An inventory of the entire tree species ≥10cm diameter at breast height (dbh) was carried out within Forestry Research Institute of Nigeria (FRIN) investigation 133 Shasha in Osun State, Nigeria. This study was carried out to ascertain the tree species diversity, conservation status and utilization potentials in the study area. The results were obtained from 16 sample plots of 50×50m in four tracts located through cluster sampling technique. In all, an average total of 295 stands distributed among 66 tree species and 28 families were encountered. High value of Shannon-Weinner index H'=3.73 and Evenness of E=0.89 were obtained for the reserve. At present, only few trees have attained the merchantable size of 48cm dbh. The 63 tree species in the study site were categorized into four groups namely, stable, vulnerable, endangered and threatened status. The result revealed that stable group had 1.59%, vulnerable 4.76%, endangered 44.44% and threatened 49.21%. Result of the Utilization potentials revealed that utility classes 7 - 8 accounted for 55.6% (comprises of tree species with no potential use for sawn timber), while 45.4%. of trees in classes 1 – 6 comprises of trees with timber potentials. This study highlighted species population diversity, conservation status and utilization potentials of the study site and called for ecological application in the management of forest reserves in Nigeria.

With the increase in the rate of tree removal and construction of buildings within the Forestry Research Institute of Nigeria premises, there has been concomitant rise in habitat modification. These changes in habitat composition affect the insect population. This study therefore investigated the insect species diversity and abundance within some selected locations within FRIN with the view to determining different insect species available in FRIN premises. Sweep nets were used to trap the insects along a predetermined line transect. Data were analyzed using Microsoft Excel 2007 and Paleontological Statistics were used for the data analysis. Descriptive statistics, one-way analysis of variance (ANOVA) and species diversity and composition were all assessed. A total number of 1073 individual insects belonging to 6 orders, 27 families and 34 species were recorded across the three locations. Out of this, Order Lepidoptera had the highest relative abundance (53%), followed by Coleoptera (22%), then by Hymenoptera, Hemiptera, Heteroptera and Diptera with 10%, 9%, 4% and 2% relative abundance respectively. The result of ANOVA showed that there was no significant difference in species composition/richness across the locations at probability level of 5%. The insect species diversity, evenness and richness also varied across the locations. This study therefore, brings to the fore the diversity and abundance of insects within FRIN premises and highlighted the need for a more intensive study by the entomology section and for sustainable actions to be taken in conserving beneficial rare species while, managing the abundant pestiferous ones.

The anthropogenic factors which drive land use change are primarily population pressure on land (i.e. mean population per unit area) which has resulted in undue depletion and degradation of most forest land in Nigeria. Deforestation, reduction in biodiversity, depletion of stratospheric ozone, increases in greenhouse gases, and changes in sea level were among the effects causing climate change. The study investigated the impact of urbanization on Greenhouse gases emission and estimated greenhouse gases emitted in the last twenty years of deforestation using Alalubosa forest reserve in Ibadan, Oyo state, Nigeria. Greenhouse gases emission (carbon emission) for each prominent tree species at the study area were calculated using standard method to estimate carbon emission. The estimated carbon emission from the selected tree species: Tectona grandis, Cassia siamea, Pinus caribea, Gmelina arborea, Cedrela odorata, Triplochiton scleroxylon amounted to 2.09×10-4 MTCha-1 of carbon loss during this period. The emission of Greenhouse gas (GHG) like CO2 will induce climate change hence the need for the Government to enumerate carbon stock in forest trees in order to regulate Greenhouse gas (GHGs) emission and embrace reforestation programmes to restore lost economic trees.Keywords: Greenhouse gases, urbanization, prominent tree species, Alalubosa forest reserve

Effects of forest fire on the regeneration potential of trees at Olokemeji Forest Reserve was established in this study. The Olokemeji fire experimental plot was selected at the reserve. The site was divided into three plots; late fire treatment was applied to Plot A, Early fire treatment was also applied to Plot B and no fire treatment at plot C (Control plot). The diameter at breast height (dbh) and tree height (m) of the tree species in the plots were assessed prior and post fire treatment. The regeneration potential of the selected plots after burning were assessed through the occurrence of saplings and seedlings obtained. The highest basal area (m2) were found in plot C followed by plot B and Plot C with mean value of 0.64, 0.55 and 0.30 m2 respectively. The number of stems per plot ranged from 25 to 67. The regeneration potentials of the three plots were found to be noteworthy. Early and late year fire regime adopted had both positive and negative effect on the regeneration potentials of tree species. This study has established the effect and relevance of fire on forest and wildlife management. It’s therefore recommended in this study that Prescribed or controlled burning should be encouraged as appropriate sivilcultural management tool for stimulating basal area growth, natural regeneration, production of tree species seedlings and saplings.