Uzoma D. Chima and Ebele A. U. Ofodile
The capacity of trees to contribute to climate change mitigation and adaptation in urban areas will depend, to a large extent, on their abundance, diversity and the possession of appropriate structural characteristics. This study evaluated the climate change adaptation and mitigation capabilities of avenue tree species in three campuses – Choba, Delta, and Abuja, of the University of Port Harcourt by examining their abundance, alpha and beta diversity, diameter at breast height, total height, crown diameter, and basal area. Species relative abundance was highest for Elaeis guineensis (41.10%), Polyalthia longifolia (15.29), and Terminalia mantaly (25.00%) in Abuja, Choba, and Delta Campuses respectively. Avenue tree species richness for Abuja, Choba, and Delta Campuses, was 8, 12, and 16, respectively. No significant difference (p > 0.05) was observed in mean values of diameter at breat height, total height and crown diameter, for Azadirachta indica, Dacryodes edulis, Elaeis guineensis, and Terminalia catappa, in the campuses where they occurred. Avenue tree species diversity was slightly higher in Delta campus (H = 2.3950) than Choba Campus (H = 2.3300) when Shannon index was used, but slightly higher in Choba Campus (Simpson 1 –D = 0.8891) than Delta Campus (Simpson 1 –D = 0.8731) when Simpson index was used. Abuja Campus (H = 1.5670; Simpson 1 –D = 0.7295) was the least diverse of the three campuses. The highest similarity in avenue tree species (42.11%) was observed between Choba Campus and Delta Campus, while the least similarity (17.65%) was observed between Choba Campus and Abuja Campus. Delonix regia, Eucalyptus camaldulensis, Gmelina arborea, Mangifera indica, Azadirachta indica, Albizia lebbeck, Irvingia gabonensis, Terminalia catappa, Pinus caribaea, and Tectona grandis with better growth attributes and high capacity for climate change mitigation and adaptation, were represented by few individuals in all the campuses. Low tree species diversity especially in the permanent site (Abuja Campus) and low relative abundance of species with high capacity to address climate change indicate that the university is not making the best use of trees in confronting the menace of climate change. Tree planting in urban institutions should consider climate change mitigation and adaptation capabilities of tree species
