Many government and non-governmental organizations directly engage in programs of afforestation to create forests, increase carbon capture and carbon sequestration, and help to anthropogenically improve biodiversity.
Gap dynamics is the pattern of plant growth that occurs following the creation of a forest gap, a local area of natural disturbance that results in an opening in the canopy of a forest. Gap dynamics are a typical characteristic of temperate and tropical forests, and have a wide variety of causes and effects on forest life.
In some places, forests need help to reestablish themselves because of environmental factors. For example, in arid zones, once forest cover is destroyed, the land may become dry and inhospitable for the growth of new trees. Other factors include overgrazing by livestock, especially animals such as goats, cows, and over-harvesting of forest resources. Together these may lead to desertification and the loss of topsoil; without soil, forests cannot grow until the long process of soil creation has been completed - if erosion allows this. In some tropical areas, forest cover removal 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 because people are using the land. 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 needed.
Several new studies suggest that forests attract rain and this may explain why drought is occurring more frequently in parts of the world such as western Africa. A new study by Carol Rasmussen, NASA's Jet Propulsion Laboratory gives the first observational evidence that the southern Amazon rain forest triggers its own rainy season using water vapor from plant leaves. The finding helps explain why deforestation in this region is linked with reduced rainfall. A study by Douglas Sheil and Daniel Murdiyarso hypothesises that forest cover plays a much greater role in determining rainfall than previously recognized. It explains how forested regions generate large-scale flows in atmospheric water vapor. Makarieva and Gorshkov have developed a hypothesis to explain how forests attract moist air and increase rainfall in area covered by trees.
In Adelaide, South Australia (a city of 1.3 million as of June 2016), Premier Mike Rann (2002 to 2011) launched an urban forest initiative in 2003 to plant 3 million native trees and shrubs by 2014 on 300 project sites across the metro area.Thousands of Adelaide citizens have participated in community planting days on sites including parks, reserves, transport corridors, schools, water courses and coastline. Only Native trees were planted to ensure genetic integrity. He said the project aimed to beautify and cool the city and make it more liveable; improve air and water quality and reduce Adelaide's greenhouse gas emissions by 600,000 tonnes of C02 a year.
There is also ongoing afforestation effort in Brazil. In an afforestation hotspot outlined in Para, Brazil, 1 billion trees are intended to be planted to restore deforested lands by 2013.
China has deforested most of its historically wooded areas. China reached the point where timber yields declined far below historic levels, due to over-harvesting of trees beyond sustainable yield. Although it has set official goals for reforestation, these goals are set over an 80-year time horizon and have not been significantly met by 2008. China is trying to correct these problems by projects like the Green Wall of China, which aims to replant a great deal of forests and halt the expansion of the Gobi desert. The Green Wall of China Project has historical precedences dating back to before the Common Era. However, in pre-modern periods, government sponsored afforestation projects along the historical frontier regions were mostly for military fortification.
A law promulgated in 1981 requires that every school student over the age of 11 plants at least one tree per year. As a result, China has the highest afforestation rate of any country or region in the world, with 47,000 square kilometers of afforestation in 2008. However, the forest area per capita is still far lower than the international average.
According to Carbon Brief, China planted the largest amount of new forest out of any country between 1990 and 2015, facilitated by the country's Grain for Green programme started in 1999, by investing more than $100bn in afforestation programmes and planting more than 35bn trees across 12 provinces. By 2015, the amount of planted forest in China covered 79m hectares.
From 2011-2016, the city Dongying in Shandong province forested over 13,800 hectares of saline soil through the Shandong Ecological Afforestation Project, which was launched with support from the World Bank. In 2017, the Saihanba Afforestation Community won the UN Champions of the Earth Award in the Inspiration and Action category for "transforming degraded land into a lush paradise".
Europe has deforested the majority of its historical forests. The European Union (EU) 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 more than 1000 square kilometres of land (precise statistics not yet available). A third such program began in 2007. Europe's forests are growing by 0.8 million a year thanks to these programmes.
According to Food and Agriculture Organization statistics, Spain had the third fastest afforestation rate in Europe in the 1990-2005 period, after Iceland and Ireland. In those years, a total of 44,360 square kilometers were afforested, and the total forest cover rose from 13,5 to 17,9 million hectares. In 1990, forests covered 26.6% of the Spanish territory. As of 2007, that figure had risen to 36.6%. Spain today has the fifth largest forest area in the European Union.
In January 2013 the UK government set a target of 12% woodland cover in England by 2060, up from the then 10%. In Wales the National Assembly for Wales has set a target of 19% woodland cover, up from 15%. Government-backed initiatives such as the Woodland Carbon Code are intended to support this objective by encouraging corporations and landowners to create new woodland to offset their carbon emissions. Charitable groups such as Trees for Life (Scotland) also contribute to afforestation and reforestation efforts in the UK.
Alpine and Subalpine regions have undergone a lot of deforestation and then forestation in the last 300 years. Out of this has emerged much practical experience. One example is the clustered group, which is a method to bring in stable age mixed tree communities.
