maoris. These beetles are very destructive, particularly in carvings, but they are easily destroyed by fumigations; the large worm is very common in old trees lying in the forest, and I have seen it in piles that had not been barked, but never in wrought timber.
The marine animals most destructive to timber are the Teredo navalis or marine worm, and Limnoria terebrans, a small boring crab of the leech family, both of which are common in New Zealand waters. Captain Hutton finds that our Teredo is somewhat different from the European one, consequently it is called the Teredo antarctica. The Teredo is a worm-like animal from three to twenty-four inches in length, and from a quarter to an inch in diameter, according to the nature of the wood in which it has taken up its abode. It is furnished with a wonderful boring apparatus, like a pair of shell augurs, by which it perforates the hardest timber with astonishing rapidity. The smaller animal, which Mr. Kirk says is allied to Limnoria lignorum, although scarcely larger than a grain of rice, is as destructive as the Teredo. Large numbers attack the timber and speedily destroy it by fairly eating it away; indeed some animals of this species are able to penetrate stone.
The effectual preservation of timber in all conditions is a problem not yet solved. Oleaginous and bituminous substances retard the progress of
decomposition, but without thorough seasoning and ventilation they are of little value. On the contrary, anything that closes the pores of the timber while it contains sap promotes decay. One of the best preservatives of timber is the creosoting process, invented 40 years ago by Mr. Bethell, which consists in extracting the natural juices by pumping and refilling the pores with creosote. Timber prepared in this manner resists decay of all kinds for a long time, but on account of the inflammable nature of the preparation and its obnoxious smell, timber that has undergone the process cannot be utilized in ordinary architectural work.
There is no subject connected with New Zealand timbers that is in such an unsatisfactory state as the nomenclature. The utmost confusion exists in the names of many kinds, and there are very few that bear the same name throughout all parts of the colony. In consequence of our ignorance on this point many of the best timbers have been rejected, and inferior ones accepted in their place, a proceeding which has led to disappointment and loss both in private buildings and public works. With the view to remedy this evil I have prepared a table (No. I.) hereto appended, showing the various names of all the principal Otago woods: the popular name is that by which the tree is best known, whether botanical, native, or given by the settlers, and the synonyms consist of the proper botanical name, and any native or vernacular names that have been applied to the plant. Many of the trees were formerly known by other botanical names, but the one given is now universally accepted, consequently the others are not required. The great majority of all these old botanical names can be found in “Hooker's New Zealand Flora” and “Gordon's Pinetum.” As the leading Colonial authorities have been consulted in preparing this table, I have considerable confidence in its accuracy and completeness. The identity of two or three of the smaller plants with some of the native and vernacular names is not fully established, but there is little or no doubt with regard to all the others.
According to a return made to Parliament in 1874, Otago possesses about 2,250,000 acres, or 3,500 square miles of forest lands. With the exception of a block of 600 square miles in the north, which is almost treeless, the forests are well dispersed throughout the province, and the largest supplies are in very accessible situations. Practically there is a belt of forest along nine-tenths of the Otago coast. It is quite unbroken from the north-west boundary at Martin Bay to Riverton, a distance of 200 miles, and the gaps from thence to Waikouaiti, near the north-east boundary, are few and short. The West Coast belt extends with greater or
less continuity right across the country to the Waiau valley, and its resources are comparatively unknown. The timber on the seaboard is good, but that in the interior is supposed to be scrubby. There is a considerable quantity of birch in the seaboard forest from Martin Bay to Preservation Inlet, but round the south and east coasts they consist of pines and the other common varieties. Stewart Island is one large pine forest, with a fair sprinkling of rata. Southland is remarkably well supplied with timber. A glance at the map shows an alternation of bush and open country that resembles the conception of a landscape gardener more than a natural arrangement. These isolated patches of forest embrace the whole width of the country, and extend 50 miles inland. One of the largest bushes in the interior of the province extends along the face of the Eyre mountains from the Five rivers to the Te Anau lake, including the Mararoa district. It covers about 400 square miles. This and the lake forests, altogether about 400,000 acres, are all birch. The principal forests now available near the sea, in Southland, are from Riverton to the Waiau, sixteeen miles long by twelve broad; and the seaward bush, from Invercargill to the Mataura, twenty miles long, and from two to three broad. The Ototara, Waikiwi, and Makarewa bushes in the vicinity of Invercargill are also of considerable extent. Following up the coast the next large forest is the Tautuku bush, extending from Waipapa point to the Clutha river, a distance of forty-five miles and inland about twelve. We have then smaller patches at Kaitangata, Akatore, Dunedin, Waikouaiti, and Otepopo. The principal isolated bushes in the interior occur at Waiporai, Tapanui, and Switzers. Except on the west coast, where it descends to sea level, birch does not exist in forests below an altitude of 900 feet.
The principal supply of provincial timber for the Dunedin market comes from Southland and Catlin river, where the forests are accessible to water and railway carriage. Although Stewart Island is particularly well favoured in respect to harbour accommodation, its isolated situation has hitherto been a barrier to the development of the timber trade, and the west coast supplies have never been touched.
Timbers are usually arranged into classes, according to their botanical or structural affinities and peculiarities. The most common arrangement at home is to divide them into leafwoods and pinewoods, which keeps the hard and soft kinds separate; but this mode of classification would not have the same result in New Zealand. I shall therefore consider the Otago timbers under two heads, with the conventional names of “Hardwoods” and “Softwoods.”
The trees in this family are too small to yield useful building materials; but it is important in furnishing the strongest wood in Otago, I have therefore given it the first place in the tables. The five trees that will be considered under the generic name of Mapau are not all members of the same botanical order. The first three are pittosporeal; the fourth, red mapau, is the only Otago representative of a large New Zealand family; and the fifth, white mapau, although belonging to an extensive order, has no immediate relatives in the colony. The mapaus are found in all the low-lying forests, and are particularly plentiful in the neighbourhood of Dunedin.
No. 1. Black mapau—Pittosporum tenuifolium. A small tree seldom exceeding 30 feet in height, and twelve inches in diameter. It has pale green shining leaves and purple flowers. The wood, which is of a dirty white colour, is tough and fibrous. Mr. Balfour's experiments at the New Zealand Exhibition, showed it to be nearly 90 per cent, stronger than English oak.*
No. 2. Black mapau—Pittosporum Colensoi. With the exception of being generally larger, this tree is identical with the former; indeed, some authorities suppose that they are merely varieties of the same species.
No. 3. Turpentine—Pittosporum eugenioides. This is the largest of the mapau family; it sometimes attains a height of 40 feet, with a diameter of 24 inches. The bark is thin, and of a light colour; the leaves are silvery green, and the flowers pale yellow. Altogether, this is one of the handsomest trees in Otago. The bark exudes a thick gum, and the juice of the leaves, which is somewhat similar, was formerly used by the Maoris as a perfume, but I fear it is too resinous for European tastes.
The three trees above described yield a close, compact, heavy wood, hard, tough, and fibrous in the grain, but much given to warping when used green. It is not durable in fencing posts, or similarly exposed situations, but answers well for rails. Hitherto this timber has not been used in constructions of any kind; it is not suitable for many building purposes, but would do for handles and implements where strength is required.
No. 4. Red mapau—Myrsine urvillei. This is a small tree, well known
[Footnote] * This and all subsequent comparisons of the same kind throughout the paper are made from the results of Balfour's experiments as compared with those of Barlow, the standard authority in Balfour's time. Recent experiments by Laslett give, in some cases very different results, so a better comparison between the strengths of Otago and other timbers can be made by inspecting Table IV., where Barlow's and Laslett's experiments are both given.
to everyone from its conical shape and dark foliage. It seldom exceeds fifteen inches in thickness, but is much prized by settlers on account of its durability and straightness of grain. The timber is strong, heavy, and compact, like English beech, but much darker in colour. Red mapau will not stand long in the ground; but, so far as ordinary decay is concerned, it seems almost indestructible in most other situations. Many of the braces in the old Dunedin Jetty, erected seventeen years ago and recently removed, were of mapau sapling three or four inches in diameter. They were nearly all in good preservation, and free from the ravages of marine worms. Slight symptoms of approaching decay were observed in the braces that had their butt-ends in the water, but all others were quite sound. The timber is, however, very subject to the attacks of a small boring beetle when kept dry. Hitherto red mapau has only been used for firewood and fencing, but it is suitable for making furniture and carpenters' tools.
No. 5. White mapau—Carpodetus serratus' A small tree like the black mapau, No. 1. It has mottled green leaves, and large white flowers; the wood is white and fibrous. Although its absolute strength is not so great as that of the red mapau, it is tougher, and consequently better suited for the handles of tools.
According to observations made by Mr. T. Baber, C.E., Auckland, young trees of the mapau family attain a height of thirteen to seventeen feet in ten years.
Manuka and Rata.
These trees belong to different branches of the Myrtle family, one of the most extensive in the world. They resemble each other in the quality and appearance of the timber and the bark, but are very different in size of trunk and character of foliage; they also affect different localities and soils.
No. 6. Manuka—Leptospermum scoparium. This is the variety known as white manuka, which is much smaller than the red. It grows best on stiff clayey soils that will scarcely produce anything else, but is common on the margin of large bushes in all the low-lying districts of the province, where it acts as a breakwind to less hardy plants. This tree is best known as an ornamental shrub, but occasionally attains to a diameter of from nine to fifteen inches. Its properties as a timber are generally the same as those of the next variety:—they will be considered further together.
No. 7. Manuka—Leptospermum ericoides. Is common in isolated positions on the whole of the eastern seaboard, and occurs in considerable quantities in the vicinity of Dunedin, Purakanui, and Otepopo. The tree occasionally attains a height of sixty feet, with a diameter of from two to three feet at the butt; but these are extreme sizes—logs thirty feet long and ten inches diameter at the smaller end may be considered the practical limit of
workable timber. So far as habits and habitat are concerned, this tree is identical with the preceding variety. Like most other hardwoods, manuka does not grow straight, and it is much given to warping and cracking; but I do not know that it inherits these defects to a greater extent than is done by jarrah, ironbark, and other Australian timbers of the same class, and it is freer from heart shakes and knots.
Manuka is noted for its great strength and hardness, combined with a considerable amount of toughness, although, as a class, it did not give the highest average. One specimen stood the greatest transverse strain of any Australasian timber tested at the New Zealand Exhibition. Manuka is one of the best timbers in Otago for firewood, consequently there has been a great demand for it, particularly in the vicinity of Dunedin, and the supply is running short; but it is satisfactory to note that young trees grow up rapidly when the old ones are removed. This timber is well adapted for piles in situations where they are kept constantly wet, for swingletrees, spokes, and handles of tools, also for the teeth of wheels. This last is a purpose that requires wood of a particularly good quality, and although not quite so suitable as rata, manuka has been found to answer admirably. The teeth in the spar-wheels of the “Express” and other coasting steamers are made of manuka, and they are wearing remarkably well.
