Transactions and Proceedings of the New Zealand Institute/Volume 17/Article 38
Art. XXXVIII.—Notes on the New Zealand Beeches. By T. Kirk, F.L.S.
[Read before the Wellington Philosophical Society, 1st October, 1884.]
Fagus menziesii, Hook. f.
Hook. Ic. Pl., t. 652.
Silver Beech.
Brown Birch, White Birch, Red Birch.
Silver Birch.
Although this species exhibits a considerable amount of variation in the shape, toothing and texture of the leaves, it is the most easily recognized of all the New Zealand beeches, especially when the fruit is fairly developed: the curious glandular scales on the valves of the cupules at once distinguish it from the other species, while they show its close affinity to F. gunnii, Hk. f., of Tasmania, F. moorei, Muell., of New South Wales, and F. betuloides, Mirb., of Cape Horn and South Chili.
This forms a fine tree, 60′–80′ feet high, with a trunk 2′–3′ in diameter, but larger specimens are by no means unfrequent. The twigs are clothed with a fine brown pubescence; leaves glabrous, rigid, orbicular, or broadly ovate, or rhomboid ovate, shortly petioled, with the margins cut into very short blunt teeth, or more frequently crenate, each crenature being irregularly notched. In the young state the leaves are sometimes deeply toothed, stipules linear-oblong. The valves of the cupule are pubescent and clothed with from 5 to 7 horizontal scales, the margins of which carry a fringe of stalked glands. Nuts trigonous, 3-winged, the wings being divided or fringed at the apex.
In common with all the local species, the bark varies considerably at different periods of growth. Before reaching maturity, the tree is characterized by a thin silvery whitish bark much resembling that of Betula alba, L. This becomes gradually thickened, and rugose, although patches of smooth bark may often be seen even on the largest trunks. This retention of the smooth bark has led to the adoption of the common name of silver beech for this species.
The timber is of a deep reddish-brown colour, compact in texture, and splits easily. It is well adapted for inside work as rafters, flooring joists, etc., and especially for the manufacture of ordinary furniture, French bedsteads, sideboards, etc.; also for wine casks, tubs, buckets, etc. A considerable demand for these purposes may be anticipated when the progress of road-making has afforded more easy access to the silver beech forests, but at present I am not aware that any timber-merchant considers it worth while to keep the wood in stock. So far as Wellington is concerned, a supply could be obtained from the Rimutaka. When used for fencing purposes it lasts from three to seven years; house blocks in dry ground, and sheltered from the rain, are in a partially decayed state after having been fixed for eleven years. Shingles require renewal at the end of six or seven years.
The silver beech attains its northern limit on the Te Aroha Mountain at the head of the Hauraki Gulf. It is abundant on the mountains of the East Cape, on the Ruahine, Tararua and Rimutaka Ranges, and the Wainuiomata Hills in the North Island. In the South Island it occurs on the Kaikoura Mountains, Mount Arthur Range, Spencer Mountains, and more or less throughout the Southern Alps, especially on their western slopes. In the Makarora Valley it is the only species found between the head of Lake Wanaka and the Haast Pass, the timber in this district being of decidedly better quality than in the lowlands. The most southern specimens known to me occur at Colac Bay and Lake George in the Longwood district.
Sometimes it forms the chief portion of the forest, but is commonly mixed with other species. In the south it often occurs singly, or in small quantity in mixed forest, as in the Makarewa district.
It descends to the sea-level at Colac Bay, Dusky Bay, Preservation Inlet, and other places, but is most frequent at elevations between 1,200 and 2,500 feet. Its highest levels are but little above 3,000 feet.
Specimens from humid situations, at low levels on the west coast of the South Island, generally have leaves of thinner texture, and less closely set than those from higher levels. In both these points as well as in the margination, a wide range of variation is exhibited.
This species is subject to a remarkable foliar transformation: crowded panicles of scaly, fulvous bracts are developed at the tips of the branchlets. Usually four scales form a kind of flask-shaped perianth, which is sessile in the axil of a larger bract-like scale, and covers a number of minute scales. These panicles are often produced in great abundance, and present a close resemblance to the early stages of a true inflorescence.
Black Birch of Auckland and in part of Otago and Southland.
Black or Bull Birch of Lake Wakatipu.
Red Birch of Wellington, Nelson, and in part of Otago and Southland.
It is not easy to see why any difficulty should have occurred in the identification of this fine timber-tree apart from the misleading tendency of the common names generally applied. The thin yet firm texture of the leaf, the prominent veins, the sharply-toothed margins, are characters that can only be confused with those afforded by other species by a careless observer. Yet merely owing to the use of common names based upon colour, and applied or rather misapplied to the leaves, bark, or wood at the fancy of the bushman, no species has been more misunderstood.
