People mostly have thought of mangroves as noxious impenetrable swamps full of diseases, and they used to be destroyed as a public health measure. But now we know better. Mangroves are very productive coastal resources that are useful in many ways. 

Mangrove trees grow well within their special conditions - where no other trees could be planted - and, like the tropical forest, they produce a lot of leaves and other organic matter, detritus. Instead of accumulating in the soil, the leaves fall in the water, where they rot and provide food for microbes and planktons. This, again, is excellent fish fodder and the areas near mangroves, often, are very important for the fisheries. 

Mangroves have proven to be an important source of food and materials for many coastal people. Crabs, clams, oysters, fish and other food are often collected there. Even the mangrove fruits are sometimes eaten. 

Also the trees in themselves are useful. Mangrove wood is often collected as firewood, and it can also be used for constructing. The bark has tannin, which has craft and medicinal uses. If properly managed, mangroves can provide timber for construction, charcoal for energy, food for livestock, shellfish for local consumption, and so on. In fact, the natural resource base is that rich, that a Fijian cost benefit analysis analysing a possible conversion of mangroves into agricultural land concluded that this would not increase revenues produced per hectare per annum. Most conversions actually would reduce revenues drastically. 

One very important environmental service produced by the mangroves is that they also build land or keep it from being washed away. Mud and sediment are generally washed down rivers and streams. When there is a mangrove swamp at the river’s mouth, the water spreads out into the mangroves, and the sediment settles to the bottom where it is trapped by the mangrove roots.

As the bottom gets shallower, the mangroves can grow further out, while those on the inside eventually find themselves on dry land, where they are replaced by ordinary land plants. 

In this way, the mangrove forest advances slowly outward, leaving dry land behind. Even in areas where there are not arriving enough sediment from the rivers to build new land, the mangroves protect the shoreline from being washed away in storms. The roots and trunks break the force of the waves, and the leaves and branches reduce the effects of the wind and rain. There are examples of islands which were built by mangroves, and then were washed away when the mangroves were cut. 

Even in the cities, mangroves can be important when the city wastes run off and pollute the nearby coastal waters. When these wastes run into a mangrove swamp, they normally are absorbed and used by the plants and animals in the swamp.

 The swamp filters the water, making use of the nutrients and also absorbing toxics and leaving clean water. As long as cities do not produce too much waste for the mangroves, and the waste does not contain too much toxic from industries, the mangroves are an excellent waste treatment system, and much cheaper than any sewage treatment plant. Mangroves, however, are sensitive to pollution, particularly oil pollution. Too much toxic waste will kill the forest. 

Lately, also the value of the mangroves for tourism has been discovered. Senegal in particular has known to appreciate this resource. Two important national parks are based on the mangrove resource - Parc National du Delta du Saloum and Parc National de la Basse Casamance. The Casamance park is located close to the tourist centre Cap Skirring and with its over 200 species of sea birds, it is a popular resort for photo safaris and bird watching excursions.