Promote the careful use of afforestation as a means to sequester carbon, restore degraded ecosystems, foster biodiversity, and support vulnerable communities.
Afforestation involves the deliberate introduction of trees to areas that have never or not recently had trees in order to create a forest. The practice has the potential to sequester a significant amount of carbon, given that a single tree can absorb one ton of carbon in its lifetime. Some afforestation projects plan to grow one trillion trees. Afforestation can help create living barriers that stave off desertification, protect land from flooding, and generate income from sustainable forest products. However, it must be done carefully. Afforestation should only be attempted where it is ecologically appropriate, the new trees harmonize with native flora and fauna, and the risk of monocultures is minimized. Projects must be equitable and involve the participation of the Indigenous peoples and local communities who call the land home.
Learn about the practice of afforestation and its many environmental benefits. Done diligently, afforestation can be an important climate solution that connects people to nature and supports local economies. Afforestation and reforestation both involve the planting of trees to create a forest. The two terms are sometimes used interchangeably, but the former typically occurs on land that has been without forest for a long period of time, due to severe land degradation for instance, or ever. Notable points:
- Afforestation is occurring on small and large scales in areas such as Iceland, where forests were first cleared centuries ago; in Bangladesh, on degraded coastal land; and in Beijing, to connect previously fragmented forest patches in the city.
- The world’s forests absorb a net 7.6 billion metric tons of carbon dioxide a year, which is 1.5 times more carbon than the United States emits annually.
- Afforestation can have many environmental benefits. The practice can restore biodiversity, prevent soil erosion, stabilize water tables, provide shade in cities, and reduce local air pollution. Mangrove afforestation projects in places such as Thailand are crucial to combating coastal erosion (see Mangroves Nexus).
- The practice can support economies, particularly when used in conjunction with agroforestry (see Agroforestry Nexus). One teak afforestation project in Mexico supports over four hundred jobs and meets local demand for timber products.
- Both afforestation and reforestation can be a precursor for proforestation, which refers to the practice of letting forests grow to old age (see Proforestation Nexus).
Support credible tree-planting initiatives. Tree-planting projects big and small have gained popularity in recent years around the world. Cities, countries, and corporations often commit to planting trees as a means to meet their net-zero goals. However, some afforestation projects are controversial and can amount to greenwashing if they are poorly executed. When looking to support a tree-planting project, whether through donations or volunteering (see next bullet), here are some topics to keep in mind when evaluating project credibility:
- Focus on planting a mix of native trees in the right places. Afforestation that displaces other ecosystems, such as grasslands, can amount to arboreal imperialism. The indiscriminate planting of trees without care as to species selection can lead to the creation of harmful monocultures. It can also meet resistance from local communities, as this project in Ireland did (see best practices below in Groups).
- Look for projects that have clear community connections. For instance, successful urban tree-planting projects have been executed in Lima, Peru, where the planting has engaged caregivers with young children, and in Los Angeles, where the city partnered with tech companies, academia, and nonprofits to green underserved neighborhoods.
- Be skeptical of afforestation initiatives linked to carbon offsetting. While afforestation can sequester carbon, it should not be viewed as an indefinite excuse to continue burning fossil fuels under a business-as-usual approach (see Offsets Nexus).
Volunteer with a credible afforestation project. Trees are not only beneficial for environmental reasons, they also improve mental health. Many studies have shown that being around trees reduces both blood pressure and the stress-related hormones cortisol and adrenaline. Trees also hold spiritual significance in many communities, such as the baobab tree in African cultures and redwoods for Native Americans.
- TreePeople in Southern California provides volunteer opportunities to plant trees as a means to respond to forest fires, green concrete schoolyards, and combat food insecurity.
- Many cities have dedicated urban tree-planting programs or associated tree-planting nonprofits that individuals can get involved with, including Trees Atlanta in Atlanta, Georgia; OneMillionTrees in Singapore; Youth Loves Egypt in Cairo, Egypt; and ReForest London in London, Ontario.
