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2

The disadvantages attending winter work in the bush have led to the anomalous fact that by far the larger portion of timber used in New Zealand is felled during the spring and summer months ; and this has given rise to the erroneous idea that some of our best timbers—the kauri, totara, and others—season imperfectly, contracting in length and breadth long after they are used. Except, possibly, with white pine grown in swamps, there is not the slightest valid foundation for such a statement: the shrinking has arisen solely from the use of summer-cut timber worked up while in an unseasoned condition. Exactly similar results would attend the use of the best European and American timbers under similar circumstances. The wide differences sometimes observed in the durability of the same kind of timber in different localities, has in most cases arisen from one or other of the following causes : — 1. Trees having been felled during the growing season. 2. Timber having been used immediately after being felled. 3. Trees having been felled before the heart-wood was sufficiently matured. 4. The use of defective timber, whether sappy, shaky, laggy, worm-eaten, or soft, from having grown in unsuitable situations. 5. Defective workmanship ; no care having been taken to exclude rain from imperfect joints, exposed hewn beams being left with a concave upper surface so as to retain rain, &c, &c. 6. The application of paint, tar, &c, to the surface, while the timber is in an unseasoned condition. The importance of timber being felled only during the winter months, and of its being well seasoned before it is worked up, is so generally admitted, that no further remark is needed. -In the early days of a new country or district, timber must unavoidably be used as soon as cut; but persistence in this course involves constant expenditure for repairs and renewal, and is accompanied by great public inconvenience, as is proved by the continuous complaints that are being made relative to the defective and decayed state of bridges and wharves in all parts of the colony. No plan of seasoning timber is so effective as keeping it for the necessary time in well-ventilated sheds: in fact, simply preserving it from the rain; but this process will not meet present requirements. The plan generally pursued is to place the timber to be seasoned in close buildings, in which it is exposed to a high temperature generated by steam or hot-air pipes. The present loss to the public, both in money and labour, would speedily pay the additional cost of preparing timber in this way. Timber of large dimensions is rendered more durable by Hyett's method, which consists in forcing a solution of acetate of lead through the pores of the wood. The solution is placed in a cistern of a size proportionate to the quantity of timber to be operated upon, and constructed at an elevation of 15 to 20 feet above the ground level. A cap is tightly fitted on the butt end of each log of timber, and connected by a tube with the cistern containing the solution. In newly-cut timber treated in this way, the sap is driven out before the solution, and may be collected at the upper end of the log. This process is most efficacious against dry-rot, and seems well adapted for a preservative of the white pine (kahikatea) against the insect ravages to which it is occasionally subject. Saturation with creosote is extensively employed in Britain for the preservation of railway sleepers, and of timber used in constructive works. Chloride of zinc is highly recommended as a preservative. Anything tending to increase or preserve the durability of timber, is of much greater value in New Zealand than in any part of Britain. Not only is the first cost of material usually greater, but, from the greatly enhanced value of labour in all respects, repairs and renewal are far more serious items of expenditure. There can be no question that certain native timbers possess greater durability when grown in particular situations than in others. For example: north of the Auckland Isthmus, the hinau affords a small proportion of heart-wood, and is, therefore, considered of little value. In the Province of Wellington, the proportion of heart-wood is large, and the timber is valued for its durability. The Northern rata (Metrosideros robusta), when growing in moist places, produces timber of inferior quality to that grown in ordinary situations, and liable to become attacked by dry rot; in fact, the fungus is often found on this timber, grown in moist places, before it is cut down. It is notorious that kahikatea grown in dry places affords more durable timber than when grown in swamps; although at the same time inferior to the swamp timber for bearing transverse strains. Other instances might readily be given. It seems, therefore, important that the timber required for public works of any extent, should be selected in the forest by some competent person, so that "unsuitable timber, whether defective from having grown in situations not naturally adapted for the particular kind required, or from not having arrived at maturity, might be rejected at the outset. Also, that all timber should be deprived of its sap either by simple exposure to currents of air while protected from rain, by desiccation, or by infiltration with some preservative solution. 1. Kauei. — (I)ammara australis.) The kauri is the finest tree in New Zealand, and produces the most valuable timber. It is restricted to the northern part of the North Island, and does not occur in any quantity south of a line drawn from Port Waikato to Tauranga, although solitary trees or small groups are found as far south as Maketu on the east coast, and Kawhia on the west. It attains the height of 120 to 160 feet, and upwards : clean symetrical trunks may be seen from 50 to 80 or even 100 feet in length, varying from sto 12 feet and upwards in diameter. The timber has acquired a reputation above all other New Zealand kinds from its value for masts, spars, and other purposes of naval architecture, which, about the commencement of the present century, led to its being exported for use in the British dockyards. Except for general building purposes, its use has been chiefly confined to the North Island, where there is abundant evidence of its durability for more than thirty years in some of the old mission