When the Portuguese opened the way around the Cape of Good Hope to India, they found the same vegetation along the coasts, that was similar to regions that they had previously discovered. They gave this strange vegetation the name "mangue", as they were called in Brazil. Over the centuries, the name changed to mangrove. Today it is used for the typical plant life that grows along tropical coasts between the levels of high and low tide. It also describes a plant species that has adapted to the salty soil and the special conditions in a tidal area.

When the first European discovered the tropics, they were amazed by the unusual collection of trees, that grew out of the sea water, on slippery mud sediments and in infertile salt marshes. Sailors on the first trade ships reported negative and painful experiences, that resulted from exploring these areas. They described an impenetrable chaos of roots, a labyrinth of canals that made orientation difficult and the silt mud that made the passage a near life-threatening adventure. Most of all, the inhabitants of this strange biosphere, a myriad of biting insects, crocodiles and other predators, increased their negative impression of the area. The swamp forests were seen as an origin of tropical diseases. The decaying plant waste imparted an unpleasant odour. They were and continue to be seen as a hideaway for pirates, criminals and hostile natives.

400 million years ago, when the first creatures came out of the water to settle on land, their first contacts were the plant communities of the swamp forests. Fossil findings give evidence, that the mangrove forests played an important role in the evolution and inter-relationship between organisms of the sea, salt water, fresh water and the terrestrial biosphere. Pollen studies show, that two typical plants of the coastal forests of Southeast Asia, the Nipa Palm and the spike-leafed fern Acrostychum, belong to the oldest higher plants on earth that have changed little during the last 60 million years. Mangrove forests are limited to the humid climates between the Tropic of Capricorn and the Tropic of Cancer. They are found along shallow coasts, where a periodical change of fresh and seawater occurs and certain differences exist between high and low tides.

To survive in such a hostile environment, mangrove trees have made adaptations to their anatomy, metabolism and reproduction mechanisms. To solve the problem of stability in the soft silt ground, the members of the Rhizophora family have developed two kinds of additional roots. One comes from the stem to grow in elegant bows towards the ground. The other grows from branches in the crown of the tree parallel to the stem into the ground. Both give the tree enough stability to withstand the strong coastal winds and the enormous amounts of sediment, that are transported by the rivers during the rainy season and deposited in their estuaries. Another species has a net of primary roots just below the surface. They not only support the tree's stability, but also help the tree to get enough oxygen by short root elements, that grow vertical through the surface. They are called pneumatophores and are an important feature because the silt mud is nearly anaerobic because of its small grain size.

The fruit of the mangrove have adapted to the special problems of this environment. Conditions such as crystalline crusts of salt from sea water, dry soil during low tide and long periods of time floating in sea water must be overcome. To protect the seeds from animals, a hard outer shell developed.

Compared to the tropical rain forests of Southeast Asia with their immense diversity of plants and animals, less than 60 trees and shrub species are seen in mangrove forests. Another 300 species are found, but are not limited to the coastal swamp forests. Some of them such as ferns, orchids and Bromeliaceae grow as epiphytes on the trees. While others such as liana vines and air plants are parasitic plants.

For many animals, sea creatures and birds the mangrove community is either a nursery, temporary or permanent living area. Crocodiles are found in the mangrove forests, except in Thailand where they are extinct. Various species of monkeys can be observed living in the mangroves. They come out of the forests during low tide to feed on crabs and other molluscs. Others animals use the shelter to eat their catch and this area becomes a safe refuge during the night, as their predators cannot traverse this biosphere.

People use the mangrove forests in different ways. In some regions they are used to build houses and small settlements, in others as industrial zones or as garbage dumps. Often, such activities are allowed because the real value of this terrain is not realised. The heavy and water-resistant wood of fast growing trees is used for cooking either directly or as charcoal. Some tropical countries burn high amounts of mangrove wood to charcoal and sell it in the temperate countries with the sticker "not from tropical woods". The nutrient content of the canals, swamps and the artificial basins that have been created in the mangrove forests make these ideal waters for raising oysters, several fish species and the popular tiger prawns. Thailand is currently the largest exporter of tiger prawns in the world.

After cutting the mangrove trees along some coastal regions on a wide scale, it became obvious, that their existence is an important protection against typhoons and the high waves caused by them. Especially Rhizophora mangroves that stand in the first row with their arched roots serve as breakwater. The regeneration of mangrove forests to the original condition will take several decades.

On Lanta Island, mangrove forests are found along the eastern coast of Lanta Noi and Lanta Yai. Where the two islands come close together a remarkable area of intact mangrove forests exists and is worth exploring.