and Magazine of the Ceylon Agricultural Society.— August, 1910. 



185 



RUBBER TREES AS SHABE 

 FOR CACAO. 



Mr A E Casse, who left Kew in March, 1900, 

 to take up the position of Superintendent of 

 the Plantations, Bayeux, Haiti, has sent the 

 following notes on rubber trees as shade for 

 cacao to the Director for publication. The 

 question as to ' Shade or No Shade ' for cacao 

 has received considerable attention in the West 

 Indies. 



' 'As well among colonial planters as in the pages 

 of periodicals devoted to tropical agriculture, a 

 question often discussed is this : ' (Jan India 

 Rubber and Cacao successfully and economically 

 be cultivated on the same held, and are the advan- 

 tages derived from mixed cultivation sufficiently 

 great to counterbalance the pernicious influence 

 which one species may exercise upon the other? 



" It is generally accepted that the cacao tree 

 during all stages ot its development requires 

 some shade and shelter, and it becomes natu- 

 rally desirable to use for these purposes trees 

 which could at the same time yield a product, 

 and add to the revenue of Che estate. 



" Shade or shelter in cacao planting must be 

 considered under two different heads according 

 to its purpose and character, namely as temporary 

 and permanent shade. 



" Under the term temporary shade we wish 

 to refer to the protection required during the 

 first years after the establishment of the planta- 

 tion, before the trees planted for permanent 

 shade have grown up. Since young cacao trees 

 under all circumstances require more shade than 

 mature ones, the temporary shade has to be 

 more dense, and for this purpose therefore 

 rapidly growing plants with large and abundant 

 leaves are generally employed, as for example 

 bananas. No rubber plants aro suitable for tem- 

 porary shade, and in the notes which follow, con- 

 ditions govering the planting of permanent shade 

 trees will therefore be exclusively considered. 



" The requirements for shade vary consider- 

 ably according to locality, variety of cacao and 

 distance at which the cacao trees are planted ; 

 whilst protection against prevailing winds will 

 almost always be necessary. Overshadingis often 

 practised and the prevalence of much fungoid 

 disease is often due to mistakes in this direction. 



" An ideal shade tree should answer the fol- 

 lowing requirements : — 



" A tall-growing tree developing its bran- 

 ches about 12 feet above the ground ; the 

 branches should be strong and elastic, not 

 liable to breakage in storms. The tree 

 should be a subsoil feeder and should 

 change its leaves annually, without being de- 

 cidedly deciduous. It should be a rapid grower, 

 and yield a remarkable product, without draw- 

 ing too much on the fertility of the land. It 

 should of course be a tree not requiring shade 

 for its own proper development. 



"It would carry us too far to review here the 

 numerous trees which are met with planted as 

 shade among cacao ; few or none answer all the 

 above mentioned requirements. What parti- 

 cularly interest us are the commonly planted 

 rubber trees. 



24 



l Hevea brasiliensis is a tall and rapid grower, 

 developing a good and high shade. It is how- 

 ever a surface feeder with a very dense root 

 system, liable to mat the soil and thus interfere 

 with the development of the cacao roots. As 

 has been proved in the West Indies, Hevea may 

 grow well without developing sufficient latex 

 to pay tapping, and it cannot therefore be 

 generally recommended. 



"Funtumia elastica is decidedly a forest tree, 

 requiring shade for its own development andean 

 therefore be left without further consideration, 



"The species of Ficus offer great advantages 

 as windbreaks, planted at some distance from 

 the cacao, as for instance on the opposite side 

 of roads or canals. For shade inside the plan- 

 tation they are too bulky and the root system 

 is too wide and dense. 



" The Manihot species, except Manihot Ola- 

 ziovii, which is of a doubtful value as a rubber 

 producer, grow too low. To this it must be added 

 that the branches of all species of Maniliot are very 

 brittle, and that these trees prefer soil and cli- 

 matic conditions which do not suit the cacao tree, 



" Castiiloa elastica, therefore, remains as the 

 rubber tree most likely to give satisfaction, and 

 it is probably also this tree which has most 

 frequently bben tried and recommended. A 

 native of the same countries as Theobroma Cacao, 

 its general climatic requirements are the same. 

 As regards soil, Castiiloa thrives well on any 

 good cacao land, but it is less particular, and 

 will grow well on both lighter and heavier soils 

 when the drainage is satisfactory. Castiiloa elas- 

 tica, liko the cacao, prefers much water and 

 atmospheric humidity, but it is very susceptible 

 to damage through the least stagnation of sub- 

 soil water and acidity of soil. 



" Although Castiiloa in its native country is 

 found growing in the forests it is not really a 

 forest troe, but a ' Tree weed ' as it has been 

 termed by Mr O F Cook, in his report on ' The 

 Culture of the Central American Rubber Tree,' 

 Washington, 1903, by which term he unders- 

 tands a tree which cannot grow up in the 

 natural forest, but will develop rapidly on clear- 

 ings, old garden sites, &c, where the slower 

 growiug forest trees follow and surround it. In 

 cultivation it is able to develop to perfection 

 without shade, even on rather dry land, though 

 it grows more rapidly when slightly shaded 

 during the first years. 



" On fair cacao land, Castiiloa will reach a 

 height of 25 to 30 feet within the first four 

 years, and it is only when the tree is about three 

 years old that it commences to develop perma- 

 nent branches ; before this the only branches 

 developed are pseudo-branches which, liko the 

 leaves, are shed every year. The pseudo-bran- 

 ches carry all the foliage of the tree and 

 when the growth is healthy the development 

 both on the main stem and on the permanent 

 branches is very rapid. The permanent branches 

 remain few, but with their abundance of 

 pseudo-branches, they form a dense crown 

 affording good shade. 



"In localities where dry weather prevails 

 during the months of March and April, the 

 habit of Castiiloa is decidedly deciduous, and it 



