PART VI. 



SUGGESTIONS FOR RATIONAL TAPPING 



METHODS. 



According to my observations and the conclusions to be 

 deduced therefrom, and also according to other experiences made 

 to date, I believe that in the case of young plantations and with 

 regard to their future condition, it will be best to perform the 

 tapping operations in the following manner : 



Do not begin to tap the trees till they aresix to 

 old^triaTTs.' till the~~ciHumterence of Tfie^tree~lsabout 50 cm_ 

 at one metre above the ground"! Adopt Ihe^halfherring-bojie 

 incision as your tapping system, orTjetterstill, the full herring- 

 T3OTie7 the ^v^haped incision. The incisions must not be too 

 little vertical, as otherwise [Tie conveyance of sap from the sides 

 is rendered too difficult. An angk-of-sixtv degrees woujdjprobably 

 prove the best. The tapping system must only cover a vertical 

 .strip of bark, the breadth of which does not exceed a quarter 

 of the tree's circumference. Make the upper incisions at about 

 the height of a man, by no means higher than where the tree 

 attains a circumference of 45 cm. 12 Make the incisions one 

 .above the other in vertical distances of 30 to 35 cm. Tap daily, 

 or every alternate day, with the knife only, and earlv_in the 

 morning. 13 Impress on the workmen that the strips of bark they 



12 Compare J. C. Willis and M. K. Bamber. " Tropical Agricul- 

 turist," Vol. 29, 1907. Pages 244, ff. 



1S A circumstance which points to the morning as the best time, 

 is, that the diurnal period of expansion in girth attains its maximum in 

 the morning. The periodicity of expansion in girth in the case of trees 

 belonging to our latitude and to the tropics, has been discovered by 

 Gregor Kraus. (Ueber die tagliche Schwellungsperiode d. Pflanze. 

 Abhandlungen Naturf. Gesellsch. Halle. Vol. 15 and Annales d. jard. 

 bot., Buitenzorg, Vol. XII. 1895. Pages 210, ff.) 



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