Composition and Structure of Tiwoho Mangrove Vegetation at Bunaken National Parkional Park (Komposisi Dan Struktur Vegetasi Mangrove Tiwoho di Kawasan Taman Nasional Bunaken)

Tiwoho mangrove forest islocated in north coast of North Sulawesi province.This area functions as life buffer system for community and sustainability of Bunaken National Park. Due to t he important and strategic role s of mangrove in protection and ecological functions, therefore , it is need ed to know scientific information about mangrove population dynamics. This research aims to know the vegetation composition and structure vegetation of Tiwoho mangrove forest. D ata collection used 20x20 m sample plot s that were sistematically laid from the sea to the land side up to the highest tidal line. D istance between plots along 25 m . Results showed that at tree level Sonneratia alba ha d the highest Important Value Index (IVI) of 206,88 % and Brugueira sp of 46,06 % . Although Rhizopora apiculata value is lower than Brugueira sp . B ut the values of relative frequency of these species are almost similar . It means that both species are frequently found in observation plot s . Rhizophora apiculata dominate at pole and sapling levels , but frequency of occurance this species is lower than Brugueira sp in pole level .