Assessment of Urban Forest Tree Species Population and Diversity in Ibadan, Nigeria

Abstract

This research focuses on the urban tree species population and diversity within Ibadan metropolis as a means of creating biodiversity database for the urban centre in South west, Nigeria. This was determined by assessing urban forest tree abundance, species diversity and growth yield. All trees with diameter at breast height (dbh) ≥ 10 cm were identified, dbh measured and their frequencies taken in all the area enumerated within Ibadan. There are 155 tree stems belonging to 26 families and 54 tree species within Ibadan built-up areas and 101 tree stems belonging to 16 families and 19 tree species in peri-urban centre of Ibadan. The two most abundant species and families were Delonix regia of Fabaceae family and Terminalia ivorensis of Combretaceae family (18 and 17 stems) respectively while Fabaceae family has (7 species). The value of the Shannon's max diversity index (Hmax) of (3.99 and 2.94), Shannon-Wiener diversity index (3.35 and 2.48) and species evenness 0.84 were the same for peri-urban centre, while the growth variable were basal area and volume of (22.8m2 and 18.5m2) and (284.8m3 and 275.3m3) respectively. This study provide information on the level of tree species biodiversity due to infrastructure development that has reduced forest cover within the built-up areas of Ibadan which can expose the city to lot of environmental hazard.