Carbon storage and tree diversity in the urban vegetation of Dhaka city, Bangladesh: a study based on intensive field investigation

Abstract

ABSTRACT Carbon storage in urban vegetation plays a vital role in mitigating CO2 concentration in the atmosphere and may ensure long-term stability of stored carbon in fluctuating environments. This study was conducted to quantify the current above-ground carbon stock with tree diversity in various urban vegetation types in Dhaka city, Bangladesh. Using allometric equations, the site-specific totals of above-ground biomass were 106.46, 90.94, 387.01 and 223.27 Mg ha−1, whereas carbon stocks were 53.23, 45.47, 193.50 and 109.53 Mg ha−1, in urban park, playground edge plantation, botanical garden and roadside plantation, respectively. The mean values of tree diversity and density were 1.80 and 494 trees ha−1 respectively which showed a positive relation with carbon stock. Similarly, the mean basal area and diameter of trees at breast height (dbh) also showed a significant positive relation with carbon stock (p < 0.001 and p < 0.01) across all sites except in the basal area for playground edge plantation sites (p =.08). This highlighted that neither the carbon storage nor the tree diversity of Dhaka city is satisfactory due to inadequate vegetation coverage, suggesting that an increase in tree diversification, maintaining site specific appropriate tree density and conservation practices could substantially enhance the number of trees and the associated carbon storage.