NATIVE HARDWOODS

Evening Post, Volume CXII, Issue 53, 31 August 1926, Page 2

NATIVE HARDWOODS

PUKATEA AND KOHEKOHE

USE COULD BE EXTENDS©

FOREST SERVICE LEAFLETS,

Two New Zealand hardwoods, tbe pukatea and the kohekohe, tfre the subject of leaflets issued by the Dire»tor of Forestry, and prepared by Mr. A. R. Entries, Engineer in Forest Product! to the Forest Service.

Kohekohe is commonly known ai the New Zealand mahogany, and is a suitable substitute for such imported timbers as mahoganies, cedars, rosewoods, oaks, etc., which are largely used for interior finishing, fitments, fixings, and furniture.

Pukatea, which stains well, is also good for furniture and fixtures; but, further, its strength, toughness, and lightness rn^z it of especial value for boat building; its resistance to' the teredo and marine borers (no New Zealand timber save totara excels it in this respect) make it valuable for wharf piles and bridge piles; also, although it is a hardwood, its easy working and good nailing quality fit it for the same class of work as the lighter softwoods —weatherboards, interior lining, and panelling (in which its natural grey-brown colour and cloudy silvery lustre are attractive).

The pukatea is one of the tallest trees in the native forest, and produces a millable log from 50ft to 6uft long, and from 2ft to 3ft average diameter. The kohekohe is a comparatively small forest tree (height 30ft to 60ft), and produces on the average a log 20ft long by 16 inches diameter.

Both trees are found in" the North Island and in the Nelson-Marlborongh conservation area. In the North Island the supplies of pukatea are considerably less than 1 per cent, of the total timber available, but in Nel-son-Marlborough it ranks as the third most important hardwood so far at valuable supplies are concerned. Tha total supplies are estimated approximately at 150 million, feet b.m. Bnt the available supplies of kohekohe of millable size are estimated to produc* not more than 50 million feet b.m., and it ia probably that not more than onequarter of that amount will ever b« milled i£ present methods of forest exploitation continue indefinitely. Kohekohe may be exploited in. conjunction with associated species in the Bay of Plenty and Nortu Taranaki; bnt the most important commercial area is that on d'tTrville Island, where it occurs in the valleys in an almost pure stand.

Prom the above it will be gathered that Nelson-Marlborough has a particular interest in the two leaflets from which the above details are gathered.

Under the head of "production" the leaflets state:—

Pukatea: "The average annual c»t of pukatea is estimated to total only 100,000 feet, broad measure, per year. The largest reported cut in the annual returns published by the Government Statistician was, for recent years, that of 154,000 feet, broad measure, for the year ended 31st March, 1925. The Nel-son-Marlborough conservation region is the most consistent producer of pukatea, although the various 'North Island forest-conservation regions contribute small quantities from time to time. The average mill value f.o.r, for the year ended 31st March, 1924, was 21s 9d per 100 feet, broad measure; whereas for the corresponding period, 1925, it wa« only I6s 9d per 100 feet, broad measure." . . .

Kohekohe: "Kohekohe timber is produced in small quantities, and seldom figures in the reported annual cut of timber published by the Government Statistician. The quantity produced in any single year probably has not for many years exceeded 100,000 feet, broad measure. It seldom appears on tije open market, being sawn in general for some particular market. Small logs up to 18 inches average diameter produce a large amount of sapwood. The most valuable timber is produced from logs varying from 2ft to 3ft in average diameter. These produce a largo proportion of heartwood." . .

In kohekohe the sapwood is a clear brownish-white in colour, well adapted for staining in a wide variety of finishes. The heartwood is of a pinkish colour when first cut, but seasons to a deep blood-red tint similar to that of many mahoganies. The flat grain is more attractive than the quarter. The growth-rings are extremely difficult to distinguish even by the microscope. Kohekohe timber weighs approximately 361b per cubic foot at 12 p«r cent, moisture content. The green timber may weigh as much as 641b per cubic foot. Pukatea is the lightest of the native hardwoods, weighing from 271b to 291b per cubic foot at 12 per cent, moisture content (based on the oven-dry weight of the wood). The wood is soft, and does not split readily. Nails may thus be applied close to the ends of boards without splitting the wood. Pukatea does not ignite easily, and is slow-burning. Its fuel-valna is low. Present uses of pukatea could be greatly extended.

If pukatea is prprjerly exploited, manufactured, and seasoned, however, and intelligently used, it may be considered very durable of contact with the ground. Kirk reports that external roofing-boards were in good condition after seventeen years' use.

Kohekohe is not durable in the ground except in loose sand, in which is the most durable of all native timbers. Out of the ground its durability is dependent upon its intelligent use. Properly manufactured and thoroughly seasoned, the wood should give good satisfaction for many years.

Other useful information will be found in the leaflets, including the question of susceptibility to insect attack.