Edward Bartley on Native Timber

Edward Bartley

Edward Bartley, like many of his generation, was passionate about the natural sciences and the new understandings of the natural world which occurred with increasing rapidity during the 1800’s. 

We think of our own time as being one of the greatest technological breakthroughs, but the reign of Queen Victoria saw phenomenal advances across a range of fields.

The Museum Institute was a valuable forum for information exchange on scientific and historical matters.

 As an early member, Edward attended the meetings and lectures regularly and, on occasion, presented material himself on topics which interested him personally or professionally.

On arriving in 1854 as a young man, Edward worked in the building trade, with his brother Robert. The construction of the Supreme Court building was an unusual subcontract for them, as it enabled the brothers to work in stone, as they had been used to do in the Channel Islands. Predominantly construction in the Auckland province was in timber – a plentiful resource in the new colony. Yet surprisingly little was known of the native timbers. Their properties and usefulness were still disputed, even after Anton Seiffert had produced outstanding cabinetmaking with carved and marquetry detail using local species.

Edward observed and experimented with local woods and, as an architect, was particularly fond of exploiting their decorative value for interior work. In 1885 he presented a paper to the Institute on the subject of native timbers and their suitability for use in building. An extract of text from this presentation is reproduced for you here:

By Edward Bartley, Architect.

[Read before the Auckland Institute, 30th November, 1885.]

Specimens of Timber to Illustrate the Paper.

Kauri.—Four specimens: Red, white, black, and a soft kind from Tairua.

Piece of kauri joist destroyed by dry rot.

Piece of kauri destroyed by grubs.

Piece of window-sill from St. Andrew's Church, built in 1847.

Rimu.—Piece of 12 in. x ¾ in. board, to show the difficulty in discriminating between sap and heart.

Totara.—Piece with the commencement of small spots of decay.

Kahikatea.—Piece of flooring completely destroyed by the grub.

There are only four kinds of New Zealand timbers used in Auckland for building purposes. I place them in the following order of merit: Kauri, rimu, totara, and last kahikatea. After touching on these various timbers, I propose to say a few words on seasoning and decay of timber. Permit me to remark that the statements are not gathered from hearsay, but from thirty years' experience in the building trade in Auckland. I have of late years taken down buildings that I either took part in erecting or saw erected; I have had, therefore, many opportunities of studying the durability and other characteristics of our Auckland-grown timbers.

First, the kauri (Dammara australis).—I have here specimens of four kinds of kauri: the red, white, black, and a soft kind, quite distinct in grain and quality from the others, which I will hereafter explain. The red kauri is the best general building timber; it is well adapted for heavy framework, beams, joists, and the like; it is close-grained, rather gummy, very durable, but is liable to cast and twist; it shrinks endways as well as in width. The shrinking endways is a great drawback to kauri, and more especially this kind. I have known a forty feet beam shrink 1 ½ inches in length. I have also known a weatherboard shrink ¾ of an inch in twenty feet, and most of us will remember ceiling mouldings and other joiners' work shrinking so as to quite disfigure the building. This red kauri should only be used for beams or other framework, and not for mouldings or joiners' work. The next is the white kauri, a tough kind of timber; will bear a greater breaking strain than the red, but not so durable; I have seen it quite soft in a few years; it is a splendid timber for moulding and joiners' work. The shrinking endways is almost nil, if worked up after a fair amount of seasoning, neither will it cast. It is largely used by boat-builders on account of its readiness to bend. Black kauri is not very abundant, it comes from the west coast of the island, it is only fit for rough work, is heavy with gum, and the most durable of all; in fact, for fencing-posts or the like, I believe it would last as long as puriri. I need hardly say it is not fit for mouldings or joiners' work; it is so hard it would require very strong machinery to work it, and after being worked it would cast into all shapes. The last specimen of kauri (No. 4) is the timber for joiners' work and mouldings; there is a peculiar grain marking in this kind of kauri not to be found in any of the other specimens—this kind should only be used for mouldings and joiners' work. We have often heard it remarked that kauri is noted for its casting, twisting, and shrinking: well, this last kind of kauri will neither cast, twist, nor shrink endways. I have seen slight scantlings, say 3 in. by 3 in., 20 feet long, quite straight, after being exposed to the weather without any care. I have seen joiners' work made up out of this timber standing as well as cedar. I have already said it should only be used for joiners' work and mouldings, it is so light and soft; it should never be used for beams or heavy framework; but if this kind of kauri and the white only were used for joiners' work and mouldings, we should seldom hear of ruined ceilings, and twisted doors and sashes. This kind of kauri is only found in the Tairua District.

The next timber on my list is the rimu (Dacrydium cupressinum). It is known in the South Island as red pine. The rimu, I believe, grows in the South to a very large tree, but in this province the average size tree is two feet six inches to three feet diameter; it is a timber with a large proportion of sap-wood—a two-feet diameter log will have nine inches of sap-wood, leaving only six inches of heart, the heart not being very well defined. By this specimen of rimu (a board twelve inches wide) the difficulty in discriminating between sap and heart will be seen, even by an expert. There is a hard white gum, and frequently many shakes, near the heart, that renders this tree unfit for boards, but it answers well for scantlings, joists, and framework. The sap-wood, if exposed to weather or damp, will not last, but the heart is very durable. I have known rimu fences standing many years. Of course, with kauri so plentiful, we have not used much rimu; but at the rate the kauri is being cut, before many years we shall, I am sure, have to fall back on the rimu. Picked heart of rimu is a very good furniture wood, and very suitable for church furniture.

