Gums, Resins, 



Trees with short trunks of large girth 

 may be more productive than taller ones 

 of less girth. The commencement of 

 tapping is determined by the size of the 

 trees rather than their age, and all trees 

 do not grow at the same rate, It may 

 be pointed out that even in the 

 most detailed rubber plantation reports 

 up-to-date statements of yield, as 

 a rule, include in one total the pro- 

 duce of mature trees tapped through- 

 out the year and that of trees just 

 come '' into bearing," which may have 

 been tapped once or twice only. 



It would be desirable to have, from 

 each of several well-managed plant- 

 ations, a record of the yield of a definite 

 number of rubber trees, of uniform size 

 and age, tapped the same number of 

 times in a year, by the same system, 

 and with the same method of treating 

 the latex. It is not wholly satisfying to 

 have included in one total a large tree 

 yielding five pounds or more, and a 

 smaller tree from which half jjouud or 

 less has been obtained. In default of 

 such figures the following details have 

 been culled from the sources most avail- 

 able, 



In the latest edition of his " Heve a 

 Brasiliensis" Mr. Herbert Wright ha s 

 compiled a lot of data on the yields re- 

 ported from rubber estates, though 

 without any effort to establish any rules 

 as to yields as related to the age of the 

 trees tapped. From one of his tables we 

 have taken twenty-three items, referring 

 to as many properties, on which, in 1905, 

 166,740 trees yielded 215,933 pounds of 

 rubber, or 1 235 pounds per tree. The 

 average per tree on one estate was as 

 low as '32 pound, the largest reported 

 for anyone was 5*5 pounds per tree. A 

 list of sixteen of those properties showsaa 

 average yield per tree of 1'351 pounds. 

 Six estates showed averages per tree of 

 2 pounds, 2-2, 3'2, 3"25, 3'5, and 5'5 res- 

 pectively. 



From another table in Mr, Wright's 

 book a list has been compiled of eight 

 estates, on which 79,631 trees, in 1906, 

 yielded 220,200 pounds of rubber— an 

 average of 2-52 pounds. The average per 

 tree on various estates was 2 03 pounds, 

 2-37, 2-46, 2 75, 2'79, 2"88, 3, and 7*1 pounds 

 respectively. 



A particularly interesting item appears 

 in the report of the Anglo-Malay Rub- 

 ber Co., Limited, for the calendar vear 

 1907, On their Terentang estate 28,043 

 Hevea trees, aged 7-8 years, are stated 

 to have yielded 105,655 pounds of dry 

 rubber, or an average of 3 76 pounds per 

 tree. On their Ayer Angat estate, how- 

 ever, 14,540 older trees (9-10 years) yielded 

 only 42,970 pounds, or an average of 



508 • [June, 1909. 



2-95 pounds. On the other hand, 5,440 

 trees on their Batang Bali estate mostly 

 only 6-7 years, though a few were 9-10, 

 gave 18,112 pounds, or an average of 3 82. 

 The total tapping for 1907, on these 

 and another estate, covered 68,236 trees, 

 yielding 224,778 pounds, or 3'29 average. 



An attempt has been made by the 

 writer to analyse the ages of the Hevea 

 trees tapped during three years by the 

 Bukit Rajah Rubber Co., Limited. 

 Taking account of the approximate ages 

 of their trees, so far as can be gathered 

 from the company's various reports, 

 and their definite statements of the 

 number of trees tapped and their yield, 

 these results appear : 



Year ending March 31, 1906.— Trees 

 tapped 34,457, yield 33,203 pounds, 

 average age of trees at end of period, 6*23 

 years, average yield per tree, *97 pound. 



Year ending March 31, 1907.— Trees 

 tapped, 88,341, yield 118,982 pounds, 

 average age of trees, 5*94 years, average 

 yield T345 pounds. 



Year ending March 31, 1908.— Trees 

 tapped, 89,295, yield 163,521 pounds, 

 average age of trees, 7*27 years, average 

 yield, 1*83 pounds. 



Some very definite information is 

 given in the report of the Highlands 

 and Lowlands Para Rubber Co., Limited, 

 tor 1906. It is stated that on one block 

 of 16 acres 807 Hevea trees, 9 years old, 

 planted 30 x 25 feet, were tapped during 

 three periods of the year mentioned, 

 with these results : 2,5C0 pounds at the 

 first, 1,469 at the second, and 1,773 at 

 the third, or a total of 5,742 pounds— 

 an average of 7 01 pounds per tree for 

 the year, 



During the business year 1906-7 the 

 Federated Malay States Rubber Co., 

 Limited, collected 32,175 pounds of rub- 

 ber from 12,335 trees, wide planting- 

 averaging 2'60 pounds. 



It may be added that the total pro- 

 duction of plantation rubber in the 

 Federated Malay States for 1906 was 

 861,738 pounds, from 441,482 trees, of 

 varying ages, or an average of 1*95 

 pounds per tree. 



From all the preceding data it would 

 appear safe to estimate not less than 2 

 pounds annually from trees, say 8 years 

 old, with reason to expect an increased 

 yield with greater age. But much larger 

 yields, in exceptional cases, have been 

 authenticated. Eleven-year-old trees 

 on Culloden estate, especially tapped, 

 gave 14 pounds of rubber from 8 months' 

 tapning, and trees of unknown age (pro- 

 bably 20 to 25 years), from 10 to 25 

 pounds each in one year. 