The tooth-leaved beech forms a fine tree 70–100 feet with a trunk from 3 to 8 feet in diameter, the bark varying greatly in colour and rugosity in different localities and at different stages of growth. In the north and in lowland situations in the south it is usually blackish, but in sub-alpine localities the prevailing tint is of a rich deep brown. In the young state it is smooth and whitish.
The wood varies in colour but is usually reddish or reddish-black, stout in the grain. It is one of the strongest and most durable timbers in the colony.
In the young state the twigs are pubescent, leaves oblong-ovate, shortly petioled, with rathar large acute teeth; pubescent or glandular when young. Cupules with membranous scales at the back; nuts winged, the wings being divided at the apex.
Varieties with the teeth more or less abbreviated are occasionally met with, but on the whole these are rare and can scarcely be mistaken for either of the entire-leaved forms by an observer of ordinary intelligence.[1]
The good qualities of this timber are so generally admitted that it is needless to discuss the question or offer further evidence on the subject. On the Thames Gold Field it has been so generally appreciated by the miners that it has now become extremely rare and is said to be extinct in some localities where it was once plentiful. I may add that I have examined stock-yard fences which have been erected twenty-one years, and which are still in good condition.
This is the most widely distributed of the species; it extends from Ahipara in the extreme north to Southland, in many southern localities forming the greater portion of the forest. In the South Island it is more plentiful on the western side of the main range than on the eastern, and is decidedly rare in the central districts: in Canterbury its chief habitat is in the mountain district between the Waimakariri Gorge and Bealey, where it forms the chief portion of a zone ranging from about 2,400 to 3,000 feet, extending up the valley of the Poulter and adjacent ranges. Between the Cass River and Bealey it is so strongly marked in contrast with the mountain beech that it can readily be descried from the terraces on the southern bank of the river. As its occurrence in the interior of Canterbury had been warmly denied, Mr. Blair, the Directing Engineer for the South Island, suggested that I should finally determine the point by an examination of the growing timber. When on a visit to the district in January, 1881, I had the pleasure of carrying out this suggestion in company with my friend Mr. J. D. Enys, and found the tooth-leaved beech occurring freely between the limits already stated, mixed with mountain beech which forms the greater portion of the forest. Most of the mature specimens were from 50 to 70 feet high, with clear unbranched trunks of from 35 to 45 feet, measuring 10 feet in girth at six feet from the ground. The oldest specimens were unsound in the middle, but the shell was firm and hard. Trunks cut down twelve years before the date of my visit and left on the ground were still perfectly sound, the logs retaining the wedges that had been driven to split them. Subsequently I examined a stock-yard fence constructed with timber cut at this spot at the time to which I have referred, and found all the posts of tooth-leaved beech in a perfectly satisfactory state, sound and good; while it had been found necessary to renew all the posts of mountain beech at the end of six years, and the renewed portion was in bad condition, requiring immediate replacement, many of the rails even being worthless.
This species is not found in the Oxford and Alford Forests, although reported to occur there by Mr. Robertson, who was instructed to examine those forests in October, 1876.
It descends to the sea-level in many localities, as Ahipara, Kawau, Omaha, Wairoa East, etc., but rarely in large quantities. It is more abundant and attains larger dimensions at elevations between 1,200 and 3,000 feet, and in a few localities ascends to 3,800 feet, which, so far as I am aware, is the greatest altitude which it attains.
Myrtilloides cinerascens, Banks & Sol., MS.
Cliffortioides oblongata, Dryander.
Entire-leaved Beech.
Black Birch of Wellington, Canterbury, and in part of Otago and Southland.
White Birch of Nelson, and in part of Otago.
Black-heart Birch of Otago.
White, Black, Red, and Brown Birch of Oxford and Alford Forests.
A fine tree, sometimes attaining the height of 100 feet, but usually 60–80 feet, with a trunk from 2 to 4 feet or more in diameter. Branchlets pubescent, leaves narrow oblong, quite entire, with appressed cinereous pubescence beneath in the mature state at least. The leaves vary in width, but are oblique or cuneate at the base. Timber reddish, sometimes streaked with black, stout, and durable under certain conditions, but in all respects inferior to tooth-leaved beech. It has the disadvantage of forming oblique or longitudinal cracks in the sawn state when exposed to the weather.
