Mangrove Forests

evergreen forests with low-trunked trees (5-10 m) found on silty tropical shores that are protected from the surf but are flooded when the tide is in. Mangrove trees have prop roots, which hold the plants in the silt, and aerial roots (pneumatophores), which protrude from the silt in the form of columns and supply the trees with oxygen. The leaves are often fleshy, with hydathodes through which excess salts are exuded; the old leaves have reservoirs of fresh water. The fruits have aerenchyma, which enable the fruits to float in water.

Mangrove forests consist of only a few species of trees, usually members of the genera Rhizophora, Avicennia, Aegiceras, Sonneratia, and Bruguiera. Many of the trees are viviparous. The interior belt of the mangrove forest serves as a transition to the tropical rain forests of the mainland and consists of such palms as Nipa fruticans and Phoenix paludosa. Epiphytes, mainly Spanish moss and other Bromeliaceae, are also found in the forests.

Mangrove forests are concentrated along the flat eastern shores of Africa, on Madagascar, on the Seychelles Islands, on the Mascarene Islands, and along the shores of South Asia and Australia; they are also encountered along the Atlantic shores of Africa, Central America, and South America, as well as along the Pacific coast of America from southern California to 4° N lat. The plant species in the mangrove forests of the Malay Archipelago are particularly diverse and lush.