ages that shrank other African rainforests to a few small islands; they therefore did not suffer the heavy extinctions this pressure put on existing species. Secondly, the oxisol soils of the LEM in the region are sufficiently well drained to support a wider range of plant species than the adjacent freshwater and brackish water alluvial ecozones, where waterlogging limits diversity.
There may at one time have been around 5,000 plant species in the LEM ecozone, many of them large trees. Today a limited range survive; nonetheless many are highly valued for their social and economic uses.
- The following examples are all taken from the Botam-Tai area of the Ogoni plain, and are as also described by Cooper:
Ceiba pendantra, the Silk Cotton tree, used locally to determine the beginning of the planting season (when the leaves fall) and recognisable by its red flowers in November. This heavily buttressed tree would have been the tallest in the forest, needing especially fertile soils but tolerant of high water tables. It would have been found beside the lakes and swamps, but not in them. It is a good pioneer tree.
Lophira procera. The Iron-Wood, with its characteristically red young leaves and red timber. It is locally known as Gwulee Gwure and is used to making gongs, and also the pestles and mortars for pounding yam. Commercially, the tree is famous for making railway sleepers and is still exported to France for this purpose. The tree has survived because until the arrival of the modern chain saw it was extremely difficult to cut.
Piptadenia africana. This is locally known as Gboo and is characterised by large wavy buttresses. It is a very good saw wood, and survives for the time being around Botam-Tai as a number of sacred trees on the sites of early settlements.
Terminalia superba. This is known locally as Gara. It is a tall, spreading tree with a small crown of whorled branches which often suddenly terminate the trunk, and a light yellow slash. This tree is good for general carpentry and grows easily and fast from seed.
Cynometra hankei is tall, with a fan shaped crown and high buttresses. It may be an allied species of Brachystegia but it is common in Southern Cameroon, to which the Ogoni Forest was related.
Albizzia zygia is a light-loving leguminous tree of the secondary forest. It has a short trunk and an orange slash, which gives out a gummy resin. The timber is not strong but is used for light furniture. A good pioneer species, in the natural forest this tree may have colonised riverine margins because of the available light, but only along the higher wider river banks (it does not like wet feet).
Secondary Forest: where primary forest (which developed before the impact of human society) has been cleared, for instance for farming, and forest subsequently re-colonising the land.
Anthocleista vogelli is also a tree of the secondary forest, having a short trunk and needing light. Now the most common tree around Botem-Tai, because it is resistant to fallow burning, it is also the second most common pioneer tree in Southern Nigeria (after the Umbrella Tree, Musanga cecropioides).
Other likely tree species and their relations are as follows (with thanks to Sylvestor Orchiere, Manager of the Okomu Wildlife Sanctuary in Edo State):
