3 neglected tree species that feed millions and restore land

The world does not eat enough fruit and vegetables, while at the same time an estimated 25% of the world’s land area is degraded. This issue is particularly acute in dry regions like the Sahel; an estimated 75% of land in Niger is degraded, according to a study of land degradation in seven African countries.

The challenge is complex, but there's good news: indigenous trees that are vital sources of nutrition and thrive in arid areas can help address both these crises.

The World Health Organization recommends a minimum of 400g of fruit and vegetables per day to prevent diseases such as heart disease, cancer, diabetes, obesity and deficiencies of micronutrients like Vitamin A and zinc.

But global supply is about 22% short of population needs with low- and middle-income countries falling an incredible 58% short. In East Africa, consumption is estimated to be a staggering one sixth of the WHO target - nearer 68g per day - with as little as just 19g of fruit consumed daily in Ethiopia.

Yet the Global South abounds with trees that can provide nutrition in their fruit pulp, fats, oils, starchy shoots and other edible parts.

Besides widely known pan-tropical trees like mango and papaya, a myriad of lesser-known indigenous trees makes a major contribution to diets. At my organization, we have opted to refer to them as “food” trees. To lump them together as “fruit trees” does not do them justice, missing out on their often edible leaves, gum, nuts, roots, sap and other parts.

These trees are also far more than "famine foods", a term often used by aid workers when they see displaced people collecting food from the wild, often leaves. Tree leaves may be resorted to when vulnerable and hungry populations are on the move. But they are also a routine part of the diets of millions, as in West Africa where baobab leaves are cooked with onion as a stew.

Rural people with settled lives also harvest “wild” food where the natural vegetation has not been pauperized. Callers to a recent radio show in Uganda lamented that this nature’s supermarket is disappearing as trees are cleared for farming and charcoal. “As a child, I herded cattle and ate fruit from the bush. Now I can’t find these plants. It’s very irritating,” said one.

Tropical tree-sourced foods are sometimes clustered as “lost, underutilized or neglected” because they are overlooked by governments and development agencies. But hundreds of millions depend upon them, and they have huge potential to contribute significantly to the availability of fruit and vegetables.

At World Agroforestry ICRAF, these trees jump out at us in surveys. We found fruit from the Balinites tree to be the most frequently eaten fruit by women in northwest Uganda in the previous 24 hours. In still unpublished data, the Center for International Forestry Research CIFOR found rural women across all agro-ecological zones in Zambia had eaten wild fruits more than twice as frequently as cultivated fruits in the previous seven days.

“We have strong evidence of their value, and they may be contributing even more than we know,” says ICRAF’s Stepha McMullin, who designs tree portfolios to cope with seasonal availability.

“Given how much they show up in the research and in markets, it is baffling that so few policymakers and practitioners recognize the role of these trees,” says CIFOR’s Amy Ickowitz, who studies dietary quality and tree cover.

Indeed, why do global nutrition bodies and national policies miss them? And given that they are resilient to drought and other stressors, shouldn’t they be more prominent in restoration efforts too?

Admittedly, scraggly trees like Balinites are easy to miss. Observers may see the dry bush in which they grow as mere unproductive scrub. Nothing could be less true. So, let’s examine just three examples of essential trees that grow in drylands in Africa and into Asia.

Balanites aegyptiaca (Desert date, Dattier du désert, Zeguene in Mali, Lalok in South Sudan)

This tree’s fruit is a source of iron and calcium when dried. Fresh, it has proportionally as much vitamin C as an orange. New leaves are a nutrient-rich dry season vegetable. Extracts of the fruit and bark kill the hosts of Bilharzia and carriers of Guinea Worm. The tree can be regenerated by Farmer-managed natural regeneration (FMNR), a method that nurtures living stumps. Seedlings and young trees need protection from fire and livestock.

Ziziphus mauritiana (Pomme du Sahel, Ber in Ethiopia, Masawo in Malawi, Jujube in India)

A hardy tree that copes with extreme temperatures, its fruit contains high levels of minerals, Vitamin C, and β-carotene, which converts to vitamin A. The fruit can be eaten fresh, dried, juiced or pounded. Importantly for reforestation, the tree grows well from direct seeding and it is an ideal agroforestry tree. ICRISAT found that Ziziphus increased millet yields by 41%. The leaves of this tree are eaten by livestock.

Borassus aethiopum (Rônier in French, Palymira in India, Mwumo in Swahili, Tugo in Luo)

These palms with fan-shaped leaves provide thatch, mats, medicine, beehives, tool handles, oil, sap for toddy and jaggery, and termite and fungi resistant poles and timber. The large fruit is rich in Vitamin C; the first shoot from its seed is eaten boiled or roasted. The presence of the tree increases the yield of crops like sorghum. It is also best propagated by direct seeding, as seedlings are hard to transplant.

More than just a tree

Clearly there is nothing niche or rare about these trees. They are major players in food systems from Somalia to Senegal, in the Miombo biome across Southern Africa, and even in the Near East and South Asia. It would not be unusual for a family to consume products of all three in a day – children sucking Ziziphus fruit as mothers cook Balinites leaves and Borassus shoots for meals.

These trees are so essential that in Senegal farmers are planting them as a key component for the Great Green Wall. Meanwhile, sale of their products brings in cash.

Governments and the international community have overlooked them, but these trees can help us achieve the UN Sustainable Development Goals by 2030. Indigenous food trees are intrinsic to SDG 2: Zero Hunger, which aims to end all forms of hunger and malnutrition, and SDG 15: Life on Land, which aims to reverse land degradation and halt biodiversity loss.

Long harvested from the “wild”, they now need to be brought onto farms as a nature-based solution for the intertwined crises of climate, malnutrition, and biodiversity and ecosystem collapse.

This year is the International Year of Fruits and Vegetables. Let’s make sure trees aren’t forgotten and are recognized for their contribution to diets. It is also the start of the UN Decade on Ecosystem Restoration. Indigenous trees, especially those that provide food and are loved by communities, should play a central role.