12 CENTRAL AMERICAN RUBBER TREE. 



especially in Brazil and in adjacent countries of South America, and 

 probably means that the natural supply of rubber will never entirely 

 cease, but will gradually become the basis for the development of 

 scientific forestry in the Tropics. There is, however, no probability 

 that any large proportion of the present producing areas will become 

 permanent sources of supply, and the cultural production of rubber 

 well deserves the serious consideration it is now receiving- in all agri- 

 cultural regions of the Tropics. 



Rubber culture is no new or recent proposition, since beginnings 

 were made nearl} T three decades ago. With an annual plant twenty 

 years of experience would teach us much, but for dealing with long- 

 lived trees that period is very short, and it need not be a matter of 

 surprise that rubber culture is still in the experimental stage. Many 

 cultural mistakes are still made with plants that have been in domes- 

 tication for thousands of years, and the failure of the first attempts 

 with rubber might have been predicted simply on the grounds of 

 probability. Nevertheless, a distinct period of discouragement 

 resulted, the effects of which are still felt and will doubtless remain 

 until more detailed knowledge makes plain the possibility of avoiding 

 the obstacles previously encountered. 



.Progress in practical matters as well as in purely scientific subjects 

 depends much upon theories. On the failure of the first experiments, 

 the theory that rubber trees could be profitably cultivated was dis- 

 carded by many who came to the conclusion that planted trees will 

 not produce rubber. This view is by no means extinct, especially 

 among those who have abandoned rubber planting- in disgust. An 

 adverse opinion of this kind is popular with some because it serves as 

 a general explanation of failure and spares the annoying suggestion of 

 cultural errors and oversights. 



Like other members of the vegetable kingdom the performances of 

 rubber trees have been found to depend upon the conditions under 

 which they grow, whether planted or self sown, unless they were 

 injured in planting. In the American Tropics and in the East Indies 

 the possibility of the cultural production of rubber has been demon- 

 strated. This fact is giving the pendulum the return swing in the 

 direction of sanguine expectations, and the assurance that rubber can 

 be produced culturally is too often taken as a verification of the origi- 

 nal estimates of yields and profits in spite of the fact that some of 

 these have been disavowed by their authors. A future of easy pros- 

 perity for the rubber planter is held to be assured, and the opinion 

 that rubber culture is still experimental is resented as blindly con- 

 servative. The lesson of the former miscalculation is forgotten by 

 the new generation of promoters, and the fact that rubber trees have 

 been found to thrive in a given locality is taken as sufficient evidence 

 that they will meet even the most reckless estimates of productiveness 