- The Plant-for-the-Planet app is a platform where individuals, companies, and schools can register the trees they plant or donate to tree-planting organizations. Some of the listed projects are foresting degraded farmland, including one program in Columbia that is planting trees in a former ranching area.
- Mongabay’s Reforestation.app is a catalog of forest restoration projects occurring around the world (projects that explicitly include afforestation can be found through a keyword search for “afforestation”). Mongabay also has a reforestation newsletter.
- If there are not any existing projects in a particular locality, an article from TRVST explains how to start one by following forest restoration guidelines. And cities such as Boston allow you to request street trees be planted on city property.
Professional Foresters and Local Forest Stewards
Follow afforestation best practices that rely on a diverse array of native tree species. Nonnative trees can accelerate the release of carbon because these trees often grow and decompose faster than native species. A recent study found that trees grown alongside at least one other species were taller, wider, and had about 25 percent more mass than trees grown in monocultures. Monocultures can degrade land by depleting soil nutrients, choke out native understory vegetation, and go against Indigenous forest-management practices.
- Scientists from the Royal Botanic Gardens and Botanic Gardens Conservation International have released ten rules for afforestation. They focus on centering local communities, maximizing carbon sequestration, and fostering biodiversity recovery.
- The Miyawaki Method is one of the most effective tree-planting methods. It replicates natural forest generation by using dense stands of native tree species to create a multilayered forest. While the Miyawaki Method can be effective in any degraded landscape, it has become popular in urban areas such as Delhi; Cambridge, Massachusetts; and Hong Kong.
- If nonnative trees are being considered (particularly if available natives will not be successful in certain extreme microclimates, such as cities), follow these global guidelines for the sustainable use of nonnative trees.
Develop innovative strategies to ensure success. Afforestation involves tree genetics in order to propagate healthy seedlings, as well as site selection and preparation, forest management, and potential harvesting once a new forest has been established. Foresters and others involved must be diligent in these stages of afforestation in order to maximize the practice’s benefits and minimize the chances of any harmful effects:
- Site selection is critical, as afforestation can be detrimental if it drains peatlands or replaces grasslands (see Grassland Nexus). And tree-planting projects may accelerate warming in the Arctic by absorbing heat and thus counteracting the albedo effect from the remaining ice in the region. GIS mapping and machine-learning algorithms are being explored to identify sites most suitable for afforestation.
- Site preparation can involve activities such as removing debris, tilling soil, and using prescribed burns to increase seedlings’ chances of success. A wildfire accidentally caused by an excavator used in a tree-planting project in Spain shows that this practice still needs to be perfected.
- Tree-species selection must not only consider native species, but also species that are resilient to climate stressors such as increased heat, drought, and disease risk. A report by TreePeople identified such tree species in the Los Angeles area. And an American-Chinese hybrid chestnut tree has been developed that is resistant to the invasive chestnut blight that decimated American stands.
- Seedling-planting drones are being piloted in areas such as fire-stricken British Columbia as a means to plant trees. Manual tree planting can be difficult in rural and rugged terrain, but more research is needed to optimize the cost of drone-planting and the survival of the seedlings.
- Partial (or selective) harvesting on afforested lands may provide income and be less destructive than clearcutting, but it comes with risks that foresters must account for, such as high-grading and the increased growth of weeds and vines that can choke out remaining trees.
Further explore the consequences of afforestation. Afforestation has been taking place for hundreds of years in many places including the Nordic countries, the Scottish uplands, Ethiopia, and South Africa. However, the scale and speed of afforestation today has been ratcheted up across the world. There are many areas of scientific study for researchers to explore given this trend, including:
- The carbon sequestration potential of afforested land. Scientific consensus is needed to evaluate and standardize how much carbon afforestation projects absorb. There are unanswered questions on how to factor in variables such as forest permanence, emissions associated with harvested wood products sourced from afforested land, and the carbon sequestration effect of prescribed fire in afforestation projects.
