NATURAL REGIONS.—Except in the north-east and north-west, the greater part of Southern Nigeria is covered by the tropical forest, which also extends up the valley of the Niger into the southern part of Northern Nigeria. The remainder of the country falls within the savanna lands of the Sudan, as far north, at least, as the eleventh parallel. Beyond this limit, the character of the vegetation changes, and the savanna gives place to a more arid region, in which the gum-bearing acacia and other trees of a similar character are conspicuous. Three natural regions may, therefore, be recognised : the forest, the savanna, and the semi-arid lands.
THE FOREST.—In this region the natives only grow food-stuffs sufficient to meet their own requirements, and depend for their exports mainly upon the natural products of the country. Of these, palm oil and palm kernels, which together hold the first place, are almost entirely obtained from trees growing wild in the forest, the resources of which in this respect have not yet been fully developed. Rubber is procured in a variety of ways.
Funtumia elastica and Landaphia ozvariensis are indigenous to the region, but both have suffered greatly from reckless overtapping. The former is now grown in communal plantations, but the latter is unsuitable for cultivation. In addition, the Para rubber tree (Hevea brasiliensis) has been introduced into the country, and appears to be doing well in those districts where soil and climate are favourable. Cacao was formerly grown mainly in the west, where the trees seem to have suffered from the long, dry season, but plantations have recently been established in the south-east, where the rainy season is more prolonged ; and cacao is now an important article of export. Other forest products include mahogany and ebony. Coal of Tertiary age is found on both sides of the Niger ; and among other minerals known to exist are gold, iron, and tin.