mangroves are trees or shrubs that grow in salty water in hot places like the tropics. mangroves make a special saltwater woodland or shrubland habitat, called a "mangrove swamp", "mangrove forest", "mangrove" or "mangal". mangroves grow on 1/3 of tropical shores. they are also found in sub-tropical africa, asia, and the southwest pacific. their twisted, tangled roots collect sediment. over time, the sediment may become islands, or extend the shoreline.