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The Pamphlet Collection of Sir Robert Stout: Volume 64

Hardwoods. — Mapaus

page 143

Hardwoods.

Mapaus.

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 hand-somest 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, I 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. Bed mapau—Myrsine urrillei. This is a small tree, well known page 144 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 serratas. 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.

* 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.