Since the founding of the crown colony in the 19th century, afforestation has taken place to prevent soil erosion in the catchment areas of the reservoirs that were built. During the Japanese occupation in the Second World War, the countryside was deforested as the remaining population required fuel to survive. Most of the trees were cut down and extensive reafforestation was carried out after the war. Trees that were planted are mostly non-native species, such as: Pinus massoniana, Acacia confusa (Formosan acacia), Lophostemon confertus and the Paper Bark Tree.
According to the NASA study, China and India have led in increasing the Earth's greenery over the past two decades. In 1950 around 40.48 million hectares was covered by forest. In 1980 it increased to 67.47 million hectares and in 2006 it was found to be 69 million hectares. 23% of India is covered by forest. In 2018, the total forest and tree cover in India increased to 24.39% or 8,02,088 km2. The forests of India are grouped into 5 major categories and 16 types based on biophysical criteria. 38% of the forest is categorized as subtropical dry deciduous and 30% as tropical moist deciduous and other smaller groups. Only local species are planted in an area. Trees bearing fruits are preferred wherever possible due to their function as a food source.
On Thursday, 29 August 2019, Prime Minister of India Mr. Narendra Modi released ₹47, 436 crores (over 6.6 Bn USD) to various states for compulsory afforestation activities. The funds can be used for treatment of catchment areas, assisted natural generation, forest management, wildlife protection and management, relocation of villages from protected areas, managing human-wildlife conflicts, training and awareness generation, supply of wood saving devices and allied activities. Increasing the tree cover would help in creating additional carbon sink to meet the nation's Intended Nationally Determined Contribution (INDC) of 2.5 to 3 billion tonnes of carbon dioxide equivalent through additional forest and tree cover by the year 2030 - part of India's efforts to combat climate change. The Maharashtra government planted almost 20,000,000 saplings in the entire state, and will pledge to plant another 30,000,000 next year. According to The Telegraph, the Indian government has attributed $6.2 billion for tree-planting in order to increase “forestation in line with agreements made at the Paris climate change summit in 2015.” The Indian government has also passed the CAMPA (Compensatory Afforestation Fund Management and Planning Authority) law, which will allow about 40 thousand crores rupees (almost $6 Billion) will go to Indian states for planting trees.
Iran 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 pistachio. Due to soil substrates, 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. Consequently, most of the afforestation is conducted with non-native species, leading to habitat destruction for native flora and fauna, and resulting in an accelerated loss of biodiversity.[page needed]
With over 240 million planted trees, Israel is one of only two countries that entered the 21st century with a net gain in the number of trees, due to massive afforestation efforts. Most Israeli forests are the product of a major afforestation campaign by the Jewish National Fund (JNF).
Critics argue that many JNF lands inside the West Bank were illegally confiscated from Palestinian refugees, and that the JNF furthermore should not be involved with lands in the West Bank. Shaul Ephraim Cohen has claimed that trees have been planted to restrict Bedouin herding. Susan Nathan wrote that forests were planted on the site of abandoned Arab villages after the 1948 war.
Afforestation projects in Japan started after the rebuilding that followed World War II, when large areas of forest were clear-cut for timber and to create pastures to attract immigrant farmers. A new management plan for the forests of Japan was instated after many pastures were abandoned and there was a recognized decline of old growth and secondary forests.
Many African countries that border the Sahara desert are cooperating on the Great Green Wall project. The $8-billion project intends to restore 100 million hectares of degraded land by 2030.
Also in North Africa, the Sahara Forest Project coupled with the Seawater greenhouse has been proposed. Some projects have also been launched in countries as Senegal to revert desertification. As of 2010, African leaders are discussing the combining of national resources to increase effectiveness. In addition, other projects as the Keita Project in Niger have been launched in the past, and have been able to locally revert damage done by desertification. See Development aid#Effectiveness
As Turkey was deforested over the past few thousand years some authors refer to the restoration of these forests as "afforestation" and some "reforestation". In Turkish "ağaçlandırma" can mean either of these or "forestation". So for readability the process is all described in the reforestation article.
The United States is roughly one-third covered in forest and woodland. Nevertheless, areas in the US were subject to significant tree planting. In the 1800s people moving westward encountered the Great Plains – land with fertile soil, a growing population and a demand for timber but with few trees to supply it. So tree planting was encouraged along homesteads. Arbor Day was founded in 1872 by Julius Sterling Morton in Nebraska City, Nebraska. By the 1930s the Dust Bowl environmental disaster signified a reason for significant new tree cover. Public works programs under the New Deal saw the planting of 18,000 miles of windbreaks stretching from North Dakota to Texas to fight soil erosion (see Great Plains Shelterbelt).
At their summit in Copenhagen in 2009, organised by the UK based The Climate Group, leaders of subnational governments – states, regions and provinces – unanimously supported a recommendation by Premier Rann to plant one billion trees across their varied jurisdictions. The initiative was strongly supported by leaders present including Quebec Premier Jean Charest, California Governor Arnold Schwarzenegger and Scottish First Minister Alex Salmond. At a subsequent meeting in Rio de Janeiro in June 2012, The Climate Group announced that it had already received commitments by member governments to plant more than 500 million trees.
The use of afforestation as strategy of conservation of forest biomes is seen as a menace to the conservation of natural grassland and savanna biomes, as the ideal would be the reforestation of areas where forest occurs naturally.