A group of plants that live on the beach. Various species are spread out widely along the coasts of Jakarta and big islands in the Thousand Islands in regions called mangrove swampy forests. The main product from the mangroves is wood, which includes heavy wood weighing 0.8grams/centimetre cubed and above, yellow or red brownish in color, smooth texture with straight fibers, high rigidity with a quite high possibility of cracks and shrinking.
Mangrove wood can be used as pillars only if submerged. It can also be used as charcoal material, firewood, and pulp. The charcoal from mangrove wood has quite a high heat value, which is used in the iron-steel making process. Mangrove included in the Zophora species is easily spotted because of its curvy roots from the trunks and branches, and its primary leaf from the tip of the secondary leaf. The surface of the bottom of the leaf has black spots. Its supporting leaves are large with glands in the armpits. Mangroves from the Bruguiera species are easily spotted by their breathing roots, which are knee-shaped and the primary leaves do not have any secondary ones.
Apart from wood, mangroves also produce bark that contains dyeing properties. For the fishing community, the young fruit of Rhizophora mangroves are extremely beneficial as a vegetable. This mangrove has other functions related to the conservation of the beach, the surrounding air quality, and other forms of fish life in the surrounding waters.
Because it has a unique rooting system, mangroves are able to hold the mud, which is stored in its structure. Mangroves also protect the beach and riversides from the blows of waves and the impact of tidal currents. Mangroves are able to obtain heavy metal elements such as Hg that it functions as a filter for pollution effects. Mangroves also provide organic materials that function as breeding areas for various types of fish. In addition, various types of birds and bats use these swampy forests as nests or resting areas. Thus, these mangrove forests are a wildlife sanctuary.