Browsing by Author "Oke, S. O."

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    Floristics and Structure of the Fallow Vegetation in the Ile-Ife Area of Southwestern Nigeria
    (1997) Oke, S. O.; Isichei, A. O
    A study was made of the vegetation of seven fallow plots in Ile-Ife Area of Southwestern Nigeria. The aim is to provide detailed information on the current state of the Secondary Low-land Forest Vegetation and on the various successional stages formed as a result of human activities. Results show that there are differences in species composition of the plots. Young plots (1-5 years old) had fewer woody species and individuals than the secondary forest plots. The secondary forest plot which is the oldest plot, had the highest mean basal area, mean crown area and greater number of trees in the height class ≥7m while the youngest plot had the lowest mean basal area, mean crown area and had no tree in the height class ≥7m. The woody basal and crown area of the plots depend entirely on the density and size of the woody species. The mean aerial cover of herbaceous plant was more than 100% in all the plots except the secondary forest plots where there was no herbaceous plant at all. The differences in species composition could be attributed to level of human activities on the plots. The knowledge of this species composition in the plots (Biological diversity) can be directed at and preserving the plants for both perceived and economic benefits and for their aesthetic value.
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    Open Access
    Seed Bank Dynamics and Regeneration in a Secondary Lowland Rainforest in Nigeria
    (2006) Oke, S. O.; Oladipo, O. T.; Isichei, A. O.
    Seed bank dynamics and forest regeneration in a secondary lowland rainforest in Nigeria were studied with a view to determine the potential contribution of the soil seed bank to the regeneration of the forest. Six 25 x 25m plots were used and in each plot, ten replicates top soil 0-15cm were collected in March, June and October. The soil samples were subjected to seedling emergence for 20 months to determine density and species composition of the seed banks of the study plots. The results showed that there were more individuals in plot C (a disturbed plot) and herbaceous species dominated (more than 96%) the seed bank of all the study plots and across the seasons. Few woody species emerged in all the plots and there was significant difference (p < 0.05) in density both between the plots and months. Similarity between seed bank and vegetation composition, no matter the forest state, is very low. The most frequent species in the vegetation are absent in the seed bank and vice versa. The seed bank is mainly composed of early successional species and seeds of primary forests are rare in the soil. The few woody species recorded indicate that the soil seed bank may not be an important conservation tool for the regeneration of the degraded forest, therefore reforestation is recommended for restoration of the degraded forest.
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    Open Access
    Soil Properties of Seven Study Fallow Plots in Nigerian Rainforest Region
    (1999) Oke, S. O.; Isichei, A. O.; Amusan, A. A.
    The soil properties of seven fallow plots in a Nigerian rainforest region were studied with the objectives of providing profile descriptions which would aid their recognition in the field, and of presenting their physical and chemical properties which are important for their use. The soils of younger plots are well drained while the soils of the older plots are poorly drained. Sand fraction was significantly higher than clay and silt within each plot, but showed no significant difference between different plots. Organic matter content was low in all the plots and there was no significant difference between the plots, but the content was significantly higher in the upper layer than in the lower layer in all the plots. In general the soils of the fallow plots are not seriously leached of bases. Percentage: base saturation significantly varied among different plots. The cation exchange capacity is low in correspondence with kaolinitic nature of soil clay and low organic matter content.
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    Vegetation Characteristics of Fallow Plots and Soil Erosion in South-Western Nigeria
    (1999) Oke, S. O.; Isichei, A. O.; Aina, P. O.
    A study was carried out to find out the magnitude of runoff and sediment yield and various vegetation parameters .in Ile-Ife area of south western Nigeria. Seven 50 x 50 111 sample plots in Ile-Ife area, Nigeria were selected; one plot in a relatively undisturbed secondary forest and six other plots in disturbed areas with ages ranging from one year to five years old. Results showed that plots in younger fallows had fewer woody species and individuals than the older plot. A comparison of the bare and vegetated plots clearly sided that development of vegetation affects physical and chemical soil characteristics. The bare plot produced the highest values of both runoff sediment yield followed distantly by the natural forest plot while the disturbed young plots with lesser tree densities had the lowest runoff and sediment yield.