Survey of naturally regenerated economic timber species in a tropical rainforest of South-East Nigeria.

Abstract

The study surveyed preferred and non-popular economic timber species of the tropical rainforest of southeastern Nigeria (which have been intensively exploited over the years) and assessed their regeneration status in this highly disturbed tropical rainforest as typified by the Stubbs Creek. Systematic sampling was adopted using line transects (1000 m long and 500 m apart) and quadrats which were placed at randomly selected points. Linear Diagnostic Sampling (LDS) technique was employed to assess the frequency and distribution of regenerating economic timber species within a quadrat size of 2 m × 2 m at 30 randomly selected points. Sympson's index of diversity was used to determine the complexity of individuals by species. A total of 130 taxa were enumerated in 0.12 ha and these belonged to 23 families, 34 genera and 35 species. Only 9 species or 26.5% belonging to 7 families were among the preferred economic timber species, and these constituted only 10% of total regeneration, considered critically low and highly endangered, while 25 species or 73.5% belonged to the non-popular economic timber species. Three (3) species or 8.6% were classified 'Abundant', while 32 or 91.4% were 'Not Abundant'. A very low complexity index of 0.05867 reflects lack of stability in the forest ecosystem. Urgent management intervention is therefore required to save these species from extinction.