THE PARA RUBBER TREE 121 



design, but it is of interest to note that sonic of the best 

 tapping is done with the simplest appliances, such as 

 an ordinary gouge or a simple modification of the farrier's 

 knife. No detailed notice of the different forms of 

 knives is possible here, but it may be stated that the 

 essential feature of a good tapping tool is a very sharp 

 cutting edge which can be easily maintained, as a clean 

 cut is necessary in order to secure a good flow of latex. 



The methods of tapping Hevea hrasiliensis trees which 

 have been evolved on the plantations in the East depend 

 upon the important fact that if the initial incisions are 

 reopened after a short interval by cutting off a thin 

 slice of bark from one of the edges of the cuts, a further 

 flow of latex takes place, and that this procediu'e may be 

 repeated again and again with a similar result. This 

 capacity of the Para tree to furnish latex repeatedly at 

 short intervals is one of its most important characteristics, 

 and gives the tree its unique value for plantation pur- 

 poses. Another interesting point in this connection is 

 that in tapping trees for the first time, or after a long 

 interval, the yield of latex from the first two or three 

 incisions is usually very small, but that it increases 

 considerably from the subsequent tappings. The Hevea 

 trees in the Amazon valley also exhibit this characteristic, 

 which is well known to the rubber collectors there. 



This behaviour of the Para tree has been termed 

 " wound response," on the assumption that the incisions 

 made in the bark act in some way as a stimulus to the 

 production of latex. 



An important point in connection with the use of 

 this paring method is that the tapping should be so 

 arranged that the whole of the original bark is not 

 removed until the renewed bark on part of the tree is 

 ready for retapping. It is now generally agreed that 

 it is not advisable to tap renewed bark until it is at 

 least four years old, and consequently most of the 

 methods of tapping at present in use are arranged to 

 ensure this. The usual plan is to divide the trunk into 

 four vertical sections which are tapped in successive 

 years, so that after all the original bark has been excised 

 the renewed bark on the first section will be four years 

 old and ready for retapping. 



The method of tapping Para trees which is most gener- 



