Rehabilitating a landfill site of lowland tropical landscape into an urban green space: A case study from the Open University of Sri Lanka

Abstract

This study examines vegetation, carbon sequestration, and spatial and temporal changes of green space at the premises of the Open University of Sri Lanka (OUSL). The primary objective of this study is to examine floral diversity of the OUSL premises that was rehabilitated from a landfill site and to determine suitable trees for landfill sites based on growth performance and biomass carbon stocks. The girth and height of plants ⩾5 cm dbh were measured to estimate biomass carbon stocks of each individual tree. GPS coordinates of each individual tree were taken for spatial mapping. Urban green spaces were extracted from Satellite view of Google Earth for a decade using screen digitizing techniques. A total of 722 individuals, comprising 95 plant species belonging to 75 genera and 33 families, were recorded. Of the total species 45% were native species. The above-ground and below-ground biomass were estimated to be 50 (t C/ha) and 10 (t C/ha) respectively. These results are comparable with above-ground biomass and below-ground biomass in the dry zone forest (60 and 17 (t C/ha) respectively). The study recognized that Terminalia catappa, Filicium decipiens, Mangifera indica, Cassia bacillaris and Tabebuia rosea species grow well in such landfill with effective carbon accumulation, and the species list presented in this paper will provide useful information that will help city planners to maximize biomass carbon sequestration by choosing optimal plants for landscaping in landfill sites.