Great difference of opinion has existed respecting the durability of the timber of this species. In a Report on the Durability of New Zealand Timbers which I had the honour to prepare for the Government in 1874, and again in Captain Campbell Walker's Report on State Forests, I wrote:—"Owing to the confusion arising from the misapplication of the common names of the different beeches, even in the same district, I have been unable to obtain precise and satisfactory evidence on this point." At that date the timber was generally considered to be of inferior value with regard to durability, but recently evidence has been obtained, showing that this opinion requires considerable modification.
The West Oxford Forest consists in its lower parts exclusively of this species, so far at least as could be ascertained during the few hours that I was able to spend there; formerly it was stated officially to contain a large amount of tooth-leaved beech, and it was supposed that any durable timber obtained from the forest was furnished by that species. I failed, however, to find tooth-leaved beech, either at West Oxford or at View Hill, several miles higher up the river, although there can be little doubt that it occurs on the ranges. All the men engaged at the sawmills had heard of "tooth-leaved beech," but only one or two of them had seen it growing, and no one had seen it converted. I am quite satisfied that it must be extremely rare in the locality so that it has not come within reach of the sawmillers.
Now along with numerous instances of lack of durability exhibited by this timber are a comparatively few in which it has shown a much higher degree of durability than it has generally been considered to possess. Several fences are pointed out, the posts of which have been in the ground for periods varying from twelve to twenty years; the longer period, however, has in most cases exhausted their durability; those that have been erected ten or twelve years only will last several years longer. House blocks have proved durable, lower wall plates, and sleepers also. In the cases which I examined there can be no doubt as to the timber being "entire-leaved beech."
In estimating the durability of this timber, however, it must be remembered that these instances of fair durability are comparatively exceptional. It has been largely used in the Oxford district and other places for fences, but in numerous cases these fences have become dilapidated in so short a period as five or six years, even when the timber has been apparently sound and good at the first. How far this may be due to its being cut during the period of active growth, or to its having been used while in a green condition, both practices being the rule rather than the exception, it is impossible for me to say. Another possible cause of its early decay in certain cases may be its having grown upon wet ground. It must be admitted at least that its durability cannot have been fairly tested in the majority of cases. But making all possible allowances on these points I am compelled to place its good properties considerably below those of the tooth-leaved beech.
In the Oxford Forest it is sparingly mixed with white pine, miro, and matai, the last decidedly rare. A few fine trees run up to from 60 to 75 feet in height, but the bulk do not exceed 40 feet in the clear trunk. The manager of one of the largest sawmills informed me that "trunks capable of giving 4–14 feet lengths were extremely rare." I learned that the tree was termed "red birch," "brown birch," "white birch," "black birch," and "yellow birch," at different stages of its growth, but the application of these terms varied greatly: perhaps "black birch" was most generally applied to the mature condition before decay commenced, and "white birch" to the young state; but there were too many exceptions to allow of the names being other than misleading.
Unripe trees of this kind never afford durable timber, however large their dimensions; unless the tree is allowed to stand for a few years after attaining its full growth decay speedily commences. The time required for ripening, at present undetermined, cannot be very long, and when once the process is completed decay sets in very quickly, and progresses with greater or less rapidity. Sometimes it commences at the heart before full growth has been attained; the trunk appears perfectly sound, but on being squared or sawn its defective condition is exhibited at the expense of the woodman. All our beeches are more or less subject to this peculiarity, but I am inclined to believe that the period between the ripening of the wood and the commencement of decay is unusually short in the entire-leaved beech, and as the timber is of but little value at any other period, we have here one cause of its frequent early decay after conversion.
In this species the medullary rays of fully ripened timber are more durable than the wood formed by the fibro-vascular bundles of the annual cylinder. Logs decaying in the forest often present a curious appearance from this cause: after the sapwood has perished the outer surface of the heart-wood appears to be divided into numerous short laminae running longitudinally. These laminæ project more or less beyond the general mass owing to the early decay of the wood of the cylinder. If the log has been kept from the ground, the appearance is still more remarkable, the medullary plates often projecting from one to two inches beyond the sound portion of the trunk, and exhibiting thin, rounded, weather-worn edges, but perfectly sound, and extremely hard. They vary from 116 to 18 inch in thickness at the base, and may be easily broken off by a sharp blow with a hammer. Unripe trees do not exhibit this peculiarity.
The remarkable difference in the pubescence of the leaf at different stages of growth has not received the attention it deserves. In the young state the leaves are nearly membranous, and perfectly glabrous. In exposed mature specimens the under surface of the leaves is clothed with a layer of closely appressed hairs; but it is quite a common occurrence to find trees thirty feet high or more with leaves destitute of this hairy covering when growing under the shelter of taller trees. These hairs are unquestionably adapted to prevent undue evaporation and injury from sudden variations in temperature. Accordingly we only find them developed on leaves fully exposed to the sun and air, whether on young trees or old. They are never developed on seedling plants, or on branches growing under the shade of taller trees. The series of specimens now exhibited will be found very instructive on this head.
