Effects of Urban Forestry on the Local Climate in Cotonou, Benin Republic

Abstract

The effect of urban green on meteorological parameters such as temperature and relative humidity was assessed on one major city street in Cotonou called "Boulevard de Missèbo-Zongo" (BMZ). Tree inventory and field measurement of meteorological parameters were performed on the roadside and central median of the BMZ. Dendrometric data collected were the number of tree species, the number of tree individuals per species, the diameter of trees at breast height, the tree heights, the tree crown shape, shade form on the ground when the sun is at Zenith; while the meteorological data were the air temperature and the relative humidity inside and outside of urban green at 1.5, 2 and 3 meters height measured from 7am to 6pm at one hour interval. Data were analyzed using Mixed Generalized Linear Model under R 3.3.1 software. Results showed that street alignment trees were poorly diversified and dominated by Khaya senegalensis. This species appeared to be highly pruned and threatened because of its numerous medicinal virtues. Moreover it was found that air temperature and relative humidity were influenced by the time and the place of measurement. The coolness effect of urban green was evidenced by the decrease in temperature under alignment trees compared with that recorded on roadside free of trees. These results suggested that urban green could be adopted as adaptation strategy to address the issue of global warming in the city.