Bangladesh is located between latitudes 20°34' to 26°38' north and longitudes 88°01' to 92°41' east. The country consists mostly of flood plains (80%) with some hilly areas (12%), with a sub-tropical monsoon climate. In winter, temperature ranges from a minimum of 70 to 13°C to a maximum of 230 to 32°C. In summer, the temperature varies from 36°C to 41°C. The mean annual rainfall ranges from 143 to 434 cm (BBS 1994). The population stood at 131.6 million in 2001.
Bangladesh has a total area of 14.39 million hectares, of which 9.12 million ha is cultivated, 2.14 million ha public forests, 0.27 million ha village groves, and 1.64 million ha constantly under water. The remaining land area (1.22 million hectares) is occupied by tea gardens, uncultivable areas, rural and urban houses and ponds (Kibria et al. 2000). The area covered by government and village forests is about 16% of the total land area; however only 0.93 million ha (6.5%) is under tree cover, which is about 40% of the forests controlled by the government. The remaining 60% includes denuded lands (grassland, scrubland and encroached areas). About 24 000 ha of forest is lost annually as a result of homestead development, urbanization and deforestation (Anon 1992).
The mangrove forests are composed of two major components, viz., the Sundarbans and the Coastal Afforestation. The Sundarbans forest is spread over 0.58 million ha in the south-western region (Ali 1989), with an annual depletion rate of about 1.7%. A large-scale coastal afforestation programme has been undertaken since 1966, covering about 170 000 ha. The hill forests cover an area of 0.67 million ha. The growing stock has been estimated to be about 28 million m3 or 100 m3 ha-1 (Anon 1992). Annual depletion of the growing stock stands at 1.65%. The estimated average annual forest growth is 2.5 m3 ha-1. The forests cover of 0.12 million ha and to a great degree consists of Shorea robusta (sal) located in the central and northern part of the country. The area under tree cover in this region has been estimated to be 32%. A large portion of this forestland has been encroached. About 0.02 million ha of plantations has been established. The unclassified state forests include 0.73 million ha of hilly land located at the southeast corner of the country. The village forest area is 0.27 million ha (TFYP 1985). The growing stock of the woodlots and bamboo resources were estimated to be 54.7 million m3 and 7480 million culms respectively.
The contribution of forestry to the national Gross Domestic Product (GDP) at current prices has been estimated to be 3.28% (BBS 1994). The supply of various forest products such as timber, poles, fuelwood, bamboo, etc. cannot meet the present demand. Village forest areas, being one-tenth of the national forest area, supply 70% of sawlogs, 90% of fuelwood and 90% of bamboo consumption of the country (Douglas 1982). The annual per capita consumption of timber and fuelwood was estimated to be 0.01 m3 and 0.08 m3, respectively, based on a population of 90 million as at 1980 (Byron 1984). The figure would be less if the present forest production and population were considered. The gap between demand and supply has been increasing with the increase in population. This gap may be narrowed through the establishment of plantations of fast growing trees in the denuded forest areas, wastelands as well as homestead areas.
Bangladesh, located in the humid tropical region is rich in species diversity and is unique in the diversity of genetic resources compared to its land area. It has about 5700 species of angiosperms and four species of gymnosperms (Khan 1977; Troup 1975) of which some 2260 species are reported from the Chittagong region (Anon 1992). The major forest tree species of the country are shown in Appendix 1.
Khan (1996) reported that there are about 86 timber species, 130 species yielding fibre and 29 medicinal plant species available in the country. The Bangladesh National Herbarium (BNH) prepared a list of 500 medicinal plants. Bamboo resources of 18 taxa, both wild and planted are available in the country (Alam 1982). There are at least nine species of rattans, including a recently reported one (Alam and Basu 1988), along with 12 other palm species (Khan 1996). However, it must be noted that comprehensive information on forest genetic resources (FGR) is not available in the country. Information on species diversity in terms of (i) chromosome numbers, (ii) morphological variation, (iii) flowering and seed production habits, (iv) flowering time and nature and (v) seed morphology and viability, etc. are available only for a few agricultural species. Forest species are neglected in this respect (Hassan 1995).
Forests in Bangladesh are declining at an alarming rate. An estimated 73 000 ha of forests was lost due to encroachment for agriculture and aquaculture by the year 1980. Some species are disappearing fast and are considered as threatened. A total of 19 tree species and nine rattan species need immediate conservation measures (Khan 1996). The on-going loss of germplasm is a threat to FGR. High population pressure on land, clearing of forests, exploitation, draining and filling of wetlands, introduction of exotic species, introduction of improved genotypes, pests, improper silvicultural techniques and management and lack of public awareness are some of the major threats to FGR. Poverty and the attitude of the people towards exploitation of natural habitats of plants as free goods also contribute to the loss of germplasm in the country.
The destruction of forests by shifting cultivation is another problem in Bangladesh. The forests are cut and cultivated for a short time only, and when the residual nutrients in the soil are leached as a result of erosion removing the topsoil, the shifting cultivators move to another location.
The country has four wild gymnosperms, viz. Cycas pectinata, Gnetum scandens, G. funiculare and Podocarpus nerifolia. C. pectinata is regionally threatened and the two Gnetum species have become very rare while the populations of P. nerifolia are much depleted. Immediate appropriate conservation measures are needed to protect these species in the country. Khan (1996) reported that the number of plant species threatened in the country is 45. Among mammals, birds, reptiles and amphibians, 15 species have become extinct and 33 species are endangered. According to the Government of Bangladesh (GOB 1992), there are 27 threatened and 39 endangered species of wildlife in Bangladesh at present.
