20 



THE COCO-NUT 



CHAP. 



the only tree that suffers. The explanation is probably 

 that a tree struck by lightning becomes a breeding- 

 place for infection, and unless it is removed insects 

 will breed in this tree and then attack its neighbours, 

 and in this way they too are killed. 



The light is a very important factor in the climate 

 because it furnishes the energy for the formation of the 

 organic food of plants. If other conditions are favour- 

 able the coco-nut tree cannot receive too much light. 

 It therefore will not produce good crops in any place 

 whose climate is characterized by prevailing cloudiness. 

 For the same reason individual trees which are shaded 

 by other trees by being planted too close together, or 

 in any other way, will never be vigorous. Light also 

 increases the temperature of the leaves, and in that way 

 is favourable to the activity of the tree. 



On the temperature the coco -nut makes such 

 demands as are to be expected from a lowland tropical 

 perennial plant. The figure usually given for the 

 lowest tolerable average temperature is 22° C, and 

 this is probably too low. At any rate no such 

 luxuriant growth and production can be expected at 

 this temperature as in places where the average is 3 

 degrees or more higher. This is to be understood as the 

 average temperature for the year. A temporary fall 

 to 15° certainly does no evident harm, and probably 

 happens occasionally in all places in the tropics. 

 Semler, whose discussion of climate and the coco- 

 nut is most sane, suggests 10° as the lowest point 

 temporarily tolerable. There is no evident reason why 

 a still lower temperature, so long as it does not 

 nearly reach the freezing-point, would do the coco- 

 nut any considerable damage. However, the tropical 

 climate is more distinctly uniform than it is hot, and 

 the coco-nut thrives best where it is most constantly 

 warm. So long as the heat is not too drying it is 

 unlikely that coco-nuts are ever injured by too high 

 temperature. 



It is usually the temperature which fixes the limit 