The old settlers had a high opinion of the durability of manuka, and used it extensively in fencing posts, house blocks, and similar situations of the most trying kind, but it has not proved equal to their expectations. Under ordinary circumstances manuka will decay in the ground in from six to ten years, according to the situation. The longest lived fence that. I have heard of is at the Beaumont Ferry, where the posts were not decayed quite through in eleven years. This is, however, an exceptional case, as the fence was erected on dry, porous, alluvial soil, that did not retain moisture. Manuka has proved very durable in marine works;—the great majority of the piles in the old Dunedin Jetty, erected seventeen years ago, were of this timber, and remained quite sound till its removal last month. The George Jetty at Port Chalmers, erected a year later, is in the same condition, but here the test has been more complete—all the other timbers are very much affected by the Limnoria, and the manuka is untouched. Mr. Kirk, in 1874, reported that he had seen manuka fender piles at Port Chalmers much perforated by the Teredo; but the piles he refers to must have been removed since his visit, for there are no signs of the worm in the manuka piles now. The only evidence of its having attacked this timber is in the Bowen Pier, erected four years ago, where one white manuka has been perforated to a small extent.
No. 8. Rata—Metrosideros lucida. This tree grows on high ground at Catlin River and the Longwood Ranges, but descends to sea level at the Bluff, Stewart Island, and the West Coast. It grows best on a light gravelly soil, and attains to a height of thirty or forty feet, and an extreme diameter of about six. Logs can be obtained twenty-four feet long and three feet diameter. The tree sometimes grows with a clear straight stem of this height, but frequently it divides into large branches three or four feet from the ground; this kind furnishes valuable bent timbers for ship-building. Rata has a thin stringy bark like manuka, but larger leaves, and beautiful red flowers. The timber is the heaviest in Otago, being a little heavier than water. It is very dense and solid, with little or no sap-wood, and of a dark red colour like mahogany. Although not nearly so strong, rata is suited for many of the purposes to which manuka is applicable, and has an additional advantage in being larger, straighter grained, and less liable to warp. Its dark colour might render it suitable for furniture, but I fear the absence of figure will be an objection. Hitherto rata has been little utilized. The construction of railway waggons at Invercargill, and the making of teeth and bushes, are almost the only purposes to which it has been applied, but the result is very satisfactory. The bearings of a water-wheel at Waikara are in good order after eighteen years' service, and the railway waggons are pronounced equal to those made from imported timber. Mr. M'Queen prefers rata to any other native wood for teeth and bushes. He says that manuka and kowhai do not wear so well—they wear off in grit or threads, whereas friction only increases the glassy hardness of rata.
Although this timber has not been used in situations that would test its durability, there is every reason to believe that it possesses this property to a considerable extent. I show a sample taken from an old log on a part of the Kaihiku Ranges, where no living rata tree has existed since the settlement of the province. It is still quite sound, and there is a large quantity in the same condition.
No. 9. Kowhai—Sophora tetraptera. This is the sole New Zealand representative of a large genus of the pea tribe, but it is intimately related to the well-known Clianthus of our gardens. The tree, which is of solitary habits, is found in shady damp situations and on light soils in all the seaboard forests. It grows to a height of about forty feet, and has a clear straight stem about twenty-five feet long, and from eighteen inches to three feet in diameter. It seldom exceeds two feet in the vicinity of Dunedin, but from that to three feet is quite common in Southland, particularly at Forest Hill. Kowhai when young has a smooth, tough, and stringy bark, which gets coarse and brittle as the tree approaches maturity. It has beautiful drooping foliage of a feathery appearance, and yellow flowers like laburnum. Altogether
the plant is one of the handsomest in our forests. It is popularly supposed that kowhai is a very slow grower, and the settlers believe that it takes twenty years to produce an axe handle, but this is an erroneous idea. So far as can be determined from the annular rings, an ordinary sized tree reaches maturity in from 150 to 200 years. It should also be noticed that the tree is easily raised from seed, and easily transplanted.
The timber is remarkably straight grained and free from knots, but is subject to a heart-shake that impairs the strength of beams and induces splitting in piles. It is stronger than rata, but weaker than manuka, It is, however, superior to both in toughness, and warps very little. The sap-wood, which is clearly defined, is very small; in about 200 logs, ranging from six to twenty-two inches in diameter, it never exceeds one and half inches in thickness. The wood is of a yellow colour like laburnum, but resembles oak in grain and figure. It contains a strong resin or gum, the peculiar smell of which never leaves the timber however well seasoned.
Kowhai is used for the same purposes as manuka and rata, together with fencing posts, house blocks, piles and similar work in a damp situation, for which it is better adapted than either. The screw shaft bearings of the “Betsy Douglas,” and the pins and bushes of the paddle floats of the “Coomerang” are of kowhai, and Mr. Sparrow pronounces it equal to lignum vitœ for such work. Messrs. Guthrie and Larnach use this timber extensively for carved work, such as the rims for carriage wheels, the top of circular windows and tilt frames. A good proof of its toughness and straightness of fibre is given in the teeth and bows of hay rakes. The latter are turned to the diameter of a quarter of an inch, and bent into a semicircle of nine inches without sign of giving way.
The durability of kowhai is thoroughly established. It has never been known to fail in any situation in which it has been tried. But it was scarcely necessary to make a trial, for the old trunks that have been lying in the forests from time immemorial are still as sound as when they fell. Indeed this old timber is frequently used for fencing posts and house blocks. Kowhai has been little used in marine works. The only instance that I know of is some bracing in the old Dunedi jetty, which was perfectly sound after being in place for seventeen years. The same remark applies to fencing and house blocks that have been in use for a much longer period.
No. 10. Fuchsia—Fuchsia excorticata. The fuchsia, which is the parent of many of the cultivated varieties, can scarcely be called a timber tree, but as it possesses many good qualities, and has been applied to useful purposes, it is entitled to a passing notice. The tree, which is found along the seaboard, sometimes attains a height of thirty feet, and a diameter of two feet, but it is so twisted and gnarled that it seldom yields a straight
fencing post. The timber is hard, tough, and imperishable, but much given to warping and cracking. It has been used in house blocks for 20 years without showing symptoms of decay.
No. 11. Broadleaf—Griselinia littoralis. There are few trees in the bush so conspicuous, or so well known as the Broadleaf, which is the sole Otago representative of its species. It is found in all the low-lying forests, but attains its maximum size on the East Coast. It grows to a height of fifty or sixty feet, and a diameter of from three to six; the bark is coarse and fibrous, and the leaves a beautiful deep green of great brilliancy. Although much larger, this tree, like the fuchsia, furnishes very little serviceable timber; it is bent and twisted, irregular outside, and hollow in the heart. The timber is very hard and brittle, and, although crooked, is easily split; it is red in colour, and sometimes prettily marked, and not liable to crack or warp, consequently it would make furniture. Hitherto it has only been used in fencing, house blocks, and knees for boat-building. The durability of broadleaf any situation is fully established; it has never been known to fail, and old settlers consider it the most lasting of Otago timbers.
No. 12. Kamai—Weinmannia racemosa. There are two trees of this species in New Zealand, but this is the only one in Otago: it belongs, however, to the same order as white mapau, which it resembles slightly. The properties of this timber, and its identity, have for the last year or two been the cause of considerable misconception and confusion throughout the Province. I shall therefore endeavour to describe it so as to clear up all doubts.
As will be seen by the tables of names, kamai is called black birch in the Catlin River District and Southland, which name is given on account of a supposed resemblance to the “birches,” or, more correctly, “beeches,” a number of which occur in that locality. I cannot understand how such an idea could have originated, for, except in the case of the bark of one, there is not the slightest resemblance between the birches and kamai. Furthermore, the birch that is like in bark is quite unlike in foliage, and it does not grow in the same forest as kamai. Whatever be the reason, the misapplication of names is complete, for the birches are still commonly called kamai in Southland, and this has brought the latter into disrepute, the birch with which it is most frequently confounded being very subject to decay in damp situations. Kamai is little known on the east coast, north of the Clutha River, but is common from thence right round the south and west coast to Martin Bay, and particularly plentiful at Catlin River and the western districts. Like the pines, it is rare on high altitudes.
Hitherto this timber has been considered of little value by scientific and professional men; it is described as small, and inferior in strength and
durability. Mr. Kirk questions all its good qualities, and Dr. Hector says “the use of this timber must be guarded against, as it is perfectly worthless.” I hope to give it a much better character. Kamai is generally from fifty to seventy feet high, with a trunk from twenty to twenty-five feet long, and eighteen inches to three feet in diameter, but frequently it attains a height of from 80 to 100 feet, and a diameter of from three to four. I am assured that trees of this size are quite common on the flat land south of Catlin River. Like most hardwoods, this tree does not grow quite straight, but the bends are not so great as to become a serious defect. The bark, which is of a light grey colour, is very thin, and adheres firmly to the trunk even when dry: the leaves are of a brownish colour, about two inches long and one inch broad, with prickly edges and a sharp stiff point. The wood, which is straight grained, dense, and heavy, has a light brown ground colour, with grey and red figures and streaks, and very conspicuous medullary rays. The streaks are very curious—they look like the broad streaks of a carpenter's pencil drawn at random from top to bottom of the timber, and when dry they form a depression in its surface. Kamai has little or no sap-wood at any stage of its growth, so may be utilized, however small. The growing trees are very much subject to heart decay, few of the oldest ones being fit for sawing into large scantling. When sawn up green and exposed to the sun, this timber cracks and twists to a great extent. A number of logs now in Messrs. Guthrie and Larnach's yard are almost useless through this cause. I find, however, that there is no inordinate splitting or warping in timber that has been seasoned gradually with the bark on, and the ultimate shrinkage under any circumstances is not excessive. The strength of kamai has never been tested; it will, in all probability, stand a considerable strain, but may give way without much warning, as it does not seem to be very flexible. The bark of kamai is rich in tannic acid, consequently it is suitable for tanning leather. An analysis by Mr. Skey, of the bark of towai, a variety found in the North Island, gave thirty-one per cent. of tannic acid, which is nine per cent. richer than the bark of young oak, the best tanning material in England.
This timber is suitable for fencing posts, house blocks, railway sleepers, piles, beams and general framing, but not for boardings or joiners' work. Being prettily marked, it might be used for turning and other small cabinetmakers' work.
The durability of kamai under the most trying circumstances is, in my opinion, thoroughly established. Mr. Kirk says that he found old specimens in the forest that were much decayed and worm-eaten, but I have never seen any in which the heart-wood was so affected, and kamai used by the settlers has never been known to fail. I show a section of a tree cut in Seaward
Bush in April, 1862, and which has lain in the forest ever since; it is quite sound and fresh right out to the bark. I also show samples of a tramway sleeper, made from a young tree, that has been in use at the Kew Sawmills, Southland, since 1866; it is still in good preservation. Mr. A. C. Purdie, on a recent visit to Catlin River, kindly collected some valuable information on the subject for me. He found a log that had lain partly buried in the earth for thirteen years quite sound, except about a quarter of an inch of the outside sap, which was beginning to decay. He also was shown saplings that had been used in tramway sleepers for five or six years. Although thus made of immature timber, and tried in the most severe manner, they are still as fresh as when put in. I could multiply similar proofs of the durability of kamai from various districts, and on undoubted authority, so I have no hesitation in giving it a high place for durability. As noticed by Mr. Kirk, it is subject to the ravages of a small boring worm, but the damage done by this animal is too insignificant to be considered a defect in the works for which the timber is best adapted.
