ASSESSING TREE DIVERSITY, REGENERATION POTENTIALAND ENVIRONMENTAL THREATS IN SHASHA FOREST RESERVE, NIGERIA: A REVIEW OF CHALLENGES AND CONSERVATION METHOD

Abstract

Forest reserves in southwestern Nigeria are important repositories of tree biodiversity, but their ecological integrity is increasingly challenged by agricultural encroachment, illegal tree cutting, settlement, hunting, grazing and fire. This study assessed tree diversity, regeneration potential and anthropogenic pressures in Shasha Forest Reserve, Osun State, Southwestern Nigeria. The reserve was divided into four locations representing the north, east, west and south, and 50 m × 50 m sample plots were used for field assessment. Tree species occurrence, density and regeneration were assessed, while saplings (DBH < 10 cm and height > 1 m) and wildlings (height < 1 m) were enumerated. Diversity and evenness indices were calculated, while one-way analysis of variance (ANOVA) and Least Significant Difference (LSD) at 5% probability level were used for comparison. The results showed considerable spatial variation in tree species representation. White Afara (Terminalia ivorensis) was consistently dominant, with density values of 5.50, 8.50, 24.00 and 19.00 across Locations 1–4, respectively. Cotton Tree (Ceiba pentandra) recorded 3.25 and 6.25 in Locations 1 and 2, while Epin (Ficus exasperata) recorded 17.00 and 15.50 in Locations 3 and 4, respectively. Natural
regeneration was evident, although it varied among species and locations. White Afara recorded sapling values of 4.75, 2.75, 3.75 and 2.75 across the four locations, while its wildling values were 3.25, 2.75, 4.75 and 2.75, respectively. Generally, several species had higher wildling than sapling representation, indicating active early-stage recruitment but possible limitations in progression to the sapling stage. Cordia Wood, Abeere and Molagbaawo recorded relatively low sapling regeneration, with values as low as 0.75 in some locations. Anthropogenic pressures included illegal farming, settlement, hunting, tree cutting, grazing and fire. Cocoa cultivation accounted for 50%, 30% and 40% of reported activities in Locations 1, 2 and 3, respectively, while plantain accounted for 30%, 60%, 20% and 5% in Locations 1–4. The findings demonstrate that Shasha Forest Reserve retains substantial tree diversity and natural regeneration capacity, but uneven species representation and persistent anthropogenic disturbances may affect long-term forest sustainability. Species-specific regeneration support, protection of mature parent trees, control of agricultural encroachment and illegal activities, community participation and continuous monitoring are recommended.