165 



CASTILLOA VERSUS HEVEA. 



The preceding paragraphs may serve to explain why no decision has 

 been reached on the very important question of the relative agricultural 

 value of the different rubber-producing trees. It has been supposed 

 thus far that the climatic and cultural requirements of the Para ruhber 

 tree (Hevea) and the Central American rubber tree (Castilloa) were quite 

 different, but the results of the present study seem to indicate that the 

 differences, if any, have been much overestimated The comparative 

 experiments thus far carried on in botanical gardens have, at most, but 

 a local value, and can uot be accepted as final. In Java, for example, 

 both Castilloa and Hevea were condemned in favor oi Ficus elastica 

 (Assam rubber), but it now seems probable that the continuously humid 

 mountainous district in which the experiments was tried was quite 

 unsuited for testing the productive powers of Castilloa, and probably of 

 Hevea also. 



It may be tl at no one rubber- producing species will attain any great 

 or exclusive preponderance, but that different climatic and s"il condi- 

 tions can best be met by planting different trees The wisest policy in 

 untried regions will be to make experimental plantings of all of the 

 more promising rubber trees. At present these are three in number : 

 ("astilloa, Hevea, and Ficus. Manihot (ceara rubber) can probably be 

 omitted from the list except for regions too dry for the others. 



UNCERTAINTIES ATTENDING RUBBER CULTURE. 



Some few rubber planters have not been contented to plant any- 

 where that the rubber trees could be made to grow, or even where 

 they grew wild, but have emulated the northern farmers who planted 

 young sutj;ar maples close by the productive parent trees. Some of 

 the plantations of Mexico seem to be outside the natural range of Cas- 

 tilloa, as they have found it necessary to import the seeds from other 

 districts. Others are in localities where the rubber tree grows wild but 

 produces little or no rubber. For example, in Soconusco it would be 

 entirely possible to establish a mbber plantation on the lower slopes of 

 the mountainous and humid coffee district, where wild Castilloa is not 

 uncommon. Fortunately, hovvever, rubber planting has been confined 

 to the warmer and drier coast plain and to localities where both wild 

 and planted trees have been found productive. That it will become 

 possible by correct method to produce rubber in countries where the tree 

 is not native, and even in localities where the wild trees do not yield 

 M ell, is to be expected, but it can scarcely be repeated too often tbat the 

 planting of more thm experimental quantities under untried conditions 

 is a hazardous enterprise, to say the least, und not to be indulged in 

 except by those who can afford to lose. 



In the British dependencies of the Malay peninsula. Para rubber 

 for several years past has enjoj^ed an era of rapidly increasing popu- 

 larity, heightened recently by the fact that some of the eurlier plant- 

 ings have begun to produce and that good prices have been obtained 

 for the samples shipped to Europe. But even yet the prize of success 

 may escape, since it appears that the new East Indian Para rubber, 

 though received with high approval by the importers, has been found 

 seriously defective in quality. 



