ASSESSMENT OF WOODY PLANT DIVERSITY AND CARBON STORAGE IN URBAN SECONDARY SCHOOLS IN ABUJA

Abstract

This study investigates woody plant diversity and carbon storage across three secondary schools in Abuja, Nigeria: Government Secondary School (GSS) Jiwa, GJSS Jiwa, and GGSS Dutse Alhaji. Using a systematic sampling method, five plots per school were analyzed for tree diversity, with measurements of above-ground and below-ground biomass obtained through allometric equations. Tree diversity was quantified using Shannon and Simpson indices, while carbon storage and CO2 emissions were calculated based on biomass measurements. At GSS Jiwa, Plot 2 (West) exhibited the highest species diversity with a Shannon index of 1.367 and Fisher’s alpha of 3.538, while Plot 5 (Central) had the lowest diversity with a Shannon index of 0.3488 and Fisher’s alpha of 0.7972. At GJSS Jiwa, Plot 2 (West) demonstrated the highest diversity with a Shannon index of 1.082 and Simpson’s 1-D index of 0.6563, whereas Plot 1 (East), Plot 4 (North), and Plot 5 (Central) had the lowest diversity with Shannon indices of 0 and Simpson’s 1- D indices of 0. Plot 2 (West) at GGSS Dutse Alhaji showed the highest diversity with a Shannon index of 0.6931 and an evenness value of 1, while Plots 2 (West), 4 (North), and 5 (Central) had the lowest diversity with Shannon indices of 0. Regarding carbon storage, GJSS Jiwa Plot 2 (West) with Swietenia macrophylla (Mahogany) had the highest carbon storage of 15,3356.44 kg and CO2 emissions of 562.31 tons. In contrast, Plot 5 (Central) at GGSS Dutse Alhaji had the lowest carbon storage with 16,535.68 kg and CO2 emissions of 60.63 tons. GSS Lafia's Plot 2 (West) contributed significantly with CO2 emissions of 164.29 tons and carbon storage of 44,808 kg. The findings highlight the importance of maintaining diverse tree species to maximize carbon sequestration and minimize CO2 emissions, with implications for urban green space management and climate action