Ethnobotanical Leaflets 12: 1168-71. 2008.
Ethnobotany and Traditional Management of Drought Tolerant Tree Species in Homestead Forests of Bangladesh
1Mahbubul Alam and 2Yasushi Furukawa
1United Graduate School of Agricultural Sciences
Ehime University, Matsuyama, Japan
2Forest Management Laboratory, Faculty of Agriculture
Kochi University, Japan
Issued 15 December 2008
A study has been conducted in the homesteads of drought-prone northwestern region of Bangladesh. Since there is no natural forest, the overall climatic condition is very harsh and progressive trend of desertification is threatening the livelihood of poor people. So it is important to carry out extensive plantations throughout the region to reverse the current trend of drought and desertification. The study identified a list of 19 drought tolerant species suitable for planting in the homesteads as well as in the vacant spaces. The rural people are heavily dependent on those species for their daily requirement of timber, fruits, fuel, and other non-timber products.
Different terminologies are used to describe and define the homestead forests in different regions of the world. Most common terms used are, among others, homestead agroforestry (Leuschner and Khaleque 1987), mixed-garden horticulture (Terra 1954), homegarden (Ramsay and Wiresum 1976; Millat et al. 1996), Javanese homegarden (Soemarwoto et al. 1985), and homestead forest (Motiur et al. 2005). Homestead forests of Bangladesh constitute multi-storied vegetation of shrubs, bamboos, palms and trees that produce materials for a multitude of purposes, including fuel, shelter, structural materials, fruits, fodder, and medicines (Dauglas 1981). Though Bangladesh is predominantly a riverine country, the northwestern region is threatened by desertification. In addition to the environmental consequences, desertification is also threatening the livelihood of rural people. This is also one of the forest poor regions of the country too. Hence, it is urgently required to increase vegetation cover through development of homestead agroforestry traditionally adopted by rural people within their homesteads (Alam and Furukawa 2008). This agroforestry system in drought-prone areas provides a healthy ecosystem for humans, animals, birds, livestock and miscellaneous flora and fauna. The present study has been conducted to identify a list of drought tolerant tree species, their use and overall management.
The study area and research methodology
The current study is a part of a larger research project operated in the drought-prone northwestern region of Bangladesh located between 24º54' and 25º06' north latitudes and between 88º24' and 88º39' east longitudes. The study area is a part of Barind Tract, the largest Pleistocene physiographic unit of the Bengal Basin (Banglapedia 2008). The average annual rainfall of the region varies from 1400mm to 1600mm. The value of the ratio of annual rainfall (R) to potential evapotranspiration (ET0) for northwest Bangladesh is often less than the 0.65 threshold value. The results of existing drought situation and the trend of desertification can partly be attributed to the immediate effect of climate variability and change in the form of rainfall shortage and decreased level of atmospheric moisture. Generally, average temperature ranges between 25-35 ºC during summer and 9-15 ºC during winter. The hottest days in the region experience temperature about 45ºC (Banglapedia 2008). Long-term observation of variation in climatic parameters shows that Bangladesh’s drought-prone areas have become warmer and drier than 50 years ago and current projections suggest that the areas will become hotter, its nights will be warmer, and there will be an increased rainfall variation.
An explorative field survey has been conducted among the thirty-two randomly selected households. Semi-structured questionnaire was provided to the respondents to investigate the ethnobotanical use of tree species present in their homestead. Focus group discussions were also arranged to identify a list of species locally adapted in the region. Experts were also consulted to cross-check the information from scientific point of view.
Results and Discussion
In total 19 species has been identified during field survey as drought tolerant and suitable for extensive plantation in the vacant and bare spaces within the homesteads of northwestern region. Table 1 shows the scientific names of the species along with their English/local names, family, and principal ethnobotanical use. Acacia catechu is a leguminous species that produces, besides wood, important medicinal products. Acacia nilotica, a species of the same family provides a wide range of goods and services including timber, fodder, resin, and medicine. But in Bangladesh this species is well known for production of quality gums. Aegle marmelos produces fruits having medicinal value. Anthocephalus chinensis is used for timber and fuel and is also used in match factories as raw material. Chewing betel leaf with betel nut (Areca catechu) is a tradition among rural people throughout the subcontinent. Jackfruit is a multipurpose tree species that produces timber, fuel and fodder. The species bears national fruit of Bangladesh. Averrhoa carambola Citrus grandis Lychi chinensis Phoenix sylvestris and Ziziphus jujube produces quality and delicious fruits that are consumed for family nutrition and sold in the market for additional family income. Bamboo is known as “poor man’s timber” (FAO 1994; Paudel and Lobovikov 2003) because, it is widely used in rural construction works including fencing, house construction, and making agricultural implements. The study area is famous for producing quality mangos (Mangifera indica) of various varieties and the farmers produce mangos in commercial basis which are sold throughout the country. This is the most economically important fruit species of the region. There are extensive plantations of the species Morus alba throughout the region. This species are grown for rearing of silkworm for producing silk in sericulture enterprises.
Table 1: A list of drought-tolerant tree species locally adapted in the Bangladesh.
M=medicinal; Fr= fruit; T=timber; Fu=fuel
All the aforementioned species provides the rural people with a wide range of products and services beyond what is said here. Rural poor depend on these valuable trees for their subsistence and additional income when sold in the market. In addition, these tree species ‘fill gaps’ and acts as ‘safety nets’ during economically hard situation. Thus, in the cases when the agricultural crops fails due to severe drought spells and resulting in destruction of main income source, the farmers rely on homestead grown vegetation for their nutrition (in the form of fruits) and cash income ( by selling timber and fruits in the market). In this way, vulnerability of livelihood is decreased to some extent in extreme environmental consequences. Thus growing drought tolerant species in the premises of living quarters is a significant adaptation to climate variability and change.
The study conducted on the traditional management exercises followed by the farmers in managing their homestead agroforestry resources showed that despite high socio-economic contribution, this traditional production system is being managed in traditional ways. Scientific knowledge and techniques are lacking. The farmers reported that they manually carry out cultural operations like weeding, mulching, and fencing. Of the tree level management, pruning, pollarding, and thinning are done at different intensity. Only few species are given special care as in the cases of mango, Palmyra palm, and coconut.
Growing more trees in the homesteads, around agricultural fields and other vacant spaces will increase the livelihood adaptation capacity of rural poor besides increasing forest coverage in the forest poor northwestern region. So, it is important that people are motivated and supplied with quality planting materials. Traditional management practices should be supplemented by scientific techniques.
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