FOREST IN RELATION TO AGRICULTURE 495 
lation, in that over an area of fully 30,000 square miles it is possible 
to raise two crops a year on the same land, and over roughly an area 
of 10,000 square miles of the country it is possible to raise three crops 
per year (in each case under a rotation of crops). In this manner less 
land is required per person than, in a temperate climate in order 
to grow food either for local consumption or for export. 
So far we have dealt with shifting cultivation. However, in most 
civilized countries, sooner or later a system of permanent cultivation 
is started instead of shifting farms. In England this was begun at 
a time in which the population was less dense to the square mile than 
it is now in the Southern Provinces of Nigeria (average 101 persons 
per square mile). In Germany the density of population is 323 
persons per square mile, yet they had (before the war) 25 per cent. 
of the land area of their country covered with permanent forests. 
If it were possible to start permanent cultivation with a rotation of 
crops in England when the population was less dense than in the 
Southern Provinces of Nigeria, it should be feasible in Nigeria now. 
Again, if it is found possible for Germany to retain 25 per cent. of 
the land area under permanent forest crops, with a density of popula- 
tion three times greater than that of Nigeria, at the same time main- 
taining a prosperous system of permanent agricultural cultivation, 
it should also be much easier to have a similar proportion of permanent 
agricultural cultivation in the Southern Provinces of Nigeria; at the 
same time, taking into consideration the more favourable climatic 
factors, it should be possible not only to grow sufficient foodstuffs 
for local use, but also to grow sufficient to develop into a large export 
trade for ground nuts, maize and beans, besides cocoa and rubber. 
