THE CULTIVATION OF COCOA 151 



near houses, which are constantly weeded in order to 

 prevent the formation of secondary bush, are soon in a 

 very bad condition, and if the soil consists of compact 

 clay nothing but poor, sour grass will grow on it. When 

 such places have to be taken into cultivation, much 

 work must be done in order to improve the structure of 

 the soil tilling, manuring, the growing of soil-improving 

 plants before they are again suitable for use. This 

 injury to the soil caused by its unshaded condition is of 

 course specially noticeable in the tropics, but it is also 

 well known in cooler climates, especially in forestry. 

 Where open places are found in a forest in consequence 

 of the death of trees, the forester is anxious to have 

 such places replanted as soon as possible by suitable 

 plants in order to prevent the soil being spoiled. This 

 bad influence exercised on the soil by want of shade 

 must be attributed, at any rate for the greater part, to 

 the oxidation and destruction of the humus by the 

 direct influence of the sun's rays, the high temperature 

 in the daytime, and the free access of oxygen. 



The shading of the soil is therefore the most im- 

 portant function of the shade trees, and the close 

 planting of cocoa trees, where shade trees are not used 

 (e.g. in Grenada), is simply a means of obtaining the 

 shade otherwise afforded by the shade trees. Wide 

 planting of cocoa trees without shade will always result 

 in a spoiling of the soil, soon followed by the death of 

 the trees, at any rate if care is not taken to keep the 

 soil in good condition by intensive tillage and heavy 

 manuring. 



These considerations may be briefly summarised as 

 follows : Though it is possible that in some countries 

 the cocoa tree will not thrive in untempered sunlight, 

 we may assume that in most countries this is not the 

 case, and that the untempered sunlight is not in any 

 way detrimental to the tree. The usefulness of the 

 shade trees lies not in giving shade to the tree but in 

 giving shade to the soil ; in enriching the soil with 

 nitrogen, by means of the nodules of the roots, and with 



