226 



THE RUBBER INDUSTRY 



safer to allow this extra yield to compensate for any 

 shortage of sections that may from unforeseen circum- 

 stances fall below the estimated ultimate average yield 

 of 4 hundredweights to an acre. 



The following table gives the actual yield from 1906 

 to 1913, and the estimated output from 1914 to 1919 : 



ACTUAL YIELD, 1906 TO 1913 



ESTIMATED OUTPUT, 1914 TO 1919 



The estimated return is calculated on the ages of 

 trees in tapping, allowing 260 pounds per acre for trees 

 averaging six years old, 336 pounds for seven-year-old 

 trees, and 392 pounds for an average of eight years. 

 For 1916 and 1917 only 336 pounds per acre is cal- 

 culated, on account of the large proportion of young 

 trees yielding for the first time ; in 1918 an average 

 return of 392 pounds per acre is estimated for nine-year- 

 old trees ; and in 1919 a yield of 448 pounds per acre is 



