Maxwell Ochoo’s first attempt at farming was a dismal failure.
In Ochieng Odiere, a village near the shores of Kenya’s Lake Victoria, “getting a job is a challenge,” the 34-year-old says. To earn some money and help feed his family, he turned to farming. In 2017, he planted watermelon seeds on his 0.7-hectare plot.
Right when the melons were set to burst from their buds and balloon into juicy orbs, a two-month dry spell hit, and Ochoo’s fledgling watermelons withered. He lost around 70,000 Kenyan shillings, or about $650.
Ochoo blamed the region’s loss of tree cover for the long dry spells that had become more common. Unshielded from the sun, the soil baked, he says.
In 2018, Ochoo and some neighbors decided to plant trees on public lands and small farms. With the help of nonprofit groups, the community planted hundreds of trees, turning some of the barren hillsides green. On his own farm, Ochoo now practices alley cropping, in which he plants millet, onions, sweet potatoes and cassava between rows of fruit and other trees.
The trees provide shade and shelter to the crops, and their deeper root systems help the soil retain moisture. A few times a week in the growing season, Ochoo takes papayas, some as big as his head, to market, bringing home the equivalent of about $25 each time.
And the fallen leaves of the new Calliandra trees provide fodder for Ochoo’s five cows. He also discovered that he could grind up the fernlike leaves as a dietary supplement for the tilapia he grows in a small pond. He now spends less on fish food, and the tilapia grow much faster than his neighbors’ fish, he says.
Today, nearly everything Ochoo’s family eats comes from the farm, with plenty left over to sell at market. “Whether during dry spell or rainy season, my land is not bare,” he says, “there’s something that can sustain the family.”
Ochoo’s tree-filled farm represents what many scientists hope will be farming’s future. The present reality, where fields are often cleared of trees to raise livestock or plant row after row of single crops, called monocultures, is running out of room.
About half of all habitable land on Earth is devoted to growing food. More than 30 percent of forests have been cleared worldwide, and another 20 percent degraded, largely to make room for raising livestock and growing crops. By 2050, to feed a growing population, croplands will have to increase by 26 percent, an area the size of India, researchers estimate.
Humans’ collective hunger drives the twin ecological crises of climate change and biodiversity loss. Cutting down trees to make room for crops and livestock releases carbon into the atmosphere and erases the natural habitats that support so many species.
Humankind is in danger of crossing a planetary boundary with unpredictable consequences, says landscape ecologist Tobias Plieninger of Germany’s University of Kassel and University of Göttingen. As land continues to be cleared for agriculture, “there’s high pressure … to shift toward more sustainable land use practices.”
Farmers like Ochoo, who intentionally blend crops, trees and livestock, a practice loosely called agroforestry, offer a more sustainable way forward. Agroforestry may not work in every circumstance, “but it has great potential,” Plieninger says, for working toward food production and conservation goals on the same land.
Integrating trees onto farms may seem like a recipe for lower yields, as trees would replace some crops. But such mixing can actually squeeze more food from a given plot of land than when plants are grown separately, Plieninger says. In Europe, blended farms that grow wheat or sunflowers between rows of wild cherry and walnut trees, for example, can produce up to 40 percent more than monocultures of the same crops for a given area.
Agroforestry was the norm until modern agricultural methods swept the globe, especially after the Industrial Revolution and the rise of chemical fertilizers in the mid-20th century. But small farms in the tropics are still big on trees. Worldwide, about 43 percent of land used for agriculture has at least 10 percent tree cover, according to a 2016 study in Scientific Reports.
Increasing that percentage could have profound and wide-ranging benefits, if done right. “Trees have to be integrated [onto farms] to not create extra problems” for farmers, says Anja Gassner, a senior scientist at World Agroforestry in Bonn, Germany. And the approach looks very different depending on the region and the goals of the people who live there. What Spanish farmers need from their oak-dotted fields where pigs get fat on acorns will be different from what farmers in Ecuador want from their coffee plants growing under the cool shade of tropical inga trees.
The way agroforestry is carried out in three very different parts of the world illustrates the promises and challenges of coupling trees and crops.
Made in the shade
If you’re enjoying a morning cup of coffee while reading this, there’s a chance the beans in that brew came from farms practicing agroforestry.
Coffee plants evolved in the understory of Ethiopia’s highland forests; they are well-suited to shade, says Eduardo Somarriba, an agroecologist at the Tropical Agricultural Research and Higher Education Center in Cartago, Costa Rica.
A diverse canopy of native trees can help coffee plants thrive. Certain trees pump nitrogen into the soil, removing the need for intensive fertilizer application, Somarriba says. Native vegetation suppresses weed growth, stabilizes soil and temperature, improves water retention and supports pollinating animals.
But as global thirst for coffee has grown, planting practices have shifted toward shadeless plots filled only with coffee plants that require a steady stream of chemical fertilizers. From 1996 to 2010, the worldwide share of coffee grown under a canopy of diverse trees fell from 43 percent to 24 percent, researchers reported in 2014 in BioScience.
Removing trees is seen as good for increasing yields, though the evidence is mixed. This focus on numbers misses the more diffuse benefits of diversifying farms, Somarriba says, especially small farms, which still produce most of the world’s coffee.
“If coffee prices go down and stay low for five or six years, a small farmer will not be able to make it only from [selling] coffee,” Somarriba says. But adding a mix of trees can build in economic and climate resilience, he says.
Valuable timber trees, like mahogany, can serve as savings accounts, harvested when coffee profits aren’t enough. Mango, Brazil nut or acai trees can supply income, too. But not all places have well-developed markets for these goods, Somarriba says, which presents a challenge to increasing the share of coffee grown under shade.
Some conservationists are trying to boost consumer demand for shade-grown coffee by highlighting how it benefits biodiversity. The Smithsonian Migratory Bird Center, for example, grants a Bird Friendly certification to plantations with ample native tree cover and diversity, a boon for migratory birds. Certified farmers are able to charge a slightly higher price, on average 5 to 15 cents more per pound.
Migratory birds flock to such plantations. “When you’re in a bird-friendly coffee farm, it kind of feels like you’re in the forest,” says Ruth Bennett, an ecologist at the Smithsonian Migratory Bird Center in Washington, D.C. “You hear a lot of bird calls, and it’s a huge diversity of birds, including really sexy tropical species like the turquoise-browed motmot,” she says.
Bird Friendly coffee plantations also appear to be good for mammals. In Mexico, Bird Friendly coffee plantations had more native wildlife, including deer and mice, than other coffee plantations, according to a 2016 study in PLOS ONE.
Ecosystems brimming with diverse species of plants, animals and more make the planet livable by filtering water, cycling nutrients through soils and pollinating crops. While undeveloped forest is clearly best for biodiversity, shade-grown plantations can outshine other land uses. After more than a decade, high-diversity coffee agroforestry systems in southeastern Brazil were ecologically healthier — as measured by tree canopy cover and species richness — than plots set aside for nonagricultural restoration, researchers reported in the September 2020 Restoration Ecology. About 90 percent of the canopy was intact on shaded coffee plots versus about 60 percent for restored forest areas, on average.
Beyond the biodiversity benefits, Bennett says shade-grown coffee just tastes better. Under shade, coffee cherries take longer to develop, which can boost sugar content.