Birches.

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 cast. 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. solaiulri, and the nicks page 165 in the former are in many eases 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 800 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.

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The growing timber is remarkably free from heart-shakes and other defects of a similar kind. Trees that have stood long after reading 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 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 page 167 ten to twelve feet at the base. Mr. Surveyor Innes states that the Wakatipu reel birches range from three to four feet six inches, but he has seen them at To Anau from seven to nine; and six to eight feet trees are frequently met with on the Five Rivers Plain. The Bun-wood 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 Shirty-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 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.

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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 groat 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, I 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 South-land, 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 1807-8, is still in good preservation. I also show the following examples as proofs of the durability of red birch.

1st.	Piece of split timber that has lain in the West Taieri Bush for ten years.
2nd.	Portion of fencing post, eight years in the ground, at Tuapeks Mouth.page 169
3rd.	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, tut the only difference he makes is in the shape of the leaf. Mr Kirk, in a note to me, says, "I do not know Fatjus 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, page 170 and heart coarse in the grain, stringy and very tough. Some samples resemble very much English elm, 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-grow 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.