102 MOZAMBIQUE 



machine to do the barking. In the case of 

 the root a few taps with a hammer are sufficient 

 to loosen the bark, which can then be sHpped 

 oS the wood, but bark from the stem has gener- 

 ally to be stripped off with a knife. 



I have been in communication with several 

 foresters and rubber concessioners on the subject 

 of the time required for the vines to grow again 

 to a tappable size — say 3 inches in circumference 

 — and opinions vary from six to twenty years, 

 but no practical trials on a forest scale have as 

 yet been made in East Africa, and hence these 

 opinions, though given by men who have devoted 

 special attention to Landolphia rubber forests, 

 have but a restricted value. 



Taking the period for the sake of discussion 

 at fifteen years, in the somewhat dry climate 

 of Portuguese East Africa, I should like to put 

 the question : Is there any economic product 

 known to tropical agriculture that pays to cul- 

 tivate if fifteen years are required before returns 

 can be obtained ? The capital expenditure 

 would be prohibitive; no product that I have 

 ever heard of could stand such a locking 

 up of capital. But it may be argued that cul- 

 tivation of the vine is not contemplated, the 

 idea being to let Nature herself restore the vines. 

 Nature would no doubt induce the growth of 



