TREES THAT COUNT MANIHOT GLAZIOVII 67 



mainly due to their discoveries and to the strenuous 

 investigations of certain German experts that 

 the United States authorities were led to embark 

 upon those remarkable experiments which are re- 

 corded periodically in the " Hawaiian Agricultural 

 Bulletins ", and upon which the local planters now 

 rely for most of the data for carrying on their work. 

 We learn from these experiments a great deal con- 

 cerning the results of various modes of tapping to 

 which trees of different ages were subjected, but un- 

 fortunately we get nothing definite or conclusive as 

 to which system might be accepted as the standard 

 for general adoption. 



Many of these experiments were carried out quite 

 as recently as 1906. An estate in the island of Kauai 

 was selected, a grove at Koloa possessing trees 

 thirteen years old being marked in juxtaposition to 

 another at Lihue, where the trees were seven years 

 old and under. Funds were subscribed locally, pre- 

 liminary operations being confined to the testing and 

 determining of tapping tools, latex cups, etc. 



The first experiments were directed to the tapping 

 of a few isolated trees not more than four years old. 

 Two of these were tapped for nine days consecu- 

 tively, and yielded 12 J oz. of dry rubber. In June a 

 number of four-year-old trees averaging 19 inches in 

 circumference were tapped for nine days, and yielded 

 A Ib. of dry rubber. These trees were entirely bare. 

 It was found that the Manihot is peculiarly sus- 

 ceptible to atmospheric influences so far as the flow 

 of the latex is concerned. Trees tapped at midday 

 or in the afternoon yielded almost no latex, whilst 



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