88 RUBBER AND 



it should be the aim of the planter to discover just that 

 rate of tapping which will lead to the most rapid 

 increase of yield under the conditions affecting each 

 particular field. 



Just as in the case of many other physiological 

 functions, the yield of latex at any given age would 

 appear to be controlled by a number of limiting factors. 

 The system and rate of tapping represent one such 

 factor. Others are the available space, soil and water 

 supply, and climatic conditions generally. These con- 

 ditions severally react upon what is probably the most 

 important factor of all, namely the individual character 

 of the tree. 



The rate of increase of yield will be reduced if the 

 trees are planted too closely. But the most profitable 

 number of trees which can be borne by any given acre 

 at any given age, is a problem which can only be solved 

 by prolonged trial and experience. When the soil is 

 rich, more space is required for the full development of 

 the trees than when the soil is poor. Similarly, more 

 space is required at any given age at low than at high 

 elevations. 



The condition of the water supply seems to have an 

 even more immediate effect upon the yield of latex. 

 Where the water level is close to the surface of the soil, 

 as in parts of the Federated Malay States, large yields 

 are obtained at an early age. When the water level is 

 deep below the surface, the roots may not penetrate 

 to the requisite depth for some years, and during this 



