Mangrove plays the importance of roles for the small island sustainability, both physically and ecologically. In the high-risk Pacific Ocean’s islands, small islands in Biak face typhoons, earthquakes, high waves, and tsunami effects. The study was conducted at 100 10mx10m-quadratic-plots scattered on seven small islands in Biak-Numfor Regency. Research objectives were to investigate the mangrove community structure of each island, i.e., canopy coverage, density, and morphological size, and to analyze the correlation among those parameters. The result found that mangrove was in pristine condition, large individual size with low anthropogenic threats. They were covered by a medium and dense canopy from 61.323.04% in Pasi to 93.880.14% in Meos Mangguandi. Substrate significantly influenced the level of canopy coverage and the MDS ordination of species composition. Sonneratia alba tended to be dominant in rocky sand in Pasi, Owi, Padaidori, and Wundi, while Ceriops and Rhizophora were mostly occupied the muddy sand, or Bruguiera gymnorrhiza has the highest domination in sandy mud substrate in Auki, Pai, and Meos. The canopy coverage had a significant correlation only with total density but none with the others. The height of the tree (up to 21.2 m) was found highly related to the diameter size (max: 124 cm).

红树林在物理和生态方面对小岛的可持续性发挥着重要作用。在高风险的太平洋岛屿中，比亚克的小岛面临台风、地震、大浪和海啸的影响。该研究在 100 个 10mx10m-quadratic-plots 进行，分布在 Biak-Numfor Regency 的七个小岛上。研究目标是调查每个岛屿的红树林群落结构，即树冠覆盖度、密度和形态大小，并分析这些参数之间的相关性。结果发现，红树林处于原始状态，个体规模大，人为威胁低。它们被中等密集的树冠覆盖，从 Pasi 的 61.323.04% 到 Meos Mangguandi 的 93.880.14%。基质显着影响冠层覆盖水平和物种组成的MDS排序。Sonneratia alba倾向于在 Pasi、Owi、Padaidori 和 Wundi 的岩石沙中占优势，而Ceriops和Rhizophora则主要占据泥沙或Bruguiera gymnorrhiza在 Auki、Pai 和 Meos 的砂质泥基质中占有最高的优势。冠层覆盖度仅与总密度显着相关，而与其他无关。发现树的高度（高达 21.2 m）与直径大小（最大：124 cm）高度相关。