Agriculture and Current Deforestation Practices

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.[1] 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.[2][3] 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.[4] History

Historically, slash-and-burn cultivation was practiced throughout much of the world, in grasslands as well as woodlands. 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.[5]

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, and other such basic tools. [edit] 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.[6] 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.[7] 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. [edit] 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.[8] [edit] 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.[9] 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.[10] [edit] 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.[6] [edit] Ecological implications

Effects of slash-and-burn on primary forest can be devastating. Seen in this photo is a patch of forest in Namdapha National Park in Northeast India cleared for Jhum cultivation. 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.[citation needed] 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.

Slash and Burn Agriculture
Slash and Burn Can Contribute to Envirnonmental Problems
From Colin Stief, Geography Intern
http://geography.about.com/od/urbaneconomicgeography/a/slashburn.htm

Slash and burn agriculture is the process of cutting down the vegetation in a particular plot of land, setting fire to the remaining foliage, and using the ashes to provide nutrients to the soil for use of planting food crops. The cleared area following slash and burn, also known as swidden, is used for a relatively short period of time, and then left alone for a longer period of time so that vegetation can grow again. For this reason, this type of agriculture is also known as shifting cultivation. Generally, the following steps are taken in slash and burn agriculture: 1. Prepare the field by cutting down vegetation; plants that provide food or timber may be left standing. 2. The downed vegetation is allowed to dry until just before the rainiest part of the year to ensure an effective burn. 3. The plot of land is burned to remove vegetation, drive away pests, and provide a burst of nutrients for planting. 4. Planting is done directly in the ashes left after the burn. Cultivation (the preparation of land for planting crops) on the plot is done for a few years, until the fertility of the formerly burned land is reduced. The plot is left alone for longer than it was cultivated, sometimes up to 10 or more years, to allow wild vegetation to grow on the plot of land. When vegetation has grown again, the slash and burn process may by repeated. Geography of Slash and Burn Agriculture

Places where open land for farming is not readily available because of dense vegetation are the places where slash and burn agriculture is practiced most often. These regions include central Africa, northern South America, and Southeast Asia, and typically within grasslands and rainforests. Slash and burn is a method of agriculture primarily used by tribal communities for subsistence farming (farming to survive). Humans have practiced this method for about 12,000 years, ever since the transition known as the Neolithic Revolution, the time when humans stopped hunting and gathering and started to stay put and grow crops. Today, between 200 and 500 million people, or up to 7% of the world’s population, uses slash and burn agriculture. When used properly, slash and burn agriculture provides communities with a source of food and income. Slash and burn allows for people to farm in places where it usually is not possible because of dense vegetation, soil infertility, low soil nutrient content, uncontrollable pests, or other reasons. Negative Aspects of Slash and Burn

Many critics claim that slash and burn agriculture contributes to a number of reoccurring problems specific to the environment. They include: •Deforestation: When practiced by large populations, or when fields are not given sufficient time for vegetation to grow back, there is a temporary or permanent loss of forest cover. •Erosion: When fields are slashed, burned, and cultivated next to each other in rapid succession, roots and temporary water storages are lost and unable to prevent nutrients from leaving the area permanently. •Nutrient Loss: For the same reasons, fields may gradually lose the fertility they once had. The result may be desertification, a situation in which land is infertile and unable to support growth of any kind. •Biodiversity Loss: When plots of land area cleared, the various plants and animals that lived there are swept away. If a particular area is the only one that holds a particular species, slashing and burning could result in extinction for that species. Because slash and burn agriculture is often practiced in tropical regions where biodiversity is extremely high, endangerment and extinction may be magnified. The negative aspects above are interconnected, and when one happens, typically another happens also. These issues may come about because of irresponsible practices of slash and burn agriculture by a large amount of people. Knowledge of the ecosystem of the area and agricultural skills could prove very helpful in the safe, sustainable use of slash and burn agriculture.

Alternative Strategy: Middle and Senior School Potential

Following are two readings taken from the Internet case study of deforestation in one area of the world, the Amazon region of Brazil. Reproduce the articles and distribute to students. The goal of the lesson is to try to help students understand the relationship between the effects of deforestation in one area, with the larger issues of global implications. A basic chart form designating LOCAL IMPACT and GLOBAL IMPACT might be organized around the major scientific and economic findings. Discuss the Amazonian example, clearly using geographic location, scientific information, and human interactions as keys to helping students to understand the basic notion of deforestation. Then, using the reading concerning ALTERNATIVES, have students weigh the theoretical and practical aspects of the alternatives, from the points of view of the various interested parties in Brazil, as well as those from other areas of the world concerned about the broader global implications.

