Slash-and-burn agriculture is a farming method that involves the cutting and burning of plants in a forest or woodland to create a field called a swidden. The method begins by cutting down the trees and woody plants in an area. The downed vegetation, or "slash", is then left to dry, usually right before the rainiest part of the year. Then, the biomass is burned, resulting in a nutrient-rich layer of ash which makes the soil fertile, as well as temporarily eliminating weed and pest species. After about three to five years, the plot's productivity decreases due to depletion of nutrients along with weed and pest invasion, causing the farmers to abandon the field and move to a new area. The time it takes for a swidden to recover depends on the location and can be as little as five years to more than twenty years, after which the plot can be slashed and burned again, repeating the cycle. In Bangladesh and India, the practice is known as jhum or jhoom. Slash-and-burn is a type of shifting cultivation, an agricultural system in which farmers routinely move from one cultivable area to another. A rough estimate is that 250 million people worldwide use slash-and-burn. Slash-and-burn causes temporary deforestation. Ashes from the burnt trees help farmers by providing nutrients for the soil. In low density of human population this approach is very sustainable but the technique is not scalable for large human populations. A similar term is assarting, which is the clearing of forests, usually (but not always) for the purpose of agriculture. Assarting does not include burning.

History

Historically, slash-and-burn cultivation has been practiced throughout much of the world. Fire was already used by hunter-gatherers before the invention of agriculture, and still is in present times. Clearings created by the fire were made for many reasons, such as to provide new growth for game animals and to promote certain kinds of edible plants. During the Neolithic Revolution, groups of hunter-gatherers domesticated various plants and animals, permitting them to settle down and practice agriculture, which provided more nutrition per hectare than hunting and gathering. Some groups could easily plant their crops in open fields along river valleys, but others had forests covering their land. Thus, since Neolithic times, slash-and-burn agriculture has been widely used to clear land to make it suitable for crops and livestock. Large groups wandering in the woodlands was once a common form of society in European prehistory. The extended family burned and cultivated their swidden plots, sowed one or more crops, and then proceeded on to the next plot.

Technique

Slash-and-burn fields are typically used and owned by a family until the soil is exhausted. At this point the ownership rights are abandoned, the family clears a new field, and trees and shrubs are permitted to grow on the former 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, so land is not bought or sold on the open market and land rights are traditional. In slash-and-burn agriculture, forests are typically 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 crops such as rice, maize, cassava, or other staples. This work was once done using simple tools such as machetes, axes, hoes and shovels.

Benefits and drawbacks

This system of agriculture provides millions of people with food and income. It has been ecologically sustainable for thousands of years. Because the leached soil in many tropical regions, such as the Amazon, are nutritionally extremely poor, slash-and-burn is one of the only types of agriculture which can be practiced in these areas. Slash-and-burn farmers typically plant a variety of crops, instead of a monoculture, and contribute to a higher biodiversity due to creating mosaic habitats. The general ecosystem is not harmed in traditional slash-and-burn, aside from a small temporary patch. This technique is most unsuitable for the production of cash crops. A huge amount of land, or a low density of people, is required for slash-and-burn. When slash-and-burn is practiced in the same area too often, because the human population density has increased to an unsustainable level, the forest will eventually be destroyed.

Regionally

South Asia

Tribal groups in the northeastern Indian states of Tripura, Arunachal Pradesh, Meghalaya, Mizoram and Nagaland and the Bangladeshi districts of Rangamati, Khagrachari, Bandarban and Sylhet refer to slash-and-burn agriculture as podu, jhum or jhoom cultivation. The system involves clearing land, by fire or clear-felling, for economically important crops such as upland rice, vegetables or fruits. After a few cycles, the land's fertility declines and a new area is chosen. Jhum cultivation is most often practiced on the slopes of thickly-forested hills. Cultivators cut the treetops to allow sunlight to reach the land, burning the trees and grasses for fresh soil. Although it is believed that this helps fertilize the land, it can leave it vulnerable to erosion. Holes are made for the seeds of crops such as sticky rice, maize, eggplant and cucumber. After considering jhum's effects, the government of Mizoram has introduced a policy to end the method in the state.

Americas

Some American civilizations, like the Maya, have used slash-and-burn cultivation since ancient times. American Indians in the United States also used fire in agriculture and hunting. In the Amazon, many peoples such as the Yanomami Indians also live off the slash and burn method due to the Amazon's poor soil quality.

Northern Europe

Slash-and-burn techniques were used in northeastern Sweden in agricultural systems. In Sweden, the practice is known as svedjebruk. Telkkämäki Nature Reserve in Kaavi, Finland, is an open-air museum where slash-and-burn agriculture is demonstrated. Farm visitors can see how people farmed when slash-and-burn was the norm in the Northern Savonian region of eastern Finland beginning in the 15th century. Areas of the reserve are burnt each year.

