Janvarv I, 1909.] 



THE INDIA RUBBER WORLD 



129 



Yield of Wild and Planted "Para" Rubber. 



WHAT is the yield of a rubber tree? Simple as the ques- 

 tion may appear — and it is asked incessantly — giving an 

 intelligent answer to it is by no means simple. One 

 must consider what variety of rubber is involved, where the 

 tree grows, whether "wild" or cultivated, and, if the latter, 

 the conditions under which planted. A remark may be recalled 

 here from a report by a former British consul at Para writing of 

 native lirvcas in the Amazon region : "Two trees growing close 

 tdgether and under apparently precisely similar conditions will 

 often vary very much as regards their yield." 



There is no question that rubber trees do yield, else what 

 would become of the rubber market ? On one day during the 

 past month the customs authorities at New York reported the 

 arrival of rubber of an invoice value exceeding $2,000,000. The 

 custom house at Para dealt last year with 80,638,800 pounds, and 

 some years the figures have been larger. Besides, the Amazon 

 region doesn't supply all the rubber used. We hear over and 

 over again that the Brazilian rubber is derived from trees scat- 

 tered in dense forests, and that the native tappers gain a very 

 small amount of latex from each day's tapping. But the Para 

 shipments argue either a tremendous number of wild rubber 

 trees or a very considerable average annual yield per tree. 



Since it must be admitted that trees do yield rubber, the ques- 

 tion remains, how much? This subject, as relating to forest 

 rubber, has been treated at some length in former numbers of 

 The Ixni.x Rubber World, including quotations from Mr. Vice 

 Consul Temple, who once reported having had access to the books 

 of some operators in the Brazilian field, indicating an average 

 yield of 2.2 to 3.3 pounds yearly per tree. He was of the 

 opinion, however, that very many trees were being worked with 

 no larger average yield than i.i pounds. His report, however, 

 had to do only with the state of Para, where the rubber fields 

 have been worJ<ed longer and more thoroughly than in the up- 

 river regions. It does not seem to have occurred to the Amazon 

 rubber trade to consider the yield of individual trees so long as 

 total results are satisfactory. But chance details which have 

 come to hand from time to time point to the probability of a yield 

 of 4 to 10 pounds yearly per tree, varying with the degree to 

 which cstradas have been "worked out." 



With the coming of cultivated rubber, on plantations owned by 

 capitalists and with shares listed on stock exchanges, the question 

 of yields becomes of particular interest in connection with the 

 analysis of company reports. If one tree will afford a given 

 quantity of rubber, will i.ooo give a thousand fold? In con- 

 sidering any of the figures which follow — all relating to the 

 yield of plantation Para (Hnra) in the Far East — it must lie 

 remembered that such yields may be influenced — 



By the character of the soil, altitude, or climatic conditions ; 



By the closeness or width of the planting ; 



By the frequency of tapping; 



By the method of tapping; 



By the care with which the latex is handled. 



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 produce of 

 mature trees tapped throughout 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 man- 

 aged plantations, 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 5 pounds or more and a smaller 

 tree from which y, pound or less has been obtained. In default 

 of such figures the following details have been culled from the 

 sources most available. 



In the latest edition of his "Hevea Brasilieusis" Mr. Herbert 

 Wright has compiled a lot of data on the yields reported from 

 rubber estates, though without any eflfort to establish any rule 

 as to yields as related to the age of the trees tapped. From one 

 of his tables we have taken 23 items, referring to as many proper- 

 ties, 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 .t,2 pound ; the largest reported for any one 

 was 5.5 pounds per tree. A list of 16 of those properties shows 

 an 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 

 respectively. 



From another table in Mr. Wright's book a list has been com- 

 piled of 8 estates, on which 79.631 trees, in 1906, yielded 200,220 

 pounds of rubber — an average of 2.52 pounds. The average per 

 tree on the 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 Rubber Co., Limited, for the calendar year 1907. 

 On their Terentang estate 28,043 Hevca trees, aged 7-8 years, 

 a,re stated 'to have yielded 105,655 pounds of dry rub'oer, or an 

 average of 3.76 pounds per tree. On their Ayer Angat estate, 

 however, 14,540 older trees (9-10 years) yielded only 42,970 

 pounds, or an average of 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 3.32. 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 analyze 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 va- 

 rious 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, 

 I.,i45 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 delinile information is given in the report of the 

 Highlands and Lowlands Para Rubber Co., Limited, for 1906. It 

 is stated that on one block of 16 acres 807 Hceea trees, 9 years 

 old, planted 30x25 feet, were tapped during three periods of the 

 year mentioned, with these results : 2,500 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 rubber from 

 I-.335 trees, wide planting — averaging 2.60 pounds. 



It may be added that the total production 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 



