National Geographic : 1903 Nov
RUBBER PLANTATIONS IN MEXICO AND CENTRAL AMERICA NEXT to coffee and sugar, crude rubber is the largest of the tropical imports of the United States. It is the only one of these three for which we are entirely dependent on foreign countries. The value of the crude rubber that we import every year, 55,000,000 pounds, reaches about $30,000,000, but none of it comes from Porto Rico or the Philippines. Over one-half of the total is imported direct from Brazil, while considerable quanti ties come from the United Kingdom, presumably the products of her colonies, and from Belgium, chiefly the product of the Congo Free State. It occurred to the Department of Agri culture, while pondering what new in dustries might be found for Porto Rico and the Philippines to improve condi tions on the islands, that rubber trees might be grown profitably on them. An agent of the Department, Mr O. F. Cook, was therefore sent to Central America and Mexico, where millions of dollars are invested in rubber planta tions, to study rubber culture and to report on the advisability of starting similar plantations in our new island possessions. Mr Cook spent several months at the different rubber planta tions, and his preliminary report has been published by the Department. It is yet too soon to state definitely whether rubber trees can be successfully grown in Porto Rico, but the prospects seem favorable for growing the Castilla rubber tree, as the southwestern part of the island is dry and hot. It should be noted that crude rubber may come from three different kinds of rubber trees, each requiring different climate and soil. There is the Para rubber tree (Hevea),which thrives in the wet valley of the Amazon, but which will not grow in a dry climate; the Assam rubber (Ficus elastica) of Java, also needing a humid atmosphere; and the Castilla rubber tree of Central America and Mexico, which prospers best where it is dry and hot and will not grow in swamps or wet soil. Mr Cook recommends that experiments be begun by planting a number of Castilla rubber trees in Porto Rico and the Philippines, but he warns the American public against investing large sums in starting rubber planta tions until it has been proved that the rubber tree will grow successfully on these islands. The accompanying illustrations, for the use of which the NATIONAL GEO GRAPHIC MAGAZINE is indebted to Mr Cook, give interesting information about the rubber tree and the native Mexican method of tapping it for its milk.* It would seem to be a very simple matter to improve on the rude gashes made by the machete of the rubber gatherer, but this has not proved to be easy. The rubber milk is not the sap of the tree and can not be drawn out by boring holes in the trunk, as is done with the sugar maple. The milk is not in the tissues of the tree, but is con tained in delicate tubes running length wise in the inner layers of the bark, and to secure milk in any quantity it is nec essary to open many of these tubes by wounding the bark. The rubber is formed in floating globules inside the tubes and can not pass through their walls, so that even a suction apparatus would not bring it out unless the tubes were cut. The method by which the natives of Soconusco, Mexico, have been accus tomed to extract the milk is shown in * Consult"' The Culture of the Central Amer ican Rubber Tree." By0. F.Cook. U.S. Department of Agriculture: Bureau of Plant Industry-Bulletin 49.