SHIFTING CULTIVATION IN BANGLADESH

Shifting Cultivation

Shifting cultivation, locally known as jhum is a traditional agricultural land use in Chittagong Hill Tracts (CHTs) of Bangladesh. This cultivation system practiced by tribal communities and accounts for the major proportion of agricultural land use in this area. About 60,000 families involved in shifting cultivation that covers an area of about 85,000 hectares of the hill forests. Clearing a patch of vegetation, growing varieties of crops in the cleared land for one or two seasons, and then moving to another plot is a major characteristic of this extensive land use system. There are twelve tribal communities and migrated Bengali practices largely wetland farming in available valley land. Traditional shifting cultivation, considered as ecologically and environmentally sustainable land use in mountain areas, is provided subsistence requirements for mountain people for long time. The long fallow period enables regeneration of soils and vegetation quickly and thus soil erosion remains minimal and hydrological balance is maintained. Moreover, cropping diversity under shifting cultivation conserves the land ecologically keeping pace of genetic diversity.

With the growing population, and state control over forest, fallow period has been shortened in most parts of Asia creating serious pressure on shifting cultivation systems, which destabilizes the system. However, shifting cultivation with short fallow accelerates deforestation, soil erosion, soil nutrient depletion and biodiversity degradation. It also adversely affects the physical and chemical properties of soil.

STOP CARBON EMISSION: PROMISES FIVE COUNTRIES

Natural Forest of Bangladesh

Carbon emission from burning fossil fuel is mainly responsible for recent global warming. Bangladesh, a least developed country where more than 60% people are in village areas, releases a remarkable amount of carbon in daily basis by using cow dung and fuel wood to cook their foods. Carbon emission by burning fuel causes the air pollution inside their houses. Considering the category of air pollution inside the houses, Bangladesh ranking 10th of the world. To overcome carbon emission problem, five countries such as United States, Canada, Mexico, Sweden and Bangladesh agree to work together after constructive discussion in an international conference titled “Air Pollution inside the Houses” held in Bangladesh. As a part of an international cooperation, Sweden agrees to help Bangladesh by financially and it is about 3,955,174 US Dollar. This amount mainly goes for preparing new cooking stoves those can produce less smoke and control air pollution, and distribute to the rural remote areas. Bangladesh is now becoming a most vulnerable country of the world due to climate change and sea level rise. Reduction of carbon emission and increase the forest areas are the best solution to mitigate climate change during the upcoming years. Different countries already take effective initiatives in recent years to reduce carbon emissions where Sweden decided to reduce their carbon emission about 40% within 2030; on the other hand, Australian government imposes high taxes for the carbon emitting industries there. Consequently, Bangladesh creates more attention towards the developed countries for financial and technical supports to control carbon emission and air pollution during the last few decades.

FOREST COVER IN ASIAN REGION

Dipterocarpus turbinatus

In 2010, the World forests cover were estimated 4,033 M ha which distributed in Africa (674 M ha), Asia (593 M ha), Europe (1,005 M ha), America (705 M ha), Oceania (191 M ha) and South America (864 M ha). Extensive forest resources are available in Asian region where forest types mainly are tropical evergreen, semi-evergreen and deciduous suitable for diversified forest ecosystems. Forest coverage according to the total land area in percentage are spreading over South Asia, lower Mekong and insular southeast Asia such as in Bangladesh (2.53 M ha, 17.5%), Bhutan (3.2 M ha, 68%), India (67.7 M ha, 23%), Nepal (3.6 M ha, 25%), Cambodia (10.5 M ha, 60%), Laos (16 M ha, 70%), Thailand (14.5 M ha, 28%), Vietnam (13 M ha, 40%), Indonesia (88.5 M ha, 50%), Papua New Guinea (29.5 M ha, 65%), Philippines (7 M ha, 24%) and Malaysia (21 M ha, 64%). Recently, many countries in that region face severe rates of forest loss and it was over 41 M ha during 1990 to 2005. Since highly deforestation rates in the last few decades, some countries such as China, Cambodia and Thailand were decided to ban commercial logging, and in the mean time some others such as China, India and Vietnam have been increasing their forest cover due to significant reforestation efforts. Reducing deforestation and encouraging afforestation are considered important for both carbon sequestration and biodiversity conservation in Asian region.

