, October, 1908. J 



315 



GUMS, RESINS, SAPS AND EXUDATIONS. 



OBSERVATIONS ON THE TAPPING 

 OF HEVEA. 



(Observations sur la Saignee de l'Hevea. 

 Journ. d'Agr. Trop., April, 1908, p. 106.) 



Abstracted by R. H. Lock. 



After several years of trial and experi- 

 ment both by practical and scientific 

 men, there still exists considerable 

 difference of opinion as to the most 

 rational arid economical method of tap- 

 ping cultivated Hevea trees. 



The rapid increase in the area culti- 

 vated with this product makes the sub- 

 ject an important one. 



The effect of tapping depends upon the 

 physiology of the particular species 

 tapped and the effect upon the future 

 life of the tree may be different in 

 different cases. It has been shown that 

 damage to the cambium is much more 

 prejudicial to Hevea than the mere 

 removal of latex. 



What is required is a simple and prac- 

 tical method which will reduce to a 

 minimum the time required for the 

 recovery of the tree, and at the same 

 time assure a large yield and a low cost 

 of manipulation. 



According to Dr. Willis' tapping 

 should not be started until the tree 

 measures 18 inches in girth from 

 the ground, and should then only be 

 done lightly. Johnson and Wright 

 increase this minimum size to 2 feet or 

 more in circumference. 



Attention is always paid rather to the 

 size of the tree than to its age in these 

 cases. 



The time required for the renovation 

 of the bark is put at four years by Wright 

 and at from two years to twenty-eight 

 months by Willis, according to the opi- 

 nion of various planters. 



Tapping every other day is regarded 

 by Wright, Carruthers, Ridley and Pit 

 as better than daily tapping, the ques- 

 tion of a longer interval is still under 

 discussion. 



Dr. Willis has recorded the remark- 

 able fact that left-handed cuts yield 

 more rubber than right-handed. 



Further research is required to deter- 

 mine whether tapping should be adjusted 

 to the wet and dry seasons of the year, 

 or simply carried out at regular 

 intervals. 



Tromp de Haas, after a visit to the 

 plantations of Ceylon, has published 

 observations from which the notes con- 

 stituting the remainder of the paper are 

 chiefly taken. 



Descriptions are given of the herring- 

 bone method, and of the half spiral 

 employed at Culloden, with tapping 

 alternately to the right and to the left. 



Pit in Java is said to have obtained 

 good results with what is described as a 

 quarter-spiral— a series of separate cuts, 

 the distribution of which is not fully 

 described. 



A diagram is also given of the longi- 

 tudinal series of V cuts employed by 

 Holloway on Kepitigalla. 



No decision is arrived at with regard 

 to the respective merits of these several 

 methods, though it is pointed out that 

 the full spiral is the most likely to affect 

 the vitality of the tree. 



SOMETHING DOING IN MEXICO. 



There is reason to believe that Mexi- 

 can exports are beginning to include con- 

 siderable rubber obtained from planted 

 trees. It is true that these trees for the 

 most part were planted primarily for 

 the purpose of shading cacao or coffee, 

 but the same was the case with the 

 first trees that yielded commercial rub- 

 ber in Ceylon. They are planted trees, 

 and the rubber is a plantation product 

 just as much as if the original idea had 

 been to form plantations of rubber. And 

 if these trees yield rubber, why should 

 not those trees which were planted for 

 this purpose and no other prove equally 

 productive on attaining the proper size, 

 as they are beginning to do in Ceylon ? 



The quantity of plantation rubber pro- 

 duced in Mexico thus far cannot be 

 stated so accurately as in the case of the 

 Ceylon product, but some figures on this 

 subject printed in another column appear 

 worthy of confidence. The Mexican 

 representative of an important New 

 York firm states that their purchases of 

 locally produced rubber for export have 

 increased from 7,000 pounds seven years 

 ago to 182,219 pounds in 1907. He is con- 

 vinced that not over 4,000 pounds of this 

 was " wild" rubber. Besides, he credits 

 the other merchants in the same town 

 with buying half as much more. Sup- 

 posing the situation to be as stated by 

 this merchant, the plantation rubber 



