Abstract:
The aim of this study was to assess the diversity of mangrove tree species and to estimate
above ground biomass in mangrove-forested areas. While there has been extensive research on
mangroves both in tropical and sub-tropical regions of the world, there is limited available
information on the community structure and carbon stock of mangroves in Mullaitivu District. The
community structure, species diversity, and aboveground biomass of mangroves were estimated
and distinct community types were identified. Aboveground biomass was estimated as the product
of tree volume and wood density. Four very common species, two common species and one rare
species and six mangrove associates were documented from seven locations distributed randomly
over lagoon. Four communities had Avicennia marina (Forssk.) Vierh. as dominant species but with
different structure and habitat. Among the sampled locations, Karunaddukerny had the highest
number of species. More numbers of A. corniculatum (L.) Blanco seedlings and saplings were
observed compared to other species. Seedling population was higher than the sapling population
and this may be due to the anthropogenic activities. In general the forest was dominated by small
sized trees, maximum mean height was 5.5 m and highest mean dbh was 27.6 cm which indicates
that forest has not reached the climax stage. Estimated total carbon stock in study area was 54.89
t/ha. Maximum mean carbon stock was exhibited by A.mariana (25.28 t/ha) and least carbon stock
was exhibited by A. corniculatum (0.64 t/ha). The people have been benefited from this ecosystem
throughout the year such as medicinal, fuel, timber and other products and it is a breeding sites for
fauna especially shrimp and crabs. However, major threat for mangroves were harvesting of sapling
and parking of boat.
