186 SYLVICULTURE IN THE TROPICS pt.h 



to rot them. This is particularly necessary after a 

 heavy fall of rain, when the weight of water bends 

 down the shading material over the plants. In some 

 plantations, instead of shading with twigs or ferns, it 

 may be advisable to raise a nurse-croip beforehand. 

 This would usually consist of quick-growing trees with 

 a light foliage. Such nurses, for example, are raised on 

 cacao plantations, the trees most used being some species 

 of Erythrina, Albizzia moluccana, etc. In coco-nut 

 plantations in Ceylon native planters are in the habit 

 of raising shade crops of manioc or banana, but these 

 have the drawback of being very exhausting for the soil. 



Wherever weeds spring up readily, it will be 

 necessary to do a certain amount of weeding. In 

 Ceylon plantations, where the whole area has been 

 cleared, it is usual to weed the whole over again. But 

 this does not seem to me to be really necessary, at any 

 rate for plantations of forest trees. What is required is 

 that weeds should not invade the soil round the plants 

 to such an extent as to retard their development, 

 whether this hindrance may be due to suppression 

 of the portions above ground or choking of the roots. 

 For this reason it is necessary to weed out round the 

 plants sufficiently far to prevent this. Particular 

 attention should be paid to plants having creeping 

 rhizomes, to climbers, and to root -parasites. I have 

 seen a whole field of young Ceara-rubber trees ruined 

 by a parasitic Striga, which was considered a harm- 

 less weed, while, all the time, it had been drawing its 

 sustenance from the roots of the young plants. 



In places where drains have been made, whether 

 for draining water-lo<ied soil or for carrying off surface 

 water, the drains should be frequently inspected and 

 cleared of debris which have accumulated within them 

 and might cause them to get choked. This is especially 

 necessary for drains on hill-sides, which are most liable 

 to get silted up. 



However well kept a plantation and however success- 

 ful it is, there will be some plants which will die during 



