234 



THE RUBBER INDUSTRY 



teristic features extending over the undulating lands 

 reaching to the foot-hills of the mountain ranges. In 

 Nos. i and 2 the water is near the surface, extensive 

 drainage is necessary, and the root growth of the trees 

 is principally lateral, the tap-root not penetrating below 

 the water-level. On the laterite soils the tap-root 

 penetrates to great depth, frequently as much below- 

 ground as the height of the tree is above the surface. 

 Intelligent appreciation, amongst planters, of this radical 

 difference of root growth is lacking, and no allowance 

 or consideration is given to it when laying out estates. 

 Trees are planted the same distance apart on high 

 lands, where a deep tap-root develops, as on low lands, 

 where the tap-root disappears, and its place is taken by 

 abnormal lateral growth. The trees develop rapidly 

 on both low or high lands ; but on the former they are 

 specially liable to serious damage from the severe 

 storms which constantly occur on the east coast of 

 Sumatra, and at times reach hurricane force. 



The rainfall on the East Coast varies considerably ; 

 it is controlled to a great extent by the high mountain 

 ranges intersecting the whole length of the island. The 

 following records for 19 n give a general idea of the 

 precipitation of moisture in different districts : 



