253 



DIFFERENT METHODS OF TAPPING. 



Incisions and Excisions. 



Throughout the East all plantation rubber is obtained by some 

 method of excising the bark whereas in Brazil the process is one of 

 incisions. This latter method has been fully tried in this Garden 

 and discontinued for the reason of slow bark recovery of the incised 

 wounds, combined with the poor return of latex — although in Brazil 

 it is claimed that the amount of rubber is higher per tree. This is 

 very doubtful and probably refers to the average of old trees com- 

 pared with young trees in the East. From one of the oldest and 

 largest tree in the Singapore Garden (see p. 252, table 4) 1245 ozs. of 

 latex were obtained in three periods of tapping during 1909 resulting 

 in 26 lbs. of rubber. (This tree was actually excised on 80 days only 

 for one year), a much larger return than could be obtained by 

 incisions and only a small area of bark operated on. 



V-Shaped Method. 



So far as we know there is not any difference of opinion as to 

 what part of the tree should be tapped. It should be the trunk of 

 the tree from the base to a height of 5 ft. In our own experiments 

 we find that the dry weight of a biscuit of rubber is most from 

 nearest the base, there is naturally a larger yield of latex from the 

 single or double herring-bone excisions — being 4- 5 or 8-10 excisions 

 against 2 basal excisions — but the dry weight is slightly less from 

 the same quantity of latex while from the upper branches the dry 

 weight is considerably less and — with young trees — the exudation of 

 latex soon ceases. 



It is no doubt due to the fact of the richest latex being nearest 

 the base of the tree that the V-shaped method obtains so many 

 votaries. Where the full V is practised half of the girth of a tree 

 is operated on or excised and the objection to this method lies in 

 the interval of rest between completion of the first half of the area of 

 bark and commencement of the second half. If the second half is 

 followed on immediately the tree is only able to partially fulfil all its 

 functions, it is really stagnated and weakened and this should be 

 avoided, a half V would only return a scanty yield of latex, the 

 lialf-herring bone would therefore be an improvement as this amounts 

 to 4 or 3 half Vs. 



Herring-Bone iVIethod. 



riu- double herring-bone method- something like 4 or 5 pairs of 

 full Vs has proved too expensive in bark excision and the single 

 herring-bone method — a vertical channel with 4 or 5 half Vs, or 

 oblique- excisions at an angle of 4.S ' about l' apart — is now adopted, 

 rhib wc think the most practical method, both as regards yield of 