Totara (Podocarpus totara) is the third timber of importance. It is largely used in the South for building purposes, but in Auckland we only know it as a good “pile” timber, and for that purpose it has not been equalled by either native or imported timbers. I have seen a “stringer” taken from Queen-street Wharf quite sound, after being under water twenty-eight years. Of course it was heart, the sap will not last; hence the folly of using round sticks for piles. All piles should be squared timber—all heart. It is at times specified for plates and window sills, with a view, I presume, that it will last longer than kauri. I think this is a mistake: my experience is that it will not last as long as the heart of red kauri. There is a small “rot” speck found in the heart of mature trees; I have here a specimen cut from a new plank with this kind of decay, still the totara must be classed as one of our most durable timbers.

The last, and the worst of our building timbers, is the kahi-katea (Podocarpus dacrydioides). It will decay very soon, exposed to the weather or damp—in damp situations it will not certainly last longer than four years—and inside, or under cover, such as flooring, ceiling or lining, it is attacked by a small grub, completely destroying the inside of the scantling or board. I have here a specimen of kahikatea flooring destroyed by this grub; the destruction is so complete that I have known a floor rendered dangerous to walk on, the chairs having gone through in many places. I consider kahikatea is far inferior to all sap kauri. If used for rough lining, the perforations made by this grub will appear through scrim and paper of the room; in an instance that came under my notice, one kahikatea board had been fixed for rough lining, the remainder being sappy kauri: the board, scrim, and paper were quite destroyed, like a band nine inches wide, the remaining lining being quite sound. It is said that kahikatea grown on high ground grows better than that grown on low ground; but the greater portion, I should say nine-tenths, grows on flat swampy districts.

Seasoning and Decay of Timber.

The causes of decay are various, the worst being “dry rot”—a term giving a wrong idea of the nature or cause of the decay. I have here a specimen of heart kauri destroyed by “dry rot.” It is covered with a fungus of extraordinary growth in Auckland. I have seen a plant measuring over five feet in diameter. Whether the fungus grows in consequence of the decay, or the decay is caused by the fungus, I am not quite clear; but I should rather think the fungus grows after the decay, and is not the cause of the decay. At any rate we know the first cause is by using unseasoned timber in unventilated positions, such as a ground-floor without a space left for ventilation. Nearly if not all the ground-floors on the east side of Lower Queen-street are decaying with “dry rot.” I have known 12 in. x 3 in. all heart kauri joists quite rotten in twelve years; the joists will break off in pieces from six inches to two or three feet long, and will be found flat on the ground, with square ends, the timber always breaking at right angles to the fibre of the wood. The kauri is also destroyed by a small grub, similar in some respects to the grub in the kahikatea, but with this difference: the grub in the kahikatea always bores with the fibre of the wood; the grub in the kauri will bore in any direction. I have here a sample of kauri bored with this grub. The sap-wood will be attacked first; but if found in a building, it will soon go right through, heart and sap falling a prey to it.

One great reason for kauri and other timber decaying is the constant use of young and unmatured timber. A mature kauri will be at least five feet diameter, showing well defined sap-wood of not more than three to four inches. Now, a large quantity of logs cut up in Auckland will not measure more than 2 feet 6 inches to 3 feet in diameter: this size log will have nine inches of sap-wood, leaving on a log 2 feet 6 inches only 12 inches of heart, and that soft and white. Next to using young timber is the constant use of unseasoned timber, and the practice of our mill-owners cutting down trees all the year round, and full of sap. I consider the trees should be “barked” at least six months before being fallen; the barking, of course, simply means cutting out a ring of bark, say four or six inches in width, close to the ground. Another plan, adopted in America, is to bore two holes right through the trunk, crossing each other in the middle of the tree; either or both are inexpensive operations, and should be tried by the mill-owners. As to the time of year for felling our New Zealand timbers, I consider, if barked or bored as I suggest, it would not matter a great deal. It will be seen at once that if we get rid of the sap or gum before falling we have overcome half the difficulty (if not more) experienced in seasoning. Hence the failure of artificial seasoning by the hot chamber, used a short time ago by some of the mills, the hot chamber simply baking the outside, leaving the sap and gum inside the plank. It is a fact known to all carpenters that kauri will season better in the rain and wind of winter than the hot sun of summer. Most of us know the effect of new kauri shingles on a tank of water: the gum and sap is washed out to such an extent by the rain, that the first water off the roof is like weak turpentine, and dark in colour. Then we have another cause of decay, consequent upon using unseasoned timber, that is the injudicious use of tar. It is right to tar a well-seasoned piece of timber, but utter folly to tar green timber, and all round, as we see repeatedly done in our buildings and wharves. I have known a 4in. x 3in. plate of heart of kauri quite rotten in two years, solely on account of being tarred all round; the proof being that other plates in similar situations, and quite near, were quite sound. If the durability of timber is to be studied, it should be a rule not to paint or tar timber before being seasoned. That kauri will last, I have had many instances brought under my notice. Here is a portion of a window-sill taken from St. Andrew's Church, built in 1847; it will be found not the least impaired by thirty-six years' exposure to the weather. It was removed about two years ago. It was resting on a stone sill; the under side, it will be observed, has not been painted. Only one other instance: The two first grave fences in the Auckland Cemetery, erected thirty-three years ago, are still standing, and quite sound. The posts are of red kauri, and had been charred.