Urbanization is a pressing issue of concern especially in Africa where it is expected to continue and increasingly, threaten the efficiency of natural carbon sinks and sustainability of cities. This paper assessed the diversity and carbon storage of trees in Zaria metropolis, North-western Nigeria through fieldwork and allometric equations. A total of 200 assessment plots were randomly generated using Idrisi Terrset software. Quadrats of 30 × 30 m dimension were established and all trees, ≥5 cm diameter were identified and enumerated. Diameter was measured at breast height while tree height was measured with Suunto clinometer. The study recorded 836 stems, belonging to 51 species in 21 families. Species diversity and evenness were considerably high (H’ = 3.30, J = 0.8) with more exotic than native stems. The trees stored 657.05t carbon with the highest proportion contributed by Azadirachta indica, Mangifera indica and Khaya senegalensis. One-way ANOVA revealed significant difference in tree diameter (p < 0.020), basal area (p < 0.008) and height (p < 0.001) across the different land use/cover types but no significant difference in carbon stock (p > 0.657). This study demonstrates the contribution of urban trees in reducing global atmospheric carbon which largely varies with tree species and diameter.

城镇化是一个迫切需要关注的问题，尤其是在非洲，在非洲，这种城市化进程预计将持续并越来越多，威胁到自然碳汇的效率和城市的可持续性。本文通过实地考察和异速生长方程评估了尼日利亚西北部Zaria大都市树木的多样性和碳储量。使用Idrisi Terrset软件随机生成了总共200个评估图。建立了尺寸为30×30 m的四边形，并鉴定并列举了所有直径≥5 cm的树木。直径是在乳房高度处测量的，而树高是通过Suunto倾斜仪测量的。该研究记录了836个茎，属于21个科的51种。物种的多样性和均匀度很高（H'  = 3.30，J = 0.8）比本地词干更具异国情调。这些树木储存的657.05t碳，比例最高的是印度的Azadirachta，印度的Mangifera和塞内加尔的Khaya。单向方差分析显示，不同土地利用/覆盖类型的树木直径（p <0.020），基础面积（p <0.008）和高度（p <0.001）存在显着差异，但碳储量无显着差异（p> 0.657） 。这项研究表明，城市树木在减少全球大气碳方面的贡献很大，而碳的变化随树木的种类和直径而变化。