Survey of Epiphytes on Plantation Trees of Gmelina arborea in Ondo State Forestry Plantation

Plantation forests of Gmelina arborea established across Ondo State, South West Nigeria, provide timber but may also harbour epiphytic plant communities that contribute to local biodiversity. This study surveyed epiphytic plants on Gmelina arborea plantation trees in Oluwa Forest Reserve, Ondo State, to assess species composition, diversity, and phorophyte preferences. Forty Gmelina trees of similar age (15 years) were randomly selected across three sectors of the plantation. All epiphytic plant species (vascular epiphytes and bryophytes) were recorded on each tree, noting canopy position (base, trunk, crown), substrate condition, and light availability. Epiphyte species richness, diversity, and cover were quantified. A total of 31 epiphyte species from 18 families were recorded, comprising 16 vascular epiphytes and 15 bryophyte species. Orchidaceae and Polypodiaceae were the most species-rich vascular epiphyte families. Bryophytes dominated the trunk bases of all sampled trees. Epiphyte species richness was positively related to host tree trunk diameter (r = 0.67, p < 0.01) and negatively related to direct sun exposure in the crown zone. Crown position epiphytes showed the highest diversity (H' = 2.87). Epiphyte cover was significantly higher in the interior of the plantation than at the edges, suggesting microclimate modulation by the plantation. The study concludes that even monoculture Gmelina plantations support notable epiphyte biodiversity, and recommends incorporation of epiphyte diversity into the ecological assessment protocols of the Ondo State Forestry Corporation. Keywords: epiphytes, Gmelina arborea, plantation biodiversity, Oluwa Forest Reserve, Ondo State