The only two trees of this genus in New Zealand occur throughout the whole eastern seaboard of Otago, and are very common in the vicinity of Dunedin. So far as habitat, size of trunk, and general habits are concerned they resemble closely the kowhai, but differ greatly from it in character of leaves and timber.
No. 13. Pokako—Elœocarpus hookerianuis. This tree grows to a height of sixty feet, with a clear trunk of from thirty to forty feet long, and two and half feet diameter at the base. The sap-wood is of a dirty white colour, and the heart a blotched or marbled brown. There is, however, very little heart-wood. A tree three feet in diameter will have at least six inches of sap all round. The wood is tough and flexible and difficult to split, but not durable in a damp situation. Pokako is frequently sawn up and sold as white pine, and used for the same purposes as that timber. It has also been made into earth waggons on the Southland railways, and found to answer admirably. The heart-wood is suited for turning or light cabinet work.
No. 14. Pokako—Elœocarpus dentatus. This is recognized as a distinct tree from the last in the North Island, but not so in Otago. The two are found together, and are almost identical in size and appearance, but the wood is different. This one yields a much harder and more lasting timber than the other. It is also freer from sap-wood and easier split. The wood has a pinkish brown colour. Having been little used here in exposed situations we cannot speak as to the durability of pokako, but it is much prized for this property in the North, where it is known by the name of Hinau. Mr. Kirk found mine props and tramway sleepers quite sound
after being in use for nine years. This timber is used in Otago for much the same purpose as the preceding variety.
Table I. gives the name of three different trees (Nos. 15, 16, and 17) that are popularly known by the name of Ribbon Wood. They are, botanically, quite distinct, but possess some properties in common, and are of little economic value, consequently I shall treat them collectively. The trees are seldom more than eighteen inches diameter. The wood is white or light brown, with strongly marked medullary rays, tough and easily split, but quite worthless in point of durability. One variety is so straight grained that long rails can be split quite parallel though only an inch thick. For this reason the timber was formerly in great demand for fencing and shingles, but experience of its liability to decay has brought it into disrepute. Ribbon wood is not durable in any situation that is in the least exposed to the action of the weather.
No. 18. Grass Tree—Panax crassifolium, is common everywhere throughout the province, and well known from its unique appearance. It grows to a height of twenty-five feet, but the trunk seldom exceeds twelve inches in diameter. When young the leaves are from twelve to eighteen inches in length, and droop against the stem, but as the tree grows old they gradually decrease to three or four inches, and become quite erect and rigid. The timber is hard, strong, and durable. The young wood being particularly tough and elastic is suitable for axe handles and similar purposes. The piles in the first jetty erected by the settlers at Port Chalmers in 1850 were of grass tree. A portion of it, still in existence, shows the timber to be in good preservation, and perfectly free from the ravages of marine animals. A piece of the piles between high and low-water mark is discoloured and soft, but the fibre of the wood is still intact, and the remainder of the piles are as sound as when erected. It is worthy of remark that these piles emit a strong offensive smell like that from a cow byre, and that cattle will not eat the leaves of any of the grass trees, which is quite in keeping with the general character of the ivy tribe to which they belong. They have all a strong smell more pungent than agreeable. Probably this may account for the fact that the piles at Port Chalmers were not molested by marine animals.
So far as the constructive arts are concerned this is the most important of the botanical orders. According to Dr. Hooker, it is represented in New Zealand by five genera and thirteen species, as follows:—
Dammara, consisting of 1 species
Libocedrus" " 2 "
Podocarpus" " 5 "
Dacrydium" " 3 "
Phyllocladus" " 2 "
Total number of species 13
Of the above one in each of the three last genera is a mere shrub or small Alpine tree frequenting the mountain ranges of the interior, generally from an altitude of 3,000 feet upwards. They are therefore of no economic value. The first in the list is the famous kauri, monarch of New Zealand timbers. Unfortunately it is absent from Otago, therefore does not come within the scope of our inquiry. This reduces the number of the Conifera timber trees in the province to nine. I shall now consider them seriatim in the order established by Hooker, as above, which is also followed in Table I. hereto appended.
No. 1. Cedar—Libocedrus bidwillii. This tree belongs to a small subdivision of the coniferæ family that has only three representatives out of New Zealand, all of which, like our native plants, frequent mountain ranges. These three are all found on the western side of the American continent, from British Columbia to the Straits of Magellan. The members of this genus were formerly classed as Thuja or Arbor vitœ; but the present name, which means incense cedar, is now universally adopted. I do not know why they should be so named. The New Zealand varieties do not emit incense, and under any circumstance the name seems inapplicable, for the genus was not discovered until long after the practice of burning wood for incense had ceased.
“The Handbook of New Zealand Flora” gives two species of cedar—Libocedrus doniana and Libocedrus bidwillii; the former of which is stated as furnishing good and the latter worthless timber. In naming L. bidwillii Dr. Hooker says:-” I advance this species with much hesitation. It is difficult to suppose that a timber tree described as having excellent wood, and growing at the Bay of Islands at the level of the sea (I gathered L. doniana on the banks of the Kawa-kawa river) should be the same as one inhabiting the mountains of the Middle Island, and described by Buchanan as having soft worthless wood, but I can find very little difference between the specimens.” He further points out that they are botanically alike, and seems to depend to a great extent on the difference of the timber in making them distinct species. I hope to prove that instead of being worthless this is one of the most valuable and durable timbers in Otago. It is therefore possible that the trees in the North and South Islands are identical. Mr. Buchanan refers to the Otago cedar as L. doniana, and mentions no Other, but Mr. Kirk seems to recognise two distinct species, and calls the Otago one L. bidwillii. I shall therefore adhere to the latter name, but assume that the tree that I describe is the same as Buchanan's L. doniana.
Gedar is plentiful on the mountain ranges of the east coast, from the Mataura River to Waikouaiti, but scarce in all the other forests of the province; it is generally found from an altitude of 1,000 to 2,000 feet. The greater portion of the timber trees on Mount Cargill, and the northern slopes of Flagstaff and Mihiwaka, are of cedar. This tree is easily recognized: the trunk is usually quite -free of branches, and the head is of a handsome conical shape. The lowest branches, which are also the widest, grow in a horizontal direction, consequently the base of the cone is well-defined. The bark is rough and fibrous like totara, but the foliage, which is erect and stiff, has a greater resemblance to old rimu. The tree grows to a height of from sixty to eighty feet, with a clear trunk of from twenty to forty feet long, and two to three feet in diameter, but the larger of these sizes is rare. At Mihiwaku the trunks are generally from eighteen inches to two feet in diameter, and twenty feet long, but they are somewhat longer near the head of the Waitaki. The tree from which one of the boards shown was cut grew on Pine Hill, the trunk of which measured thirty-five feet in length. The cedars of the Kaihiku Ranges are the same size as at Blueskin, but some trees at Catlin River are much larger. One trunk recently measured was forty feet long, three feet six inches in diameter at the butt, and three feet at the top; the log had a slight twist in the grain, but was straight and sound throughout. Buchanan mentions a cedar, cut in the vicinity of Dunedin, that was four feet in diameter.
The wood is of a dark red colour, straight grained and solid, but rather weak. It resembles very much the famous redwood of California (Sequoia sempervirens), which is the timber most used in America for railway sleepers, and here for Venetian blinds. Buchanan says that the heart-wood of L. bidwillii is so soft that soap-bubbles may be blown through a foot length of it; but this is no criterion of its value, for the same thing may be done with most straight grained timbers. Blowing bubbles through new planes, which are made of solid beech wood, is a favourite amusement among young carpenters in the Old Country, and I have seen bubbles blown quite easily through an oak stave three feet long that had been taken from an old beer cask. As a matter of curiosity, the experiment was tried with cedar; samples of old and young timber, seasoned and unseasoned, were tried, but in no case could bubbles be blown through three inches of heart-wood. We must therefore conclude that Mr. Buchanan's specimen was more porous than usual.
Cedar grows faster than most European timber trees; judging from the annual rings, it reaches maturity in from 170 to 400 years. There is very little sap-wood generally—not more than from an inch to an inch and a
half in ordinary trees. The large one cut at Catlin River had two inches at the butt and three at the top.
This tree is very much subject to heart decay; probably a third of the aged trees in the Blueskin and Kaihiku districts are more or less affected in this way, but those on lower ground on Catlin River are nearly all sound. The decay is usually a core three or four inches in diameter, but occasionally reaching seven inches, and having similar patches throughout other parts of the trunk. This is a serious objection so far as economical cutting up is concerned, but it does not affect the durability of the timber, as the decay ceases as soon as the tree is felled. Although a roughness of bark does not always indicate a hollow heart, it has been observed that a smooth one is a sure indication of sound timber. Cedar has been objected to as subject to excessive and irregular shrinkage and warping, but my experience of it does not warrant such a conclusion. I believe that the sound timber is as little subject to these defects as any other of the pines.
Hitherto this timber has been little used, except for fencing posts, house blocks, piles, and railway sleepers; but it is suited for ordinary house framing, and other purposes of a similar character, where great strength is not requred; the straighter grained portions would make shingles, mouldings, and small cabinet-work. I am assured that good samples work as freely as clear pine.
I have already referred to the low opinion entertained of this timber by leading authorities. It is further described as not durable by Dr. Hector, Mr. Buchanan, and the Jurors of the New Zealand Exhibition. I cannot understand how it could have got into such bad repute, for I can find no evidence against it; on the contrary, there is abundant proof that cedar is one of the most durable timbers in Otago—even the sap-wood lasts for years in situations where the heart of many other pines would fail. Much of the timber found on the ranges, where no tree has lived for centuries, and which is still in good preservation, is cedar. I show several samples found on the bare ranges at Kaihiku. There is a fence of this timber at Tokomairiro twenty-two years old. Mr. James Elder Brown sent me a post in 1872, the heart-wood of which was quite fresh, and he said that the whole fence, about thirty-five chains long, was in the same condition. I show a portion of a cedar post taken a fortnight since from a stockyard on the old Waikouaiti Road, near Flagstaff, erected twenty-three years ago. The heart-wood is as sound as when the tree was felled, and the sap is only decayed for a short distance at the ground level. All the posts in the enclosure are in the same condition; they average from ten to twelve inches in diameter, with about one and a half inches of sap-wood. Mr. Peter Thompson, Queen-street, has a sapling cedar four and a half inches diameter for a flagstaff; it has been eight years
in the ground and is still perfectly fresh. Any other pine sapling, under the same circumstances, would be quite rotten in twelve months.
This section of the Coniferæ comprises about 60 species that are scattered over all parts of the world except Europe and North America. Of this number Otago possesses five, four of which are timber trees, and one an Alpine shrub.