CLIMATE CHANGE: BANGLADESH PERSPECTIVE

Coastal Belt

The main victim of the unfavorable consequences of accumulation of green house gases is the developing countries of the world as per they have narrow scope to tackle with the natural disasters. Low economic countries such as Bangladesh are four times more victims by different disasters than high income countries. After 1990s, there were three storms, four floods, one tsunami and two cyclones killed more than 400,000 people, and indirectly affected another 42 million people, damage to coastal infrastructure estimated as much as 12% of GDP by the year 2010. According to IPCC (Intergovernmental Panel on Climate Change) prediction, about 20 cm sea level may rise within year 2030, and end of this century it will be more than 1 m. Sea level rise will inundate coastal areas about 2.29 million hectares which is about 15.8% of the total land of Bangladesh. Net-cropped area about 13.74% and about 401,600 hectares mangrove forests will be lost from map of Bangladesh. Recently, a large number of native tree species such as Arthocarpus chaplasha, Cassia fistula, Michelia champaca etc. become in endangered and extinct conditions due to change their favorable site conditions in hill forests. From different research findings, it predicted that natural and mangrove forests of Bangladesh may lose its native economically valuable species in near future due to temperature become high and low precipitation during the year. Only forests react sensitively to climate change; and measures to protect, restore and sustainably management can offer climate change mitigation potential.

DEFORESTATION RELATED TO ENVIRONMENTAL ISSUES

Deforestation in Bangladesh

Tropical forests of the world are degrading at an alarming rate because of population growth and human poverty, acute shortage of fuelwood, fodder and timber and a continuous decline in the amount of per capita cultivable land. 
Bangladesh, a South Asian least developed country, has been experiencing severe deforestation over the last 3 to 4 decades. During the period 2000-2005, deforestation rate in Bangladesh has been estimated at 3.3% per year. In Bangladesh, deforestation results mainly clearing agriculture land, principally shifting or jhum cultivation. About 85,000 hectares of the hill forests reserves under the practice of shifting cultivation and about 60,000 families engaged there. Of the three major forest categories (hill, inland Shorea robusta, Gaerten. f., and mangrove forests), the hill forests (48%) are the most important watershed areas of the country and are composed of tropical evergreen and semi-evergreen tree species. 
A rapid deforestation not only diminishes vegetative cover and species diversity; it may accelerate surface runoff, increase soil compaction and deteriorate soil biochemical properties, and often affects climate by releasing stored soil carbon as CO2 into the troposphere. 
The natures in which the tropical hill forest ecosystems are being deforested and degraded are becoming an ecological concern. Under regular protection, allow for natural regeneration and improvement of soil quality in the degraded forest ecosystems can be achieved over time.

CARBON STOCK CAPACITY OF PLANTATION FORESTS

Plantation Forests in Bangladesh

The large portions of natural forests in Bangladesh have already been significantly degraded and fragmented, leaving the country with only a small percentage of forest cover. Plantations have high annual carbon sequestration rates and establishing plantations on degraded land has been proposed as an effective carbon management approach. Through the Clean Development Mechanism (CDM), carbon management approach can be achieved by plantation program in developing countries such as Bangladesh. Developing countries are mostly affected by the consequences of the “global warming”. The global warming issue focuses on the increasing accumulation of greenhouse gases, mainly CO2 in the atmosphere due to emissions caused by industrial activities and deforestation. Creating and maintaining carbon stocks in the tropical forests is an important response option for global warming in tropical developing countries such as Bangladesh. Among three plantations of 18-year old, the total (above- and below-ground) carbon stocks were found highest in Acacia auriculiformis (110.25 and 100.84 ton•ha−1, respectively), followed by Tectona grandis (91.28 and 80.33 ton•ha−1) and Anthocephalus chinensis (63.70 and 85.26 ton•ha−1) plantations. The capacity of plantations of Acacia auriculiformis, Anthocephalus chinensis and Tectona grandis to sequester atmospheric carbon and that reforestation makes a significant contribution to carbon sequestration and generating carbon credits in Bangladesh. The carbon stock of three plantation species indicates that Bangladesh has a capacity for carbon sequestration. To overcome the problem of global warming and climate change, sustainable forest management is the best way to achieve optimum carbon sequestration; and more easy, applicable and fast scientific methods are required to estimate the carbon stock in plantation forest.