What are the causes and effects of deforestation?

Answer 1

Environmental effects





Atmospheric pollution

Deforestation is often cited as one of the major causes of the enhanced greenhouse effect. Trees and other plants remove carbon (in the form of carbon dioxide) from the atmosphere during the process of photosynthesis. Both the decay and burning of wood releases much of this stored carbon back to the atmosphere. A.J.Yeomans asserts in Priority One that overnight a stable forest releases exactly the same quantity of carbon dioxide back into the atmosphere. Others state that mature forests are net sinks of CO2 (see Carbon dioxide sink and Carbon cycle).
Wildlife

Some forests are rich in biological diversity. Deforestation can cause the destruction of the habitats that support this biological diversity - thus causing population shifts and extinctions.
Hydrologic cycle and water resources

Trees, and plants in general, affect the hydrological cycle in a number of significant ways:

* their canopies intercept precipitation, some of which evaporates back to the atmosphere (canopy interception);
* their litter, stems and trunks slow down surface runoff;
* their roots create macropores - large conduits - in the soil that increase infiltration of water;
* they reduce soil moisture via transpiration;
* their litter and other organic residue change soil properties that affect the capacity of soil to store water.

As a result, the presence or absence of trees can change the quantity of water on the surface, in the soil or groundwater, or in the atmosphere. This in turn changes erosion rates and the availability of water for either ecosystem functions or human services.

A policy report published in 2005 by the FAO concluded that for south east Asia, deforestation had no discernable effect on the damage incured by large floods[3]. They argued that the extra storage of water in soils, which they termed the "sponge theory", did not impact flooding during the time of year large scale floods occurred. These floods take place at the end of the wet season, when soils are close to saturation.
Soil erosion

Deforestation generally increases rates of soil erosion, by increasing the amount of runoff and reducing the protection of the soil from tree litter. This can be an advantage in excessively leached tropical rain forest soils. Forestry operations themselves also increase erosion through the development of roads and the use of mechanized equipment.

China's Loess Plateau was cleared of forest millennia ago. Since then it has been eroding, creating dramatic incised valleys, and providing the sediment that gives the Yellow River its yellow color and that causes the flooding of the river in the lower reaches (hence the river's nick-name 'China's sorrow').

Removal of trees does not always increase erosion rates. In certain regions of southwest US, shrubs and trees have been encroaching on grassland. The trees themselves enhance the loss of grass between tree canopies. The bare intercanopy areas become highly erodible. The US Forest Service, in Bandelier National Monument for example, is studying how to restore the former ecosystem, and reduce erosion, by removing the trees.
Landslides

Tree roots bind soil together, and if the soil is sufficiently shallow they act to keep the soil in place by also binding with underlying bedrock. Tree removal on steep slopes with shallow soil thus increases the risk of landslides, which can threaten people living nearby.
Alternatives
Produce substitution

A proposed solution to deforestation is to reduce consumption of forest based products. Switching to brick, stone, concrete, fiberglass and plastic for construction, or the use of hemp for paper products are amongst options often considered. However, these options do present their own downsides. Construction materials require fossil fuel derived materials to produce and tend to degrade much more slowly. Conversion of forestlands to agricultural lands to produce hemp can cause deforestation itself. Deforestation can also occur in mining and petroleum exploration.
Farming

Agriculture is one of the primary causes of deforestation. Once forestland is converted to agricultural land it is rarely allowed to regenerate back into forestland. However many farmers are now reforesting their land into tree plantations. Although an intensively managed tree plantation does not fully recreate the biodiversity found in less intensively managed forestlands, it still will provide more biodiversity than a monoculture hemp or potato plantation.

New methods are being developed to farm more food crops on less farm land, such as high-yield hybrid crops, greenhouse, autonomous building gardens, and hydroponics. The reduced farm land is then dependent on massive chemical inputs to maintain necessary yields. In cyclic agriculture, cattle are grazed on farm land that is resting and rejuvenating. Cyclic agriculture actually increases the fertility of the soil. Selective over farming can also increase the nutrients by releasing such nutrients from the previously inert subsoil. The constant release of nutrients from the constant exposure of subsoil by slow and gentle erosion is a process that has been ongoing for billions of years. Slash-and-burn agriculture has recently needed re-evalution as it appears to be more sustainable than originally believed.

Grass is encouraged to grow on the resting farm land. The cows eat the grass and leave behind their dung, which is also a source of fertilizer. This process can reduce deforestation by using farmland to graze instead of using forest land if this is considered advantagious.
Control of deforestation

Efforts to stop or slow deforestation have been attempted for many centuries because it has long been known that deforestation can cause environmental damage sufficient in some cases to cause societies to collapse. In Tonga, paramount rulers developed policies designed to prevent conflicts between short-term gains from converting forest to farmland and long-term problems forest loss would cause, whilst during the seventeenth and eighteenth centuries in Tokugawa Japan the shoguns developed a highly sophisticated system of long-term planning to stop and even reverse deforestation of the preceding centuries through substituting timber by other products and more efficient use of land that had been farmed for many centuries. In sixteenth century Germany landowners also developed silviculture to deal with the problem of deforestation. However, these policies tend to be limited to environments with good rainfall, no dry season and very young soils (through volcanism or glaciation). This is because on older and less fertile soils trees grow too slowly for silviculture to be economic, whilst in areas with a strong dry season there is always a risk of forest fires destroying a tree crop before it matures.

