442 



The ratio of growth all trees varies at different periods, with 

 the Para rubber tree the best growing period is undoubtedly be- 

 tween the 6th and 15th years during which time trees may 

 increase from about 24 inches in girth to 60 inches or more, thus 

 shewing an annual increment of growth from 3-6 inches. We 

 have shown that trees closely planted do not make a satisfac- 

 tory increment of growth, and that the yield of rubber increases 

 with the size of the tree from under \ oz. of dry rubber to the 

 inch of girth for small trees, to over \ oz. for large ones and to 

 further emphasise the fact and the error of close planting we 

 submit the following statements taken from the figures of the 

 experiments : — 



Number 

 of Trees 

 Tapped. 



Average 

 girth PER 

 Tree. 



Aggre- 

 gate 

 girth. 



Dry 

 Rubber. 



Remarks. 





Ft. in. 



• 



Ft. in. 



Lbs. ozs. 





40 I 



2 3 



90 7i 



18 ;i 



Tapped 18 times. 



20 J 



4 2 



83 7* 



25 6 





50 1 



1 9 



88 7 i 



18 8j 





15 ) 



5 8 



85 7 



33 8 





This we think conclusive, and that the first object of every 

 Para rubber cultivator should be to aim at well developed trees, 

 and this can only be attained with trees which have been well 

 distanced from the time of planting, for as soon as the roots touch 

 and become intermatted the growth of the tree is impaired. We 

 also think that whatever be the methods of tappings — whether 

 those now in vogue, or those to come — the result can only be 

 safe when the annual increment of growth is up to standard as is 

 shewn by the figures quoted. 



There is still a further objection to close planting by the 

 reason of the probability of the spread of fungoid disease. We 

 do not now enter into all the different pests and diseases of Para 

 rubber which are familiar to readers of the Agricultural Bulletin 

 but none of which need be regarded seriously excepting the 

 fungus (Fomes semitostus) this if once established might prove 

 very serious on estates closely planted, for the roots already inter- 

 matted remain and the fungus is not apparent until a tree drops. 



The thread-like mycelium is exclusively underground and 

 when well developed some fruits may appear at the base of a tree 

 but the tree is then doomed and past recovery. Only one thing 

 can be done, to clear a sufficiently large area and isolate the ground^ 



