ABSTRACT

This research focused on the urban tree species population and diversity within Umuahia urban metropolis and their impact as a means of creating biodiversity database for the urban centre in South East. Nigeria. This was determined by assessing urban forest tree abundance, species diversity and growth yield. All trees dbh were measured and their frequencies taken in all the area enumerated within Umuahia urban. A well structured questionnaire was distributed to assess the impact of urban trees on human activities within the study area. There are 151 tree stems belonging to 7 families and 8 tree species within Umuahia built-up areas. The two most abundant species and families were Polyallhia longifolia of Annonaceae family (72 stems). The value ofthe Shannon's max diversity index (Hmax) of (3.99 and 2.94), Shannon-Wiener diversity index (3.35 and 2 18) and Pielou’s Evenness Index (EH) was 0.84. The highest basal area and -volume of trees within Umuahia Urban 106.85m2 and 1581.38m3 respectively were contributed by Polyalthiu longifolia. This was followed by Terminalia ivorensis with basal area and volume of 85.44m2 and 1025.28m3 respectively. The least basal area and volume (0.01m2 and 0.12m3 respectively) were recorded by Hura crepetans. However Polyalthia longifolia had the highest species importance with an IVI of 50.9%, this was closely followed by Terminalia ivorensis with an IVI of 41.33%. The results of this research indicated that the people with tree within their houses, shops, streets, offices enjoy tree shades which reduces ultraviolet radiation and its associated health problems, improved air quality based on reduced pollutant through the trees’ leaves, beautification, medicinal values and carbon sequestration. It was also gathered that trees are used as wind break and provide fruits for the people's nutritional intake. 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 ofIbadan which can expose the city to lot of environmental hazard.