Afforestation offers many climate-related benefits. Several new studies suggest that forests attract rain, which may explain why drought is more common in some parts of the world, such as West Africa, where trees are more sparse. [14] A 2017 study provides the first observational evidence that the southern Amazon rainforest triggers its own rainy season with water vapor from plant leaves, which then forms clouds above it. [15] These results help explain why deforestation in this region is associated with lower rainfall. A 2009 study hypothesizes that forest cover plays a much larger role in determining precipitation than previously thought. [16] It explains how forest regions generate large-scale streams in atmospheric water vapor and highlights the benefits of afforestation in currently barren regions of the world. Iran is considered a region with low forest cover in the world with a current cover of about seven percent of the earth`s land area. This is a value that has been reduced to about six million hectares of virgin forest, which includes oaks, almonds and pistachios. Due to soil substrates, it is difficult to achieve large-scale afforestation compared to other temperate zones with more fertile soil conditions and less rocky and dry. According to the specific statistics of the Iranian Forest, Rangeland and Watershed Management Organization, many afforestations have been carried out each year using appropriate methods and native tree species in each region, which has resulted in greater natural stability.
According to statistics from the Food and Agriculture Organization of the United Nations, Spain recorded the third fastest afforestation rate in Europe between 1990 and 2005, after Iceland and Ireland. During these years, a total of 44,360 square kilometres were reforested and the total forest area increased from 13.5 to 17.9 million hectares. In 1990, forests covered 26.6% of Spain`s territory. By 2007, this figure had risen to 36.6 per cent. Spain now has the fifth largest forest area in the European Union. With more than 240 million trees planted, Israel is one of only two countries to enter the 21st century with a net gain in trees thanks to massive reforestation efforts. Most of Israel`s forests are the product of a major reforestation campaign led by the Jewish National Fund (JNF). [Citation needed] Afforestation is the establishment of a forest or tree population (afforestation) in an area where there was no previous forest cover. Many governmental and non-governmental organizations are directly involved in reforestation programmes aimed at creating forests and increasing carbon capture.
Afforestation is an increasingly sought-after method to combat climate problems, as it is known to improve soil quality and soil organic carbon content and avoid desertification. The maximum amount of CO2 that could be removed from the atmosphere through afforestation depends on the amount of land devoted to afforestation and reforestation. The annual rate of carbon sequestration could reach up to 3.6 billion tonnes of carbon dioxide (GtCO2) per year by mid-century and up to 7 GtCO2 by 2100, equivalent to a total cumulative sequestration of 80 to 260 GtCO2. Afforestation is the conversion of abandoned and degraded agricultural land into forests, while reforestation is the reintroduction of trees on deforested land. Both practices can contribute to negative emissions because the growth of additional plants binds atmospheric CO2 and naturally sinks it into their biomass and soil. Ni et al. [56] estimated that an average of 2 to 2.5 Gt C/year could be stored in the global forest, with a higher contribution from tropical forests. Humpenöder et al. [60] found that large-scale afforestation could lead to a cumulative distance of more than 189 Gt C by 2095. Significant afforestation programmes have been carried out and in 2010 the wooded area was over 264 Mha (1 Mha = 106 ha). In China, existing reforestation projects increased forest area by 2 Mha/year in the 1990s and have increased to 3 Mha/year since 2000. This resulted in a total reduction in emissions estimated at 4.4 Mt CO2 equivalent.