Reforestation
Reforestation is the practice of restoring previously existing forests and woodlands that have been destroyed or damaged. The prior forest destruction might have happened through deforestation, clearcutting or wildfires. Three important purposes of reforestation programs are for harvesting of wood, for climate change mitigation, and for ecosystem and habitat restoration purposes. One method of reforestation is to establish tree plantations, also called plantation forests. They cover about 131 million ha worldwide, which is 3% of the global forest area and 45% of the total area of planted forests.
Globally, planted forests increased from 4.1% to 7.0% of the total forest area between 1990 and 2015. Plantation forests made up 280 million ha in 2015, an increase of about 40 million ha in the previous ten years. Of the planted forests worldwide, 18% of that area consists of exotic or introduced species while the rest consist of species native to the country where they are planted.
There are limitations and challenges with reforestation projects, especially if they are in the form of tree plantations. Firstly, there can be competition with other land uses and displacement risk. Secondly, tree plantations are often monocultures which comes with a set of disadvantages, for example biodiversity loss. Lastly, there is also the problem that stored carbon is released at some point.
The effects of reforestation will be farther in the future than those of proforestation. Instead of planting entirely new areas, it might be better to reconnect forested areas and restore the edges of forest. This protects their mature core and makes them more resilient and longer-lasting. It takes much longer − several decades − for the carbon sequestration benefits of reforestation to become similar to those from mature trees in tropical forests. Therefore, reducing deforestation is usually more beneficial for climate change mitigation than is reforestation.
Many countries carry out reforestation programs. For example, in China, the Three Northern Protected Forest Development Program – informally known as the "Great Green Wall" – was launched in 1978 and scheduled to last until 2050. It aims to eventually plant nearly 90 million acres of new forest in a 2,800-mile stretch of northern China. Such programs often blur the boundaries between reforestation and afforestation.
Definition
Reforestation according to the IPCC means the "conversion to forest of land that has previously contained forests but that has been converted to some other use".According to FAO terminology, reforestation is defined as the re-establishment of forest through planting and/or deliberate seeding on land classified as forest.
Afforestation on the other hand means establishing new forest on lands that were not forest before. It is the process of restoring and recreating areas of woodlands or forests that may have existed long ago but were deforested or otherwise removed at some point in the past or lacked it naturally.
Purposes
Harvesting of wood
Reforestation is not solely used for recovery of accidentally destroyed forests. In some countries, such as Finland, many forests are managed by the wood products and pulp and paper industry. In such arrangements, trees are planted to replace those that have been cut, much like other crops. The Finnish Forest Act from 1996 requires that forest be replanted after felling. In such circumstances, the industry can cut the trees in a way to allow easier reforestation.Reforestation, if several indigenous species are used, can provide other benefits in addition to financial returns, including restoration of the soil, rejuvenation of local flora and fauna, and the capturing and sequestering of 38 tons of carbon dioxide per hectare per year.
Climate change mitigation
There are four primary ways in which reforestation and reducing deforestation can increase carbon sequestration and thus help with climate change mitigation. First, by increasing the volume of existing forest. Second, by increasing the carbon density of existing forests at a stand and landscape scale. Third, by expanding the use of forest products that will sustainably replace fossil-fuel emissions. Fourth, by reducing carbon emissions that are caused from deforestation and degradation.Ecosystem restoration
Plantation forests are intensively managed, composed of one or two species, even-aged, planted with regular spacing, and established mainly for productive purposes. Other planted forests, which comprise 55 percent of all planted forests, are not intensively managed, and they may resemble natural forests at stand maturity. The purposes of other planted forests may include ecosystem restoration and the protection of soil and water values.Methods
Forest plantations
Plantation forests cover about 131 million ha, which is 3 percent of the global forest area and 45 percent of the total area of planted forests.Over 90% of the world's forests regenerate organically, and more than half are covered by forest management plans or equivalents.
Globally, planted forests increased from 4.1% to 7.0% of the total forest area between 1990 and 2015. Plantation forests made up 280 million ha in 2015, an increase of about 40 million ha in the previous ten years. Of the planted forests worldwide, 18% of that planted area consists of exotic or introduced species while the rest consist of species native to the country where they are planted.
Using existing trees and roots
Planting new trees often leads to up to 90% of seedlings failing. However, even in deforested areas, existing root systems often exist. Growth can be accelerated by pruning and coppicing where a few branches of new shoots are cut and often used for charcoal, itself a major driver of deforestation. Since new seeds are not planted, it is cheaper. Additionally, they are much more likely to survive as their root systems already exist and can tap into groundwater during harsher seasons with no rain. While this method has existed for centuries, it is now sometimes referred to as farmer-managed natural regeneration or assisted natural regeneration.Financial incentives
Policies that promote reforestation for incentives in return have shown promising results of being an effective and motivative concept to re-plant globally on a mass scale.Some incentives for reforestation can be as simple as a financial compensation. A compensated reduction of deforestation approach has been proposed which would reward developing countries that disrupt any further act of deforestation: Countries that participate and take the option to reduce their emissions from deforestation during a committed period of time would receive financial compensation for the carbon dioxide emissions that they avoided. To raise the payments, the host country would issue government bonds or negotiate some kind of loan with a financial institution that would want to take part in the compensation promised to the other country. The funds received by the country could be invested to help find alternatives to the extensive cutdown of forests. This whole process of cutting emissions would be voluntary, but once the country has agreed to lower their emissions they would be obligated to reduce their emissions. However, if a country was not able to meet their obligation, their target would get added to their next commitment period. The authors of these proposals see this as a solely government-to-government agreement; private entities would not participate in the compensation trades.
Another emerging revenue source to fund reforestation projects deals with the sale of carbon sequestration credits, which can be sold to companies and individuals looking to compensate their carbon footprint. This approach allows for private landowners and farmers to gain a revenue from the reforestation of their lands, while simultaneously benefiting from improved soil health and increased productivity.
Alongside past financial incentive strategies, reforestation tax benefits have been another way the government has encouraged companies to promote reforestation tactics through the promises of a tax break.
As many landholders seek to earn carbon credits through sequestration, their participation also encourages biodiversity and provides ecosystem services for crops and livestock.
Challenges
There is often insufficient integration between the different purposes of reforestation, namely economic utilization, enhancement of biodiversity and carbon sequestration. This can lead to a range of different challenges.Competition with other land uses and displacement risk
Reforestation can compete with other land uses, such as food production, livestock grazing, and living space, for further economic growth. Reforestation can also divert large amounts of water from other activities. A map created by the World Resources Institute in collaboration with the IUCN identifies 2 billion hectares for potential forest restoration and is criticized for including 900 million hectares of grasslands. An assessment of the pledges of governments for reforestation found that the sum of global pledges translates to a required land area of 1.2bn hectares, until 2060, which is equal to a tenth of the global land area und thus deemed unrealistic without a significant encroachment on non-forest areas. Experts are calling for a better integration of social data, such as the dependence of livelihoods on specific land uses, into restoration efforts. Possible solutions include the integration of other land uses into forests through agroforestry, such as growing coffee plants under trees, reducing the delineation between forests and other land uses.A study found that almost 300 million people live on tropical forest restoration opportunity land in the Global South, constituting a large share of low-income countries' populations, and argues for prioritized inclusion of "local communities" in forest restoration projects.
There are calls for a more selective approach to identifying reforestation areas, taking into account the possible displacement of customary land uses.