Svedjebruk

Svedjebruk is a Swedish and Norwegian term for slash-and-burn agriculture derived from the Old Norse word sviða, which means "to burn". This practice originated in Russia in the region of Novgorod and was widespread in Finland and Eastern Sweden during the Medieval period. It spread to western Sweden in the 16th century when Finnish settlers were encouraged to migrate there by King Gustav Vasa to help clear the dense forests. Later, when the Finns were persecuted by the local Swedes, svedjebruk farming was spread by refugees to eastern Norway, more specifically in the eastern part of Solør, in the area bordering Sweden known as Finnskogen ("the Finnish woods"). The practice also spread to New Sweden in North America. Reinforced by the use of fire in agriculture and hunting by American Indians, it became an important part of pioneering in America.

Description of process

Svedjebruk involved stripping a ring of bark completely around the trunk of coniferous trees like pine or spruce or felling them, allowing them to dry, setting fire to the dried forest and growing crops on the fertile ash-covered soil. The resulting ash was highly fertile, but only for a short period. The clearing was initially planted to rye as soon as the ash had fully settled and sufficiently cooled. When the rain came, it packed the ash around the rye. The rye germinated and grew prolifically, with anywhere from 25 to 100 stalks (or straws), each with multiple grains. Only two tools were required, the axe and the sickle. The axe cut the trees to start the cycle. When the rye had ripened, it was harvested with a sickle, which could reach among the rocks and stumps where a scythe would have been ineffective. In the second and third year the field would be sown with turnips or cabbages. It then might be grazed for several years before being allowed to return to woodland.

Svedjebruk culture

Svedjebruk required felling new forest and burning a new area every year. It was necessary to allow the former fields to regrow with forest for 10–30 years before repeating the cycle. As a result, the dwellings were often many kilometers from the fields. Furthermore, since the process was man-power intensive, extended families tended to work together and live in compact communities. The svedjebruk farming approach required a large area. When forest was plentiful, the Finns were very prosperous. As population grew and restrictions were placed on the forest which could be burned, it became increasingly difficult. By 1710, during the conflict with Sweden, because of their suspect loyalties Norwegian authorities considered expelling them from the border area, but did not do so because it was judged they were too poor to survive if evicted.

