Slash-and-burn is an agricultural technique which involves cutting and burning of forests or woodlands to create fields. It is subsistence agriculture that typically uses little technology or other tools. It is typically part of shifting cultivation agriculture, and of transhumance livestock herding.
Older English terms for slash-and-burn include assarting, swidden, and fire-fallow cultivation. Today the term "slash-and-burn" is mainly associated with tropical rain forests. Slash-and-burn techniques are used by between 200 and 500 million people worldwide. In 2004 it was estimated that, in Brazil alone, 500,000 small farmers were each clearing an average of one hectare of forest per year. The technique is not sustainable beyond a certain population density because, without the trees, the soil quality soon becomes too poor to support crops. The farmers have to move on to a virgin forest and repeat the process. Methods such as Inga alley farming have been proposed as an alternative to this ecological destruction.
During the Neolithic Revolution, which included agricultural advancements, groups of hunter-gatherers domesticated various plants and animals, permitting them to settle down and practice agriculture which provides more nutrition per hectare than hunting and gathering. This happened in the river valleys of Egypt and Mesopotamia. Due to this decrease in food from hunting as human populations increased, agriculture became more important. Some groups could easily plant their seeds in open fields along river valleys, but others had forests blocking their farming land. In this context, humans used slash-and-burn agriculture to clear more land, and make it suitable for their plants and animals. Thus, since Neolithic times, slash-and-burn techniques have been widely used for converting forests into crop fields and pasture. Fire was used before the Neolithic as well, and by hunter-gatherers up to present times. Clearings created by fire were made for many reasons, such as to draw game animals and to promote certain kinds of edible plants such as berries. Slash-and-burn fields will typically be used and "owned" by a family until the soil is exhausted. At this point the "ownership" rights are abandoned, and the family will clear a new field, and the forest is permitted to grow on the old field. After a few decades, another family or clan may then use the land and claim usufructuary rights. In such a system there is typically no market in farmland, and land is not bought and sold in the open market. Such rights are "traditional." In slash-and-burn agriculture, forest will typically be cut months before a dry season. The "slash" is permitted to dry, and then burned in the following dry season. The resulting ash fertilizes the soil, and the burned field is then planted at the beginning of the next rainy season with crop such as upland rice, maize, cassava, or other staple crop. Most of this work is typically done by hand, using machetes, axes, hoes, makeshift shovels and other such basic tools.
Modern Western world 
Slash-and-burn could be distinctly defined as the large-scale deforestation of acres of forests for agricultural usage. The ashes that come from the trees would also help farmers, for it provides nutrients for farming.
In regions which industrialized, including Europe and North America, the practice was abandoned over the past few centuries as market agriculture was introduced, and land came to be owned. For example, slash-and-burn agriculture was initially practiced by European pioneers in North America like Daniel Boone and his family who cleared land in the Appalachian Mountains in the late 18th and early 19th Centuries. However, the land of such slash-and-burn farmers was eventually taken over by modern systems of land tenure which focus on the long-term improvement of farmland, and discourage the older subsistence practices associated with slash-and-burn agriculture.
Preserving the northern European heritage 
Telkkämäki Nature Reserve(Kaavi, Finland) is a farm, which cherishes the old slash-and-burn heritage. At Telkkämäki farm, the visitor can see how people lived and farmed in the past, when the slash-and-burn agriculture was practiced in the North Savonian Region in Eastern Finland from the 15th century. Some areas of Telkkämäki Nature Reserve are burnt annually.
South Asia 
Tribal groups in the northeastern states of India like Arunachal Pradesh, Meghalaya, Mizoram and Nagaland, and also in the districts of Bangladesh like Khagrachari and Sylhet refer to slash and burn agriculture as "Jhum" or "Jhoom cultivation". This system involves clearing a piece of land by setting fire or clear felling and using the area for growing crops of agricultural importance such as upland rice, vegetables or fruits. After a few cycles, the land loses fertility and a new area is chosen. Jhum cultivation is most practiced on the slopes of hills in thickly forested landscapes. The cultivators cut the treetops to allow sunlight to reach the land. They burn all the trees and grasses for clean and fresh soil. It is believed that this helps to fertilize the land, but can leave it vulnerable to erosion. Later seeds and crops are planted. Plants on the slopes survive the rainy season floods. Looking at all the effects, the government of Mizoram has launched a policy to end Jhum cultivation in the state.
Slash-and-burn is typically a type of subsistence agriculture, and not focused by the need to sell crops in world markets. Rather, planting decisions are made in the context of needs of the family or clan for the coming year.
South America 
In about the 1960s lands in Bolivia, near the Andes Mountains, were burned down to make room for fleeing migrants. They were offered about 30-50 acres of land. After a while the Argentinian government found that after a forest was been cleared the federalization washes away with rain. It was after events such as this where South American countries started to realize the negative effects that deforestation has on the environment.
Ecological implications 
Although a solution for overpopulated tropical countries where subsistence agriculture may be the traditional method of sustaining many families, the consequences of slash-and-burn techniques for ecosystems are almost always destructive. This happens particularly as population densities increase, and as a result farming becomes more intensively practiced. This is because as demand for more land increases, the fallow period by necessity declines. The principal vulnerability is the nutrient-poor soil, pervasive in most tropical forests. When biomass is extracted even for one harvest of wood or charcoal, the residual soil value is heavily diminished for further growth of any type of vegetation. Sometimes there are several cycles of slash-and-burn within a few years time span; for example in eastern Madagascar the following scenario occurs commonly. The first wave might be cutting of all trees for wood use. A few years later, saplings are harvested to make charcoal, and within the next year the plot is burned to create a quick flush of nutrients for grass to feed the family zebu cattle. If adjacent plots are treated in a similar fashion, large-scale erosion will usually ensue, since there are no roots or temporary water storage in nearby canopies to arrest the surface runoff. Thus, any small remaining amounts of nutrients are washed away. The area is an example of desertification, and no further growth of any type may arise for generations.
The ecological ramifications of the above scenario are further magnified, because tropical forests are habitats for extremely biologically diverse ecosystems, typically containing large numbers of endemic and endangered species. Therefore, the role of slash-and-burn is significant in the current Holocene extinction.
Slash-and-char is an alternative that alleviates some of the negative ecological implications of traditional slash-and-burn techniques.
See also 
- Tony Waters, The Persistence of Subsistence Agriculture, p. 3. Lexington Books (2007).
- Slash and burn, Encyclopedia of Earth
- Skegg, Martin. True Stories: Up In Smoke The Guardian 24 September 2011
- Elkan, Daniel. Slash-and-burn farming has become a major threat to the world's rainforest The Guardian 21 April 2004
- Jaime Awe, Maya Cities and Sacred Caves, Cu bola Books (2006)
- Tony Waters (2010) "Farmer Power" at http://www.ethnography.com/2010/12/farmer-power-the-continuing-confrontation-between-subsistence-farmers-and-development-bureaucrats/
- Tony Waters, The Persistence of Subsistence Agriculture." Lexington Books (2007), p. 48.
Further reading 
- Karki, Sameer (2002). Community Involvement in and Management of Forest Fires in South East Asia (PDF). Project FireFight South East Asia. Retrieved 2009-02-13