PARA RUBBER. 73 



These results show that the maximum yield, per given area, is to 

 be obtained from the base up to a height of about five feet. Other 

 experiments have proved that the yield from the base to three 

 feet is considerably more than that from three to six feet. 



Experiments in Ceylon. 

 Experiments carried out in Ceylon * strongly support the same 

 conclusion, and the following are typical examples of the results 

 obtained : — 



Number of . , d Yield of 



Incisions. Area tapped. T.atex in c.c. 



26 .. 12 inches from base .. 24-5 



26 . . 36 „ „ .. 180 



26 72 ,, .. 18-5 



111 . . At base of trunk . . 30 



14 . . At 48 inchesf rom base . . 14 



14 .. At 108 ,, •• 11*5 



The conclusions which Parkin drew from his experiments were, 

 " that there is a greater exudation of latex from wounds made at the 

 base of the trunks of Hevea trees than at any higher region : that 

 the exudations from one to five or six feet up the trunk differ little ; 

 and that above five or six feet the latex exuded falls off very consider- 

 ably." Experiments in the Straits have shown that the first 

 four feet from the base contain the maximum amount of latex, but a 

 height of six feet is allowed by many planters. It is well-known to 

 planters in Ceylon that the quantity of latex obtained at five to six 

 feet from the ground is little more than half that at the base of 

 the trunk ; nevertheless, a yield of over 1 to 3 lb. of rubber, per tree, 

 is expected on certain estates by tapping the area from six to 

 ten feet above ground. The latex obtained from areas twenty 

 feet from the base is often very sticky and may not yield good 

 rubber, but this is by no means always the case. On some 

 estates in the Ambalangoda, Kalutara, and Matale Districts the 

 old rubber trees are said to give latex of good quality from six 

 feet upwards. 



According to Dr. Haas, the trees in Java gave the largest yield 

 in their lower parts, and tapping up to a height of 15 metre gave 

 the best results. 



Tapping the Higher Parts of Trees. 



Base to 50 feet. 



As previously indicated, it is possible to obtain rubber in paying 

 quantities from parts of the stem above six feet. At Henaratgoda 

 the trees have really never been cultivated, and many of them, 

 though thirty years old, have never been tapped. The result is the 

 stems are very high, and present smooth surfaces such as one would 

 desire for ideal tapping operations. Such trees are occasionally found 



* Parkin, I. c, pp. 128 and 131. 



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