May, 1910.] 



393 



Saps and Exudations. 



DANGERS, MISTAKES, AND 

 IMPROVEMENTS IN THE CAOUT- 

 CHOUC PRODUCTION OP ASIA. 



(By D. Sandmann in Tropenpflanzer, 

 March, 1910.— Abstracted by 

 J. C. Willis.) 



Commencing with a statement of the 

 rapid growth of the industry, Dr. Sand- 

 mann points out that tropical Asia will 

 be producing some 70,000 tons in 1913, 

 according to the figures of production 

 of the Malay States. This will greatly 

 cheapen rubber, which should come into 

 use in many new ways. 



Trees measured in the Botanic Garden 

 of Para, in Brazil, showed the following 

 diameters at 3 feet from the ground :— 



8 years old 14 1/3 cm. (5h inch) 



9 „ 16 ... (6| „ ) 



10 ,, 26 ... (10Jr „ ) 



11 „ 28i ... (Ill » ) 



These dimensions were much exceeded 

 by trees of corresponding age in the 

 Malay States and in Java. 



The yield in Brazil he calculates to be 

 about 1| to 3£ kilos (3-8 lbs.) a year, 

 at the age of at least 15. This also is 

 beaten by the cultivated trees. 



He then goes on to describe the 

 various enemies that attack rubber in 

 Asia, e.g., the root fungus, the white 

 ant, &c. 



The labour difficulty is then dealt with. 



Dr. Sandmann next goes on to consider 

 the raising of milk production, pointing 

 out that in the future it will not pay to 

 tap such trees as are now tapped. He 

 saw, for instance, trees of ten inches girth 

 being tapped, with a yield of 3| oz. He 

 recommends selection of seed from heavy 

 bearers; the rubber tree being, as is well 

 known, very variable in this respect. 



He compares the growth of seedlings 

 planted out with that of stumps, show- 

 ing that the former is decidedly better. 

 He describes the various theories held 

 about weeding, the abandonment of 

 thumbnail-pruning, and the various 

 knives in use for tapping. 



He considers the question of how often 

 to tap, pointing out that so many 

 factors enter into it that each planter 

 must decide for himself. 



(To be continued.) 



50 



THE JEQU1E MANICOBA 

 RUBBER TREE. 



By R. Thomson. 



(From the Indian Forester, January and 

 February, 1910, Vol. XXXVI., Nos. 1 & 2.) 



This new species of rubber is indi- 

 genous to the State of Bahia, Brazil. 

 It is a small tree, attaining a height of 

 some 25 feet, with stems from 18 to 

 20 inches in ciicumference. It is a 

 closely-allied species of the Ceara-rubber, 

 the native habitat of which is separated 

 from this Manicoba region by some five 

 or six degrees of latitude. Until a few 

 years ago this rubber was unknown to 

 commerce. It grows under peculiar 

 conditions as a product of the forest. 

 In the region I traversed there are 

 millions of trees, including saplings. 

 The soil in which the Manicoba grows 

 is peculiar. (I have samples of it in 

 London). It is a porous kind of clay, 

 more porous than sticky, the texture 

 of which is eminently conducive to the 

 well-being of the tree during prolonged 

 periods of drought to which it is ex- 

 posed. Apart from the peculiar character 

 of the soil, its great depth powerfully 

 contributes to the conservation of the 

 moisture which it freely absorbs during 

 the short rainy reasons. In other words, 

 the absorbent power of this great body 

 of earth, not only relieves the surface 

 of any excess of moisture, but retains 

 the moisture during severe droughts, 

 so that the soil is never water-logged, 

 and never excessively dry. This soil, 

 therefore, coupled with the aridity of 

 the climate, is the secret of the ex- 

 istence and diffusion of this rubber tree. 



A few years ago I was deputed by 

 Messis. Elder, Dempster & Co. to 

 investigate the resources of the pine- 

 apple region of Florida. I mention this 

 by way of pointing out the disparity 

 between that soil and the Manicoba 

 soil, I quote from my published re- 

 port: -"If the soils of Florida were 

 anything like the soils of Jamaica, it 

 is safe to say that Pine-apples would 

 not be cultivated there at all. The 

 soil in which they are plauted consists 

 of from 96 to 98 per cent, of silica. 

 The growers furnish all the food by 

 fertilisers, which bring forth luxuriant 

 crops . . . On examining a large pine- 

 apple field that had been some months 

 before uprooted in order to prepare the 

 land for replanting, I saw many hun- 

 dreds of rejected suckers that had been 

 cast away over the land actually bear- 

 ing fruit I In other words, these suckers 

 yielding fruit had no connection with 

 the soil; other than lying on the surface. 



