RUBBER PLANTING 75 



length in Chapter v, the selection of seed-bearers may 

 be expected to play an important part in the future 

 development of the rubber-planting industry. 



Tapping Intervals. 



The increased yield associated with wound response 

 is clearly manifested when the interval between suc- 

 cessive tappings is anything between one and ten days 1 . 

 The longest interval over which this effect can persist is 

 not known, and would doubtless be found to vary in the 

 case of different trees. It was observed, however, in the 

 case of a very large tree which was tapped daily, that, 

 when daily tapping was renewed after an interval of a 

 month during which tapping had been suspended, the 

 first day's yield was much smaller than the average, 

 and was followed by a rapid increase on the days 

 immediately following. A longer interval than a week 

 between successive tappings is not likely to enter into 

 the calculations of the practical planter. Which is the 

 most profitable among intervals shorter than seven days, 

 i.e. which will lead to the largest permanent yield, is a 

 question that requires to be made the subject of further 

 discussion and experiment. 



The view generally accepted at the present time is 

 that, with a view to obtaining the largest possible yield 

 without permanent damage to the tree, tapping should 

 proceed at such a rate that the paring of the whole area 



1 Except perhaps in the case of very young trees. 



