Vol XII. No. .JOi. 



THE AGRIOULTDRAL NEWS. 



403 



VEGETABLE OILS. 



'WOCD-OIL' TREES IN THE WEST INDIES. 



The correspondence began in I'ebruarj- IIUI, when the 

 Iiui>prial Commissioner of Agriculture for the West Indies 

 wrote to the Director of the Uoyal Gardens, Kow, for 

 information concerning wood-oil and its bot^inical sources. 

 After an examination of the references* obtain'^d as a result 

 of this correspondence, it was considered desirable to procure 

 seeds of the more economically val lable species of the wood- 

 oil trees {AUiirites I'ordii) from Hong-Kong. 



With this object, the Superintendent of the Botanical and 

 Forestry Deijartni' nt, Hong Kong, was communicated with 

 from this Office and from Kew, with the result that early in 

 January 1912, a small bag of A. Fuidi' seeds from trees 

 grown in one of the Department nurseries was safely received 

 in Barbados. A few weeks later two other and larger con- 

 signiaents arrived. These were from Foochow and weie 

 obtained by the Superintendent only after considerable de'a}- 

 and trouble occasioned by the disturbed state of affairs in 

 China at that time. 



The seeds were distributed to .Antigua, St. Kilts, Mon'- 

 sertat, Dominica, and St. Lucia. Tliey germinated success- 

 fuliy According to the report on the .Agricultural Depart- 

 ment, Dominica, 1 91 "2- 1.'!, the seedlings are ])roniisiDg while 

 in the nursery: but on being planted out in the field at low 

 elevations, remarkably little growth is made. It must be 

 remembered, however, that this tree in its native habitat 

 thrives best on rather drj' and rocky hillsides. A few plants 

 aie under trial in the Dominica hills, in which places 

 it is expected better results will be 'obtained, though 

 po.'fibly the rainfall is too heavy. Evidently the tree 

 has shown some jjromise in St. Kitt.=, for in the Report 

 or. the I'otanic Station of that island lor 1912-13, it is seen 

 that foity plants have been raised in the nurseries and are 

 being distributed in the Presidency. In all the islands, 

 germination and early developtnf n!; have been satisfactory, 

 but more time is required before final judgement can b-j 

 passed as to subsequent growth and general suitability. 



The genus to which this particular 'wood oil' tree 

 belongs is, as already intimated, Aleurites — a genus belong- 

 ing to the Natural Order Euphoibiaceae. It contains si.'c 

 species, all trees and natives of extreme eastern Asia and 

 Malaysia. The setds of all the species are rich in useful fixed 

 oils — hence the economic value of the genu.s. Although 

 A. Fcrda is a new introduction into the West Indies, 

 A. trilohii, one of the less useful species occurs on a fairly 

 large scale in Nevis, and is also to be found regularly bear- 

 ing fruit, in the Botanic Gardens at Antigua, Montserrat, 

 I)ominica and other places. 



The chief species of commercial importance, however, 

 other than A. Fordii, are A. Montanu, Wilson, n. comb., 

 which is restricted naturally to an area in south-eastern 

 China (^1. Fordii being confined to the central provinces of 

 China from the coast to near the borders of Thibet), and 

 A. cordato, 1!. Brown apiul Stendel, a native of southern 

 Japan. For an account of the distinguishing botanical 

 characteristics of these species the reader is referred to the 



*(1) 'Wood-Oil: Its source, cliar.acter and uses'. Compiled 

 by F. Boehui, 16, Jewry Street, London, 1902. 



(2) Keir BnUf'in, No. 4 of 1900. 



(."i) Excluini,'e Oat.iluijui: of the Eala Botanic GanltMi 

 (Belgian Cv.ngo)'for 1!I09. 



f4) Bvlhtiii ut the Jiitperid Instilnte, VoL V ( 1'. 07), p. IM 

 (See also Ihid, Vol. XI, No. 3, p. 441 ef, se.,.) 



liidlHin of tliK Iiiqjtrud Institute, Vol. XI, No 3 (1913), 



p 441 et seij. 



From the economic asj^ect, the important point to bear 

 in mind is that the oil from the seed of any of these species 

 has been indiscriminately known to foreigners trading with 

 China as 'wood oil'. According to the reference i|M"ted 

 above, tung-oil (oil from A. Fordii) possesses characten.-tic 

 properties. Its specific gravity is higher than that of almost 

 any other vegetable oil except castor and tallow-seed oils; it 

 has a refractive index considerably higher than that of any 

 knon-n vegetable oil, and it has a high viscosity. The most 

 characteristic property of the oil is its conversion into a firm, 

 gelatinous mass when heated to a temperature of 2.50°C. or 

 over, for a short time: this change appears to be due to 

 polymerization and not to the absorption of oxygen. This 

 polyn.erized oil does not melt on being further heated, and is 

 insoluble in ether and the other usual s ilvents for oils. 

 Genuine tung oil should, on being heated, yield a firm jelly 

 which will crumble readily in the fingers and is not sticky. 

 Samples adulterated do not possess this property. 



It would appear that these characteristics may be com- 

 mon to the oil of both .1. I'ordii and A. montnni. At least 

 nothing is stated in the reference to the contrary. But the 

 oi! '.„m the .lapinese .species is entirely different. When 

 heated at 2.50°C., this oil does not solidify. Also its specific 

 graviiy is lower than the Chinese oil. 



The principal uses of tung oil are in the paint and varn- 

 ish industries, and there is a big and increasing ilcniand for 

 lue pioduct. It fetches a higher price than linseed oil. 

 A significant feature of this demand in regard to the West 

 Indies is that it exists principally in the LTnited States and 

 Canada. Already this Office lias been in communication 

 with a Canidian and an American firm in connexion with 

 the matter, anl indeed one of the first specimens of the seeds 

 received at this Office was kindly sent from a firm in the 

 LTnited States. 



As already stated, the tung-oil tree is essentially a hillside 

 j)lant and prefers a dry rocky soil. If the trials which are now 

 being conducted in Dominica and elsewhere show tliat the tree 

 can thrive on West Indian hill-land, it might conceivably be 

 possible lo plant the tree in sufficient numbers for com- 

 mercial purposes. The tree is a quick grower, bearing in 

 four to five years. .According to Ciiridar No. Id-', Iiureau 

 of Plant Indu.stry, United States Department of Agriculture 

 (1913), the imparts of the oil into the United States in 1911 

 amounted to -5 million gallons, to produce which 40,000 

 acres of trees would be required, planted 20 feet by 20 feet — 

 that is 108 trees to the acre A. Fordii has been .success- 

 fully cultivated in the Southern States and it is believed that 

 it would thrive in any warm- temperate, rocky locality. In 

 the part of China where the tree luxuriates, the temper.ture 

 seldom falls below 2.j°F.. whilst the summer temperature is 

 as high as 100°F. or more. 



Since the above was written the November is>ue of 

 Tropical Life has been received. This contains an article 

 which is headed the Biao nut, Tung, or Wood oil. It states 

 that in the Philippines the tree which produces the liiai nut 

 is known botanically as Aleurites trUolia. The oil from this 

 tree is sought after by the United States varnish maker.s, 

 and it appears to be justifiable to assume that the I'.iao nut 

 oil is in the same class commercially as tung oil, which as 

 already stated in this article is derived principally from 

 Aleurites Fordii. This information is naturally of consid- 

 erable interest, in view of the fact that Aleiintex frdofvi has 

 been well established in several of the West Indian islands, 

 especially in Nevis. 



