Specific diversity, structure and carbon stock of urban plant formations in southern Benin

The sustainable management of urban green spaces requires the monitoring of the structural parameters of theirs trees. This study, which was carried out in the cities of Abomey-Calavi, Allada and Cotonou in southern Benin, aimed to describe the dendrometric parameters and the rate of carbon stored by urban trees. The inventory of trees planted in two types of urban forests (greened public spaces and shade rows) was performed using the roving survey method at the level of each city. Then, presence and absence data of all trees, as well as diameter at breast height (DBH) >= 10 cm and height >= 2 m were measured. These data were analyzed using R 4.0.5 software. The calculated dendrometric parameters were subjected to variance tests to assess their significance. The different counts allowed us to identify 5128 individual trees. The density per hectare varied from 36.7 to 83.1 between cities and from 40.5 to 80.4 between types of green spaces. Basal area varied from 2.25 to 11.4 m²/ha within cities. In all three cities in the study, trees had an aggregative spatial distribution, but with low numbers of individuals per site. All of the trees studied have a carbon sequestration rate of 689 t/ha. It is therefore necessary to take precautions for the strengthening and preservation of urban trees and their diversity for a more sustainable urban ecological balance. Keywords: Benin, Biomass, Carbon storage, Tree structure, Urban forest