No. 2. Miro—Podocarpus ferruginea. Miro is common in all the forests of Otago that lie under an altitude of 1,000 feet, and occasionally in those above that level. It is generally found associated in the same bush with red pine. The tree grows to a height of from fifty to ninety feet, with a clear straight trunk twenty to fifty feet long, and eighteen inches to three feet in diameter, but the tallest trees are not always the thickest, particularly in dense forests. This timber, which is far inferior to black pine in point of durability, is so like it in many respects that they are frequently confounded. I shall therefore describe their leading points of resemblance and difference. Generally black pine is a heavier timber than miro, but this is scarcely a distinction, for a full grown tree on the one hand may be compared with a young one on the other. The scales on black pine bark are thicker, and the furrows deeper than those of miro. The foliage of black pine is flat like the English yew, and of a light green colour, shiny on the lower side. That of miro is roundish and erect, and of a deep dull green, which turns to rusty red on drying. Black pine has a cluster of from four to seven small dark berries, scarcely noticeable among the foliage; while miro has a conspicuous single berry like the dog rose or sweet briar, almost identical therewith in size and shape, but of a redder colour. This berry has a strong odour of turpentine. Although black pine is sometimes marked in a decided manner, it has always a ground colour of clear yellowish-brown, but miro is blotched throughout, and the ground colour, which is light dirty red, varies every few inches. A horizontal section of the latter shows that the heart contains a considerable portion of dark-colored wood, which runs in star-like points towards the circumference, hence the blotched appearance of the timber. The figure can be varied at pleasure by simply changing the direction in which boards are cut. The annual rings and other markings in black pine are generally concentric. Consequently a great variety of figures cannot be obtained. Generally the wood of black pine is lighter and brighter in colour and easier worked than miro. The timber can also be distinguished when green by the taste and smell. These are strong and pungent in both cases, but there is a peculiarity in each easily recognised when once known. These particulars may seem too much detailed, but when we consider the disappointment and loss that have
frequently resulted from the substitution of one timber for the other, their points of difference can scarcely be too well known. Miro is a fast growing tree, and the annual rings are tolerably distinct. A stump twenty-two inches diameter on Pine Hill gave the age at 160 years. There is frequently more sap than heart in the timber, and the distinction between the two qualities is not well marked, consequently it is not suitable for exposed work, even if durable. A log from a young miro on Pine Hill, twenty feet long eighteen inches diameter at the base, and twelve inches at the top, had an average of seven and a half inches of heart. At Catlin River the smaller trees are almost three-fourths sap, but the full grown ones have only from two to four inches.
Aged miro has usually a crack in the heart, but it is small and straight, so cannot be considered a serious defect. The timber is the strongest of the New Zealand pines, consequently is well adapted for beams in a dry well ventilated situation. As it does not shrink or warp to any inordinate extent, it is suited for ordinary house building, but being more difficult to work than red pine, the latter is preferred by carpenters. Miro is not durable in any exposed situation, except under water. It will perish in a few years if in contact with damp, and is very subject to the ravages of the large grub, which perforates the timber to the heart. I have seen bridge piles at Wallacetown a perfect mass of rottenness through the latter cause, but the portion below water level was sound to the bark. Mr. Kirk reports the same state of things at the railway protective works in Bluff Harbour. The outside piles exposed to the influence of sea water were perfectly sound, but those in the embankment a few feet further in were quite rotten. He attributes the preservation of the former to the action of salt water, but the example at Wallacetown would indicate the same result in any wet situation. Twelve-inch miro piles in the George-street jetty, Port Chalmers, erected in 1860, are eaten away to about four inches by the Limnoria, but are otherwise in good preservation.
No. 3. Totara—Podocarpus totara. Totara, which is the best known and most easily recognized of our timber trees, is common in all the forests of the province up to an altitude of 1,000 feet. It is generally found mixed with black pine, but occasionally, as on Inch Clutha, forms an entire bush of itself. The supply of totara in the vicinity of Dunedin and Invercargill is getting scarce, but there is still a considerable quantity about the Clutha mouth, and the west coast supplies are still untouched.
The timber seems to grow well on any ordinary soil, but prefers rich alluvial flats. Ordinary sized trees attain to a height of from sixty to eighty feet, with a clear straight trunk from twenty to fifty feet long and three to five feet in diameter; occasional trees are found up to seven and
eight feet, but these dimensions, though common in the North Island, are rare in Otago. Forty stumps recently examined on Inch Clutha range from three to four feet, with a few up to five; the thick trees are generally much shorter than those of medium diameter. The bark is of a light grey colour, thick, furrowed, and stringy; it was formerly used by the natives and old settlers in covering the walls and roofs of whares and huts.
Totara is a comparatively slow grower—a tree three feet six inches in diameter is estimated to be 550 years of age. Mr. Hay, of Auckland, found young trees to grow about twelve feet six inches in ten years; when fully established, they grow two feet in a season. Totara is one of the easiest reared of our native trees. The tree has very little sap-wood, but is subject to decay in the heart, like cedar; it commences on Inch Clutha when three feet six inches in diameter, and increases with the growth beyond that. The timber is of a reddish colour, like pencil cedar, but varies considerably, according to its age and the soil in which it is grown; it is straight in the grain, easily wrought, and not given to warping, but brittle, and apt to shrink if not well seasoned. Totara is suited for fencing, railway sleepers, and piles, together with architectural and engineering purposes generally, except beams, for which, on account of weakness, it is not so well adapted as many of the other timbers.
The durability of totara under the most trying circumstances is well established and well known. I show a piece of a log found at an elevation of about 1,300 feet, on the Mount Pisa Ranges, where no tree has stood for centuries; it is as sound as when the Moa found shelter beneath its branches. I also show a survey peg from the division between Sections 1 and 2, Block X., Waihola survey district, put in by Mr. Kettle in 1848, and taken out in 1874, which is still quite fresh. All the oldest house blocks and fencing posts throughout the province that were of heart of totara are in the same condition, so further proof of its durability is unnecessary. I should, however, remark that piles or posts made of saplings with little heart-wood will not last long in the ground. Mr. Kirk, of Wellington, observed this in bridge piles, and I noticed it myself in fencing posts; the original telegraph poles on the Dunstan line also show the same thing. In black pine and old totara, where the heart-wood is solid, decay stops whenever the heart is reached; but such is not the case with totara saplings—the disease is communicated by the sap to the heart, and both perish together. Totara in the North Island stands the marine worm better than any other native timber, but it has not shown any great resisting powers here. The piles in the Bluff wharf were perforated to the heart, and very much riddled in a few years.
The totara of the west coast, which is generally smaller than that of the east, is considered by Dr. Hector and Mr. Buchanan as a different tree, and Mr.
A. C. Purdie informs me that there is a variety found at Catlin River not described by any of the botanists; it is of a large size, with a smooth bark, and yields very soft ornamental wood suitable for inside work.
No. 4. Black Pine—Podocarpus spicata. Like its two congeners already described, this tree frequents all the low-lying forests of Otago, but it is more plentiful on the east than the west coast; the best supplies now available are at Catlin River and Southland.
The tree grows to a height of from fifty to ninety feet, with a trunk twenty to thirty-five feet long and three to five feet in diameter; the latter, however, is an extreme size—four feet may be taken as the limit in ordinary cases. At Catlin River the sound trunks seldom exceed twenty-four feet in length and three feet in diameter. The appearance and properties of black pine have already been discussed in comparing it with miro, so it is only necessary to refer to the peculiarities of the former. The timber reaches maturity in about 400 years, and has about two inches of sap-wood when ripe. The tree is subject to a small heart-crack, which developes into decay when allowed to proceed, but the evil is not so great as in totara or cedar. Next to miro, this is the strongest and heaviest of the New Zealand pinewoods, and it is, without exception, the least given to warping and shrinking, and in all probability the most durable. It is suitable for all the purposes for which totara is adapted, as well as others where greater strength and solidity are required.
Miro, having been frequently substituted for black pine in exposed situations throughout the province, has brought the latter into disrepute, and the resemblance is so great that professional men were afraid to run the risk of making a mistake. The consequence is that its good qualities are to this day little known and little appreciated. I show a portion of a fencing post cut and erected by Mr. Horman, at Makarewa, in June 1861, and taken up this month; the part most subjected to decay, that at the ground line, is perfectly sound. I have seen a black pine log, that had lain in the Waikiwi forest from time immemorial, as fresh as when it fell; it had been there so long that a fuchsia nine inches in diameter was growing across it. I show a few inches off the end of a log that lay for twelve years in a paddock at Seaward Bush; the sap is all worm-eaten, but the heart, even to the end, is quite solid. Mr. M'Arthur sent me, in 1872, a piece of a post that had been ten years in the ground at Waikiwi; the edges at the surface of the ground were almost as sharp as when split, and there were many more in that locality in the same condition. I have already referred to the sapling telegraph posts. Those of birch and totara were rotten through in twelve months, but the heart of the black pine ones, although very small, stood for five or six years; indeed, it was not decayed when the
posts were removed to be replaced by iron ones. Black pine, however, does not stand the ravages of the marine worm as well as totara. The retaining wall at Rattray-street, erected in 1867 and recently removed, had been attacked, though so far from the open ocean.
Black pine and totara contain a resinous matter that resists the adhesion of paint when the timber is green. This property, which builders consider a serious objection, is, in reality, a great recommendation, for it promotes seasoning.
I have in this paper adhered to the popular name of black pine for this timber, but the native name matai, which is always used in the North, is becoming common in Otago also. I trust it will soon completely supersede the former.
No. 5. White Pine—Podocarpus dacrydioides. Although more gregarious than the other pines, this tree is found associated with its congeners in all the sub-alpine forests of Otago. It grows freest in low swampy ground, but the best timber is produced on moderately dry soil.
White pine grows to a height of from 120 to 150 feet, with a trunk up to seventy feet long and five feet in diameter at the base. One log lately examined on the Orepuki railway measured fifty-five feet in length, five feet in diameter at the butt, with three feet of solid heart-wood, and three feet in diameter at the top, with one foot of heart. At Catlin river the average dimensions of trunk is forty feet long, and from two feet six inches to four feet in diameter, the largest trees having about two feet of heart. As a rule there is seldom more than two or three inches of heart-wood in trees under three feet in diameter, and the difference between heart and sap-wood is in all cases very indistinct. The shape of the tree, colour of bark, and appearance generally are somewhat like black pine. Still there is little difficulty in distinguishing them when growing, and the difference in the wood is greater than between any other two of the pines. In consequence of the evenness of the colour, and the closeness of the annual rings, it is difficult to estimate the age of white pine. Ordinary-sized trees probably reach maturity in from 370 to 600 years. Young trees are easily transplanted and cultivated. They shoot about eighteen inches per annum. Old trees have a slight heart crack, but it is too small to be considered a defect.
The sap-wood of white pine is of a dull white colour, and the heart-wood of a pale yellow or straw colour. It is the weakest and lightest of the native building timbers tested at the New Zealand Exhibition. Still its strength is about ten per cent. greater than that of European red deal and English elm, and its weight is much the same as the former. The wood is straight grained, soft, flexible, and not given to warping or excessive shrink-
age, consequently it is well adapted for flooring, weather-boards, and the other ordinary joiners' work for which white deal is usually employed. Tradesmen will not allow a comparison to be made between the native and imported articles. They say the latter is infinitely superior, and that white pine is too soft and spongy for anything like good work. I do not think there are sufficient grounds for such a conclusion, which is in all probability arrived at by comparing seasoned foreign timber, the only kind that can be got here, with green colonial timber, the only kind that is used. The white pine timber of Otago is in my opinion equal, if not superior, to Baltic white deal for all the purposes for which the latter is adapted, and its supposed inferiority is due entirely to defective seasoning.
