December, 1912.] 



467 



RUBBER IN THE F.M.S. 



TAPPING EXPERIMENTS. 



The Agricultural Bulletin of the. Federated Malay States contains an 

 account on the above subject by Mr. F. G. Spring :— In April 1905 eight 

 plot? of Para Rubber at different elevations were opened up on Gunong 

 Angsi for the purpose of attempting to test the effect of climate conditions 

 on the growth of the tree and afterwards the yield of rubber at different 

 altitudes. 



The fields are arranged as follows: — plots 1, 2, 3, 4, 5, 6, 7 and 8 at 

 elevations of 300 ; 600 ; 1,000 ; 1,200 ; 1,600 ; 1,800 ; 2,100 and 2,400 feet respecti- 

 vely. In December, 1911, the average girth of the trees in each plot, with 

 the exception of field 4 which remains unplanted, was taken at a distance 

 of 3 feet from the base of the tree and the girths in the respective plots 

 found to be as follows 25-07; 16-29; 21-83; not planted ; 17-86; 16-89; 1209; 

 and 1421 inches. 



In field (1) which is situated at an elevation of 300 feet the yields of 

 total rubber in experiments 1, 2, 3 and 4 are 555 lbs ; 303 lbs ; 441 lbs. and 

 and 237 lbs.— a total of 1,536 lbs. While in field (3) at an elevation 1,000 feet 

 the yields of total rubber in experiments 1, 2, 3 and 4 are 388 lbs ; 207 lbs ; 

 308 lbs. and 195 lbs. — a total of 1,098 lbs. The increase of rubber obtained 

 in the plot at the lower elevation compared with field (3) is 167 lbs. 96 lbs ; 

 133 lbs. and 42 lbs. in the respective experiments — or a total of 438 lbs. 



The increase is no doubt connected with the large girth of the trees in 

 held (1) but indirectly to the trees being at a lower elevation. 



To what height Hevea may be grown without a rapid falling off, both 

 in girth and quantity of rubber, is difficult to say ; but, judging from the 

 present experiments, an elevation of 1,000 feet is undoubtedly too high to 

 obtain the maximum yield of rubber. 



Relative Yields of Rubber. 



The next point of interest is the relative yields of rubber from differ- 

 ent systems of tapping. It will be seen by referring to the tables that in 

 each experiment both at the first and third clearings, the adjacent quar- 

 ters (double V) gave a considerably larger yield of total rubber obtained 

 fiom adjacent quarters compared with opposite, in fields (1) and (3) where 

 two years is allowed for bark renewal, experiments 1 and 3, it is approxi- 

 mately 25*0 per cent, while in the plots where the period of renewal is 4 

 years, experiments 2 and 4, the excess is approximately 17 "0 per cent. Both 

 in adjacent and opposite systems of tapping, where two years is allowed 

 for bark renewal, the amount of total rubber is almost double that 

 obtained from the experiments in which 4 years is allowed for bark 

 renewal, in other words the quantity of latex obtaiued has been directly 

 dependent on the amount of bark removed. 



A notable and interesting feature is that this excess is more evident 

 in the first few months of tapping while at the end of one year the 

 difference is apparently not so great. This falling off of rubber in experi- 

 ments 1 and 3 is in all probability a sign of exhaustion followed on the 

 severe tapping conducted in these experiments. It will be interesting to 

 see how large the difference becomes as tapping progresses. 