Reading I
Amazon Deforestation and Global Environmental Phenomena
Over half of the world’s tropical rain forests have already been destroyed, most of which are in Brazil, and they are continuing to be destroyed today (Domroes, 1991). When the topic of tropical rain forest destruction is raised it usually brings to mind issues of biodiversity and hidden cures for cancer, both of which are important reasons to end deforestation. However, one issue which is often left out is the tropical rain forests’ part in global climate and the greenhouse effect. This is an issue which surpasses regional boundaries, that effects the atmosphere as well the biosphere. Causes of Deforestation

Tropical forests are destroyed for several reasons, each of which have both similar and differing ecological consequences, none of which are beneficial. There is an ever increasing demand for both farm and grazing land which results in the burning and clearing of rain forests for agriculture production. Another cause of deforestation is the continued urbanization of the world and thus the need for construction of roads and industrialization. The need for fuel and timber for construction is another major factor leading to the destruction of the rain forest (Domries, 1991 and Salati, 1991). Effects of Deforestation

The actual extent of the role that the rain forest and its subsequent deforestation play in global climate and its changes is difficult to gauge. This is one reason why there has been a lack of media coverage about the subject outside of the scientific community. There are numerous variables involved in changing weather patterns such as global warming and only recently have we begun to develop sufficient computer simulation models, such as those used in Shukla’s article done at the Center for Ocean-Land-Atmosphere Interactions at the University of Maryland, to accurately predict what affect one regions climate will have on another region’s. Another problem is that each model and each scientist is set towards a different agenda which can often lead to different results. These differing statistics lend themselves to a great deal of debate about numbers rather than issues, slowing down the scientists and communities ability to act. Despite this, there are certain truths which cannot be ignored, whether the figures are varied or not.

Carbon dioxide accounts for at least one half of the greenhouse effect, in which atmospheric gases, mostly produced by human activities, trap the sun’s heat, slowly warming the Earth (Myers,1991). Deforestation by burning accounts for up to 25% of the annual global CO 2 emissions (Salati, 1991). Trees are half carbon and by burning them we release all of that carbon into the atmosphere. At least three-quarters of deforestation in the tropics is due to burning, which releases about 2.4 billion tons of CO 2 into the atmosphere each year (Myers, 1991). The greenhouse effect will have several affects on global ecology, one of which is rising sea levels due to things such as the melting of several large glaciers. This could affect coastal communities through more frequent flooding and increased soil salinity (IUCC, 1993). As well, there could be implications for the organisms which live in the sea, especially if the warming of the atmosphere leads to a subsequent warming of ocean temperatures.

According to the Information Unit on Climate Change, a change in climate caused by greenhouse gases would have great affects on future agriculture as well. (1993) The other affects of deforestation on climate are more regional but no less important. Several different models and studies indicate that deforestation will lead to a reduction in average rainfall and increased surface temperature (Hastenrath, 1991 and Shukla, 1990). Because the top soil in rain forests is so thin, it lends itself to rapid soil erosion. Without the trees there to act as a buffer between the soil and the rain, erosion is practically inevitable. Soil erosion then leads to greater amounts of run off and increased sedimentation in the rivers and streams. The combination of these factors leads to flooding and increased salinity of the soil (Domries,1991 and Hastenroth,1991). Solutions and Conclusions

While rain forest destruction has been slowed during the last decade it still continues at an alarming rate and needs to be discontinued entirely. Scientists have begun to show that reforestation can actually decrease the patterns of global warming by fixing the carbon dioxide in the atmosphere (Myers,1991). A great deal of research still needs to be done on these aspects of deforestation as well as the interaction of the varying regions on global climate but preliminary studies such as those done by Shukla and Myers show that it should be one of our major concerns today and that we need to research feasible solutions to these problems. Source:

http://biology.uoregon.edu/classes/bi130/webprojects/31 /article3.html 5/18/99
Reading II
Alternatives to Deforestation in the Amazon Basin
The forest is one of the most complex and least understood ecosystems on our planet. The forests of the world are our greatest storehouse of biological diversity. They also regulate climate, protect the soil, act as watersheds for some of the worlds major aquatic systems, and provide habitat for an incredible variety of organisms ranging from fish to human beings. Several million acres of tropical forest are destroyed each year with great repercussions for all organisms within the complex forest web of life. Current deforestation practices, such as converting rainforests into pastures and fields, along with clear cutting for timber, yield higher net revenues than those that can be obtained by sustainable harvesting of natural forest products. Our current perception is that with the exception of a few specific goods, the rain forest has little economic value. The question is how to change this perception in order to promote sustainability and further development of the various organisms within the rainforest. In the following pages I will present several solutions that can help sustain biological diversity while yielding comparable or better revenues than that of current deforestation practices.

