Gums, Resins, 



446 



[Dec. 1906. 



dead tree stumps of Para rubber appear to be still keen on yielding latex, though 

 they have not produced a single leaf during the last three years. Estates in Ceylon 

 are known where average annual yields of f to 3 lb. of rubber per tree, for a 

 few years in succession, have been obtained- 



PRESENT AND FUTURE METHODS. 



As has been previously explained, the bark is the "mother of rubber," and 

 by the adoption of better systems of tapping, which obviate the necessity of 

 paring away the tissues wherein the milk accumulates, and drawing supplies of 

 latex by merely cutting and not excising the laticiferous tissues, is bound to result 

 in an increased yield since the life of the tapping area is so much prolonged. The 

 fact that a few well-developed trees have been made to give as such as 12 to 25 lb, 

 of rubber per year, and promise abundant yields in the very near future, shows 

 what a tremendous amount of material there is to draw upon, providing the 

 environs of the plant and tapping operations are fully understood. 



Ten years hence we shall probably smile, or appropriately express our 

 feelings in other ways, when we look back upon the methods we employed in the 

 collecting of latex and preparation of rubber therefrom, in the year 1906, or when 

 we reflect on the satisfaction with which we viewed our crude ideas and forecasts 

 jn the memorable year of the first Ceylon Rubber Exhibition. However, we are 

 not only willing but anxious to forget what little we know at the present time 

 for anything which will improve our future prospects. 



EFFECT OF CONTINUOUS RUBBER CULTIVATION. 



While rubber cultivation is in its infancy it will be as well to consider the 

 probable effect, in a comparative way, of its prolonged cultivation. The effect of 

 growing rubber trees is, especially with plants which, like Hevea, Castilloa and 

 Ceara, annually shed all their leaves, to be compared with that of a deciduous 

 forest vegetation ; the chemical investigations made at Henaratgoda show that 

 the soil may be improved in certain directions by growing Hevea trees for a period 

 of 29 years. If the rubber trees are grown in association with a permanent intercrop 

 of cacao, or a more or less transient crop of coffee, tea, cotton, camphor, etc., the 

 conditions are quite changed and many results are obviously possible. But when 

 the extraction of the product from rubber trees is considered, one can see that the 

 removal of the latex, and nothing more, necessitates very little exhaustion to the 

 soil. Compared with tea and even with coconuts or cacao, the soil exhaustion 

 following the removal of two pounds of latex per tree, per year, appears remark- 

 ably small. 



Unfortunately, however, we have not arrived at that stage of perfection 

 when the latex can be extracted by the simple incision of the laticiferous tubes, 

 and it is only possible to compare present methods of bark excision with those 

 meted out to cinchona in the past. 



RUBBER LAND AVAILABLE IN THE TROPICS. 



Comparing the past with the present, the planters in the tropics can already 

 profit considerably. In the old days Para rubber was planted mainly along streams 

 or the banks of rivers, near sea-level ; but to-day we know that, though in the' 

 Straits the cultivation appears to limit itself to places at a low altitude, in Ceylon 

 it can be grown successfully, and rubber of good value be obtained from trees at 

 an elevation of 2,000 feet and even at nearly 3,C00 feet about sea-level in districts 

 with a high temperature and poor rainfall. In Southern India even 3,000 feet is 

 not accepted as the maximum elevation at which Hevea brasiliensis can be slowly 

 but successfully grown. 



