- A project in the Sahel and East Africa claims to fight both soil erosion and poverty through regenerative agroforestry.
- U.S.-based NGO Trees for the Future (TREES) trains farmers in what it calls the forest garden approach, an ancient model to plant diverse species next to each other.
- The approach is one of seven selected by the U.N. as a world restoration flagship program and aims to scale up massively to plant a billion trees by 2030.
- However, some experts say the potential for scaling up is limited, especially in the semiarid Sahel region, given the need for easily accessible sources of water.
Drought, irregular rainfall, deforestation, and the legacy of unsustainable human activities have left vast areas across the arid and semiarid regions of sub-Saharan Africa degraded, causing major challenges for the human population. According to environmentalists, one solution to this problem might be forest gardens.
These “gardens” use regenerative agroforestry to revive patches of degraded agricultural land. In 2024, the U.N. Environment Programme (UNEP) and the Food and Agriculture Organization (FAO) selected a project led by Trees for the Future (TREES), a U.S.-based NGO, as one of seven world restoration flagships for its “forest garden approach” used in five countries in sub-Saharan Africa. These flagships promote restoration projects around the world that show potential to tackle challenges at scale and provide financial support.
“Forest gardens promote healthy soil and diverse crops, leading to increased income and access to healthier food,” Enoch Makobi, country director for TREES in Uganda, told Mongabay. “Farmers are fighting climate change and can overcome poverty and hunger.”
While NGO leaders say they’re optimistic about the outcomes of the project so far and their plans for expansion, some other conservationists have expressed skepticism, pointing to a lack of scientific evidence on impacts and the difficulty international NGOs face in tackling local problems and needs.
A forest garden is a modern term for an ancient agroforestry model that mixes shrubs, herbs, vines, fruit and nut trees, and perennial vegetables, with the aim of supplying communities with food, medicine and animal feed. According to scientists, forest gardens can have significant benefits for a farmer: They balance microclimates, which is particularly relevant for people in the Sahel region, the semiarid belt below the Sahara Desert, where the climate is dry and hot.
TREES adopted the forest garden approach in 2014, working in several African countries and engaging local farmers to much success, say its backers. But the Sahel is new to the NGO’s portfolio of projects. And it’s here where the dual challenges of climate change and demographic pressure on natural resources have deteriorated agricultural land in recent decades.
Expanding in the Sahel
Stretching more than 4,800 kilometers (3,000 miles) along the southern edge of the Sahara, the Sahel region is marked by extreme weather conditions, increasing periods of dry seasons, and rising temperatures. Decreasing soil fertility due to climate change, combined with monocrop cultivation, has led to what TREES’ West African regional director Mohamed Traore described to Mongabay as a “progressive decline in the productivity of agricultural land and yield.”
Traore said these developments are perpetuated by other factors such as the salinity of soils, damage to crops through insects and diseases, and conflicts between farmers and pastoralists, whose animals enter farmed land and damage crops. For Traore, TREES’ forest gardens are a way to ease some of the pressures farmers are facing.
“The forest garden approach was successfully tested in nine countries to restore arid agricultural lands across sub-Saharan Africa,” Valerie Wayte, an FAO spokesperson, told Mongabay by email. She added the project was selected as a global restoration flagship for being “an example of a highly replicable and adaptable model.”
TREES’ mission is bold: Over the next five years, the NGO wants to restore 188,000 hectares (about 465,000 acres), almost five times the area it has transformed in the last nine years. According to its 2024 annual report, TREES claims to have restored 99,743 acres (40,365 hectares) of degraded land, reaching 56,273 farmers and their families across 174 community projects in sub-Saharan Africa. There are currently 38,000 active forest gardens, each comprising about 4,000 trees.
Combined with the narrative of planting trees, which has been gaining popularity in the Global North’s discourse around climate change in recent years, TREES promises to plant 1 billion trees by 2030.
Setting up a forest garden
TREES says its approach has transformed the lives of thousands of farmers and their families in Kenya, Tanzania, Mali, Senegal and Uganda. The organization works with farmers for a period of four years. Each cohort comprises 300 to 500 farmers, whom TREES provides with equipment, tools and seeds, training them to establish a forest garden on a half-hectare (1.2-acre) plot of land within their own property.
It focuses on communities whose lands have been degraded by monocropping.
“We identify communities that rely on agriculture, but at the same time, what they do isn’t working,” said Lindsay Cobb, TREES’ former deputy director of communications. Beneficiary communities are identified by local staff who speak to community groups, local leaders and farmer co-ops.
According to the NGO, the concept is working: where farmers usually grew one or two crops, they now plant an average of 12 species, with the seeds of woody trees, fruit trees and vegetables provided to them. “By the end of the four-year program, that number rises to more than 25 species,” said TREES spokesperson Kendall Garifo.
