Phenology and seed germination improvement of two important tree species in the moist semi-deciduous forest zone of Ghana

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APRIL, 2016
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Understanding the phenology and seed germination improvement techniques of native forest tree species is crucial for their conservation and the restoration of degraded forest areas. This study examined the reproductive phenology and the effect of four chemical and physical seed germination improvement techniques on two indigenous forest tree species namely; Terminalia superba and Terminalia ivorensis. The reproductive phenology was observed and documented over 24 months. The effects of chemical and physical scarification on seed germination were also evaluated under ambient temperatures for 36 days. Period and intensity of Leaf flushing (LF), Flowering (FL), Fruiting (FR) and Seed dispersal (SD) pheno-phases of 115 selected tree stands of the species were monitored and scored using the widely adopted BBCH system of coding plant phenology. Leaf flushing (LF) in both species coincides with the onset of the wet season in April-July, and it is followed by flowering in August-September. Fruiting and seed dispersal pheno-phases occurred between October-February. A strong positive correlation (r = 0.7325, P < 0.05) was found between the highest Leaf flushing (LF) percentage and average monthly rainfall (RA). The strongest negative correlation was established between percentage of Fruiting (FR) individuals in both species and mean monthly maximum temperatures (TEmx). Chemical scarification (soaking in H2SO4 2g/l for 20 minutes prior to sowing) improved seed germination in both species by more than 50 percent. Results indicate that T. superba and T. ivorensis undergo a consistent and synchronized annual reproductive cycle dependent on temperature and rainfall. The results further suggest that large scale climatic fluctuation can affect the reproductive and vegetative phenology of the trees.
A thesis submitted to the School of Research and Graduate Studies, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, in partial fulfilment of the requirements for the degree of Master of Philosophy (Seed Science and Technology)