January, 1909.] 



3 



GUMS, RESINS, SAPS AND EXUDATIONS. 



CASTILLOA OR CENTRAL 

 AMERICAN RUBBER. 



By William Fawcett, B.sc, f.l.s., 

 Late Director oj Public Gardens and 

 Plantations, Deputy Chairman of the 

 Agricultural Society, Jamaica. 



Para rubber (Hevea brasiliensis) lias 

 supplied such a very large proportion of 

 the rubber used in the arts, the area of 

 its natural habitat is so vast, and the 

 tree has been planted so extensively, 

 that the attention of growers of rubber 

 has been mainly directed to experiments 

 with it alone. But, as the conditions for 

 the successful cultivation of the Brazilian 

 tree are not to be found everywhere in 

 the tropics, it is well to experiment also 

 with other plants, and the most pro- 

 mising of these is perhaps the Central 

 American rubber, a species of Castilloa. 



(Species.— Some species of this genus, 

 e.g., Castilloa tunu, are worthless as 

 producers of rubber, and before using 

 the seeds of any Castilloa tree it is 

 important to ascertain whether the 

 latex of that tree yields rubber of good 

 quality. Castilloa elastica is the species 

 that has been considered the main 

 source of Central American rubber. 

 Professor Olsson-Seffer thinks that 

 Castilloa lacliflora gives a more ample 

 flow of latex. It is to be hoped that he 

 will favour us with the results of 

 further investigations. 



Situation. — Experience in growing 

 Castilloa under various conditions in 

 Jamaica points to several factors as 

 being important for the successful 

 growth of the tree. It will not grow to 

 advantage if the proportion of clay in 

 the soil be too high, otherwise it does 1 

 not appear to be very particular. A 

 loamy soil is the most suitable. The 

 drainage must be good ; the unsuit- 

 ability of stiff clays may be due to the 

 want of sufficient drainage, and may 

 perhaps be overcome by making drains. 

 The rainfall should be at least 70 in. per 

 annum ; but if less* and the deficiency 

 can be supplied by irrigation, the trees 

 will grow and yield quite as well. A tem- 

 perature which varies between 70° and 

 90° P. is suitable ; the elevation is not 

 material if the temperature does not 

 fall much below the lower limit. 



Shade. — Castilloa trees are found in 

 nature on the edge of forests and in 

 clearings. Overhead shade is not re- 

 quisite in the wild state, and has not 

 been found essential in plantations. The 



stem requires some protection from the 

 sun, but this can be provided in plan- 

 tations by the shade of the neighbouring 

 trees. Overhead shade is not detri- 

 mental if not too dense, but it lengthens 

 out the bole of the tree unnecessarily* 



Clearing Ground, — If woodland has to 

 be cleared, this operation should be 

 done thoroughly from the first. Some 

 recommend that a few trees should be 

 left here and there to afford shade for 

 the seedlings and young trees, but they 

 must be got rid of eventually, and the 

 cutting down and removing them leads 

 to injury and destruction among the 

 rubber trees. The large trees should be 

 sawn into boards for the erection of 

 sheds at a later period ; the smaller 

 timber will be useful as posts ; the small 

 useless branches should be heaped and 

 burned in such a manner as not to set 

 fire to other trees or bush close by. The 

 ashes are good manure, 



Distance apart and Catch Crops. — The 

 distance at which Castilloa trees should 

 be planted at first depends upon whether 

 they are to be grown with bananas 

 or other catch crop, or alone. If the 

 soil is suitable for bananas, and the 

 locality one where it will pay to grow 

 them, no other catch crop is anything 

 like as good. The bananas should be 

 planted in March at distances of 15 ft. 

 apart, and the Castilloa seedlings may 

 be put out about September, each seed- 

 ling in the centre of four banana plants, 

 or, if the cultivator or plough is used to 

 keep down weeds, the Castilloa must be 

 planted in the banana rows between the 

 bananas. The bananas may be grown 

 for three or four years, and then they 

 should be gradually thinned out as the 

 Castilloa trees spread their branches. 

 If bananas are not suitable, corn (maize) 

 and gungo or pigeon peas (Cajanus 

 indicus) may be used as catch crops 

 and temporary shade. The fields should 

 be lined out in March, and stakes put in 

 to mark where the Castilloa plants are 

 to be put out. Then the gungo peas 

 should be sown so as to leave a clear 

 space of 4 ft. round the stakes, and the 

 corn not nearer than 7 ft. The gungo 

 peas will not last more than two or three 

 years, but by that time the young 

 Castilloa plants will not require any 

 more nursing. The corn will not inter- 

 fere with the Castilloa if kept at a safe 

 distance, and if there is a market for it 

 the returns will help to pay expenses. 

 Even if there is not a market for the 

 gungo peas, they will increase the 

 introgen content of the soil, besides 



