Cultivation Of Tung Oil Trees

Growing Demand for Paint Ingredient Suggests New Industry for Islands Planters

THE oil, which is commonly called Chinese Wood Oil, is an essential raw material of present-day varnish manufacture, and its unique properties as a drying oil render it indispensable for certain types of varnish. It is also widely used as an ingredient of paint, and in the manufacture of electrical insulating varnishes.

The product was first introduced into Western Europe over 30 years ago and

was in greatest demand during the Great War, as it was essential for aero plane paints and varnishes. To-day. this oil constitutes one of the chief ex ports of China, and is worth approxi mately £3,000,000 per annum. There is keen competition for the oil and the price is maintained at a high level because all countries are dependent upon China for supplies.

The question of the cultivation of tung trees in the British Empire was taken up in 1927 by the Advisory Com mittee on Oils and Oilseeds of the Imperial Institute, London, in collab oration with the Director of the Royal Botanic Gardens, Kew, England, and the Director of the Research Associa tion of British Paint, Colour and Var nish Manufacturers. The Committee distributed supplies of seeds to many parts of the Empire, and results of trials are distinctly encouraging.

The cultivation of the trees in Flor ida, U.S.A., is successful. Over 550,000 are now growing there. In January

1930, an oil-mill was erected at Gaines ville, Florida, and this is the first com plete plant to be assembled in America for crushing tung oil seeds.

Two Species Of Trees.

There are two species of trees from which the nuts are obtained; the scien tific names being Aleurites Fordii and Aleurites Montana. The former fur nishes the bulk of tung oil exported from China.

A. Fordii is a quick-growing, small tree which occurs in the warm, tem perate parts of China, especially in the Yangtze Valley, where the Chinese grow small plantations on hillsides on land unsuitable for ordinary cultivation.

Here, the summers are warm enough for such crops as rice and giant mil let, while wheat is grown in the cold weather when slight frost and snow may occur on high ground.

The other species, A. Montana, ex tends from the province of Chekiang, in south-eastern China, to Tonkin, in French Indo-China, and the Shan States of Burma.

The presumption, therefore, is that A. Fordii is likely to thrive best in climates which are less tropical than those which favour A. Montana, and that the latter species may require a heavier hot-weather rainfall than

the former. Trials with the two spe cies in America seem to support this.

So far as is known, it appears that A. Fordii furnishes the best and most sought-for commercial oil.

Experiments In Australia.

Seeds of Aleurites Fordii were first sent to Australia in 1911. Experimental plots are now under cultivation at Pen nant Hills, near Sydney, at Grafton, N.S.W., and on the Johnston River, Queensland, where Amalgamated For ests (Australia) Ltd. have planted some 6,000 trees on red volcanic and alluvial soils.

Results of experiments with the oil produced in Australia show that it is of equivalent quality to that obtained from trees grown in China.

Through the Sydney Technological Museum, plants and seeds for experi mental purposes have been already sent to New Guinea and the Solomon Islands. On the Island of Malaita trees, which were planted in August of last year on certain selected situa tions, are doing remarkably well.

No seeds of the other species, A Montana, have yet reached Australia or the Islands, but some are now on their way to the Curator of the Syd ney Technological Museum.

Description Of The Trees.

In China the trees seldom exceed 30 feet in height and have a trunk of about 10 inches in diameter; the spread is from 15 to 30 feet. Tung trees have a low branching habit of growth. The foliage is dense, the leaves being large, dark green and more or less heart shaped. They are shed at the usual resting period for deciduous trees. The flowers are white, with pink centres.

Both in China and Florida the fruits ripen at approximately the same time— October. When fully ripe, they fall to the ground and eventually break open from the base upwards into three to five segments, each containing one seed. These seeds are composed of a fairly thick, woody shell, externally of a warty appearance, enclosing a creamy white kernel.

Some young trees in Florida com mence to bear fruit in the third year, though cropping on a commercial basis is not expected until the fifth year.

In New South Wales the experience has been that a good crop of fruit, yielding oil of satisfactory quality, is obtainable in the fourth year.

