June 1, 1916.] 



THE INDIA RUBBER WORLD 



505 



THE WIDE PLANTING OF RUBBER. 



THE Departnienl of .\griculturc of the Federated Malay 

 States is doing good work in inducing the native 

 planters to adopt modern ideas in growing rubber. It has 

 recently caused to be translated and printed in Romanized 

 Malay a paper on the thinning out of rubber plantations, 

 which is being circulated for the benefit of native holders of 

 small plantations. The subject treated in this paper is one 

 of the most important atlecting small holdings in the Malay 

 Peninsula where rubber trees v\-ere first planted very close 

 together, generally 10, 12 or 14 feet apart. Experience has 

 proved that such plantings were much too close. Most of 

 the large estates with closely planted areas are beginning 

 to thin them out, to reduce the total number of trees to 

 about 100 per acre. 



The paper above referred to advises that in planting new 

 areas, distances apart should not be less than 20 feet, which 

 would total but 108 trees to the acre. It is further stated 

 that time will probably show that 25 feet by 25 feet, or 70 

 trees per acre, is a better plotting for planting rubber trees. 



It is explained that trees that are closely planted have too 

 small a leaf area, and are much more liable to attacks of 

 disease. When tapping commences they are still further 

 weakened, and. therefore, the renewal of bark is not vigorous, 

 this renewed bark being so thin that it is impossible to tap 

 the trees without wounding after the original bark has been 

 consumed. 



Citing benefits obtained by thinning out, the paper says 

 that the trees are much healthier, yield more rubber, and 

 renew their bark quicker. It has been found that after 

 thinning out, many trees will yield double the amount of 

 rubber, and not only that, but the quality is improved, for 

 it is argued that labor is reduced and it follows that if the 

 yield per tree is doubled, a less proportion of scrap will be 

 obtained when only half the number of trees is being tapped. 

 Again, if the number of trees is reduced, there will be a 

 large saving on tapping equipment, as a less number of cups and 

 spouts will be required to bring in the same amount of latex. 



All this is clearly explained and illustrated in plain, simple 

 language which native holders can easily understand. 



Advising as to the best method of thinning out, the paper 

 says that, first, all small, weakly trees, which are very back- 

 ward in appearance, should be removed because their stunted 

 growth is sure to make of them very poor yielders of rubber. 

 The process of selection and elimination should next con- 

 cern trees which have a very irregular growth, such as bad 

 trunks and forked branches, which are liable to be split by 

 winds. After these have been exhausted it may be found 

 necessary to cut out a number of good trees in order to 

 improve the spacing of those which remain. 



If trees in the area to be thinned out have not reached 

 the tapping stage, they should be reduced to lOO trees per 

 acre immediately, but if they are producing it should be 

 carried out gradually at intervals of, say, six months, so 

 that any drop in yield will not be apparent. Trees should be 

 cut out completely and roots extracted and burned in order that 

 no disease may attack the dead stumps. To tap stumps to death 

 is unprofitable because of the small margin left by the present 

 price of rubber. 



The drop in the yield of an area in process of thinning 

 out is only temporary and after a period of six to twelve 

 months the yield per tree increases and makes up for the 

 trees which have been removed. 



When trees are very closely planted the yields fal! rapidly 

 when tapping renewed bark is commenced, and while close 

 planting may have shown good profits with rul)!)er selling 

 at high prices, today the margin of profit is very small, and 



the maxinnini yield per tree must be obtained to keep 

 down the expense of collecting. 



The longer thinning out is delayed the more difticult is 

 the work, and the longer will the remaining trees take to in- 

 crease their yields, and the lower will be the ultimate profits 

 per acre. 



COMPOSITION OF AN OLD RUBBER TREE. 



AN ANALYSIS has been made, by M. Kelway Bamber, 

 of a rubber tree 11 years old, measuring 34 inches in 

 circumference at 3 feet from the ground. It was cut before 

 leaf fall began. The trunk weighed 820 pounds and the 

 branches and leaves 305 pounds; total 1,125 pounds. The 

 trunk and branches were burned separately and yielded 

 0.445 per cent and 2.54 per cent of pure ash respectively. The 

 total ash was 11.4 pounds, equivalent to 1.01 per cent on the 

 whole tree. The total ash in 100 trees per acre would be 

 1,140 pounds, all of which has been taken up from the soil, 

 and partly from the annual leaf-fall during 11 years' growth. 

 The ash consists chiefly of carbonates and phosphates of 

 lime, potash and soda. The phosphoric acid is about one- 

 third of the lime, and one-half the potash content. The 

 average percentage of soda is higher than the potash, which 

 is unusual, and would indicate a deficiency of available potash 

 in the soil in which the tree was grown. The table shows the 

 composition of the ash as to its chief constituents: 



Total Average 



Ash Branches per acre Absorbed 



Constituents. Wood. and Leaves. Average. 100 Trees, Annually. 



Per Cent. Per Cent. Per Cent. Pounds. Pounds. 



Lime 21.20 20.00 20.60 235 21.3 



Magnesia 6,04 6.77 6.40 73 6,6 



Potash 14.96 10.34 12.65 144 13.1 



Soda 14.79 15.69 15.24 174 15. S 



Phosphoric Acid,. 7.80 6.53 7.16 81 7.3 



Sulphuric .\cid... 2.88 2.54 2.71 31 2.8 



Dry rubber contains only about 0.32 per cent ash, and 400 

 pounds per acre would only remove about l-}^ pounds of 

 mineral matter, a quantity that is negligible. 



PREPARATION OF RUBBER IN FRENCH AFRICA. 



T 



HE following translation from a circular addressed by the 

 lieutenant-governor of the French Ivory Coast Colony to 

 subordinate administrative officers is of interest: 



Auctions recently held at railway terminals clearly demon- 

 strated the fact that prices obtained for lots of rubber depended 

 solely on the methods by which the rubber was prepared. Thus, 

 fine quality vine rubber sold at 4.94 francs per kilogram [about 

 $0.43 per pound] and Funtitmia rubber that was well prepared 

 brought as high as 4.70 francs per kilogram [about $0.40 per 

 pound], whereas, poorly dried rubber brought only 3.80 francs 

 per kilogram [about 33 cents per pound]. 



Therefore, you must oblige the natives to prepare their rubber 

 properly and handle it carefully right up to the market day. 



In this connection I wish to recall to your attention that the 

 object of having rubber prepared in slabs is not merely to pre- 

 vent fraud, i. e., by mixing foreign matter with the rubber. The 

 slab form makes it possible : first, to thoroughly wash the rub- 

 ber and eliminate all soluble impurities ; second, to dry it easily 

 and rapidly. 



The latter operation should be pushed as far as possible. The 

 increase in value is always worth the additional trouble. 



Drying should be performed in the shade, in a well ventilated 

 place. Slight smoking will help to preserve the dry slabs. 



The principal deterioration of rubber is a decomposition or 

 oxidation, which is favored by high temperatures. Well pre- 

 pared rubbers, and especially vine rubber, are rarely subject to 

 this form of decomposition ; however, climatic conditions here 

 are not favorable to the preservation of crude rubber, which 

 should be delivered to the export houses as soon as possible 

 after its preparation. 



When, for any reason, the natives are obliged to hold their 

 rubber, they should be instructed to store it in dark, cool, dry 



