25/ 



volume of latex between young and old trees is considerably liigher 

 in old trees ; thus : - 



No. of Trees. 



Total 



Girth. 



Latex. 



Dry Rubber. 









Young Trees. 





90 



220' 



5" 



3511 



37 Ihs. 



120 



270' 



lOi" 



343.3 



43 „ 



100 



276' 



lO.V' 



3981 



48 „ 









Old Trees 





50 



209' 



4A" 



3323 



75 M 



In previous reports we have called attention to the necessity of 

 wide planting as the most inijiortant factor in the annual increment 

 of growth of rubber trees. Such increment, we consider, should not 

 be less, for the average of an estate, than two inches per annum be- 

 tween the third and thirtieth years. 



The increment of growth of para trees is variable according to 

 situation, soil, humidity ; but the ratio of increment also varies ac- 

 cording to the age of the tree, thus : — 



Increment 

 6 years 



I' SVa" 

 1' 6^8" 



r 1 " 



0' II" 



5 years old 



5 ). )) 

 16 



28 „ 



1904 



5%" 



6%" 



1905 



1' gVi 

 I' uy^" 



3' n%" 

 9 3H" 



We would estimate the ratio of growth where the general con- 

 ditions are fair as follows : — 



1906 



2' T%" 

 2' 3%" 



4' 3" 



9' SV4' 



1909 

 2' ii%" 

 3' 0V4" 

 4' lo-M" 

 10' oW 



From 5 to 15 years 

 „ 15 » 20 „ 

 M 20 „ 30 „ 



3 to 4 inches per annum. 



2 „ 3 



I „ 2 



however, 



mav be modified in 



The normal increment of growth, 

 any particular year through prolific seeding". It has been ascertained 

 with oaks and beeches in temperate countries that the annual 

 concentric ring of new wood may be reduced as much as 50 per cent 

 a.s a result of heavy seeding. 



There is a far more important cause which checks the normal 

 growth of Para trees when overcrowded. With trees in general there 

 is usually some excess of food assimilated which gradually accumu- 

 lates until exhausted or disposed of by a heavy crop of seeds; but in 

 rubber trees regularly tapped, the plant food formed by the tree has 

 not only to provide the formative substance of a seed crop— as well 

 as find nutriment for the cambium zone, but it has also to furnish 

 material for new cell walls which are regularly formed as tapping 

 proceeds. To meet this extra demand well developed trees with 

 abundance of leaves- -really manufacturing organs are necessary, but 

 as a consequence of overcrowding and the resulting struggle for ex- 

 istence a small crest of leaves manages to reach the light and such 

 diminished organs are incapable of elaborating the necessary food. 



It does not appear to us that such trees suffer directly as latex 

 producers. All our observations and experiments tend to show that 



