RUBBER PLANTING 89 



period the yield is more dependent upon the seasonal 

 rainfall. From old trees which have penetrated to the 

 water level, larger and more continuous yields are 

 obtained. This seems to be the case with the old 

 trees at Henaratgoda, where the water level is upwards 

 of 25 feet below the surface. 



Resting Periods. 



A question which is frequently asked concerns the 

 necessity or otherwise of resting periods. This also is 

 a question upon which definite experimental work is 

 required before a positive conclusion can be arrived at. 

 It has been recommended that tapping operations 

 should be suspended during the period of leaf-fall, and 

 this advice seems to be based upon reasonable grounds. 

 In climates such as those of South India and the north- 

 east side of Ceylon, the yield is found to be reduced 

 almost to nothing during the prolonged dry season. In 

 these climates the year is divided of necessity into a 

 season of tapping and a season of rest. 



From the available evidence it seems probable that 

 in countries not subject to periods of prolonged drought 

 continuous moderate tapping is likely to be more profit- 

 able than alternate periods of rest and severe tapping. 

 The continuous method is also distinctly more convenient 

 in connection with the working of a labour force. The 

 theoretical advantage of the continuous method is asso- 

 ciated with the habit which the tree seems to acquire of 

 manufacturing a steady supply of latex. 



