74 CENTRAL AMERICAN RUBBER TREE. 



PRODUCTIVENESS OF CASTILLA. 

 YIELD OF WILD TREES. 



That the Central American rubber tree, or at least some of its spe- 

 cies or varieties, may attain a very large size in nature and may yield 

 a very large amount of rubber, there is abundant testimony. Such 

 facts have, however, only secondary interest from the cultural stand- 

 point, because there are no means of determining the age of such trees. 

 It has been claimed that as much as a hundred pounds of rubber has 

 been obtained from a single tree. Koschnv relates that in Costa Rica 

 in the earlier da} 7 s giant rubber trees 10 to 13 and even 14 feet in cir- 

 cumference were commonly found. All such have been destroyed by 

 the rubber gatherers. Nothing but second-growth and young trees 

 are now to be found. 



The early literature of rubber culture abounds in statements exceed- 

 ing the fondest dreams which the modern stock company- dares to put 

 on paper. We may be certain, for example, that rubber culture would 

 not be still a new industry in Central America if the planters of that 

 region had found facts to warrant the statement published by Collins 

 in 1872, which probably led to the introduction of Castilla into British 

 India. 



A tree of about 18 inches in diameter bled by skillful hands in April would yield 

 about 20 gallons of milk capable of giving 50 pounds of caoutchouc. This is, how- 

 ever, the maximum yield; the average is a little below this. A tree of from 20 to 30 

 feet to its first branches is expected to yield 20 gallons of milk, and each gallon of 

 milk to give 2 pounds or 2 pounds 2 ounces of good dried rubber. « 



This estimate was somewhat reduced by Mr. Cross who visited 

 Panama in 1875 to procure Castilla for India. He says: 



A Castilla tree, with a diameter of H to 2 feet, if carefully and judiciously tapped, 

 may be expected to yield about 12 pounds of rubber per annum. Of all the different 

 species of rubber-producing trees, the Castilla should prove, under cultivation, the 

 most remunerative. '' 



YIELD OF CULTIVATED TREES. 



Two questions must be considered in attempting to judge of the 

 value of reported yields of rubber from planted trees. One is the 

 direct issue of veracity, the other the possibility of errors in some one 

 or more of the many known and unknown ways in which these can 

 come about. There can be no doubt that many direct and intentional 

 misrepresentations have been published regarding rubber culture, and 

 it would be quite gratuitous to suppose that those whose testimony on 

 other points is obviously wrong have been more careful when discuss- 

 ing the subject of yield. Until it can be shown that somebody has had 



« Report on Caoutchouc of Commerce, p. 15. 



& Report on the Progress and Condition of the Royal Gardens at Kew during the 

 YearlSSl, \>. L3. 