This species appears to attain its northern limit at the East Cape, where it forms a small tree 20 to 30 feet in height. It is plentiful on the lower slopes of the Ruahine, Tararua, and Rimutaka Mountains, in the North Island, and widely distributed in the South Island, but does not appear to extend to Foveaux Straits. It descends to the sea-level at Lowry Bay and other places, but appears to be replaced by the mountain beech, which is often mistaken for it. At altitudes above 2,800 feet, with some few exceptions.
Specimens 100 feet high were observed by Mr. Bidwill at Waiwetu, near Wellington.
Black Birch of portions of Wellington, Canterbury, Otago, and Southland.
White Birch of Nelson, and in part of Otago and Southland.
Barely distinguished by the woodman from Entire-leaved Beech.
The mountain beech bears a close resemblance to the entire-leaved beech in general appearance, although it never attains the extreme dimensions of that species. The leaves are pointed at the apex and rounded or cordate at the base, so that there is but little difficulty in distinguishing the two kinds.
In the North Island it is confined to the mountain ranges, and appears to attain its northern limit at Lake Waikare on the East Cape. It is most abundant on the mountains of the South Island, often forming the sole constituent of the forest from 2,000 feet to the limits of arboreal vegetation at about 4,000 feet. It descends to the sea-level in Preservation Inlet.
In many districts the abruptness of the higher limit is strongly marked: on the St. Arnaud Range, as on others in the South Island, the upper limit forms a tolerably even line running for miles at a little below 4,000 feet.
On Mount Torlesse a few small detached specimens attain an elevation of 4,600 feet or thereabouts.
Except in special situations it rarely exceeds 40 feet in height, and even at low elevations is frequently much smaller. At the highest levels it is little more than a shrub, often with prostrate stems, and if exposed to the full influence of the wind with the branches so densely set that it is possible to walk for long distances over the tops.
In deep narrow valleys at high elevations this species is sometimes not more than from 6 to 10 feet high, but retains the arboreal habit. At the same time the leaves are excessively reduced in size, densely crowded, and fruit is produced in abundance. At first sight this state presents the appearance of a distinct species, but a careful examination speedily dispels the idea.
On the other hand, isolated specimens growing in the open at below 3,000 feet, are often branched from the base, and form charming symmetrical specimens of great beauty. When dotted over a wide area they give a peculiar park-like character to the scene, and are peculiarly attractive.
This species resembles Fagus solandri in the leaves of the young plant being destitute of hairs on the lower surface, while full-grown specimens have the leaves clothed with a thick layer of appressed white hairs. The distichous arrangement of the leaves is a noteworthy character, although in old specimens it is often obscured.
The quality of the timber is much the same as that of entire-leaved beech, and like that species it exhibits a considerable amount of durability in certain cases, while in others it perishes within five or six years, as in sheep-yards at Lake Pearson.
In many districts it is of value as affording the only available timber, but it assumes far greater importance when viewed with regard to its influence on climate. In this respect it is not easy to overrate its importance: its restraining action in the prevention of floods in certain situations is so marked, that the destruction of the mountain beech forests would speedily bring about the devastation of large tracts of country at low levels.
In wet situations the timber of this species often proves durable. Mr. J. D. Enys informed me of an instance in which a large sleeper at the margin of a spring in a situation where it was constantly moist was sound and good after being sixteen years in use. Some of the telegraph poles of the first line erected in the Waimakariri Country were furnished by this species; those fixed in dry soils perished in four or five years, while those driven in swamps remained sound for a much longer period. Similar results have been obtained with fencing posts furnished by mountain beech.
Hitherto this species has been confused with the mountain beech, although its differential characters are easily recognized. It has been observed in the valley of the Dart and other places about Lake Wakatipu, and by the Little Grey River at elevations between 1,000 and 2,000 feet; also I believe on the Five Rivers Plain.
Usually it attains rather larger dimensions than mountain beech, being from 40 to 60 feet high: it is easily distinguished from that species by the ovate apiculate leaves clothed with appressed fulvous tomentum beneath in the mature state.
The habit and spray of this species more closely approaches F. sylvatica of Europe than any other New Zealand species.
At present nothing is known as to the durability of the timber, which in appearance resembles that of mountain beech.
- ↑ Hook. Ic. Pl., t. 630.