White pine is not durable in any situation where exposed to damp or frequent changes from wet to dry. It will not last two years in fencing posts or house blocks; even rails and beams of bridges that are clear of the ground decay in three or four years, the least moisture retained in a joint or mortice brings rapid destruction. The heart-wood is durable, but there is so little of it, and there is so much danger of using sap instead, that no advantage can be taken of its good qualities. I show a piece of white pine heart-wood taken from a large log that has been felled many years at Deborah Bay. It is still in good preservation. Some of the piles in the George-street jetty, Port Chalmers, are of white pine. They are eaten away to a third of their original diameter by the Limnoria, but the timber has not suffered much from natural decay. Although soft and weak, the fibre is still intact. Mr Kirk says that white pine in Wellington and other places in the North is subject to the attack of a minute double-winged insect, but so far as I can ascertain it has no such enemy in Dunedin.
This timber is known in all the provinces except Otago by the native name of “kahikatea.” I think we should adopt it also, not only on account of being more euphonious, but for the reason that so many timbers in other parts of the world are called white pine.
Otago possesses three members of this genus, which is a small one confined to the Southern Pacific; they consist of a large and a small timber tree, and a mountain shrub. According to Gordon, there are only two large timber trees of this family out of New Zealand; one frequents the mountains of Sumatra, and the other is the famous Huon pine of Tasmania.
No. 6. Red Pine—Dacrydium cupressimum. This is the most plentiful of the pines, and the most used timber tree in Otago; it is found in all the low-lying forests round the coast from Waikouaiti to Martin Bay. It grows to a height of one hundred and fifty feet, with a clear straight trunk up to eighty
feet high and five feet diameter. A log recently taken at random on the Ore-puki Railway measured fifty-five feet to the lowest branch; it was four feet three inches diameter at the butt, three feet six inches diameter at a height of forty feet from the ground, and four feet three inches diameter at the top. At Catlin River mature trees measure about forty feet long by two feet six inches to four feet diameter; those from sixty to eighty feet, of which there are a large number, do not generally exceed eighteen inches in diameter. The logs that came from Pine Hill are usually about twenty feet long, and from eighteen inches to two feet six inches thick. Red pine trunks have little taper, they are almost cylindrical from the ground to the lowest branches; the base is usually furnished with buttresses that run eight or ten feet up, consequently the trunk is not round for that distance. The bark is rough and scaly, and of a dark brown colour; it comes off in large flakes every year, which in course of time forms a huge mound of a peaty nature round the tree. This mound ignites readily when dry, so is possibly the cause of many bush fires. Young red pine is noted for its beautiful green foliage, which droops in feathery tassels like larch or willow; but, as the tree grows old, the foliage becomes stiff and erect like the other native pines. An ordinary-sized tree reaches maturity in about 500 years, and young plants make wood at the rate of about a foot per annum. Seedlings are very tender and difficult to rear when removed from their native forests, and large trees are easily killed by stripping a ring of bark near the roots. The bark of the red-pine is good for tanning, and the juice of the young branches was made into beer by Captain Cook; but I have not heard of its being utilized in the same way by any other white man.
This timber has a very large proportion of sap-wood which is not well defined. There is little or no heart in trees under eighteen inches in diameter, a size that is frequently cut into market stuff. The following notes give the quantity of sap-wood in a number of large trees at Orepuki.
|No. 1.—4′6″||diameter,||8 feet from ground had||10 inches of sap.|
|2.—4′ 0″ "||10 " " "||4 ½ "|
|3.—3′ 7″ "||40 " " "||4 ½ "|
|4.—3′ 6″ "||20 " " "||6 "|
|5.—3′ 0″ "||40 " " "||4 "|
|6.—2′ 8″ "||9 " " "||4 "|
The trunk of No. 1 was forty-six feet long. Three feet logs from Pine Hill, Water-of-Leith, and Blanket Bay, at Messrs. Asher and Co.'s yard, show from three to four inches of sap. One tree nineteen inches in diameter had only nine inches of heart. At Catlin River, where this tree seems to grow remarkably well, the proportion of sap-wood is smaller than near Dunedin;
three-feet trees have only about three inches of sap, which is tolerably well defined, and the heart shows at an earlier stage of growth.
Red pine frequently grows with a twist in the trunk, and more sap-wood on the one side than on the other, consequently the timber is cross-grained and irregular in strength and consistency; mature trees are also subject to heart shakes and cracks. This defect is occasionally a want of cohesion between the annual rings in the inner core of three or four inches, but oftener it consists of a straight crack from three to nine inches long, filled with gum or resin. This opening is of little moment in straight logs, but it renders the whole centre unserviceable for sawing up when the timber is twisted. The state of the bark is a good indication of the ripeness of red pine; trees in vigorous growth have large dark-coloured scales that adhere closely at certain seasons, and those of mature age have short light-coloured scales, easily removed at any season of the year.
The colour of red pine timber is very variable; it ranges from light yellow to deep red, and there is generally a handsome figure in boards. It is the third in order of strength of our Otago pines, but is more irregular in grain than black pine or miro, consequently is less trustworthy in beams. Red pine is much used in house framing and general carpenter-work, for which it is well adapted; but on account of being harder and more brittle, and more given to shrink irregularly, it is not equal to white pine for flooring, weather-boards, and internal joiner-work. Red pine is much prized as a furniture wood, some of its figures being remarkably beautiful. When well fitted and seasoned, it stands as well as most foreign timbers that are used for this purpose.
The heart of red pine is durable; any quantity can be got in the forest quite fresh after lying for ages, but in consequence of its small size, and the danger of using sap instead, we must treat the whole tree as perishable. The ordinary red pine of the market is very liable to decay in any exposed situation. A survey peg which I put into the ground at Tokomairiro in August, 1869, was quite rotten in April, 1872. Beams eighteen inches by fifteen, put into the Southland railway bridges in 1863, were a mass of putrefaction in 1868; nothing but a crust about half an inch thick remained solid, and this was in the most favourable situation possible, for there was no planking on the bridges, and no mortice holes or checks on the upper side of the beams. Although not nearly so bad, a similar state of things was observed in the old Bell Tower, Dunedin, erected in 1864, and pulled down in 1872; some of the timbers were fresh in the middle, but all were rotten at the joints.
Rimu, the native name of this tree, is now tolerably well known in Otago. So if professional men and timber merchants would only encourage
its use, it would soon supersede the vague conventional term of "red pine."
No. 7. Yellow Pine—Dacrydium colensoi. This tree is only found in small quantities on Pine Hill, Mount Cargill, and other east coast ranges, but is tolerably plentiful on the west coast.
It is a small tree seldom exceeding forty feet in height, with a trunk twenty feet long and two feet six inches in diameter. It is remarkable in having frequently two distinct kinds of foliage on the same tree, that on the lower branches being flat and pendulous, and on the top ones round, rigid, and erect. The bark is like that of young red pine, but the timber is quite different. It is of a clear yellowish colour, with little sap, straight in the grain, dense in texture, and solid throughout; altogether one of the finest looking of our Otago pinewoods.
The tree contains a large quantity of resinous matter, which cannot be expelled by artificial drying with hot air. It burns freely, emitting a dark bituminous smoke, and a strong smell exactly like the knots of larch. Some Scandinavians near Mount Cargill attempted to extract pitch from the yellow pine, but I do not know if they succeeded. It is from this resinous property in the timber that the settlers' name of tar-wood is derived.
Yellow pine is employed in the North Island for ordinary building purposes, but on account of being scarce and of a small size it is little known in Otago as a timber tree. The durability of the wood is undoubted. Three-inch saplings used as piles in a Maori pah at Waimate are still as fresh as when driven 80 years ago. This wood seems admirably adapted for turning and other work of a similar kind where evenness of grain and density are desiderata.
No. 8. Celery Pine—Phyllocladus trichomanoides. The genus to which the celery pine belongs only embraces three timber trees, one each in Borneo, Tasmania, and New Zealand. Our specimen is common in the northern provinces, and at high altitudes on the west coast, but rare on the east coast of Otago. There are, however, a few trees to be met with in the vicinity of Dunedin and from the Clutha southwards.
The tree grows to a height of from fifty to sixty feet, with a straight clear trunk two to three feet in diameter for two-thirds of the distance. It is a remarkably handsome plant of the true pine shape. The leaves are quite different from the other conifers of Otago. Instead of a mere cluster of thin foliage, the tree is covered with large well-defined leaves like the common celery plant, from which the name is derived, but of a brownish colour. The bark is smooth and solid, dark on the surface, and of a uniform brown colour inside. It is known to be good for tanning, and the natives use it as a dye. The wood is soft, straight grained, tough and flexible, with
little sap, but subject to heart decay. The colour is somewhat like miro without the irregular blotches.
This timber has not to my knowledge been used in Otago. It is suited to any and all of the purposes to which the other pines are applied. According to Mr. Kirk its durability is undoubted. He gives it as high, if not a higher place than totara.
The next most important class of softwoods is the birches, or more correctly beeches. They are, botanically, true beeches, consequently would be classed with the hardwoods in England, but as the majority of the New Zealand trees yield very soft timber, I have kept them with the softwoods. The birches are the most plentiful of the Otago timber trees, and at the same time the least known, consequently they require careful consideration at our hands. They belong to the genus Fagus, which has one representative in Great Britain, the common beech, and a few more in other temperate countries. This genus in turn belongs to the same botanical order as chestnut, oak, hazel, and hornbeam.
As already stated the birches occupy almost exclusively the forests of the interior, and are abundant on the west coast, but rare on the east. There are no large trees in the vicinity of Dunedin, but they occur with more or less frequency in all the seaboard forests south of the Taieri.
As will be seen by the tables, the utmost confusion prevails among the common names of the birches. There are scarcely two districts, a few miles apart, in which the same name is applied to the same tree, and a similar result may be obtained by consulting two bushmen in the same bush. With the view of obviating this difficulty Mr. Kirk suggests “the adoption of new names based on the obvious” characteristics of their foliage. For Fagus fusca, tooth-leaved beech; for Fagus solandri, entire-leaved beech; and for Fagus menziesii, round-leaved beech.” On first sight I thought this a capital arrangement, and did my best to establish it, but a fuller acquaintance with the trees convinced me that it was unsuitable. The difference between the leaves in many localities is too small to be noticeable by anyone but a scientific expert, and under any circumstance the peculiarity that is relied on for identification is not always the leading feature in the leaf. For instance, the teeth in some of the leaves of F. fusca, from Lake Wakatipu, are so small that they are only seen on close inspection. Indeed they might easily be confounded with the leaves of F. solandri, from the Five Rivers Plain, which are nearly as large. The latter are entire, but have a curious horizontal corrugation in the margin that gives them the appearance of being toothed. The leaves of F. menziesii, although round, are not always so conspicuously round as some leaves of F. solandri, and the nicks
in the former are in many cases so like the teeth of F. fusca that they cannot be distinguished by popular eyes. From this it will be seen that the names of the birches are still in an unsatisfactory state. Failing good native names, of which there are none that I know of, I would suggest the retention of the most common Otago names, which seem to be based on the appearance of the wood and the tree itself:—For Fagus fusca, red birch; for Fagus solandri, black-heart birch: and for Fagus menziesii, silver birch. The red birch timber is invariably red; black-heart birch is frequently white, but it has always black streaks, and the heart is generally all black. Silver birch has, when young, a silvery bark like the English birch, and the wood, although sometimes of a reddish color, has generally a silvery tinge, and always a silvery grain. It might be advisable to change to the correct botanical name of beech, as suggested by Mr. Kirk, but the other is so well established throughout the colony that there would be some difficulty in doing so, and as some of the trees are very like the old country birches, the name is tolerably appropriate.
