Global Journal of Science Frontier Research, H: Environment & Earth Science, Volume 23 Issue 1

Tree Species Diversity Status and Contributors to Forest Degradation in Shasha Forest Reserve, Nigeria © 2023 Global Journals 1 Year 2023 44 Global Journal of Science Frontier Research Volume XXIII Issue ersion I VI ( H ) (60) recorded in this study was observed to be higher than the number of species recorded (55) in the same area by Adekunle (2006) and (Onyekwelu et al., 2005). Part of the explanation for this may be that moderatelyor slightly unprotected tropical forests are likely to maintain more plant speciesthan a forest that is dense and protected (Mishra et al., 2004). This also shows the degree to which man has encroached on theforest between 2000 and 2021. The more varied a range is, and the, more its unchangeability. The overall Shannon’s equitability of 0.596 for this study is smaller than the 0.66 observed by Onyekwelu et al. (2005) for Queen Forest, an unaltered ecological community reserve in Ondo State. This showed lower naturally- occurring of individual tree species within the species reported, indicating that species evenness lesser declined as forest depletion intensified. This agrees with the finding of Nath et al. (2005) for tropical biomes in India that tree species'evenness declined with the rise in intensity of forest stress. The results of the tree relative density showed that 9 (39.91%) of the indigenous tree species observed were the predominant onespresent during the study (Table 1). Shasha Forest Reserve, generally is predominated by tree species in the families Sterculiaceae, Euphorbiaceae, and Ebenaceae.This result is corroborated by Adekunle (2006), who observed Sterculiaceae; Euphorbiaceae, has one of the prevalent families in the primary forest of the research area. Furthermore, Ihenyen et al. (2010) in Ehor Forest Reserve in Edo State also observed that Sterculiaceae, Euphorbiaceae, and Ebenaceae be among the predominant families in those forest reserves. The types of tree species such as (Pricalina nitida, Celtiszenkeri, Diospyrosspp, Strombosiapustu lata, and Sterculiarhinopetala.) primarily found in this range are immature for commercial timber uses, because most of them are below the merchantable girth of (48 cm) required for harvesting. This signifies that the ecological community has been previously logged, during which matured invaluable economic trees have been selectively exploited. Strombosiapustulata Oliv was one of the predominant tree species found by Adekunle (2006) in the primary forest of the study area 2006. Nevertheless, some of these tree species Strombosiapustulata Oliv, Diospyros spp, and Funtumiaelastica (Preuss) Stafp, were among the tree species obtained by Onyekwelu et al. (2008) to dominate Oluwa Forest Reserve, the adjacent forest reserve to the study area. Therefore, considerable numbers of the tree species found are fewer in abundance due toexploitation and degradation of the forest area and rate of conversion to cropland. This study was designed to assess the woody plant diversity to signify the number and variety of diverse species in the ecosystem within the area under investigation. Good insight on how to give proper accountability of a reserve and to preservediversity is crucial for both current and subsequent generations. The structural composition of tree species conservation within Shasha Forest Reserve is fast declining owing to the encroachment of arable farmlands into the forested area. The increasing of cultivated farmlands and non-forested, abandoned sites, uncontrolled logging, charcoal business, comer- cial fire collection, human population settlement, and habitat fragmentation are severe degrading factors within the reserve. In reversing this, urgent measures have to be taken to give a trade-off for land needed for subsistence agriculture and impaired land meant for afforestation in place of primary forest in Shasha Forest Reserve. Management interferences like enrichment planting, regulated selective logging, and protection of biological regeneration can further aid in restoring this ecological community. Finally, planned of regenerating the indigenous tree species in the forest reserve is an imperative means to confront the present rate of depletion in the area. Further study on the factors contributing tothe such menace is recommended to monitor the seasonal variations in contents of biodiversity indices and relate to the past treespecies diversity studies. The work has provided information on the extent of forest degradation in the Shasha Forest Reserve as a way of evaluating the ecological health of the study field as a result of deforestation. The work also added to the benchmark information on plant species diversity indicesstudiesin our environment. A cknowledgements The authors are grateful to Directors and Workers of Shasha Forest Reserve, Osun State for permitting the useof their reserve as sampling site for this study. The Forestry Herbarium, Ibadan (FHI) of Forestry Research Institute of Nigeria, is to be thanked for their assistance in classification and identification analysis. The Obafemi Awolowo University, Ile-Ife is also acknowledged for providing the enabling environment for the study. Statement of Competing Interests The authors declare that they have no competing interests. R eferences R éférences R eferencias 1. Adedeji, O. H and Adeofun, C. O. (2014). Spatial Pattern of Land Cover Change Using Remotely Sensed Imagery and GIS: A Case Study of Omo- Shasha-Oluwa Forest Reserve, SW Nigeria (1986- 2002). Journal of Geographic Information System. 6: 375-385. 2. Adekunle, V. A. J. (2006). Conservation of tree species diversity in tropical rainforest ecosystem of