Trees Species Structure and Diversity in the Lowland – Rain Forest Zone of Bayelsa State

Bayelsa State was divided into three zones (Bayelsa East, Bayelsa West and Bayelsa West) based on Nigeria political delineation, and a sample plot measuring 30m by 30m was selected from a forest in each zone. Tree species structure and diversity of selected sample plots were assessed. Sampling technique was employed to collect data of trees; and trees that were 2meter high at diameter at breast height (dbh) ≥4m in the sampling plots were identified and classified accordingly. Scale of abundant in relation to relative density was used to determine the abundant status of tree species encountered. A total of 164 living trees of different dimension belonging to 22 families were encountered, all trees encountered were indigenous trees. The highest and least basal areas (0.64m2 and 0.04m2) in the sample plot at Imringi community in Bayelsa East Senatorial district were contributed by Pycnanthus angolensis and Uapaca guineensis respectively. While Laccosperma secundiflorum and Garcina manii had the least and highest basal area of 0.002m2 and 0.87m2 respectively in Tombia community, Bayelsa Central Senatorial district. Eleais guineensis and Laccosperma secundiflorum with 0.74m2 and 0.01m2 respectively contributed the highest and least basal areas in the sample plot at Amatolo community, Bayelsa West Senatorial district. The sample communities had high tree species diversity, yet the tree species distribution skewed with respect to the intermediate class. This study is a pointer to the fact that forest communities in the area are rich in tree species yet, pressure from illegal logging, oil exploration and constant inundation by flood threaten tree species survival. Thus management plans to sustain and preserve forest tree species diversity in the State were proposed.