403 



Excellent work with regular shavings, as thin even as 

 20-25 to the inch, have been done with the gouge, the Far- 

 rier's knife, and with more modern specially adapted tapp- 

 ing knives. 



It is important to make certain of the periods which 

 should be allowed to elapse between tappings in order to 

 get maximum yields. After having collected figures of 

 yields on a large number of estates it is difficult to lay down 

 an absolute rule as to the procedure which experience shows 

 to be the best. 



Carefully kept data on some estates show that after a 

 period of some three months alternate days' tapping the 

 amount of latex per tree decreases to an amount which is 

 of less value than the cost of tapping, but after a rest of two 

 months the tree again on the fourth or fifth tapping yield 

 the maximum, which after some 40 tappings begins to 

 rapidly decrease. 



The reverse of these observations is to be found on 

 other estates where accurate figures of yields show that after 

 continuous tapping for some two or three years, the amount 

 obtained varies only slightly, never steadily decreasing. 

 The variation is caused by climatic conditions, short periods 

 of little or no rainfall reducing the yield and periods of 

 excessive rainfall producing somewhat the same result. 

 This is due to the relatively less active functioning of the 

 roots owing to drought or excess of water. 



Many planters believe in stopping when the trees are 

 leafless, a period of some three weeks each year. The ex- 

 periments which have been continuously carried on for 

 some 18 months by this department on 17-year old trees at 

 Krian show a slight decrease of yield during the leafless 

 period. 



The notion is also prevalent that tapping should be. 

 discontinued during the fruit bearing period. The figures 

 obtained at Krian show a decrease during the time the trees 

 were in fruit, but no sufficient decrease to seriously increase 

 the cost of tapping. The figures relating to these tapping 

 experiments will be published in the "Agricultural Bul- 

 letin." 



Careful records have been kept of the weight and bulk 

 of latex each day from each tree, and the ensuing weight of 

 dry rubber. 



The question of how far it is advisable to refrain from 

 tapping rubber trees after a period of tapping is one upon 

 which planting opinion differs very greatly. On some 

 estates, after a period of some weeks or months of tapping, 



