556 



RUBBER 



RUBBER 



keep it longer in the nursery when the plantation is 

 liable to the attacks of grasshoppers or slugs, or 

 where deer or other wild beasts are likely to attack 

 the young plant. In such cases the taproot should 

 be cut off, and, if the young plant is over twelve 

 feet in height, the top should also be removed with 

 a clean cut at eight to ten feet from the ground. 



Young plants of Hevea should be potted in 

 bamboo joints as soon as they can be safely handled ; 

 and the same applies to all the species. In the 

 bamboo pots the young plants can await time or 

 season for planting better than if grown in nursery- 

 beds, and will stand transport better. However, 

 they should not stand too long in these pots, or 

 their roots may become cramped and hinder future 

 growth. (Hart.) 



The plantation. — The soil in the plantation should 

 be rich alluvial flat, free from salt-water and well 

 drained. Rocky or very sandy soil should be avoided. 

 The ground should be cleared of trees and bushes 

 by felling and burning, and the young trees should 

 be planted about twenty-five feet apart. 



Growth. — The growth in a suitable locality is very 

 rapid, and the young trees should be about fifteen 

 feet tall in a year and a half, and should attain 

 their full height of sixty feet in about eight years. 

 If they grow very tall and slender it is advisable 

 to top them at about eight or nine feet from the 

 ground. For the first few years the ground should 

 be cleared of weeds from time to time ; afterward 

 it is less necessary, as the trees will shade out the 

 weeds. No further cultivation is required. 



The duration of the life of the tree is not known. 

 The oldest trees in cultivation are about thirty-five 

 years of age and show no signs of weakening ; and 

 there are said to be some trees in the Amazon 

 region which have been tapped for eighty years. 



It was formerly thought that the Hevea requires 

 swampy river-side lands, but the discovery of 

 forests of it in high lands shows that a moist situ- 

 ation is not essential. That it thrives in gravelly 

 soil and stands drought well has been amply proved. 

 The better the land, however, the better the growth, 

 and on well-drained river-side lands it certainly 

 reaches a larger size than on dry ground. The tree 

 thrives in the open, but grows faster when slightly 

 shaded in its younger stages by trees of similar 

 habit. (Hart.) 



The trees should fruit in their fifth year. The 

 flowering season is preceded by the fall of the 

 leaves, which in young trees takes place all at once. 

 Older trees shed their leaves more irregularly. 



Tapping. — Many methods of tapping are now in 

 use, and it is probable that as the industry pro- 

 gresses other methods may be found to which those 

 in use will eventually give way. In the original 

 forest the life of the tree is but little regarded, 

 and generally the collector takes all he can, to get 

 which the trees are badly mutilated and usually 

 die. It is evident, therefore, that very careful 

 measures are necessary on cultivated estates, not 

 to injure the trees if continuous crops are to be 

 secured. While the trees have large recuperative 

 power, yet it is certain that excessive wounding 

 for bleeding purposes must tell on them and event- 



ually diminish the yield, if indeed the trees do not 

 succumb altogether. (Hart.) 



Tapping may begin in the sixth year with Hevea, 

 but much depends on the size of the stem at that 

 age. The rubber from young trees is weaker and 

 lighter than that from older trees, which is valued 

 more highly. It is watery and contains a consider- 

 able proportion of resinous matter, a feature which 

 disappears as age advances. 



The most convenient and satisfactory method of 

 tapping the Para rubber tree is the herring-bone 



system (Pig. 793). A 



vertical incision is 

 made in the bark from 

 as high as a man can 

 conveniently reach to 

 within a few inches of 

 the ground, and as nar- 

 row as possible, as it is 

 required only to con- 

 duct the milk to the cup 

 inserted by its edge at 

 the base of the cut. On 

 either side, sloping cuts 

 are made alternately 

 about six inches apart, 

 connecting with the 

 central cut. The milk 

 runs from these side 

 cuts to thecentral chan- 

 nel and so into the cup. 

 Bach day a thin slice is 

 taken off the lower side 

 of each side cut till the 

 milk ceases to flow or 

 till the cut is about 

 one and one-half inches 

 wide, when tapping is 

 stopped and the wound 

 allowed to heal, which 

 months. Wounds may be dressed with coal-tar. 



Tapping is done all the year round, and is best per- 

 formed in the early morning at daylight, or in the 

 evening. The former gives the largest yield. Some 

 growers prefer to tap during wet weather, on the 

 theory that the sap flows faster then, and iDecause 

 the additional moisture delays coagulation and 

 thus facilitates gathering. In dry weather the 

 latex coagulates in the cuts and stops the flow. 



The instruments used for cutting the bark are 

 very varied, new ones constantly being invented. 

 Especially in old trees, a mallet and a chisel are 

 perhaps the best and most easily used. The cups 

 for catching the milk are made of aluminum, with 

 a rounded base, and contain four or eight ounces. 



The milk runs for half an hour or so and then 

 stops. The cups are collected and their contents 

 poured into jugs or other large vessels to carry 

 to the curing shed. It is advisable to put a little 

 water with a drop of formalin into each cup 

 before fixing it to the tree, to avoid coagulation in 

 the cups, which sometimes occurs. The latices of 

 all trees should be strained through a fine wire 

 mesh to remove the impurities inseparable from 

 the bleeding process. 



■f _ , 



Fig. 793. 



Para rubber tree, showing 



herring-bone tapping. 



it does in about six 



