256 



Notes on the Cultivation of Hevea Braziliensis 

 (Para-Rubber) and the yield or Rubber crop. 



Para rubber is a crop which, if the plantations in the East are 

 carefully tended, might be continued for 60 years. The life of a tree 

 or estate may be lengthened or shortened by the treatment accorded, 

 but, as will be shown in these notes, the real test of successful 

 cultivation in view of prospective crops depends entirely on the 

 annual increment of growth of the trees. It is an indisputable fact 

 that the ratio of yield increases with the size of a tree, both in respect 

 of dry weight of rubber and better latex-producing rubber. The 

 following statement illustrates both facts : — 



SMALL AND LARGE TREES. 



No of 

 Trees 

 tapped. 



Aggregate 

 girth at 3 ft. 

 from ground. 



Number of 

 times tapped. 



Fluid ozs. 

 of latex. 



Dry 

 weight 

 of rubber. 



Ratio of fluid ozs. to ozs. 

 avoirdupois. 



90 

 120 

 100 



220' 5" 



276' lOf 



276' 10^" 



Small 



24 

 26 

 28 



Trees. 

 3511 



3433 

 3981 



37 lbs. 

 43 M 

 48 „ 



SU Nov.-Dec. 

 4-1 1 Oct.-Nov. 

 5 k Sept. 



310 



774' 2i" 



26 



10925 



128 „ 



(Total small trees). 



150 



743' 4-8" 



30 



Large 

 18748 



Trees. 

 251 8 



4i Nov.-Dec. 



It should be pointed out that the large trees have not been 

 specially selected and the returns from the same trees were much 

 more favourable in igo6, when these 150 trees supplied 15,280 ozs. of 

 latex which resulted in 268 lbs. of rubber. For the purpose of this 

 comparison, large and small trees were selected which had been tap- 

 ped concurrently and the apparent facts must be convincing, viz. — 

 310 trees of an average girth of 2-6" furnish more than half (slightly 

 over 9/16) of the quantity of latex and only about half the dry weight 

 of rubber of 150 trees of an average girth of 4-10", i.e., the large trees 

 were less than half the number of youne; trees : girth less ; latex less 

 pro rata ; dry rubber nearly double. 



The difference in the quantity of latex between young and old 

 trees of nearly the same aggregate girth is not very large, although 

 variable; it is evident, however, that the ratio of caoutchouc to the 



