A researcher is on a mission to plant thousands of “miracle trees” in Tanzania. Can they mitigate climate change and strengthen the immune system of villagers?
By Anne Kidmose
Karatu. Dust clouds swirl up after the cars that come rushing along the dirt road. A girl pulls her bike on the side of the road to avoid the orange dust cloud. Next to the road, clay houses are all sprinkled with the same reddish colour.
We have turned from the main road leading towards the Serengeti and the Ngorongoro crater. To the North, the mountains surrounding Ngorongoro stand tall. To the East, the Great Rift Valley forms a green belt. Out here on the dry plains, Belgian agricultural engineer Karen Christiaens has started a project to regreen the landscape and improve the health of villagers. Her solution? A tree.
“The miracle tree” she calls the bright green moringa tree.
“It grows two meters in three months, and then you can harvest the leaves. For a tree, it’s spectacular,” says Christiaens, who holds a doctorate in BioScience Engineering from the Catholic University of Leuven. In 2015, she founded JS Foundation with her late friend John Schrooten.
“It grows two meters in three months, and then you can harvest the leaves. For a tree, it’s spectacular.”
– Karen Christiaens, researcher.
Moringa oleifera is originally from the foothills of the Himalayas. Today, is grown in Southeast Asia and East Africa due to its many nutrients and drought-resistant roots. In recent years, powdered moringa leaves have been marketed as a “superfood” crammed with vitamins and minerals. Time Magazine has hailed moringa as “the new quinoa” and HuffPost has called the tree’s content of proteins, vitamins, and minerals “impressive”.
Since 2016, Karen Christiaens and her team of local agronomists have sold about 40,000 moringa seedlings to farmers and women in the villages south of Karatu for around 20 cents (USD). Christiaens do not believe that we as humans will take care of something we get for free.
However, local schools have been given moringa seedlings as gifts, and women have been taught how to prepare moringa leaves as a spinach dish, as well as how to produce moringa powder and soaps.
“If you give moringa to children in their first five years, then studies show that there will be fewer cases of malnutrition. It’s not just about growing in height, it’s also about the development of the brain. I try to show parents that if they have strong children, they don’t need a doctor. As a result, they save money, and the children can make money for the parents when they grow up. That way, it’s an indirect investment. This is building immunity,” says Karen Christiaens.
A bitter leaf
After a bouncy ride in the four-wheel drive, we arrive at a neatly planted forest on the outskirts of the village Bassodawich. The moringa leaves hang limply in the bright midday sun. They have a bitter aftertaste, but the texture is silky.

“It’s good that you’re wearing your hat,” project coordinator Clement Kingo tells me. The sun is scorching. Villagers are left waiting for the rain that is unusually late, and there are stories of herders leading their cattle into the national parks to find water for them.
The government of Tanzania has warned that the two rainy seasons in Tanzania – the small one in November and the big one from March to May – are getting shorter and more unpredictable. In 2016, the Tanzanian minister for environment warned that 61 percent of the country was in danger of turning into desert.
It is during a dry spell like this that moringa trees could serve as green supplements to the traditional diet consisting of corn porridge, beans, and meat. However, changing the food culture of a village is not done overnight.
“We can use moringa as a vegetable, in our tea and as feed for the cows. The people in this village are still not really used to moringa, but they have started a little bit.”
– Zacharia Waya, farmer.
Farmer Zacharia Waya, 57, has lived on these plains all his life and helps prune the moringa trees. In his own farm, he grows corn, beans, sunflowers, and sorghum. Moringa is only slowly gaining ground in the village.
“We can use moringa as a vegetable, in our tea and as feed for the cows. The people in this village are still not really used to moringa, but they have started a little bit,” Zacharia Waya says, holding up a moringa leaf which insects have had their way with. They’re hard to keep away.

