80 



of the left side end between those of the right side in 

 the central canal (see fig. 



5. Half herringbone (see fig. 30). 



FIGURE 28. 



Sketch showing tapping 

 systems. 



Two Half Herringbones, opposite 

 quarter sections. 



By far the most common 

 method in the Malay Penin- 

 sula ; exclusively used on the 

 plantations which are from 

 six to eight years old. The 

 cuts cover only one quarter 

 of the trunk surface and all 

 lie on the same side of the 

 central canal (see fig. 28^). 



If it is desired to tap the 

 half surface of the tree, two 

 quarter surfaces can be tap- 

 ped, each with a half her- 

 ringbone cut, and therefore, 

 quarter surfaces can be used 

 which are adjacent to each 

 other (see figs. 2$>f & 28g). 

 As a rule the latter sytsem 

 is given the preference, as it 

 will have less effect on the 

 internal economy of the plant, 



than the tapping of adjacent quarter surfaces. 



3. THE CALCULATION OF DISTANCES BETWEEN THE 

 TAPPING LINES. 



One of the above mentioned tapping systems will have to 

 be chosen according to the ends in view and bearing in 