No. 9. Silver Birch—Fagus menziesii. This species is the most common on the east coast. It exists with the other two in the inland forests, and, according to Dr. Haast, it is the only one between Wanaka and the west coast.
It is a tall slender tree, frequently eighty feet long in the trunk, but seldom exceeding three feet diameter at the base; the average diameter at Catlin River, Tuapeka Mouth, and the Blue Mountains, is about two feet. The stem is straight and cylindrical, and free from branches, and the top is sound and compact, so the whole plant has a remarkably handsome appearance. Mr. Buchanan says that F. menziesii sometimes attains a diameter of twelve feet; but this and other remarks on the timber leads me to believe that he refers to F. fusca. The bark in young and in middle-aged trees is very thin, seldom exceeding a quarter of an inch; the colour is silver-grey, with numerous horizontal markings like cherry, hazel, and the English birch; the outer layer also peels off as in those trees. When the silver birch reaches maturity, or is allowed to stand beyond that stage the bark gets darker and rougher, and the horizontal markings disappear: but its ultimate thickness seldom exceeds half an inch, and it is never cut up into deep close vertical furrows like the bark of red birch. The leaf is from a quarter to five-eighths of an inch in length, rather thick and stiff, but without external ribs or veins; the margin is cut into by a small double notch with straight edges. The tree reaches maturity in from 150 to 300 years, and grows freely under cultivation; young plants shoot about a foot per annum. The silver birch is so tenacious of life that the removal of a ring of bark does not kill large trees.
The growing timber is remarkably free from heart-shakes and other defects of a similar kind. Trees that have stood long after reaching maturity occasionally show a small core of decayed wood in the centre; but it is so small, and occurs so seldom, that it can scarcely be called a defect.
It is difficult to determine the proportion of sap-wood in silver birch; young trees are of a uniform colour and texture from the pith to the bark, and the wood gets gradually darker and harder towards the centre in old trees, so that a sharp line of distinction between heart and sap cannot be struck; perhaps three and a half inches of sap-wood on a two feet tree will be a fair average. The colour of young timber is a pinkish-white, with occasional reddish streaks and knot-like spots. The heart in old trees is deep pink or light red, verging towards the outside into the same tints as the young wood; both kinds have a peculiar silvery lustre—this is easily recognized when once known. The wood of silver birch is even grained, soft, flexible, and tough, and not given to excessive shrinkage or warping;— perhaps there is no other timber in New Zealand so suitable for internal joiner-work and mouldings; it is also admirably adapted for tubs and other light coopers' work, and should answer for making patterns. Altogether, this is one of the most useful soft woods in Otago.
Silver birch timber is not durable in any situation where exposed to damp, or alternations from wet to dry; in this respect it is about on a par with white pine. I show a section of a tree rotten quite through after lying felled for four years in the West Taieri Bush, and a similar result was obtained under the same conditions in twelve months on Inch Clutha; further, a tree that had been cut, but left leaning against another, was completely worm-eaten in that time. I have had similar evidence from the Blue Mountains, and we have negative proof in the absence of old trunks in the forest; so silver birch must be set down as a perishable timber.
No. 10. Red Birch—Fagus fusca. With the single exception of kauri, this is the largest member of the vegetable kingdom in New Zealand. It is the chief occupant of the interior and west coast forests of Otago, and occasionally descends in small patches and individual trees to sea level on the east coast. It affects light soil on shingly plains or the mountain side, and grows in open bush with little undergrowth. The other two kinds of birches occur in the same forest, which seldom contains any other timber in large quantities. Mr. M'Arthur estimates that 80 per cent. of the trees in the Burrwood Forest are red birch.
The tree grows to a height of from eighty to one hundred feet, with a trunk, free of large branches, fifty to eighty feet long, and three to eight feet diameter; occasionally, however, it attains the enormous diameter of
ten to twelve feet at the base. Mr. Surveyor Innes states that the Wakatipu red birches range from three to four feet six inches, but he has seen them at Te Anau from seven to nine; and six to eight feet trees are frequently met with on the Five Rivers Plain. The Burrwood Forest timber is about the same size as that at Lake Wakatipu, but the few trees on Inch Clutha are much smaller; the trunks average from twenty to thirty feet long, and two to three feet in diameter. Two red birch logs from the Blue Mountains, recently measured at the Inch Clutha Bridge, were respectively thirty-five feet long by two feet four inches in diameter, and thirty-eight feet long by two feet in diameter; they were both quite cylindrical, straight, and sound throughout. The trees in a small patch of bush at West Taieri average about four feet diameter.
The bark of young red birch is somewhat like that of mature silver birch, but on old trees it is from half an inch to an inch and a quarter thick, of a dark reddish-brown colour, very rough on the surface, and cut up into deep vertical furrows as close as they can be. The leaf is of an oval shape, from three-eighths of an inch to an inch and a half long, very thin and flexible but provided with projecting ribs or veins. The edge is serrated at regular intervals with generally a curved indentation, but they vary very much. Dr. Hooker says that Mr. Travers sent him leaves of F. fusca that were quite entire, and I have seen specimens from Lake Wakatipu in which the teeth were only noticeable on close inspection. The smaller leaves of red birch can scarcely be distinguished from the large ones of silver birch, but the whole foliage of the former is more open, spreading, and pendulous than that of the latter. Although there is sometimes very little difference in the leaves, and even in the appearance of the wood of F. fusca and F. menziesii, there is always a great difference in the quality of the wood. Mr. Kirk a short time since kindly identified a number of specimens for me; I could see very little difference in some that he had referred to as separate species, but the correctness of his classification was afterwards verified in a very remarkable manner: Two trees were found in the West Taieri Bush that had been felled on the same day four years ago—one was rotten and the other quite sound. Their foliage, which still remains intact, is to the casual observer the same, but, on comparing them with Mr. Kirk's specimens, the rotten tree is found to be F. menziesii, and the sound one F. fusca, a result entirely in keeping with the respective characters of the timbers.
Red birch, like its congeners already described, grows freely under cultivation, and reproduces itself rapidly in its native forest. A tree four feet diameter is estimated to be from 300 to 350 years of age. The timber is free from twists or bends, but is subject to heart decay, like cedar and totara. All the larger trees that have passed maturity are more or less affected in this way.
This timber is generally of a uniformly reddish colour throughout, with little or no figuring or markings. It is straight grained and splits freely, but not nearly so smooth as silver birch. The sap-wood is of a dirty yellow colour, and well defined; it ranges in thickness from two to three inches in four feet trees, but those grown on swampy land have much more. Red birch is the strongest of native softwoods tested at the New Zealand Exhibition: according to these tests it is nearly 60 per cent. stronger than English oak. It has also a great advantage over many of the other Otago timbers that stand heavy strains in being so uniformly straight grained and fibrous as to give good warning before breaking. Like its near relation English oak, this timber shrinks very much in seasoning, as will be seen by Table III. I found boards to contract as much as one-tenth of their width. This shows the absolute necessity of having the timber thoroughly well seasoned, but it is otherwise no serious defect, for notwithstanding the excessive shrinkage there was little warping in the boards.
On account of its superior strength, red birch is better adapted for beams and general framing than any other Otago softwood, and it is equal to all except white pine and silver birch for general joiner-work. In reporting to the University Council eighteen months ago on the subject, I said that red birch was “not suitable for internal furnishing of houses.” This opinion was based on the idea that it became very hard with age. I now find that such is not the case. The hard samples turned out to be kamai, and a number of old red birch specimens since obtained are all tolerably soft and flexible. In addition to the uses just mentioned, this timber is suitable for piles, sleepers, and other engineering purposes. In short, it is more capable of universal adaptation than any other Otago timber.
Our experience in Otago of the durability of red birch is comparatively limited. It has hitherto been little used, except as fencing in Upper Southland, and for building purposes in the Wakatipu district, but its lasting qualities have been fully tested and universally acknowledged in the northern provinces. The well-known Waiau-ua bridge, erected by Mr. Blackett in Nelson thirteen years ago, entirely of this timber, is still perfectly sound, and fencing posts in Wellington are in the same condition after fifteen years use. Mr. Cameron, of the Dome Station in Southland, informs me that he has seen red birch posts quite sound after standing for fourteen years in the ground; and twenty miles of fencing erected by him on the Five Rivers Station, in 1867–8, is still in good preservation. I also show the following examples as proofs of the durability of red birch.
Piece of split timber that has lain in the West Taieri Bush for ten years.
Portion of fencing post, eight years in the ground, at Tuapeka Mouth.
Section of tree that has been felled in the West Taieri Bush for four years,
All of which are still quite sound and fresh.
No. 11. Black Heart Birch—Fagus solandri and F. cliffortioides. Dr. Hooker says that although very similar these plants are distinct species, but the only difference he makes is in the shape of the leaf. Mr Kirk, in a note to me, says, “I do not know Fagus cliffortioides apart from F. solandri.” We may therefore assume that they are identical, at least so far as their economic value is concerned.
Black heart birch is found in the same forest as the other two, but is particularly plentiful on the west coast. There is also a considerable quantity at the Blue Mountains in the Pomahaka district. In size this tree occupies an intermediate place between the red and silver birches. It grows to a height of from seventy to one hundred feet, with a straight, clear trunk fifty to eighty feet long, and two feet six inches to five feet diameter. Two trees lately measured at Tuapeka Mouth were respectively seventy-two and seventy-four feet from the butt to the lowest branches. Two logs from the Blue Mountains, now lying near Stirling, measure respectively forty-seven feet long by two feet two inches in diameter, and thirty-four feet long by three feet nine inches in diameter. They are both quite straight and cylindrical, and without crack or other flaw from end to end. The trunks from which these logs were cut measured fifty or sixty feet, but there are many in the same bush eighty feet high to the lowest branch.
Judging from the annual rings, this is the fastest growing tree in Otago. A trunk three feet in diameter is estimated to be 150 years old. In some cases there are only three or four rings in an inch, which shows it to be a growth almost equal to that of oak, elm, or beech, the fastest growing English trees. Black heart birch grows well under cultivation. There are a number of healthy young plants in private gardens in Dunedin. So far as I can ascertain, this tree is not subject to heart-shake or decay.
Black heart birch has, when young, a thin smooth bark of a light grey colour, like kamai, and quite free of the horizontal markings that occur in silver birch. It gets darker, rougher, and thicker with age like the latter, but never attains to the thickness or roughness of the red birch bark. The leaf of this tree is easily distinguished. It is of an oval or pear shape from one-quarter to seven-eighths of an inch in length, and entire on the edge. The size of the leaf does not change with the growth of the tree, but the same forest produces all sizes. The largest and smallest specimens I have seen are both from Five Rivers.
