NIGERIA 153 
been made in these forests, and it remains to be seen whether sufficient 
will be preserved to ensure the future fertility of the soil and the requisite 
rainfall. One of the most prominent species is the cotton-tree, with 
its great root buttresses and muscle-like protuberances from the stem. 
The Obechi, or Arere, is another magnificent timber tree, with soft 
white wood and maple-like leaves, which grows to huge dimensions. 
The African greenheart, which may grow 12 feet in diameter, is hard 
enough to break the blade of an axe. The Iroko, taking the place of 
oak in African economy, is another tree frequently met with, and it 
extends its area of distribution as the forests are opened up with 
clearings. East of the Niger this formation is only found to a small 
extent in the Onitsha province; a little larger in the northern part 
of the Owerri province, and still largest in the northern part of the 
Calabar and the southern part of the Ogoja province. In fact, the 
finest development of the mixed deciduous forests is found in the last- 
named province, just north of the Cross River, where it is really at the 
edge of the true deciduous forest. In this zone some three kinds of 
mahogany are found, in some places very diffusely scattered, in others 
up to a thousand mature trees in eight square miles, or in a third nearly 
every tree a mahogany on both sides of the road for over half a mile. 
The four species in this zone vary less from province to province than 
they do in the case of the evergreen forest zone, though the total 
number may be greater. 
Beginning again on the western side, the open deciduous forest 
or dry-zone formation shows itself over a very wide extent in Oyo, 
Northern Jebu-ode, and in the Northern Benin provinces. East 
of the Niger it is of wide extent in the Northern Onitsha and Northern 
Ogoja provinces, but it also occurs in the northern part of the Owerri 
province as an artificial product of man’s destruction of the original 
forest. In some places this formation, owing to the trees being 
close together, more nearly approaches the deciduous forest. In 
others, owing to the poor and stunted nature of the arboreal growth, 
it more nearly approaches the open grass savannah formation. Only 
north of the Oyo province near Shaki, or north of Ogoja in that province, 
could it be said that this kind of formation is seen. 
One of the most prominent kinds of trees found is the Shea Butter, 
the nut of which is used in the making of chocolate cream and margarine. 
This tree, varying in size from a large oak to a short, stunted, gnarled 
and burnt relic of better forest conditions, is found over very wide 
areas in the Oyo and northern part of the Abeokuta province. Strangely 
enough, this tree does not appear in the northern part of the Benin 
or Onitsha province, and only occurs again in the north-eastern corner 
of the Ogoja province. The locust-trees, with their open crown and 
feathery leaves and long pods similar to French beans, are conspicuous 
all through the zone, and near the villages are specially preserved. 