It is generally held that the trees will reach full bearing in their tenth year, though records of individual trees seem to indicate that progressive production may continue after this age. The oldest trees in Florida are not more than 25 years old, and they still appear to be vigorous.

Chinese trees are said to yield from 1 to 5 or more bushels of fruit, accord ing to their age.

As regards the yield of trees, a pam phlet on “The Production of Tuna Oil

in the Empire,’’ issued by the Empire Marketing Board, states: “Records for a group of 109 trees nine years of age and over growing in Florida, showed that these trees yielded 5,000 lb. (approximately) of dried fruit, equivalent to over 1,000 lb. of oil, in each of two different years. On another plot of 1.9 acres, three-year-old trees pro duced 1,096 lb. of fruit, or 576 lb. per acre, equivalent to 115 lb. of oil.”

It is estimated that 60 trees can be planted per acre.

Utilisation Of Nuts.

Concerning the utilisa tion of nuts, the pamplet says: “Although in America the intention is to crush the nuts for oil near the point of production, as re gards the produce of the British Empire it may be preferable in the early days of cultivation to export the nuts to the United King dom for the preparation of the oil. For this purpose the nuts would have to be separated from the fruits, and, after being dried in the air, if necessary, would be bagged for shipment.

“The outer husks yield only a very small amount of available ammonia, but their return to the soil would add appreciably to the humus content and this would be an important matter in sandy soil.

“The nuts are composed of about 43 per cent, of shell and 57 per cent, of kernel. In the kernels there is about 56 per cent, of oil. The nuts on ar rival in the United Kingdom would be

crushed by oil-crushers in much the same way as is practised with other nish and to other firms using tung oil. oil seeds. The expressed oil would be sold to the makers of paint and var nish and to other firms using tung oil.

It is considered that the English press ed oil would be of lighter colour and of better quality than the Chinese pro duct and, moreover, it would be of guaranteed purity.

“The oil would be readily saleable in the United Kingdom and would fetch a price equal to, or possibly a premium over, that of the Chinese oil, which was quoted at £69/10/- per ton in Lon don in January, 1930.” It has main tained its price during the past twelve months.

The Future Of Tung Oil.

Naturally, before proceeding with the planting of tung trees on a large scale, it would be essential to know the likely demand for the product in the future.

The question has been already raised abroad as to whether the larger quan tities of oil resulting from the extension of the cultivation of tung trees in America and the British Empire will have the effect of lowering the price of the oil to such an extent that the cultivation will become unprofitable.

The general opinion is that with in creased quantities becoming available, new uses will be found for tung oil, and those industries already employ ing this material will absorb greater amounts. The increased production will naturally tend to reduce the price somewhat, but it is considered that the reduction would not be so great as to render cultivation unprofitable.

As far as can be seen, there will be always a demand for tung oil, as it is a raw material which is essential in some industries —particularly the elec trical trades and aviation. It should always command a price higher than that of linseed oil.

The fact that America, which imports 80 per cent, of the world’s production, and whose annual consumption is 10,000,000 gallons—valued at about £2,400,000 —realised the urgent necessity for domestic production many years ago and is making steps to produce oil for her own needs, shows the import ance that she attaches to this crop.

In 1927-28, the first year for which individual figures are available, the im ports of tung oil into Australia were valued at nearly £36,000, and each year a slightly greater amount has been needed for local use.

Note: The Pacific Islands Monthly is endeavouring to gather all avail able information about the cultiva tion of Tung oil trees, and will publish further articles as material becomes available. Meanwhile we should be glad to hear from any of our Islands readers who are inter ested in the subject particularly about the progress of experimental plantations.

A full grown tree of average size, in China.

In the search for new crops to cultivate as an alternative for copra, islands planters might consider, the merits of the tung oil tree. The main product of this tree—tung oil—is each year increasing in im portance in the com mercial world.

Trials are being car ried out in New Guinea and the Solomon Is lands, and the results of these to date would suggest that the tree is suitable for cultivation in selected localities throughout the Islands.

There are already considerable plantations in Queensland, N.S.

Wales and New Zeal and. More information about the actual culti vation of the tree under South Pacific conditions is needed, however.

A Fordii tree 5½ years old, with fruit.