According to Edward Joy, a researcher in nutrition and sustainability at the London School of Hygiene & Tropical Medicine, a lack of familiarity with the moringa tree is an obstacle to spreading it in dry regions.
“People may not see it as something they want to eat. The powder tastes harsh and is not particularly tasty. The fresh leaves actually taste good when prepared with salt, just like regular spinach tastes very good. If you want to promote moringa, it is probably better to bet on the fresh leaves, but then storage is a problem,” says Edward Joy.
During field studies in southern Ethiopia, he learned how the Konso people have used moringa for generations. They prefer to boil the leaves in a spinach-like dish.
“In some areas, moringa is a major source of selenium that people don’t get from anywhere else. It’s not studied very well, but I think there will be regions in the world where there will be selenium deficiency without this crop,” Joy says.
Selenium is a mineral which acts as an antioxidant and is important for the body to respond to infections.
But is there enough research to conclude that it is safe to eat the leaves of trees even in large quantities?
“The best proof that it is safe is that the Konso people eat them without any problems. We’ve also studied the composition of minerals in the leaves, and there’s no cause for concern there,” Joy said.
But although the moringa tree can survive even long periods of drought and has been nicknamed the “never die tree” in Senegal, it is still only a tree. It needs water to produce fresh leaves, and this leads Edward Joy to call it a “useful crop”, but he refrains from using the term a “miracle crop”.
Herbal medicine
The schoolteacher Samuel Johanna in Bassodawich, however, has fully embraced the newly introduced crop. He plucks a branch from a moringa tree in the school garden and resolutely puts the leaves in his mouth.
“When I feel like I have a fever, I eat the leaves and I feel better,” he says. He adds the leaves to his morning tea and encourages students to do the same.
The enthusiastic use of moringa leaves as herbal medicine worries project coordinator Clement Kingo.
“It’s a problem. If you use too much of it, you can get diarrhoea because there’s so much protein in it,” he says.

There is no scientific evidence that moringa cures fever.
“The only way I can explain it is that moringa strengthens the immune system, but we don’t have research showing that it heals anything special,” Clement Kingo says.
In the past, Bassodawich residents used the moringa tree as herbal medicine, he says, and this might explain why some villagers are now again turning to it for medicinal purposes.
At the same time, Clement Kingo and Karen Christiaens teach villagers to plant moringa trees to avoid soil erosion.
“Moringa, like any tree, helps hold the soil against erosion, and it absorbs CO2, but it’s not a special climate tree,” says Clement Kingo, pointing down into the dry soil.
Life insurance
Behind the school, the landscape lays bare. Dust gets into the nose, eyes, and ears, giving the skin a rusty colour that stays for days. Karen Christiaens usually stays in the villages for a few weeks at a time, then she goes home to Belgium. We meet at her hotel in Arusha shortly before her departure to Belgium.

Christiaens did not plan to be called “mama mlonge” by villagers near Karatu (mlonge is moringa in Swahili). The Moringa project came about by chance when her best friend and fellow traveller, John Schrooten, was diagnosed with brain cancer in 2015.
On their travels around the world, they had often talked about “giving back” to communities less privileged than themselves. When John Schrooten fell ill, he asked Christiaens to embark on the philanthropic project. She came up with the idea of propagating the moringa tree but had no place to plant it. Through a Belgian organization, she got in touch with a local NGO in Karatu. They began a collaboration, and the moringa project was launched a week before John Schrooten died. It is with money from his life insurance that Karen Christiaens now plants moringa trees.
“I have a feeling that I gave John what he asked for. He asked me to do something, and I did it. I’ve asked myself; am I doing this for him, for myself, or for the people in the villages? At least I do it for the people, because I have so many good meetings in the villages, with the women and in the schools. But I also do it for myself because they give so much back to me,” says Karen Christiaens.
She has emptied her glass of white wine and is soon ready to drive towards the airport. Before she goes, I ask her whether she will still call moringa a “miracle tree”? She contemplates before answering.
“Is there such a thing as a miracle? I might call it a magic tree because magic is something you can’t explain will happen. There’s nothing supernatural about this tree. It’s not like it comes into your life and then you suddenly find gold in your bed. You still have to work with the tree. But it has some magic about it because it is a versatile tree and has so many qualities to improve people’s lives and the planet. I would call it a magical tree. But then you also have to believe in magic.”