This study aims to determine the dynamics of mangrove growth on Raised Coral Island, particularly regarding structure and composition of mangrove vegetation, mangrove zonation patterns, and human intervention in the utilization of mangrove areas. The vegetation data was collected using the line transect plot method. Research plots were made in the line transect. The area of the Seedlings plot was up to 1.5 meters high with a plot size of 2x2 m. Saplings with the height between 1.5 m - Ø <10 cm, plot size 10x10 m. Poles or small trees of Ø 10 - 19 cm, plot size 10x20 m and Trees Ø ≥ 20 cm, plot size 20x20 m. Marsegu Island, with 240,20 ha, has 46,75% Mangrove Forest with a zonation pattern formed as follows: The Proximal Zone with an area of 32.12 ha, controlled by the Rhizophora stylosa and Rhizophora mucronata species. This zone is more dominated by the growth of pole stages, specifically the stem diameter between 10 to 20 cm with a crown height ranging from 3 to 5 meters. The Middle Zone with 39.00 ha is dominated respectively by Bruguiera gymnorhiza, Rhizophora apiculata, Ceriops tagal, and Xylocarpus granatum with tree heights reaching 5 to 15 meters. The opening of the canopy as a result of cutting trees provides an opportunity for seedling and sapling stages regeneration to grow from exposure to sunlight. The tree density in this zone is 105 ind/ha with diameters ranging from 20 to 40 cm, dominated by Bruguiera gymnorhiza species. The Distal Zone, with 41.17 ha, is dominated by Bruguiera gymnorhiza, Ceriops tagal, Rhizophora apiculata, and Xylocarpus moluccensis with larger tree diameters. The trees density in this zone is 300 ind/ha and has a diameter ranging from 30 to 60 cm; however, some reach 100 cm. Many old trees suffer a natural process of destruction and death. The community carries out activities in the middle zone by cutting down the Bruguiera gymnorhiza species trees as construction materials. The middle part of the mangrove area is adjacent to the distal zone; there is a coconut plantation covering an area of 1.53 ha planted by the community.

Keywords : Mangrove Zonation Pattern, Raised Coral Island, Mangrove's Structure and Composition, Marsegu Island.