Today, in China, where large scale destruction of forests has occurred, the government has required that every able-bodied citizen between the ages of 11 and 60 plant three to five trees per year or do the equivalent amount of work in other forest services. The government claims that at least 1000 million trees have been planted in China every year since 1982. In western countries, increasing consumer demand for wood products that have been produced and harvested in a sustainable manner are causing forest landowners and forest industries to become increasingly accountable for their forest management and timber harvesting practices.

The Arbor Day Foundation's Rain Forest Rescue program is a charity that helps to prevent deforestation. The charity uses donated money to buy up and preserve rainforest land before the lumber companies can buy it. The Arbor Day Foundation then protects the land from deforestation. This also locks in the way of life of the primitive tribes living on the forest land.
















Causes of deforestation





Agents

Agents of deforestation can be individuals or groups of individuals that are clearing the forest. Commercial farmers, slash and burn farmers, cattle ranches and loggers are all agents of deforestation. Agents are usually acting in their own self interest.
Present Causes

Causes include demand for farm land and fuel wood. Underlining causes include poverty, lack of reform. The causes of deforestation are complex and change over time. Deforestation can be most easily understood by studying the causes for each forest and country separately. Government policies, such as ones in Brazil, make it a priority to resettle some of the country's many landless people.
Theories of deforestation

Three schools of thought exist with regards to the causes of deforestation - the Impoverishment school, which believes that the major cause of deforestation is "the growing number of poor", the Neoclassical school which believes that the major cause is "open-access property rights" and the Political-ecology school which believes that the major cause of deforestation is that the "capitalist investors crowd out peasants". The Impoverishment school sees smallholders as the principal agents of deforestation, the Neoclassical school sees various agents, and the Political-ecology school sees capitalist entrepreneurs as the major agents of deforestation.
History and Historical causes

* See, Timeline of environmental events

Prehistory

Deforestation has been practiced by humans for thousands of years. Fire was first tool that allowed humans to modify the landscape. The first evidence of deforestation shows up in the Mesolithic. Fire was probably used to drive game into more accessible areas. With the advent of agriculture fire became the prime tool to clear land for crops. In Europe there is little solid evidence before 5000 BP. Mesolithic foragers used fire to create openings for red deer and wild boar. On Great Britain shade tolerant species like oak and ash are replaced in the pollen record by hazels, brambles, grasses and nettles. Removal of the forests led to decreased transpiration resulting in the formation of upland peat bogs. Widespread decreased in elm pollen across Europe between 6400-6300 BP and 5200-5000 BP, starting in southern Europe and gradually moving north to Great Britain, may represent land clearing by fire at the onset of Neolithic agriculture.
Pre-industrial history

The historic silting of ports along the southern coasts of Asia Minor (e.g. Clarus, and the examples of Ephesus, Priene and Miletus, where harbors had to be abandoned because of the silt deposited by the Meander) and in coastal Syria during the last centuries BC, and the famous silting up of the harbor for Bruges, which moved port commerce to Antwerp, all follow periods of increased settlement growth (and apparently of deforestation) in the river basins of their hinterlands. In early medieval Riez in upper Provence, alluvial silt from two small rivers raised the riverbeds and widened the floodplain, which slowly buried the Roman settlement in alluvium and gradually moved new construction to higher ground; concurrently the headwater valleys above Riez were being opened to pasturage.

A typical progress trap is that cities are built in a woody area providing wood for some industry (e.g. shipbuilding, pottery) which starts consuming it so fast – and without proper replanting – that it becomes impossible to obtain it close enough to remain competitive, leading to the city's abandonment, as happened repeatedly in Ancient Asia Minor. Especially the combination of mining and metallurgy went along this self-destructive path.

Meanwhile most of the population remaining active in (or indirectly dependend on) the agricultural sector, the main pressure in most areas remained land clearing for crop and cattle farming; fortunately enough wild green was usually left standing (and partially used, e.g. to collect firewood, timber and fruits, or to graze pigs) for wildlife to remain viable, and the hunting privileges of the elite (nobility and higher clergy) often protected significant woodlands.

Major parts in the spread (and thus more durable growth) of the population were played by monastical 'pioneering' (especially by the benedictine and cistercian orders) and some feudal lords actively attracting farmers to settle (and become tax payers) by offering relatively good legal and fiscal conditions – even when they did so to launch or encourage cities, there always was an agricultural belt around and even quite some within the walls. When on the other hand demography took a real blow by such causes as the Black Death or devastating warfare (e.g. Genghis Khan's Mongol hords in eastern and central Europe, Thirty Years' War in Germany) this could lead to settlements being abandoned, leaving land to be reclaimed by nature.