The wood of the black heart birch is quite different from that of its two congeners. It is of a grey or yellowish ground colour, with dark streaks,
and heart coarse in the grain, stringy and very tough. Some samples resemble very much English ehm, and others English ash. The heart-wood generally runs in star-like points towards the circumference, and there is frequently a well-defined and handsome figure in the boards. Full-grown trees have from one and a half to three and a half inches of sap all round.
The strength, of this timber has never been tested. It will belie its appearance very much, if not found to be one of the strongest in New Zealand. It is remarkably stringy and tough. Black heart birch is rather hard and stiff for joiner work, but is well adapted for framing and similar purposes where strength is required. Some of the figured samples would make handsome furniture.
The lasting properties of this timber have never been thoroughly tested. It has been scarcely tried at all in Otago, and the experience in other provinces is very limited. Dr. Hector instances a fence in the province of Wellington that was in good preservation, after being erected 20 years, which is the only record I know of its durability.*
This completes a description of the known Otago trees that yield building materials in the proper sense of the term. There are many smaller trees and shrubs capable of producing useful and ornamental woods, but their consideration would extend my paper beyond reasonable limits, so I must leave them out.
In recapitulating the leading points of my subject, it will be necessary to revert shortly to the general properties of timber referred to at the outset, and consider the peculiarities of our native products in the order then given.
Table No. II. gives the ordinary dimensions, amount of sap-wood, and approximate age of the principal Otago trees. It shows that class for class they are equal in size to those in other countries. The kowhai, rata, manuka, kamai, and black heart birch are on an average as large, if not larger, than oak, ash, elm, and beech, the English timbers for which they are substitutes, and with the exception of yellow pine and cedar, all our pines are considerably larger and more productive than their European and American prototypes. In like manner we show that the growth is more rapid in New Zealand than most other countries that produce ordinary building timber; consequently the reproduction of native trees, if it can be successfully accomplished is more profitable than the introduction of foreign ones.
The proper season for felling timber in New Zealand is not yet fully determined. The late Mr. Balfour said “probably it may be found that
[Footnote] * N.Z. Parl. Papers. 1872. G. 16, p. 7.
midsummer is the best;” but Mr. Kirk gives a decided opinion in favour of winter felling. He fixes April to August as the most suitable time in all the forests south of Banks Peninsula. I have no doubt Mr. Kirk is correct in considering this the season in which the trees are freest of sap, for the distinctness of the annual rings in most Otago timbers shows a decided period of repose in the growth. Still it is quite possible that a similar condition exists during the two summer months, December and January, and I would have little hesitation in including them in the felling season. I have instituted a series of experiments with the view of assisting in determining the season when the trees contain the minimum quantity of sap; it consists in observing the strain required to tear off strips of bark in each month of the year. The experiments will not be complete for six months, so I cannot give the results in this paper, but will do so on a future occasion if it is found to be worth publishing. The only well authenticated proof I have obtained of the superiority of winter felling in New Zealand is given in Mr. Horman's fence at Makerewa, already referred to. All the black pine posts erected in the winter of 1861 are still in good preservation, while those felled and erected a few months subsequently were more or less decayed some years ago. Assuming that ripe trees only are felled, and that none of the sap-wood is used, the time for felling timber is, within certain limits, of secondary importance to its subsequent seasoning and desiccation. The simplest way of obtaining a fair amount of seasoning in New Zealand would be to bark the trees in spring, cut them in the following winter, then slab the logs and let them lie in a running stream for a few weeks, or, what is better, let the sawn scantlings be submerged. There is little trouble in doing this when the timber is cut up in the bush as at Catlin River and Southland. After having the sap washed out in this way, the timber should be thoroughly dried under cover in open shed.
Table III., which gives the results of some experiments I made, shows the absolute necessity of seasoning;—it gives the weight of water in a cubic foot of green timber, and the transverse shrinkage in boards twelve inches square and half an inch thick. The results may be accepted as a fair indication of what will be obtained in practice, for the samples were picked heart-wood, cut radially to prevent warping; but they were taken from green logs and subjected to severe drying at a fire, and in the hot air of the Turkish baths. It will be seen that the greatest contraction is in ribbon-wood, next the red birches, and after that the hardwoods generally; the least is in black and white pine. It is worth noticing that English oak and New Zealand red birch, members of the same botanical family, are both given to excessive shrinkage. I should add that the results in Table III. are not higher than would be obtained from European and American timbers of the same class.
As the twelve-inch samples were too short to test the contraction endwise, I did so by fixing long three by half-inch green battens in the sun on a wall. After being exposed for four weeks in exceptionally hot, dry weather they were found to have shrunk as follows:—
|White pine and totara||0.30 of an inch in20 feet.|
|Red pine||0.23 "||"|
Of course the kauri was somewhat drier than the others to commence with. There is no record of similar experiments having been made with the timber of other countries, so a comparison cannot be instituted. I believe, however, that our timbers do not shrink more endwise than foreign ones of the same class. The importance of seasoning timber has hitherto been very much overlooked in New Zealand. Instead of using well dried heart-wood from mature trees that are felled at the proper season of the year, we put into our houses wet sap-wood from young trees that are felled when most convenient, probably in their juiciest state; and, to increase the evil, the timber is painted at once, so that all the juices are retained to ferment, and thus breed corruption. It frequently happens that the timber for some of our best buildings is standing in the forest after the work has been commenced. Colonial timbers have fallen into disrepute solely on account of being used in a green state alongside foreign ones that are well seasoned. As a matter of fact, many of the latter are considered worthless in their own country for the same reason. It may therefore be set down as an axiom that no timber is good in the country that produces it.
The late Mr Balfour conducted a series of experiments on the strength of New Zealand woods at the N.Z. Exhibition of 1865. So far as they went these experiments were very satisfactory, but he himself admitted that they were not exhaustive, and suggested the further investigation of the subject by the General Government. A collection of timber specimens was made for this purpose in 1872, but the experiments have not yet been made. In reporting on the subject Mr Balfour said:—“New Zealand woods compare very fairly with those which we have been accustomed to consider as standards, the absolute strength of very many being above that of British oak, and all being stronger than elm. * * * New Zealand woods are certainly for the most part short in the grain and break with little warning. There all a number of valuable exceptions, but it will be observed that the ratio of safe load to breaking weight is high, which to a great extent compensates for this peculiarity.” Mr. Balfour's experiments were made with pieces twelve inches long and one inch square, supported at one end. I observe that Mr. Laslett, who tested the strength of most of the principal woods in the world for the Admiralty, used pieces six feet long and two
inches square, supported at both ends. As his results will probably be the standard in future, any further experiments in New Zealand should be on the same scale. Mr. Brunton, C.E., Invercargill, tested four samples each of black pine and totara on ten feet bearings. One of the former was eight, and all the others four, inches square. The large black pine piece broke with six and three-quarter tons, and the average breaking weight of the smaller pieces was—for black pine, twenty-three and a half hundred-weights; and totara, twenty and three-quarter hundred-weights. When worked out in the same manner, this makes black pine fifty-three per cent, and totara thirty-one per cent weaker than the mean of Mr Balfour's experiments with small samples. Table No. IV. hereto appended, gives the main results of Mr. Balfour's experiments put into a more popular form than the one he adopts, which is intended for professional men. My table simply gives the “weight,” “strength,” “elasticity,” and “toughness” of the principal Otago timbers, with examples of well-known varieties from other countries.
The fifth and last table that I have prepared is intended as a guide in the selection of native timbar for special purposes. It gives an abstract of the properties and uses of the various kinds referred to in the paper.
In conclusion, I claim to have shown that Otago, and New Zealand generally, is well provided with good timber suitable for all the purposes of the constructive and mechanical arts. How then is it that we import £130,000 worth annually from foreign countries? I shall leave the question to be answered by the political economist, for I can see no valid reason for the anomaly. I can only view the fact as a grave reflection on our enterprise.
|Pittosporum tenuifolium||Hooker||Botanical name.|
|Kohuhu||Maoris||According to Colenso.|
|Tawhiwhi||"||" " "|
|Tarata||"||" " Lindsay.|
|Tipau||"||" " Buchanan.|
|Maple||Settlers||Occasionally so called.|
|Pittosporum colensoi||Hooker||Botanical name.|
|Mapauriki||Maoris||According to Cunningham.|
|Tipau||"||" " "Buchanan.|
|Maple||Settlers||Occasionally so called.|
|Pittosporum eugenioidos||Hooker||Botanical name.|
|Tarata||Maoris||According to Colenso.|
|White mapau||Buchanan||Almost as common as turpentine.|
|Maple||Settlers||Occasionally so called.|
|Myrsine urvillei||Hooker||Botanical name.|
|Tipau||Maoris||According to Colenso.|
|Mapau||"||" " "|