Rainforest trees are hosts to produce, fruits, spices, edible oils, medicines, and fibers. They also produce a wide assortment of industrial compounds such as latex, rubber, dyes, and resins. Only a few rain forest products are traded on the international market, products like Brazil nuts, rubber, rattan, and illie oil (an important ingredient in cocoa butter and cosmetics). Most of these products are harvested for sustainability and trade in local markets. These products should be introduced to international markets with the other products that are already traded internationally. “Based on an assumption of sustainable harvest and annual fruit and latex collections, we estimate that the combined financial worth of the tree resources growing in one hectare of rain forest at Mishana is almost $7000. Surprisingly, this result is more than three times the net recent value of a fully stocked cattle pasture in the amazon and almost twice that of an intensely managed timber plantation.

Far from being a worthless tangle of vegetation that must be eliminated to yield profit, sustainable forest exploitation at Mishana would actually generate higher net revenues than almost any other type of land use (Peters, 1990).” Many local people in Amazonia depend on agriculture for their livelihood, but most of them practice unsustainable agriculture. If there is to be any restoration of the biological diversity of a watershed area we must incorporate more productive and sustainable agricultural systems that benefit both villagers and other organisms that share the ecosystem. Examples of more productive agricultural systems: Contour Farming/Alley-cropping where slash and burn farming permitted one or two harvests every eight years, contour planting of “Alley-Crops” between hedgerows of trees permits continuous farming of the land, with much higher annual yields. The farmer gets this productivity sustainability, without additional expense for commercial fertilizer or other chemicals. One acre produces eight times as much per year as before. Confinement Rearing where open grazing supported one cow on eight acres of fragile hillsides, confinement rearing that includes forage trees allows one acre to support as many as twenty cattle, increasing the growth rates of the animals three times!

The animals themselves are kept of the land so that desertification is avoided. Family Woodlots where “looping” of trees for firewood and forage required an average of fifty working hours per household per week and rapidly destroyed the forests, fast growing fuel wood trees allow a continuous harvest of firewood sufficient for family needs, on a small area of untillable land at the family homesite. Watershed Improvement where upland springs failed as the forest were cleared, planting wood lots above the springs permits a return of wildlife and native tree species and, within two years, can bring a spring back to life. (New Forest Project, 1989) These alternative systems can help preserve the aquatic systems and land organisms of the rain forest, by reducing pressure on the land caused by human consumption. After these practices are implemented the natural forces of mother nature can take over. After all no one can plant trees better than mother nature, especially if she has a little help.

http://www.globaled.org/issues/152/d.html
4.Biosphere
Deforestation disrupts the plant and animal kingdoms. As birds, insects and other animals help with the pollination of plants and the dispersal of seeds, the loss of bird and animal species as a result of decreasing habitats, results in less pollination and there is therefore less regeneration of the forest: fewer plants are pollinated, so fewer seeds are created. As a result there are fewer seeds to disperse, and therefore fewer new plants grow. Although all the consequences of deforestation are potentially serious, perhaps the most serious consequence is that of climate change due to the loss of trees. The earth has an atmosphere which contains a variety of gases in a delicate balance in order to sustain life. If this balance changes, then the earth is affected in different ways: one of this is the “greenhouse” effect, which is the heating of the earth due to more greenhouse gases being released into the atmosphere. This increase in the “greenhouse” gas levels in the atmosphere leads to an increase in temperature, with the possible outcomes of changing weather patterns, rising sea levels and changes in other cycles in nature that directly affect life on the earth. One of the greenhouse gases in the earth’s atmosphere is carbon dioxide. Other gases include methane, chlorofluorocarbons, nitrous oxide, and ozone.

