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.