Assessment of Tree Diversity and Abundance in Selected Forest Reserves in Osun State, Southwestern Nigeria

Abstract

Studies have shown that forest has undergone different levels of disturbance due to anthropogenic activities which impacted tree diversity, abundance and species composition. Therefore, this study examined and assessed tree diversity and abundance in five selected forest reserves in Osun State, Nigeria with a view to ascertaining the present species status for mitigation decision. Primary data include measurement of floristic composition and Key Informant Interview (KII) focusing on species inventory. A total of five sampled plots of 10 m × 10 m were demarcated in each five selected forest reserves where total enumeration of tree species within the demarcated plots were identified and classified into families, while parameters like girth (diameter at breast height) and height were measured. The result showed that the maximum height in all the selected forest reserves was 15 m. The highest total number of individual woody tree species was found in Oba Hill Forest Reserve (112). The dominant tree species were exotic species, teak (Tectonagrandis) (98 stems) and gmelina (Gmelinaarborea) (36 stems) of verbanaceae family. Indigenous woody species identified to be highly threatened and at the brinks of extinction include Terminalia Africana, Albiziazygia, Miliciaexcelsa, Anogeissusleiocarpus etc. The Shannon-Wiener index (2.499) from Ikeji-Ipeu Forest Reserve was the highest among the five selected Forest Reserves which indicated that this forest was potential biodiversity hotspot. The highest mean basal area of 3.37 m 3 and highest mean volume of 27.96 m 3 both from Oba Hill Forest Reserve showed that matured woody trees were scanty. This study revealed that anthropogenic activities had set in greatly and the forest reserves were poorly managed which had led to the reduction in number of tree diversity. This study therefore, provides baseline information for ecosystem management and control.

Assessing Forest Cover Distribution, Species Diversity, and Richness of the Buffer Zone for Strategic Forest Management Planning for Nimule National Park, South Sudan

“…The significance of the relationship between human beings and forest reserves has been increasing as a result of the conflict of the tremendous increase in population growth and crucial pressure on natural resources. Over the years, the forest has been a continuous source of fuelwood, charcoal, wild fruits collection, and land for agricultural purposes that have led to present depletion [12] [13].…”

Effects of plot size on assessment of tree species diversity in Caspian forests of Iran

“…One of the most critical issues in natural resource conservation is integrating economic development along with the protection of biodiversity on earth (Mirzaei et al 2019a). Loss of biodiversity and destruction of habitat has increased due to an increase in human population and increased human demand for natural resources, such as in agricultural practices (Asifat et al 2019;Mamnun and Hossen 2021). Today, natural ecosystems in different parts of the world are impacted by the destructive activities of humankind (Ebrahimi et al 2014).…”