- The impact of afforestation on biodiversity. While afforestation projects have the potential to boost biodiversity, many tree-planting programs are focused on planting massive numbers of similar trees. This strategy may need to be critiqued with a science-based ecological assessment of restoration needs.
- The effects of afforestation on local water cycles. While forests have the potential to store and clean a significant amount of water, that water may not be accessible to local populations. More research is needed to compare the ecological water demand of new forests to social water demand, particularly in arid climates.
Consider hosting an afforestation project on your land. Afforestation not only provides environmental benefits for the world at large, but it can also benefit private landowners in particular by creating a source of income, increasing land value and the sense of privacy, and creating a legacy for future generations.
- Tiny urban forests the size of a tennis court can be beneficial. Trees can increase property values by 5 to 18 percent. They lower neighborhood temperatures and even decrease crime rates.
- A number of jurisdictions have financial incentives tied to afforestation on private lands. The North Carolina Forest Service reimburses a percentage of the cost of tree-planting projects. The U.S. offers a federal income tax deduction for qualifying forestation expenses. Subsidies for afforestation have been available for farmers in China.
- Once a new forest has been established, landowners can receive a revenue stream from timber products for years to come. Some Indigenous communities inside the Brazilian Amazon have earned FSC certification and have made native timber management their main source of income.
Commit to and follow through with reputable afforestation initiatives. Timber companies often have the resources, expertise, and land holdings to spearhead afforestation projects. In doing this, timber companies must prevent greenwashing and the establishment of harmful monoculture plantations, such as from acacia and eucalyptus, that thwart biodiversity and are quickly clear-cut. Partnering with a nonprofit that provides compliance audits can be an important step for timber companies to ensure that their afforestation projects are credible. Here are some timber companies that are making a difference on this front:
- EcoPlanet Bamboo plants and manages bamboo plantations as an alternative to timber. The company often converts degraded land into bamboo forests (see more on bamboo in Bamboo Nexus).
- Komaza is a Kenyan commercial timber company whose mission is to revive the productivity of degraded lands. The company partners with smallholder farmers to turn underutilized land into thriving microforests.
- Symbiosis Investimentos is a Brazilian investment company that is restoring degraded pastureland in Brazil by gathering seeds from healthy native trees, planting and monitoring growth, and then partially harvesting to generate local income while keeping the new forest intact.
Deploy afforestation projects with the active participation and informed consent of local communities. Rural communities, and in particular Indigenous peoples, are key to afforestation projects. Indigenous groups manage about a quarter of the world’s lands and are experts in forest stewardship. Their lands have become degraded through historical seizure for farming, mining, and clear-cutting but may be suitable for afforestation. Key components, resources, and examples for engaging local communities in afforestation efforts include:
- Uphold Indigenous land rights. Indigenous peoples and local communities hold legal title to only 10 percent of the lands they customarily claim. The Global Land Outlook 2 published by the UN’s Convention to Combat Desertification explains that the issue of rights in land restoration can be solved with tactics such as multilateral environmental agreements that recognize Indigenous land rights.
- Obtain the consent of local communities. The concept of free, prior, and informed consent refers to the right of Indigenous peoples to give or withhold their consent for any action that would affect their lands, territories, or rights.
- Ensure gender equity. In parts of the Middle East and Africa, less than a quarter of women own land. Gender disparity in forest restoration is an issue that organizations such as the Green Belt Movement in Kenya can be looked to for guidance (see also Women and Food Nexus).
- The World Economic Forum provides five principles for partnering with communities on forest restoration: understand the local context, obtain consent, codesign initiatives, implement collaboratively, and recognize land rights.
- Africa’s Great Green Wall is an afforestation initiative that is engaging Indigenous communities. The project’s goal is to grow a forest across the entire width of the continent to prevent the encroachment of the Sahara. Despite some logistical setbacks, the project is incorporating Indigenous agroforestry practices such as the planting of native white acacia trees among crop fields in Niger.
