Wind-Dispersed Species in a Nigerian Forest

General observations in various parts of the forest zone of Nigeria have indicated that light wind-borne seeds and fruits are characteristic of many large trees, whereas under-storey trees and shrubs mostly have fleshy fruits. It has also been suggested that the lighter-seeded trees are, on the whole, more characteristic of open habitats, while species with larger seeds occupy more shaded habitats and can regenerate in more advanced phases of the succession. The latter generalization has been demonstrated for British plants by Salisbury (1942) and there is no obvious reason why it should not also hold for tropical forests. In order to test the accuracy of these general observations research was started in an area small enough to be studied in detail. The Ibadan South Forest Reserve was chosen largely because of its accessibility; it is about 32 km. (20 miles) south of Ibadan on the main Ijebu Ode road. The forest is undoubtedly secondary but has probably not been farmed for at least 80 years (possibly up to 120 years). It is in the drier part of the Lowland Rain Forest Region (Keay, 1953) and is characterized by a large proportion of Sterculiaceae and Ulmaceae. An 'Observation Plot' 122 m. (400 ft.) square was demarcated in April 1948 in a mature part of the forest and served as a focal point of the research. The research has been interrupted by my transfer to Kew in 1951, and so a full account of it cannot yet be written. The role of wind-dispersed species is the only aspect treated in this paper, and the only species considered are those actually found in the Observation Plot.