February 1, 1916.] 



THE INDIA RUBBER WORLD 



257 



takes seven years, so bad is the state of the overtapped trees. 

 .Another cause of the comparatively low yields per acre is the 

 overcrowded state of many plantings. It is not unusual to find as 

 many as 200 trees to the acre in spite of the fact that estates, 

 thinned down to 105 trees have produced more rubber than the 

 .■vercrowded ones. 



The opinion is advanced that future yields would be materially 

 increased were tapping operations stopped each year from June 

 15 to the middle of August— during the southwest monsoon— 

 when fully 50 per cent of the annual rainfall occurs. During 

 this wet. windy season the trees experience a second leaf-fall 

 quite distinct from the regular seasonal leaf-fall, which occurs in 

 the early part of the year. However, the trees do not shed all 

 their foliage as in the regular wintering season. Some are more 

 afrected than others ; one may be almost totally denuded while 

 its neighbor will retain its foliage. 



Several theories have been advanced to explain this occur- 

 rence. Some believe it to be due to disease; others hold that it 

 is a physifilogical response of the tree to climatic conditions. 



REVIEW OF RUBBER CULTIVATION IN NETHER- 

 LANDS EAST INDIA. 



SOUTH E.\ST .ASIA and Netherlands East India were the 

 only producers of cultivated Ficus rubber previous to 1900. 

 The first attempts to plant rubber trees in Java were made with 

 Ficus clastica, and thereafter with other kinds, including Hcvea 

 Brasiliensis, Castilloa clastica and various Manihot species. The 

 cultivation of the latter species attained considerable importance, 

 but compared with Hevca these varieties are given small attention. 

 It was not until 1905 that the cultivation of rubber was under- 

 taken to any great e.xtent in Netherlands East India. From that 





L.VTF.X F.VCTORV .\.\D C.\RRIERS IX THE F..\R Ef.ST. 



date the investments in this branch of agricultural industry 

 gradually increased, and numerous plantations were opened up 

 where rubber was cultivated on a large scale. 



HRVE.V BR.\SILIENSIS 



Starting in a small way in 1876, experiments were made in 

 I)ropagating this tree, and in Java and Sumatra an opportunity 

 was afforded to gather data respecting growth, etc., which have 

 been of great assistance in cultivation later undertaken on an 

 extensive scale. 



The acclimatization of Ilcvea in Netherlands East India has 

 been entirely successful. The trees look very healthy and the 

 growth appears to be satisfactory. 



It has been found possible to reduce parasitic root and stem 



diseases, by proper precautionary measures. Leaf diseases, how- 

 ever, have not proven to be of as malignant a character as in 

 other colonies. 



The important proldem of tree planting distances has been 

 settled by adopting a more open spacing than formerly and 

 interplanting with catch crops of Robusta coffee. The usual 

 planting distances for Hcrca Brasiliensis in recently opened 

 plantations have been increased to 18 x 18, 20 x 20, or 12 x 24 

 feet apart. 



-At the beginning of 1913 the planted acreage of Hcvca in 

 Netherlands East India was as follows : 



In the possessions 



In Java. beyond Java. Total. 



Hevca 63,387 168,151 231,538 



Hevea imerplanted 129,788 53,986 183,774 



Total 193,175 222,137 415,312 



In addition to the above 1,000.000 Hczca trees are to be found 

 distributed on estates in the whole colony. 



The Hcvca is considered tappable when Syi to 4 years old, but 

 in Java the trees are sometimes not tappable before their fifth 

 year. 



The preferred method of tapping young trees is a V incision 

 covering half the circumference of the stem. The stems of older 

 trees are tapped by quarters on the "Half Herringbone system." 

 The tappmg process of each quarter is extended to 1'4 to V/i 

 years, thus requiring 5 or 6 years to tap the full circumference 

 of the stem. 



Plantation labor expense has greatly increased, due to shortage 

 of laborers, but in comparison with other rubber producing cen- 

 ters, the cost of labor in Netherlands East India is not excessive. 



The following statistics show the exports of Hcvea rubber from 

 Java and the East Coast of Sumatra during 1912 and 1913: 

 EXPORTS. 



Java. East Coast Sumatra. 



1912. 1913. 1912. 1913. 



Holland tons' 194 1.006 35 384 



United Kingdom 255 1,000 102 759 



Elsewhere 37 339 1,185 1,893 



Totals 486 2,345 1,322 3,036 



•Tons of 2,200 pounds. 

 In regard to the other possessions of the .Archipelago, the total 

 exports of those islands in 1912 were 536 tons of 2,200 pounds. 



E.XTENT OF PL.\NTIXG AREA. 



In Java the area planted with rubber cannot be extended, be- 

 cause of topographical and climatological circumstances and the 

 fact that only small plots of suitable land are now available. In 

 Sumatra, however, the area for the cultivation of Hevea could 

 easily be extended to even three times the present space. The 

 same can also be said of Borneo. 



The area and exports of Ficus clastica, Castilloa and Manihot 

 Glaziovii rubber are practically negligible. ' 



GUTT.\ PERCH. \. 



Gutta percha is only to be found in East .Asia. In Nether- 

 lands East India it grows in the Rhio Archipelago, in Banka, 

 Borneo, Sumatra and in New Guinea, besides a few other 

 islands. The product is principally obtained from the Palaquium 

 species. The bulk of the product is from wild trees, which are 

 felled for the purpose of tapping. 



To prevent the extinction of the Palaquium species plantations 

 have been opened up in Netherlands East India since 1885, 

 namely, the Government Gutta Percha Plantations at Tjipetir, 

 where practically only trees of this species are grow-n. 



The exports of plantation produced gutta percha from Java 

 totaled 6 tons in 1912 and 25 tons in 1913. 



Replete with information for rubber manufacturers — Mr 

 Pearson's "Crude Rubber and CompoUnxling Ingredients." 



