TUNG OIL.

Auckland Star, Volume LIX, Issue 171, 21 July 1928, Page 15

TUNG OIL.

TREES FOR DOMINION. A NATURAL. VARNISH. USED FOR MANY PURPOSES. (By Tflogrni'li —own Corrrspondent.) WELLINGTON, this day. If asked whether tung oil was used internally or externally, probably not one person in a hundred would be able to admit of any knowledge on the matter. A hazarded answer that it was used externally would be right, but externally only on bodies of motor cais and on woodwork in general, not on human bodies. Any painter or varnisher, however, would be able to add the information that tung oil is a most valuable ingredient used in the paint and varnish trade, that supplies are hard to get, arrive irregularly, are often adulterated, and are unduly expensive. With a view to remedying this state of affairs, the Department of Agriculture has recently arranged for the introduction of the tung tree into the Dominion. The tree itself, botanical\y known as Aleurites cordata, is more generally known as the Chinese varnish tree. It is deciduous, growing to a height of 20 to HO teet, with big leaves and handsome flowers, and coming to fruition in about five years. The oil is obtained from its nuts, which, when ground, yield a considerable amount of oil.

The tree will apparently grow on poor quality hill country as long as it has a fair rainfall and not too low a winter temperature, and it also needs a fairly high summer temperature. A lew of these trees have been growing near Auckland - for some years, and seem to have taken kindly to the conditions, and it Is thought that the rough gum lands of North Auckland, the poorer hill country of the Nelson province, and some places in the Wellington district will prove suitable areas for experiment. It was about twenty years ago that the value of tung oil in the manufacture of waterproof varnishes began to be recognised. It was found that such varnishes when dry would not turn white when melted, and it was found that their drying time was superior to that of varnishes made with linseed oil, and that their weathering properties were better. Hence tung oil was in great demand commercially, but unfortunately the sole source of supply was China. Away up the Yangtse River, far in the interior, grew the tung tree, and there only. Coolie labour ground the nuts, extracted the oil and prepared It for exportation. But all inquiries about the tung oil Industry were met by bland •miles ot stoical rebuffs on the part of the Chinese growers. The process was a secret one, and a secret it would remain.

Energetic agricultural experts, however, got to work, and through the Consular services got hold of a number of young trees and planted them in varloqs parts of the United States. In 1928 the first large groves were planted in Florida. To the 3000 acres of bearing trees it is intended to add another 1000 acres each year until production has made at least a measurable approach t* the demand. The objection was made that it would be impossible to compete with the cheap labour of the Chinese coolie but it has been found that one standard press will do the work of 100 eoolies much more efficiently and quickly. From 109 trees on one grove in Florida last year, the first one to bear commercially, a yield of 1020 lbs of oil was obtained, an oil of lighter colour and higher quality than the Chinese product. Observers in China have seen with amoxement the many uses that the Chinese has for tung oil besides the manufacture of paints and varnishes. He waterproofs his boats with it; he uses it to mix with shavings to make roofing material; he uses it on silks, raincoats, paper, and a long list of articles where waterproofing is desired go if Alcurites cordata takes kindly to New Zealand's soils and climate, its introduction may prove to be a veritab.e lioob and blessing, relieving painters and ▼arniehers of all anxieties as to their supplies of tung oil, and providing an oU which all will be able to make use of in a variety of ways. Time alone will tell whether the turtg tree will come M> to expectations, but agricultural experts see no reason why it should not.