Sundarbans is known as the single largest stretch of productive mangrove forest in the world. It occupies an area of about one million ha in South West Bangladesh and South Eastern part of the state of West Bengal of India (between 88°85'to 89O55'E and 21°30' to 22°40 'N). About 62% of this forest is within the territory of Bangladesh. One third of this forest area consists of water bodies in the form of rivers, channels and tidal creeks. The forest is highly influenced by tidal interactions. Sundarbans hosts the Royal Bengal Tiger and the forest has been endowed with a number of commercially important mangrove species such as Sundri, Gewa, Goran and Keora.

In general, dicotydonous tree species are represented by 22 families and 30 genus, while Rhizophoraceae is represented by all the 4 known genera and at least 6 species. The shrubs are represented by 12 species belonging to 11 genus under 7 families. Eleven different species of climbers belonging to 6 families have so far been identified in the Sundarbans. In addition to the plants, there is epiphytic parasitic flora found in the forest. Orchids of 13 species and ferns of 7 species are found in the Sundarbans.

Mangroves have a strong interrelationship with tidal and river flows. The mangrove trees slow down these flows allowing sediment to drop out of suspension, building up the mud flats and supplying nutrients to support mangrove growth. Mangrove species are specially adapted to survive in saline waters. Different species thrive in different salinities through their own specialized adaptations to ensure growth and reproduction. The salinity distribution and degree of water logging within the forest determines the overall ecological zonation of the sundarban into fresh water, moderately salt-water and salt water zone. Differences in salinity within zones produce variations in local species. Ecological zonation and characteristic species of the Sundarban mangrove forest is presented in Table-2.10.

The Sundarbans Reserve Forest occupies an area of 601,700 hectares of which, 406,900 ha are forests, 187,400 ha water (rivers, rivulets, ponds and canals), 30,100 ha form wildlife sanctuaries and 4200 ha are sand bars. It is home to several uniquely adapted flora and fauna and provides feeding and nursery grounds for many animals. Many animals spend their entire life in the mangroves, whilst others spend some part of it.

The mangrove forest is very rich in bio-diversity and supports 334 species of plants, as : many as 77 insects of different orders, 7 crabs, 1 lobster, 23 shrimp/prawns, 400 fish, 8 amphibians, 35 reptiles, 270 birds and 42 species of mammals. There are about 12 and 23 species of orchids and medicinal plants, respectively, found in the Sundarbans. It is also the largest honey-producing habitat in the country with giant honey bees (Apisdorsata). The best tree for producing honey in the Sundarbans is Khulshi (Aegiceras comiculatum).

The Sundarbans is the only remaining habitat of the famous Royal Bengal Tiger (Panthers tigris) and estuarine crocodiles (Crocodylus porosus) occur extensively in the rivers. The forest harbors large numbers of threatened wildlife species inclusing Python, King Cobram Adjutant Stork, White-bellied Sea Eagle, Clawless Otter, Masked Fin-foot, Ring-lizard and River Terrapin. The Sundarbans is also home of thousands of spotted dear (Axis).

Out of 26 species of mangroves, the two dominant ones are the Sundari (Heriliersfomes) and Gewa (Excoecaria agallocha). Among the trees, Gewa and Goran (Ceriops roxburghiana) are being used in newsprint mills for paper production, as well as for fuel- wood. The Sundari and Keora (Sonneralia aoelala) are used as timber woods. Leaves of gol pata (Nypa frulicans) are used for thatching. At present, there is no commercial timber felling due to a moratorium imposed by the Government of Bangladesh, with the exception of Gewa and Goran.

The Sundarban has been systematically managed since 1887, when a system of forestry and fishery permits was established. Since then the forest has been a considerable source of revenue and at present contributes about 2% to the GDP of the country and about half a million people are involved in the commercial exploitation of timber fuel wood, fish, honey, beeswax etc. of the forest. The indirect benefit of the forest is a result of the protection it gives to the breeding of (shrimp and shrimp larvae, thereby protecting the marine, brackish and freshwater coastal fishing industries. The forest also provides protection for large areas of Khulna, Shatkhira and Bagerhat districts including Khulna City and Mongla port from cyclonic storm surges.

Presently, the Sundarban is in a state of decline. attributed to the combination of the effects of reduction in freshwater flow, heightened silt deposition and non-sustainable forest management. Depletion of this mangrove forest will bring serious implications for the coastal economy as well as large area of south western zone of Bangladesh will be exposed to the direct on salt and risk from tidal and cyclonic storm surges. Besides, the natural mangrove forest coastal afforestation program was commenced in 1966 by the Forestry Department (FD).

According to the RIMS wing of FD, 109000 ha of coastal plantations have been raised in the early nineties of the last century. By a Government notification dated 13th August 1976 a total area of about 500000 ha accreted lands arising out of the sea or confluence of big rivers falling in the coastal districts of Noakhali, Barisal, Chittagong and Patuakhali was transferred by the Ministry of Land to the Ministry of Forest as reserve forest for IO years for the purpose of coastal afforestation. The main objective of coastal afforestation was stated to be conservation and stabilization of newly accreted char land and soil for making the same suitable for cultivation.

The Forestry Department (FD) there after started planting trees in the said reserve forest area under an internationally funded Coastal Afforestation Project (CAP). Keora is the dominant species of coastal plantations followed by Bean. Almost 80% of the area was planted with Keora, followed by Bean of about 15% of the planted area. Remaining 5% area was planted with Gewa, Kankra, Golpata, Babla etc.

Another mangrove forest totally about 900 ha of land at Chokoria Mangroves in Cox's Bazar has been destroyed mainly due to uncontrolled logging, agricultural expansion and shrimp culture.