|Maple||Settlers||Occasionally so called.|
|Carpodetus serratus||Hooker||Botanical name.|
|Piripiriwhata||Maoris||According to Cunningham.|
|Tawiri||"||Balfour, quoting Buchanan in Jurors', N.Z Exhibition. Not seen elsewhere|
|6||Manuka—||Also native name, Colenso.|
|Leptospermum scoparium||Hooker||Botanical name.|
|Kahikatoa||Maoris||According to Colenso.|
|Tea or ti tree||Settlers.|
|7||Manuka—||Also native name.|
|Leptospermum ericoides||Hooker||Botanical name|
|Manuka-rau-riki||Maoris||According to Colenso.|
|Rawiri||"||" " Kirk|
|Tea or ti tree||Settlers|
|8||Rata—||Also native name, Lyall.|
|Metrosideros lucida||Hooker||Botanical name.|
|9||Kowhai—||Also native name, Colenso.|
|Sophora tetraptera||Hooker||Botanical name.|
|New Zealand acacia||Settlers||According to Colenso.|
|Fuchsia excorticata||Hooker||Botanical name.|
|Konini||Maoris||According to Buchanan.|
|Kohutuhutu||"||" " Colenso.|
|Kotukutuku||"||" " Colenso.|
|Griselinia littoralis||Hooker||Botanical name.|
|Pukatea||Maoris||According to Colenso.|
|New Zealand laurel||Settlers||Frequently used in Australia.|
|12||Kamai—||Proper spelling of native name.|
|Weinmannia racemosa||Hooker||Botanical name.|
|Tawhero||Maoris||According to Lyall|
|Karmahi||"||" " Hector.|
|Towai||"||" " Colenso.|
|Tawai||"||" " Cunningham.|
|Black birch||Settlers||So called at Catlin river.|
|Red birch||"||" " in North Island and South Otago.|
|13||Pokako—||Also native name, Colenso.|
|Elœocarpus hookerianus||Hooker||Botanical name.|
|Hinau||Maoris||According to Cunningham.|
|14||Pokako—||Also native name, Colenso.|
|Elœocarpus dentatus||Hooker||Botanical name.|
|Hinau||Maoris||According to Raoul.|
|Plagianthus betulinus||Hooker||Botanical name.|
|Whau-whi||Maoris||According to Hector.|
|Lace-bark tree||Settlers.||" " Buchanan.|
|Hoheria populnea variety of angustifolia||Hooker||Botanical name.|
|Howhere||Maoris||According to Colenso.|
|Pennantia corymbosa||Hooker||Botanical name.|
|Kaikomako||Maoris||According to Colenso.|
|Panax crassifolium||Hooker||Botanical name.|
|Horoeka||Maoris||According to Colenso.|
|Libocedrus bidwillii, or Libocedrus doniana||Hooker||Botanical name.|
|Kawaka||Maoris||Applied to Libocedrus doniana, according to Colenso.|
|Pahautea||"||Applied to L. bidwillii, according to Colenso.|
|Moko-piko||"||" " according to Bidwill.|
|Totara-kiri-kotukutuku||"||Applied to Liboccedrus doniana, according to Mantell.|
|2||Miro—||Also native name.|
|Podocarpus ferruginca||Hooker||Correct botanical name.|
|Podocarpus spicata||Erroneously so called in Jurors' Reports N.Z. Exhibition.|
|Black rue||Settlers||Old name now obsolete.|
|3||Totara—||Also native name.|
|Podocarpus totara||Hooker||Botanical name.|
|Podocarpus spicata||Hooker||Correct botanical name.|
|Podocarpus ferruginea||Erroneously so called in Jurors' Reports N.Z. Exhibition.|
|Matai||Maoris||Now coming into use as a popular name.|
|Mai||"||According to Cunningham|
|Black rue||Settlers||According to Hector and Buchanan.|
|Podocarpus dacrydioides||Hooker||Botanical name.|
|Kahikatea||Maoris||According to Colenso.|
|Kaikatea||Probably a corruption of the preceding name.|
|Swamp pine||Settlers||In North Island.|
|Dacrydium cupressinum||Hooker||Botanical name.|
|Rimu||Maoris||Now becoming popular also.|
|Dacrydium colensoi||Hooker||Botanical name.|
|Manoao||Maoris||According to Colenso.|
|Silver pine||Settlers||So called on West Coast.|
|Tar-wood||"||" " in vicinity of Dunedin.|
|Phyllocladus trichomanoides||Hooker||Botanical name.|
|Tanekaha||Maoris||According to Colenso.|
|Toa-toa||"||" " "|
|9||Silver Birch—||Most popular name in Otago.|
|Fagus menziesii||Hooker||Botanical name.|
|Tawai||Maoris||According to Colenso.|
|Tawai||"||" " Balfour.|
|Towai||"||" " Bidwill.|
|White birch||Settlers||Frequently so called in Otago.|
|White kamai||"||So called in South Otago.|
|10||Red Birch—||Common throughout Otago.|
|Fagus Fusca||Hooker||Botanical name.|
|Hututawhai||Maoris||According to Kirk.|
|Towai||"||" " Balfour.|
|Tawai||"||" " Bidwill.|
|Tawhai-rau-nui||"||" " Coleuso.|
|Black birch||Settlers||So called in the Northern provinces and by Balfour, but not in Otago.|
|Red Kamai||"||So called in South Otago.|
|11||Black Heart Birch—|
|Fagus solandri, or Fagus cliffortioides||Hooker||Botanical names.|
|Tawhai||Maoris||According to Colenso.|
|Tawai-rau-riki||"||" " Geological Survey.|
|White birch||Settlers||Commonly applied when the timber is mostly white Occasionally so called.|
|Popular Name.||Botanical Name.||Ordinary Length.||Dimensions Diameter.||Approximate Age.||No. of Annual Rings in an Inch.||Thickness of Sap-wood.|
|Manuka||Leptospermum ericoides||30 to 60||12 to 24||100 to 250||20||½|
|Rata||Metrosideros lucida||30 to 40||24 to 48||200 to 450||19||½|
|Kowhai||Sophora tretaptera||20 to 40||18 to 36||140 to 270||15||1 to 3|
|Broadleaf||Griselinia littoralis||15 to 25||36 to 72||340 to 700||19||2|
|Cedar||Libocedrus bidwillii||20 to 40||18 to 42||150 to 400||15 to 28||1 to 4|
|Miro||Podocarpus ferruginea||20 to 50||18 to 36||150 to 300||20||3 to 12|
|Totara||Podocarpus totara||20 to 80||36 to 60||470 to 800||26||3 to 6|
|Black pine||Podocarpus spicata||20 to 40||24 to 42||270 to 400||23||2 to 4|
|White pine||Podocarpus dacrydioides||40||30 to 48||370 to 600||25||12|
|Red pine||Dacrydium cupressinum||20 to 80||30 to 48||400 to 650||27||3 to 6|
|Celery pine||Phyllocladus trichomanoides||30 to 40||24 to 36||280 to 400||23||1 ½|
|Yellow pine||Dacrydium colensoi||5 to 20||30||300||21||1|
|Silver birch||Fagus menziesii||20 to 80||20 to 45||150 to 330||12 to 19||3 ⅓|
|Red birch||Fagus fusca||20 to 60||20 to 48||130 to 300||10 to 17||1 to 4|
|Black birch||Fagus solandri||50 to 80||24 to 45||80 to 180||6 to 9||3|
|Popular Name.||Botanical Name.||Weight per Cubic foot, Green, Pounds.||Weight of Moisture in Cubic Foot of Green Timber. Pounds.||Weight per Cubic Foot, Seasoned, Pounds.||Shrinkage in Boords 12in Square by in thick.||Remarks.|
|Rata||Metrosideros lucida||72.041||15.401||63.314||0.65||Old log.|
|Kamai||Weinmannia racemosa||61.377||27.617||38.717||0.80||Mean of two —heart of log partly seasoned.|
|Pokaka||Elœocarpus hookerianus||57.929||22.875||38.368||0.53||Old log partly seasoned.|
|Kauri||Dammara australis||45.709||8.105||39.830||0.34||Out of log partly seasoned.|
|"||" "||62.208||21.291||47.482||0.86||Partly seasoned.|
|"||" "||56.715||19.138||42.228||0.68||Old block.|
|Black pine||Podocarpus spicata||75.534||30.456||46.862||0.23|
|White pine||Podocarpus dacrydioides38.921||11.698||28.636||0.30|
|" "||" "||43.899||16.896||29.505||0.52|
|Red pine||Dacrydium cupressinum||43.117||11.533||34.294||0.48||From Taieri Mouth.|
|" "||" "||71.136||31.004||42.775||0.82|
|Yellow pine||Dacrydium colensoi||55.461||11.952||46.162||0.35|
|Celery pine||Phyllocladus trichomanoides||47.170||17.503||31.583||0.38||Mean of two old logs partly seasoned.|
|Silver birch||Fagus menziesii||52.621||26.269||28.446||0.45|
|Red birch||Fagus fusca||39.621||26.269||28.446||0.45|
|" "||" "||58.176||29.084||34.124||0.92|
|" "||" "||41.000||7.244||40.648||0.23||Old sample.|
|Blk. heart birch||Fagus solandri cliffortioides||53.485||16.738||40.292||0.54|
|Popular Name||Botanical Name.||Weight, per cubic foot, dry, according to Balfour.||Strength.||Elasticity.||Toughness.||Remarks.|
|1||Black Mapau||Pittosporwn, tenuifolium||60.14||243||215.2||114.08||Doubtful, being the result of one experiment only.|
|2||Red Mapau||Myrsine urvillei||61.82||192.4||169.88||92.94|
|3||White Mapau||Carpodetus serratus||51.24||177.6||166.86||54.64|
|11||Black Pine||Podocarpus spicata||40.74||190||156.22||90.86|
|12||White Pine||Podocarpus dacrydioides||30.43||106||127.1||49.07|
|13||Red Pine||Dacrydium cupressinum||39.25||140.2||143.38||79.66|
|14||Silver Birch||Fagus menziesii||38.99||158.2||116||62.04|
|15||Red Birch||Fagus fusca||48.62||202.5||219.5||87.28|
|English and Foreign Examples.|
|16||Australian Iron Bark||70.92||282.7||297||192.31|
|18||English Oak||55.96||128.5||127||105.36||According to Barlow.|
|22||Memel Deal||36.77||144.25||116||" Barlow.|
|24||Riga Fir||46.46||89.9||167.7||79.95||" Laslett.|
|26||English Elm||34.21||87.9||82.2||74.63||" Barlow.|
|27||" "||34.87||86||145.15||99.51||" Laslett.|
Notes on Table IV.
The “strength” given in column S is the weight in pounds required to break pieces twelve inches long and one inch square supported at one end and loaded at the other.
“Elasticity” is the greatest weight in pounds carried with unimpaired elasticity, divided by the deflection caused by it in inches, the specimen being the same size and loaded as above.
“Toughness” is the breaking weight given in column S divided by the deflection caused by it in inches at the instant of rupture. By this method the lowest tabular number indicates the greatest toughness.
Rule.—To find the breaking weight of a beam from the table, multiply together eight times the breadth of the beam in inches, the square of its depth in inches, and the tabular number S, the result divided by the distance between the supports in feet gives the breaking weight in pounds distributed over the entire length of the beam.
Example.—A kowhai beam twelve feet long between the supports, twelve inches deep and six inches broad, will break with 53 tons 7 cwts. 16 lbs., thus—
8 × 6 × 12 × 12 × 207.5/12=119,520 lbs.=53 tons 7 cwts. 16 lbs.
When the load is confined to the centre, the beam breaks with half this weight.
|Kowhai||Black Mapau||Rata||Cedar (?)||Kowhai||Cedar||Rata||Silver Birch.|
|Broadleaf||Manuka||Manuka||White Pine||Black Pine||Silver Birch||Manuka||White Pine.|
|Fuchsia||Kowhai||Miro||White Mapau||Miro||White Pine||Fuchsia||Cedar.|
|Black Pine||Red Birch||Red Birch||Totara||Rata||Celery Pine||Grass Tree||Celery Pine.|
|Totara||Miro||Black Mapau||Silver Birch||Red Pine||Pokaka||Kowhai||Red Birch.|
|Kamai||Red Mapau||Kowhai||Red Pine||Turpentine||Red Pine||Kamai|
|Red Birch||Black Pine||Red Mapau||Black Pine||Yellow Pine||Totara||Black Pine|
|Rata and Black Heart Birch are also believed to be durable, but their durability is not fully proved.||Black Heart Birch, place not determined||Broadleaf, place not determined.|
|Piles.||Beams.||Sleepers.||Planking.||Framing, Implements, and Wheelwrights' Work.||Teeth and Bearings.||Patterns.|
|Kowhai||Red Birch||Black Pine||Black Pine||Manuka||Rata||Silver Birch.|
|Black Pine||Black Heart Birch||Totara||Black Heart Birch||Kowhai||Kowhai||White Pine.|
|Kamai||Black Pine||Red Birch||Kamai||Rata||Manuka||Cedar.|
|Totara||Rata||Kamai||Red Birch||Black Heart Birch||Broadleaf||Celery Pine.|
|Black Heart Birch||Kowhai||Cedar||Black Pine|
|Fencing and House Blocks.||Framing.||Beams and Joists.||Flooring and Weather Boards.||Internal Joiners' Work.||Furniture.|
|Red Birch||White Pine||Silver Birch||Kamai.|
|Black Heart Birch||Silver Birch||White Pine||Black Heart Birch.|
|Miro||Red Birch||Red Birch||Miro.|
|Black Pine||Red Pine||Celery Pine||Red Pine.|
|As per Durability List, Table V.||All the Pines and Birches.||Totara||Cedar||Rata.|
|Red Pine||Red Birch.|