DEPARTMENT OF FOREST RESOURCES MANAGEMENT

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Author: search.filters.author.Jimoh, S. O.Subject: search.filters.subject.distribution

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    Population distribution and threats to sustainable management of selected non-timber forest products in tropical lowland rainforests of south western Nigeria
    (Northeast Forestry University and Springer-Verlag Berlin Heidelberg, 2013) Jimoh, S. O.; Amusa, T. O.; Azeez, I. O.
    Uncontrolled harvesting of non-timber forest products(NTFPs) poses a serious risk of extermination to several of these species in Nigeria. Yet, there is a paucity of information on the distribution, population status and sustainable management of NTFPs in most of the tropical lowland rainforests. We, therefore, assessed the population, distribution and threats to sustainable management of NTFPs within the tropical lowland rainforests of Omo and Shasha Forest Reserves, south western Nigeria.Data were obtained through inventory surveys on five top priority species including: bush mango (Irvingia gabonensis (Aubry- Lecomte ex O'Rorke) Baill),African walnut (Tetracarpidium conophorum (Mull.Arg.)Hutch. & Dalziel syn. Plukenetia conophora), chew-stick (Massularia acuminata(G. Don) Bullock), fever bark (Annickia chlorantha Setten&P.J.Maas syn. Enantia chloranta) and bush pepper (Piper guineense Schumach. & Thonn.).Purposive and stratified random sampling techniques were used for the inventory. Each forest reserve was stratified into three, viz: less disturbed natural forest (for areas that have been rested for at least ten years), recently disturbed natural forest (for areas that have suffered one form of human perturbation or the other in the last five years), and plantation forest (for areas carrying forest plantation). Data were collected from eighteen 10 m ×500 m belt transects located in the above strata. The species were generally fewer in both plantation and recently disturbed natural forest than the less disturbed natural forest, suggesting that forest disturbances (habitat modification) for other uses may have an effect on the occurrence and densities of the NTFPs. Exceptions to this trend were found for P. guineense and T. conophorum, which were fairly common in both planta tion and recently disturbed natural forest. Among three tree NTFP species (i.e. I. gabonensis, M. acuminata and A. chlorantha), only I. gabonensis showed a significant difference in overall DBH size classes for both reserves (t=-2.404; df =21; p=0.026).Three tree NTFP species in both reserves further showed differences from the regular patterns of distribution of trees. The fairly regular reverse J-shaped size class distribution observed for M. acuminata in the study sites, however, suggests a recuperating population. In general, destructive harvesting of species, logging operations, low population size, narrow distribution ranges and habitat degradation are the major threats to the population of NTFPs in the study area. The implications of our findings for sustainable management of NTFPs in the study area are discussed and recommendations are made for a feasible approach towards enhancing the status of the species
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    Forest Structure Analysis in the Oban Division of Cross River National Park, Nigeria
    (David Publishing Company, 2012) Jimoh, S. O.; Adesoye, P. O.; Adeyemi, A. A.; Ikyaagba, E. T.
    Information on forest structure is important for forest management decisions. This is inadequate in many situations, especially where timber is not of primary interest. We analyzed the structure of two forest types in the Oban Division of Cross River National Park, Nigeria. Systematic sampling technique was used to establish two transects measuring 2,000 x 2 m, at 600 m interval in the two forest types in four locations. Four 50 m x 50 m plots were located alternately at 500 m intervals along each transect, constituting 32 plots per forest type and 64 plots in all. Diameters at breast height (DBH), base; middle and top; crown diameter; total height and crown length were measured on all trees with DBH > 10 cm. There were 159 stems/ha in the close-canopy forest and 132 stems/ha in the secondary forest. The mean DBH were 34.5 cm and 33.62 cm respectively. The mean heights were 24.79 m and 23.97 m, respectively. Basal area/ha were 41.59 m2 ha'1 and 27.38 m2 ha'1 for the two forest types. Majority of the trees encountered in the two forest types belonged to the middle stratum which has implication for small mammals’ populations. Emergent trees which are otherwise scarce in other parts of the country were recorded, which also has implications for density thinning and seed supplies