Afzelia Smith is a small tropical genus belonging to the family Caesalpinaceae. It is represented in Nigeria by four tree species: Afzelia pachyloba, Afzelia bipindensis, Afzelia bella and Afzelia africana. The species, Afzelia africana Sm (Counter wood tree) understudy is commonly found in the Savanna fringing forests and drier parts of the forest region in Nigeria [1] . It is the most valuable in terms of economic importance among the occurring tree species. The root, bark and seeds are useful for medicinal purposes: antipyretic, gastrointestinal stimulant, aphrodisiac, oedema, hemorrhage amongst others [2] . The seed is edible and often sold in local markets as a thickner in soup preparation. The wood is termite resistant and is used for constructing furniture, mortars, cooking utensils, firewood and charcoal. A dyestuff called “Afzelin” has been isolated from the wood pores which may cause discolouration of fabrics, papers etc.

A relative number of studies on reproductive biology of tropical species from natural forest ecosystem has been reported by some authors [3] - [6] . In plants, reproductive biology mainly focuses on flowering phenology, floral biology, pollen-pollinator interaction, breeding systems and gene flow through pollen and seeds [7] . Flowering studies in tropical hardwood species help to provide vital information for the natural regeneration of existing stands and for the establishment of artificial plantations. In general, phenological behavior of the indigenous tree species in Nigeria is lacking in literature. [8] had noted the need for a comprehensive study on flowering and fruiting of local tree species throughout their natural range to facilitate the breeding of new cultivars of trees. In view of the dearth of information on reproductive biology which is a useful apparatus in any conservation approach, a study was initiated in 2009 to investigate the flowering and fruiting pattern of A. africana in Umuahia, Abia State, Nigeria. This paper forms a part of a series of other intended study aimed at examining the reproductive behavior of plantation grown A. Africana Sm from seedling stage to flowering, fruiting and seed collection phase.

The most crucial stages in the life cycle of any plant include reproduction, dispersal of seeds, germination followed by seedling establishment [10] . Detailed information on phenological studies helps in the conservation as well as framing effective measures for successful conservation of a species [11] [12] . A. africana is a self incompatible plant with comparatively low reproductive output. The predominant self incompatibility nature of forest trees is directly related to selective pressure to maintain genetic variability [3] . It is a trait of hermaphroditic species and is the most efficient method of controlling self pollination and thereby inbreeding in higher plants [13] . Hand pollination result in more fruit set than natural pollination. Pollination deficit in most tree species is mainly attributed to lack of pollinators or lower effectiveness of the pollinators. Bees are known for less effective pollinators since they are generalist, collecting pollen from various pollen resources resulting in the heterospecific pollen on the stigmatic surface [14] . Habitat loss and excessive pesticide usage may be the reasons for low number of pollinators [15] . Forest destruction and fragmentation may often cause damage to di-

verse pollinators.

Pollen production in a plant depends upon several factors including season, anther length, pollen grain size and mode of anther dehiscence [16] . Recent studies showed that effects of pollen quantity and quality on reproductive success have become an important issue in plant conservation [17] . Although in this study, specific studies were not conducted to test for pollen viability, the failure of high rate of transformation from flower to fruit observed could be indicative of reduced pollen viability. Other probable reasons for reduced fruit set include low pollen loads on stigma, the absence of pollen tubes at the base of the style, small population size, space limitation, genetic load and climatic change [18] - [20] . The intensity of flowering reflects the amount of plant resources allocated to reproductive process. Thus the more the quantity of flowers produced by a tree, the more the quantity of pollen that will be available for pollination. Compared with the mean number of flowers per tree of 107,294; 617,018; 209, 834 and 238,685 in Terminalia ivorensis [6] and 18,102; 15,438 and 23,541 in Pittosporum dasycaulon [7] , the mean quantities of flowers produced by the sample trees of A. africana (286, 138, and 54) are too low to permit appreciable level of fruit set after losses to agents of flower abortion and pollen feeders. However, duration of flowering in A. africana (3 months) appears long enough to permit the collection of genetic materials for improvement and hybridization work [7] . Also the relative young age of the trees (five years) may account for low flower production. [21] observed that variation in genetic composition and age structure affects flowering of population of plants. It was further postulated by [22] that in artificial forest and seed orchards as studied, effective breeding population sizes are reduced due to lack of flowering synchrony.

The earlier maturity period of A. africana in this study as compared to a similar study conducted in Ibadan, Oyo State, Nigeria by [23] may be due to environmental differences between the present study site in the South East and Ibadan in the South West. In her report, collection of matured, ripened fruits started in September, while the fruits started dropping in October. Flowering, she also noted occurred annually during the periods of study (2001-2003). From our study, flowering in this species was first observed in 2012 (three years after planting) with a repeat in 2014 (five years after planting) having a flowering interval of two years. No fruit was set during the first flowering until the second flowering. Thus in Umuahia, the appropriate time to collect matured fruits of A. africana on the tree is July/August. This is to ensure collection of good and healthy seeds. According to [24] , seeds collected from the ground loose viability very fast in storage. However, for immediate planting, the seeds can be collected from the ground without much loss of viability. In this case, the already dehisced fruits could be allowed to disperse the seeds which could take longer than August.

This preliminary investigation reveales that A. africana flowers biennially in Umuahia, with flowers obtained between March and April. The flower anthesis was observed between 9.00 GMT and 12.00 GMT. The flowering intensity was low with a very low flower to fruit ratio. Fruit set began by March and matured fruits were ready for harvest from late July to August, thus the appropriate time for seed collection for storage. Our study revealed the presence of some floral visitors like bees, butterflies, cored bugs and grasshoppers. The low fruit set in this species strongly suggest the requirement of some external agents necessary for effective pollination. Since this report is preliminary, subsequent investigation on the reproductive biology of this species in this area over time is suggested. This is important because the evolutionary success and survival of this tree are largely determined by the efficacy of its reproductive performance.