Afforestation
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Afforestation
"We will defeat the drought, too!". A late-1940s Soviet poster showing Marshal Stalin over a map of the national afforestation program. The map shows forest strips to be planted in the steppes of southern Russia. The term reforestation generally refers to the reestablishment of the forest after its removal, or planting more trees for example from a timber harvest. Since the industrial revolution many countries have experienced centuries of deforestation, and some governments and non-governmental organisations directly engage in programs of afforestation to restore forests and assist in preservation of biodiversity. The United States and northwestern Europe have more forest cover than at the beginning of the twentieth century.[1] However, significant deforestation in South and Central America and in South Asia still continues.
Afforestation in areas of degraded soilIn various arid, tropical, or sensitive areas, forests cannot re-establish themselves without assistance due to a variety of environmental factors. One of these factors is that, once forest cover is destroyed in arid zones, the land quickly dries out and becomes inhospitable to new tree growth. Other critical factors include overgrazing by livestock, especially animals such as goats, and over-harvesting of forest resources. Together these may lead to desertification and the loss of topsoil; without soil, forests cannot grow until the very long process of soil creation has been completed - if erosion allows this. In some tropical areas, the removal of forest cover may result in a duricrust or duripan that effectively seal off the soil to water penetration and root growth. In many areas, reforestation is impossible above all because the land is in use by people. In these areas, reforestation requires the planting of tree seedlings, treeplanting. In other areas, mechanical breaking up of duripans or duricrusts is necessary, careful and continued watering may be essential, and special protection, such as fencing, may be required. World regionsBrazilBecause of the extensive Amazon deforestation during the last several decades and ongoing,[2] the small efforts of afforestation are insignificant on a national scale of the Amazon Rainforest.[3] ChinaChina has deforested the majority of its historical wooded areas. Although it has set official goals for re-forestation, these goals were set for a 80 year time horizon and are not significantly met by 2008. China has reached the point where timber yields have declined far below historic levels, due to overharvesting of trees beyond sustainable yield.[4] At present however, China is trying to erase its sins of the past by projects as the Green Wall of China, which aims to replant a great deal of forests and halt the expansion of the Gobi desert. EuropeThe European Union has paid farmers for afforestation since 1990, offering grants to turn farmland back into forest and payments for the management of forest. Between 1993 and 1997, EU afforestation policies made possible the re-forestation of over 5,000 square kilometres of land. A second program, running between 2000 and 2006, afforested in excess of 1000 square kilometres of land (precise statistics not yet available). A third such program began in 2007. IranIran is considered a low forest cover region of the world with present cover approximating seven percent of the land area. This is a value reduced by an estimated six million hectares of virgin forest, which includes oak, almond and pistacio.[5] Due to the soil substrates that exist in Iran, it is difficult to achieve afforestation on a large scale compared to other temperate areas endowed with more fertile and less rocky and arid soil conditions.[5] Consequently, most of the afforestation is conducted with non-native species,[5] leading to habitat destruction for native flora and fauna, and resulting in an accelerated loss of biodiversity.[2] See alsoLine notesReferences
de:Aufforstung bs:Po?umljavanje es:Forestación hr:Po?umljavanje nl:Bebossing ja:????
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