Assessment of carbon sequestration rate and tree diversity in a model urban green cover study using a college campus in Mangalore city

Abstract

The extant green cover in a 140-year-old St Aloysius College campus in Mangalore, Karnataka, India, was used as a model to study tree diversity and carbon-sequestering rate (CSR), using a non-destructive biostatistics-based method. The results of the study indicated that the campus constituted a highly diverse tree flora with a Shannon Diversity index of 4.07. A total of 169 different tree species were found on the campus with an average population size of 9.98 per species. The green cover of 4.67 ha of the total area of the campus had a tree density of 361.03 trees/ha. Five tree species, namely Polyanthia longifolia, Cocos nucifera, Tectona grandis, Terminalia catappa, and Areca catechu, dominated the area. Using allometric equations, the total green cover in the campus area with biomass of 4594.6 Kg, which sequestered 8431.1 Kg of carbon at a carbon sequestration rate of 84.31 Kg per year was deduced. Olea europaea and Phoenix dactylifera, with the highest CSR of 0.09 and 0.08, respectively, were the most effective in sequestering 12.54 Kg and 11.19 Kg of carbon. The highest amount of Carbon sequestered (CS) per tree was in Olea europaea (12.54 Kg) and Phoenix dactylifera (11.19 Kg), followed by Acacia auriculiformis (10.44 Kg), and Adenanthera pavonina (10.08 Kg). It was observed that the amount of carbon sequestered decreased with the decrease in tree girth.