Tree Diversity Status of Soil Seed Bank and Overstory Vegetation of Six Different Physiognomies in Shasha Forest Reserve

Tree species in the soil seed bank (SSB) and overstory vegetation were assessed in six contrasting physiognomies; (secondary re-growth natural forest (SRNF), Terminalia superba plantation (TSP), Pinus caribaea plantation (PCP), Gmelina arborea plantation (GAP), Tectona grandis plantation (TGP) and Theobroma cacao plantation (TCP) in Shasha Forest Reserve. Eight plots 25m x 25m were randomly selected in each physiognomy for the overstory vegetation study. Tree species were identified and assigned into families. Twenty four composites soil samples were collected from three quadrats of 5m x 5m at surface soil layer (0-15 cm), in each physiognomies. The soils were spread in well-drained porous bowls and watered for a year for tree seedling emergence inside the screenhouse.
Tree diversity indicated that overstory vegetation and soil seed bank emergence varied among the physiognomies, with the trio of secondary re-growth natural forest, T. superba and P. caribaea plantations having the highest tree diversity and abundance. The highest tree emergence was observed in TSP (33.3%) followed by GAP and SRNF (26.6% and 20.0%) while the least occurred in TCP, TGP and PCP (6.6%). The study revealed poor representation of standing overstory tree species at the SSB and showed the reason why traditional abandonment of forest fail to allow restoration of most tree species without human effort. This study concluded therefore, that future restoration planning should not be based on traditional abandoment of forest that relies on SSB succession; deliberate introduction of endangered tree species through enrichment planting of forest reserves is thereby recommended.