The concept is designed to provide farmers with the ability to feed themselves while also generating an income by selling on the local markets. According to Cobb, these two aspects are the main incentives for the farmers, who she said stopped cutting down the trees that they planted “because they’re providing food or protection to the crops within the living fence.”
“We’re seeing farmers experience steady access to income and nutritious foods, while before the program they were living below the poverty line,” Cobb said.
Instead of cutting down trees elsewhere, farmers use these living fences as a source of fuelwood and livestock fodder, Garifo told Mongabay. “We have not seen evidence that farmers are cutting down trees elsewhere after being in the program.”
Over the four years of working with TREES, each beneficiary plants between 2,500 and 4,000 trees. Many of the species introduced are exotic and fast-growing for quick results, such as Calliandra and Leucaena, which are among the most-used plants for fencing in Uganda, according to Makobi. Many species on TREES’ list of seedlings aren’t native to Africa, and in some parts of the continent are considered invasive.
According to Cobb, however, the organization makes sure that the species TREES plants are indigenous or naturalized, not invasive, and that they’re beneficial to the land.
Tackling the challenges in the Sahel
The design of the forest garden and the species planted vary according to the ecosystem of the respective country. The Sahel requires a different approach than Uganda, for instance, where areas are mountainous and farmers struggle with flooding. In Senegal and Mali, the main concern is prolonged dry periods and irregular rainfall.
TREES currently has 15 projects in Mali and Senegal, where it works with 8,700 farmers, Cobb said. She didn’t say how many hectares of land have been planted. Eight of the nine projects in Senegal and three of the six in Mali started in 2024, according to the organization’s website. The other projects were started in 2021 and 2023, with no additional data available.
If designed appropriately, forest gardens can be a tool to solve some of the problems in the Sahel, Cobb said. By cutting out chemicals through the planting of fertilizing trees, maintenance costs can be reduced, she said, adding that farmers are also trained in natural pest management so they can use ingredients from their own properties rather than buying chemical products.
At the end of the four years, when farmers “graduate,” Cobb said they know how to use compost and natural fertilizers, establish a nursery, and save seeds, all while generating a stable income by selling their produce in the local markets.
While farmers and employees involved with the NGO report significant positive changes on a small scale, and aerial surveys counted the number of trees planted, data or scientific evidence about the larger impacts of the project are scarce. Mongabay was unable to verify the stated successes with farmers on the ground.
The principle of integrating trees and basic food crops by planting them in different layers has been practiced by Indigenous societies for millennia.
“Forest gardens are a well-established, very old agroforestry system,” said Peter Minang, principal scientist and lead for landscape governance research at the World Agroforestry Centre (ICRAF), who isn’t involved with TREES. “A forest garden in the agroforestry system would consist of different layers of large, medium, small, and under-the-soil trees, plants and shrubs which have to be arranged in a way that enough light reaches each of the layers, so they can perform.”
“Fruit trees indeed help improve nutrition and household income,” said Chris Reij, a sustainable land management scientist and senior fellow at the World Resources Institute (WRI), who has studied regreening and restoration practices in Niger and Burkina Faso, both in the Sahel, for decades. “But most forest gardens in drylands will require watering which means they are easiest to realize in areas where groundwater is available at an acceptable depth.”
Reij added that the scalability of such a program is limited in the Sahel as water scarcity is one of the most pressing challenges in the region. “It is a form of tree planting that is very useful, but it should only be done in specific niche areas, such as alongside rivers or in valley bottoms,” he said.
Indeed, one of the criteria for a farmer to be eligible for a TREES project is to be settled less than 1 km (0.6 mi) from a water source, limiting project locations to areas near rivers, especially in the arid countries of the Sahel.
Reij said innovation is key to fighting desertification at scale. Using numbers from Senegal, where the annual planting rate is 10,000 hectares (about 25,000 acres), he said that “the annual degradation of vegetation rate is about 70,000 hectares [173,000 acres], which means that we are losing the battle against land degradation. We need to move away from business as usual.”
Around the world, as tree-planting projects have skyrocketed over the past years, their impact is increasingly refuted. Research shows that these initiatives can often be poorly monitored, with the long-term results not matching the early promises. Often implemented with the aim of impressing donors through sheer numbers of planted trees in a short time, they fail to address the need of local communities or ecosystems.
TREES says it wants to defy this criticism: “While we have a goal to plant a billion trees by 2030, it’s not through mass tree planting. It’s by working with farmers on the land that they own and restore it in a way that works for them,” Cobb said.
Banner image: A forest gardener waters vegetables in his forest garden in Kaffrine, Senegal. Image by Todd Brown for UNEP.
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