The process whereby the carbon dioxide levels increase is quite simple and these levels increase for a number of reasons. It is believed by some scientists that one of the main factors contributing to the increase of carbon levels is the decay of woody material. The only way to help moderate the levels of carbon dioxide in the atmosphere is through plant life. Living plants and trees absorb the carbon dioxide from decaying plants and trees. With a reduction in tree and plant life (due to deforestation), it is much harder to moderate these levels. Ultimately, the amount of carbon in the atmosphere will increase due to a lack of plant life which would otherwise have kept the carbon dioxide levels in check. The effects of deforestation are far-reaching and can be irreversible if not stopped.

http://wikieducator.org/Deforestation/Effects/Teacher_Notes

Deforestation
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“Deforest” redirects here. It is not to be confused with De Forest or DeForest. Deforestation, clearance or clearing is the removal of a forest or stand of trees where the land is thereafter converted to a non-forest use.[1] Examples of deforestation include conversion of forestland to farms, ranches, or urban use. About half of the world’s original forests had been destroyed by 2011, the majority during the previous 50 years.[citation needed] Since 1990 half of the world’s rain forests have been destroyed.[citation needed] More than half of the animal and plant species in the world live in tropical forests.[2]

The term deforestation is often misused to describe any activity where all trees in an area are removed.[not in citation given][neutrality is disputed] However in temperate climates, the removal of all trees in an area[not in citation given]—in conformance with sustainable forestry practices—is correctly described as regeneration harvest.[3] In temperate mesic climates, natural regeneration of forest stands often will not occur in the absence of disturbance, whether natural or anthropogenic.[4] Furthermore, biodiversity after regeneration harvest often mimics that found after natural disturbance, including biodiversity loss after naturally occurring rainforest destruction.[5][6] Deforestation occurs for many reasons: trees are cut down to be used or sold as fuel (sometimes in the form of charcoal) or timber, while cleared land is used as pasture for livestock, plantations of commodities and settlements.

The removal of trees without sufficient reforestation has resulted in damage to habitat, biodiversity loss and aridity. It has adverse impacts on biosequestration of atmospheric carbon dioxide. Deforestation has also been used in war to deprive an enemy of cover for its forces and also vital resources. A modern example of this was the use of Agent Orange by the United States military in Vietnam during the Vietnam War. Deforested regions typically incur significant adverse soil erosion and frequently degrade into wasteland. Disregard or ignorance of intrinsic value, lack of ascribed value, lax forest management and deficient environmental laws are some of the factors that allow deforestation to occur on a large scale. In many countries, deforestation, both naturally occurring and human induced, is an ongoing issue. Deforestation causes extinction, changes to climatic conditions, desertification, and displacement of populations as observed by current conditions and in the past through the fossil record.[5] Among countries with a per capita GDP of at least US$4,600, net deforestation rates have ceased to increase.[when?][7][8] [edit] Causes

According to the United Nations Framework Convention on Climate Change (UNFCCC) secretariat, the overwhelming direct cause of deforestation is agriculture. Subsistence farming is responsible for 48% of deforestation; commercial agriculture is responsible for 32% of deforestation; logging is responsible for 14% of deforestation and fuel wood removals make up 5% of deforestation.[9] Experts do not agree on whether industrial logging is an important contributor to global deforestation.[10][11] Some argue that poor people are more likely to clear forest because they have no alternatives, others that the poor lack the ability to pay for the materials and labour needed to clear forest.[10] One study found that population increases due to high fertility rates were a primary driver of tropical deforestation in only 8% of cases.[12] Other causes of contemporary deforestation may include corruption of government institutions,[13][14] the inequitable distribution of wealth and power,[15] population growth[16] and overpopulation,[17][18] and urbanization.[19] Globalization is often viewed as another root cause of deforestation,[20][21] though there are cases in which the impacts of globalization (new flows of labor, capital, commodities, and ideas) have promoted localized forest recovery.[22]

In 2000 the United Nations Food and Agriculture Organization (FAO) found that “the role of population dynamics in a local setting may vary from decisive to negligible,” and that deforestation can result from “a combination of population pressure and stagnating economic, social and technological conditions.”[16] The degradation of forest ecosystems has also been traced to economic incentives that make forest conversion appear more profitable than forest conservation.[23] Many important forest functions have no markets, and hence, no economic value that is readily apparent to the forests’ owners or the communities that rely on forests for their well-being.[23] From the perspective of the developing world, the benefits of forest as carbon sinks or biodiversity reserves go primarily to richer developed nations and there is insufficient compensation for these services.

Developing countries feel that some countries in the developed world, such as the United States of America, cut down their forests centuries ago and benefited greatly from this deforestation, and that it is hypocritical to deny developing countries the same opportunities: that the poor shouldn’t have to bear the cost of preservation when the rich created the problem.[24] Some commentators have noted a shift in the drivers of deforestation over the past 30 years.[25] Whereas deforestation was primarily driven by subsistence activities and government-sponsored development projects like transmigration in countries like Indonesia and colonization in Latin America, India, Java, and so on, during late 19th century and the earlier half of the 20th century. By the 1990s the majority of deforestation was caused by industrial factors, including extractive industries, large-scale cattle ranching, and extensive agriculture.