i8i 



If it can be proved that the excessive tapping of intermediate 

 trees and the removal of their root stumps is calculated to aid in 

 the spread of diseases, then the system here outlined must not be 

 in any way encouraged, but until such has been established the 

 system deserves consideration. As matters stand at present, 

 where most of the rubber has been closely planted, it will be 

 necessary to adopt some process of thinning-out, if the Para 

 rubber trees are to receive the soil and light which their gradually 

 increasing size will demand. 



PERMANENT WIDE PLANTING. 

 The third possible system is that of permanent wide planting, 

 by which is meant that no thinning-out or intercrops of any kind 

 shall be entertained and the trees be planted at a distance suffi- 

 cient to last for the whole of their lives ; assuming that such trees 

 will be tapped from the time they are 20 inches in circumference, 

 a distance of twenty feet or over may perhaps be designated 

 as wide planting. A distance of twenty feet apart may not appear 

 to be a very wide one, but it is taken as the minimum in the 

 system under discussion, it may be completely covered by the 

 roots and foliage of untapped trees when 20 years old, but we have 

 no evidence of the demand which regularly tapped trees of such 

 an age will make. 



Briefly stated the advantages of permanent wide planting are 

 that the trees are never interrupted in their growth ; they attain 

 the maximum size in the minimum period of time ; thicker, shorter 

 and better yielding trees are obtained ; collecting and other opera- 

 tions are simplified ; diseases will probably not spread as rapidly 

 and can be more easily controlled. The disadvantages associated 

 with wide planting are that there is a deplorable waste of soil 

 until the ground is covered ; there is a serious reduction in the 

 available tapping area during the first ten or fifteen years the 

 fewness of the trees enhances the loss occasioned by the death of 

 a single tree ; and interplanting of such a property can only with 

 difficulty be carried out. 



The interruption in growth among closely-planted Para rubber 

 trees is one of the greatest disadvantages attendant on close- 

 planting, and the freedom from such of first importance when the 

 trees are more widely planted. But to argue that trees because 

 they are more widely planted will attain the maximum size in the 

 minimum period is apt to be misconstrued into meaning that the 

 trees always grow more vigorously and at a quicker rate ; it should 

 be clearly understood that there is an average incremental rate of 

 growth above which most Para rubber trees do not develop, and a 

 maximum annual average increase of five to six inches in stem 

 circumference is indicated by trees of varying age and planted at 

 widely different distances. The largest thirty-year-old tree at 

 Henaratgoda, neglected and grown on poor soil, has a circum- 

 ference of only 1094 inches, and the average of such trees, planted 

 at relatively wide distances does not exceed 75 inches — an incre- 

 mental circumferential growth of 2^ to 3 3-5ths per year for each 

 of thirty years. No one for a moment can doubt that, within 