The large-scale building of wooden sail ships by European (coastal) naval owers since the 15th century for exploration, colonization, slave – and other trade on the high seas and (often related) naval warfare (the failed invasion of England by the Spanish Armada in 1559 and the battle of Lepanto 1577 are early cases of huge waste of prime timber; each of Nelson's Royal navy war ships at Trafalgar had required 6000 mature oaks) and piracy meant that whole woody regions were over-harvested, as in Spain, were this contributed to the paradoxical weakening of the domestic economy since Columbus' discovery of America made the colonial activities (plundering, mining, cattle, plantations, trade ...) predominant.

In Changes in the Land (1983), William Cronon collected 17th century New England Englishmen's reports of increased seasonal flooding during the time that the forests were initially cleared, though no connection was made at the time.
Industrial pressure

The massive use of charcoal on an industrial scale was a new acceleration of the onslaught on western forests; even in Stuart England, the relatively primitive production of charcoal has already reached an impressive level. One of the best documented and successful attempts at reforestation was effected by the Prussian government in the mid-19th century to save the Curonian Spit from being engulfed by dunes.
Recent changes

The rate of clearance increased during the second half of the 19th century due to agricultural expansion in Europe. Deforestation rates peaked in New England about 1900 and in the Great Lakes region of the United States in the late 19th century. Rates of tropical deforestation have increased substantially into the post-war period as logging operations became mechanised.

Growing worldwide demand for wood to be used for fire wood or in construction, paper and furniture - as well as clearing land for commercial and industrial development (including road construction) have combined with growing local populations and their demands for agricultural expansion and wood fuel to endanger ever larger forest areas.

Agricultural development schemes in Mexico, Brazil and Indonesia moved large populations into the rainforest zone, further increasing deforestation rates. One fifth of the world's tropical rainforest was destroyed between 1960 and 1990. Estimates of deforestation of tropical forest for the 1990s range from ca. 55,630 km² to ca. 120,000 km² each year. At this rate, all tropical forests may be gone by the year 2090.

Answer 2

Causes And Effects Of Deforestation

Answer 3

Soil erosion Loss of habitat for animals Loss of carbon sink Affects the water table

Answer 4

Causes: trees being cut down

Effects: clear land, changes in the environment

Answer 5

Causes:
1. industrialization
2. migration
3. work

Effects:
1. Loss of habitat - that can never be restored.
2. Depletion of resources for animals.
3. Promotes extinction, and migration away of animals.

Answer 6

Green house effect
Increase in Co2 in atmosphere
Increased pollution
Wash away of top soil (reduce soil fertility)
Decrease in rain fall

Answer 7

Cause - trees getting chopped down

Effect - less trees

Answer 8

Causes:

-Demand for wood for making furniture, paper; building houses
-Demand for timber
-Need to clear forests in order to build roads, expressways to improve country's infrastructure (think Trans-Amazonian Highway)

Effects:
-soil erosion, since the topsoil will be easily washed away without the trees' roots holding on to it
-soil degradation (topsoil which is the most fertile is removed)
-global warming due to lesser trees to take in carbon dioxide and replenish oxygen into the atmosphere (long term)
-desertification, since trees also act as a barrier against sandstorms from expanding arid and sandy regions (Gobi Desert)

Hope it helps! :)

Answer 9

lots of things like loss of habitats... destruction of land since tree's holds the soil together... maybe even more deserts... i dont know man im no biologist

Answer 10

Cause of deforestation by

1) Conversion of forests and woodlands to agricultural land to feed growing numbers of people...

2) Development of cash crops and cattle ranching, both of which earn money for tropical countries...

3) Commercial logging (which supplies the world market with woods such as meranti, teak, mahogany and ebony) destroys trees as well as opening up forests for agriculture...

4) Felling of trees for firewood and building material; the heavy lopping of foliage for fodder; and heavy browsing of saplings by domestic animals like goats...


Effect of deforestation

1) Alteration of local and global climates through disruption of:
a) The carbon cycle. Forests act as a major carbon store because carbon dioxide (CO2) is taken up from the atmosphere and used to produce the carbohydrates, fats, and proteins that make up the tree. When forests are cleared, and the trees are either burnt or rot, this carbon is released as CO2. This leads to an increase in the atmospheric CO2 concentration. CO2 is the major contributor to the greenhouse effect. It is estimated that deforestation contributes one-third of all CO2 releases caused by people...
b) The water cycle. Trees draw ground water up through their roots and release it into the atmosphere (transpiration). In Amazonia over half of all the water circulating through the region's ecosystem remains within the plants. With removal of part of the forest, the region cannot hold as much water. The effect of this could be a drier climate...

2) Soil erosion With the loss of a protective cover of vegetation more soil is lost...

3) Silting of water courses, lakes and dams This occurs as a result of soil erosion...

4) Extinction of species which depend on the forest for survival. Forests contain more than half of all species on our planet - as the habitat of these species is destroyed, so the number of species declines...

5) Desertification The causes of desertification are complex, but deforestation is one of the contributing factors...