- India’s Forest Rights Act recognizes the rights of local communities, particularly through a provision that makes permission by village councils mandatory for forestry projects that may affect local lands. This law has allowed groups such as Dhanwar women to resist monoculture plantations that may stem from poorly designed afforestation projects.
Support international coordination on afforestation efforts to ensure responsibility is distributed equitably. The ten countries with the highest net gain of forest land per year are Romania, Italy, France, the U.S., Turkey, Vietnam, Chile, India, Australia, and China. Between 1990 to 2015, China planted the largest amount of new forest—a total area more than three times the size of the UK and some of which is included in the Great Green Wall of China. Many afforestation projects are located in developing countries, and these projects can turn into a form of neocolonialism, particularly if they are linked to carbon offset projects originating in the Global North. There are a number of ways this risk can be mitigated:
- Collaborate directly between countries on afforestation efforts. The Netherlands will offer its expertise in afforestation to Vietnam through the Mekong Delta Regional Master Plan, which will support mangrove afforestation along the Mekong Delta. There have also been recent calls for countries in the Global South to receive climate reparations from wealthier, polluting nations, which could fund afforestation projects.
- Focus on people-centered natural climate solutions, rather than just tree planting. Large-scale tree-planting projects often have high failure rates, particularly when local communities lack the incentives to care for the trees. Smaller community-based projects can be more successful, such as the 48 Cantons reforestation efforts in Guatemala that focus not only on tree planting, but on healthy homes, environmental education, and training to apply locally contextualized forestry practices.
- Further develop international frameworks that incentivize climate equity. Such existing frameworks include the principle of Common but Differentiated Responsibilities and Respective Capabilities (CBDR-RC) and Reducing Emissions from Deforestation and Forest Degradation (REDD+).
Be transparent with afforestation goals and associated milestones. Tree-planting campaigns have a history of falling short of their goals, as happened in Copenhagen and Turkey, where many of the planted saplings died. Proper planning and thorough accountability can prevent these problems from occurring, whether it be for cities, countries, or corporations with tree-planting programs. Some resources and examples to look to include:
- EcoMatcher is a Certified B Corporation that companies can engage in formulating their own tree-planting programs, including the location, species, and carbon sequestration potential of every tree planted.
- Plant a Tree with HP is a promotion developed by HP in partnership with the Jane Goodall Institute and the Arbor Day Foundation to fund the planting of one million trees globally.
- Consulting firms such as Fair Forests Consulting (U.S.) focus on community engagement programs and can help facilitate urban tree-planting programs. Organizations like American Forest’s Vibrant Cities Lab provides an online hub to connect and empower urban forest leaders.
Green Belt Movement (Kenya)
Plant a Billion Trees (A campaign of the Nature Conservancy)
One Tree Planted (U.S.)
1t.org (a World Economic Forum initiative)
Akira Miyawaki, a Japanese botanist who developed the Miyawaki Method of afforestation, which focuses on the growth of small, dense forests of native species on degraded land.
David Muffly, an arborist and horticulturist who has focused much of his work on introducing climate-adapted trees in planting projects in California.
Felix Finkbeiner, a German environmentalist who was inspired early on by the story of Akira Miyawaki. At the age of nine, Finkbeiner started Plant-for-the-Planet, a youth-centered initiative that supports tree-planting projects around the world.
Jadev Payeng, an environmental activist and the “Forest Man of India.” He planted a tree every day for thirty-five years, creating an entire forest on the drought-stricken island of Majuli.
Wangari Maathai, founder of the Green Belt Movement, an organization that works with women in Kenya to plant trees as a means to store rainwater, support crops, generate income, and stop soil erosion.
What Is Afforestation? (3 mins.)
Tree-Planting Projects Abound. Which Should You Support? (National Geographic)
Wangari Maathai: The Woman Who Planted Millions of Trees (Franck Prévot)
TIL about Planting Trees (MIT TILclimate Podcast)
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