<!-- >> >> >> The following content was added by [User:Svedjebruk](https://bliptext.com/articles/user-svedjebruk) (who seems to be an expert on the matter) and soon after removed by a bot, apparently because of Youtube references. Svedjebruk might be a Swedish citizen and his wording seems awkward to me. I add the statements again, invisible to the reader, hoping someone with more of an insight comes along and translates the meaning of these passages into digestible English. >> >> >> Note: all swedish-language terms not found in the english Merriam-Webster dictionary - excluding placenames and the names of people - should be placed inside a language tag: [term]. >> >> >> The heads of swidden family groups or clans (noite) had to have, at all times, an overview of their own clan's activities in order to put together these three parameters to a kind of "rubik-cube", according to their own experiences and conscious thought. The time frame covers the first three cues of removal of the existing vegetation, which is controlled by man. The next three deal with the new vegetation, crops, and regrowth of new forests. The time between harvest and regrowth varies from direct transition to regrowth through a number of years with a second use of swidden (vuoma) to never regrow, i.e. direct transition from the crop (pühä) to a permanent farm place / settlement (Piha). Natural influences noite need only register and take into account in assessment: climate with rain, wind, temperature, drainage conditions, soil type, topography, flora and fauna, but he mastered his seeds brought for planting. Noite coordinate so that all valves within the clans function: technology with adequate treatment of the area at the right time, cutting, burning, and social order. Runic poetry was a faithful helper in the exploitation of past experience and knowledge, and poems thankfully have the ability to survive generations. Swidden cultivation requires a large number of people in the group to survive as an operational unit. It is a complex cycle of synchronized processes performed by individuals and / or groups in binding cooperation. Such production union is often called a clan, extended family, kind, thiod, ätt, or tribe; in Russian plemja, rod; in Persian tauma, and Sanskrit jana, kula-. The village name in today's Finno-Ugric languages is küla. The word küllä is a reinforced yes: those that say yes and agree. Each man in swidden society had significance as a participant in the community, not as a person. Individualism was an unknown phenomenon in this society. Complex cultivation cycles consist of a variety of carefully synchronized tasks, performed by individuals in an intimate partnership. This interaction should be so well established that the individual is synonymous with the community. These sophisticated procedures are perceived badly by outsiders, and in older literature, are often characterized as religious rituals without being given any practical significance. Only rarely have outsiders been able to understand the functional correlation. Swidden cultivation was dependent on that the various procedures were correctly and synchronously executed. Incorrect procedure was disastrous and could not be accepted. So ruled a cult excluding, polytheistic religion. Religion set the bar of worldly knowledge, as well as a communication process where the knowledge was kept alive through constant practical use, and new knowledge was developed and displaced useless routines with new rituals. The code was ruled by the forest, air, and water spiritual beings. Skogsråa / wood nymphs, giants and dwarfs lived in the underworld (allima), and they were given three functions: to help those people who respected and appreciated the forest spirits, to punish those who broke the rules of the forest, and to remind people that in the forest, man is not the boss, and cannot act arbitrarily. Similarly, the air (taevas) and water spirits, (jumal) were both helpers and punishers. # ... Svedjebruk or Slash and burn - shifting cultivation, here means the cultivation of hominids and crops for human consumption on freshly burned vegetation area or forest within a fewer number of years than the time that area is left to natural regeneration (Conklin 1961 27). This is the oldest form of food production as proto humans have developed it over millions of years. During this long span of time, shifting cultivation developed into a complex process, requiring the coordinated interaction of larger groups of people. This way of life can be traced back to Africa and / or China, where the forerunners of Homo erectus (the erect man) had a nascent rise more than five million years ago. Later they spread out across the world, including northern Europe, less than one million years ago. But it is much less than one million years ago that Homo sapiens (the man who knows and can) came from Africa to Eurasia. They were knowledgeable and experienced people already. Shifting cultivation is highly community-forming. The smallest unit was the clan – the cultivation team – and often several clans would cooperate with one another. The manager, or Kuningas, had many functions. It was not only practical, but also political and religious. Cultivation was mobile; the clan moved to new forests to burn and grow food crops. They had no monumental construction. It is therefore difficult to trace them archaeologically, even from the study of Terra Preta (charcoal-rich soil). The swidden ranged from single ones onsite to periodic settlements, punctuated by moderately long abandonment. This rest period was required for necessary forest regrowth. Surveys of mountain caves and other natural settlements have revealed many cultural layers upon one another with natural forest regrowth in between. This stratigraphy indicates cultural development. Here in random order I will mention a few such places: Catalhöyük in Turkey, Altamira in northern Spain, Jericho in Israel, Kostenki Voronezh in Russia, Skara Brea on Orkeney, and the cave Vistehola at Jæren in Norway. Nowadays we are accustomed to excess in stationary conditions. We are trained and raised in the European tradition, which considered shifting cultivation as a simple, primitive form of life without significant cultural organization. This attitude is probably the reason why researchers have thoroughly investigated shifting cultivation. There are many characterizing features of shifting cultivation that are widely considered "primitive" and "self-taught". They were nomads who want to have a few things to carry, for their skill and knowledge was not a heavy load. Shifting cultivation is the foundation of today's society: our values, customs, ideas, and conventions. Arable farming is too young to have influenced the development of mankind's history to any significant degree, yet we still feel its effects in our daily lives. The declining tropical rainforest is the site of most of today's shifting cultivation practices. "The oldest of all farming methods is shifting cultivation. It has been in Sweden since old times and it seems to permeate every subject the further back in time we go. It is the oldest of all cultivation systems, at least in forested areas" (1923 Arenander 99). "Kauran Karjalan ahoille, Rukeheni Ruotsin maalle, -Vehnät viskoan Virohon - Kylvän ohrat Suomen maalle - Hernehet Hämehen maalle - Jost Vilja virtoavi - Vilja vierahan kätehen" (Kaukonen 1984 II, 252); Oats in Karelia svedjer - Rye on Swedish land - Hveat returns Estonia – Barley grows on Suomi fields - peas on Hämä fields, - Here the grain flows, -The grain is always next. -->

Research

This type of agriculture is discouraged by many developmental or environmentalist organisations, with the main alternatives being promoted are switching to more intensive, permanent farming methods, or promoting a shift from farming to working in different, higher-paying industries altogether. Other organisations promote helping farmers achieve higher productivity by introducing new techniques. Not allowing the slashed vegetation to burn completely and ploughing the resultant charcoal into the soil (slash-and-char) has been proposed as way to boost yields. Promoters of a project from the early 2000s claimed that slash-and-burn cultivation could be reduced if farmers grew black pepper crops, turmeric, beans, corn, cacao, rambutan and citrus between Inga trees, which they termed 'Inga alley cropping'. A method of improving the yields in a type of traditional assarting cultivation used to grow common beans in Central American called 'slash-and-cover', has been proposed, by additionally planting leguminous shrubs to act as a fallow crop after the soil is exhausted and one is ready to clear a new patch of forest.

Gallery

General literature

Citations