3i8 
EXPERIMEXTS IN TAPPING CEARA RUBBER TREES. 
Address by Dr. Wilcox at the Hawaiian Rubber Growers' 
Association Second Annual Meeting. 
Dictated after the meeting. 
The rubber experiments which are being carried on by the 
U. S. Experiment Station and Territorial Board of Agriculture 
and Forestry have been under way long enough to indicate cer- 
tain results which are of practical importance to rubber growers. 
Thus far more than 200 trees, most of them less than three years 
old, have been tapped. These trees averaged from twelve to thir- 
teen inches in circumference and were located chiefly on the 
grounds of the Koolau Rubber Company, on Maui. In tapping 
young trees it was not expected that profitable returns of rubber 
would be obtained ; but the plan involved the practical point of 
determining the rapidity with which trees could be tapped, and 
satisfactory methods of handling labor to the best advantage. 
In the first series of 80 trees, which were tapped by means of one 
vertical cut each day, it required thirty-six hours and forty minutes 
of labor to tap the trees, collect the latex, and secure ij/2 pounds 
of dry rubber. In the second series of experiments on 160 trees, 
which were tapped with two vertical cuts instead cf one, it re- 
quired only 40 hours of labor to tap the trees, collect the latex and 
obtain five pounds of first class rubber and about a pound of scrap 
rubber. In this experiment in which two vertical cuts were used 
daily, profitable returns were obtained. 
It was found that an ordinary laborer could tap rubber trees, 
by means of two long, vertical cuts, at the rate of about 50 trees 
an hour and could collect latex at the rate of 100 Ixees an hour. 
The available labor on plantations appears to be reasonably effec- 
tive in doing this work, and the amount of training required in 
order to make the cuts effectively and quickly is not excessive. 
It requires less time to tap older trees than the young trees, 
upon which our work is done, and there is also less danger of in- 
juring the trees. We have found that a good flow of latex can be 
obtained from tapping done from daylight until 8 a. m., or even 
later. 
From the experiments which we have thus far conducted it 
appears that one man can tap about fifty trees per hour, while 
another man can collect the latex from the trees which would be 
tapped in the same time by two men. Since it jppears from 
results which we have obtained from tapping mature Ceara rub- 
ber trees, that about one-third ounce of dry rubber may be ex- 
pected as a daily yield, it is evident that three men should be able 
to obtain rubber from mature trees at the rate of about one pound 
per hour. The data upon which this conclusion is based have 
been carefully considered and the estimate is probably not above 
