Two pioneers believe we can feed the world with trees
Most of the world’s 7.7 billion people rely on annual plants for food. By definition, these crops perform their entire life cycle in a single growing season. In under 12 months, they sprout, flower, go to seed, and die.
Currently, just three annual plants—rice, wheat, and corn—provide 60 percent of the world’s calories. To plant them, we destroy complex perennial ecosystems, cutting down forests and plowing prairies to create an ever-growing number of agricultural fields. To date, we’ve cleared an estimated third of the world’s ice-free land. Greenhouse gas emissions from land use, mainly agriculture, forestry, and land clearing, currently make up 23 percent of the world’s total. In short, our eating habits are wreaking havoc on the planet.
What if we tapped into nut-producing trees and shrubs as staple crops instead?
Mark Shepard started thinking about this as a kid in the 1970s in western Massachusetts. The oil embargo pushed his parents to get a wood stove, and every day after working in the garden, he was sent into the forest to collect firewood. He snacked on berries and experimented with eating acorns, and he noticed how much food the woods produced, without all the dirt and sweat of the garden. After college, he started envisioning a new kind of agriculture: one that combined permaculture and habitat restoration with the goal of using nut trees and animals to produce staple foods. He dubbed it “restoration agriculture.” In 1994, he bought 100 acres of spent cornfields in Wisconsin and initiated a project he called New Forest Farm.
Shepard began by researching biomes — the large, naturally occurring communities of distinctive flora and fauna that cover Earth. He discovered that the biome with the widest distribution across North America is the savanna, a grassy area scattered with shrubs and trees. And he discovered that the most common type is the oak savanna. The overstory was composed of tall, nut-bearing trees in the family Fagaceae: oaks, chestnuts, and beeches. Beneath that were Malus (apples), Corylus (hazelnuts), Prunus (cherries, plums, peaches), Rubus (raspberries and blackberries), Ribes (gooseberries and currants), Vitis (grapes), Poaceae
(grasses), and fungi (mushrooms). Other plants populated the oak savannas, too, of course. But Shepard zeroed in on the edible ones. Instead of growing annual grains, he decided, he would design a farm that mimicked the oak savanna, with nuts and meats as staple foods.
Shepard planted thousands of shrubs and trees. He converted the former row-crop grain fields into a wild yet organized landscape: curving lines of mixed chestnuts, walnuts, hazelnuts, apples, and elderberries alternating with alleys of grass grazed by cows, pigs, turkeys, sheep, pigs, and chickens. “It’s in rows, using machinery,” he said. But it’s not a field or an orchard, with all one kind of plant. And it’s not annual. It’s a complex perennial ecosystem that’s also a productive commercial farm.
The idea that trees and shrubs are the keys to more sustainable farms isn’t new. Nature writer William Bryant Logan posited that the widespread global availability of acorns was the scaffold on which humanity as we know it was built — that the nuts of the oak tree offered early hominids the chance to live a life we recognize as human—with houses, clothing, and a reliable staple food. The people of northern Italy have relied on chestnuts as “the bread tree” for thousands of years. Distribution of tree crops like honey locusts in North America has been linked to former indigenous village sites, and the botanist William Bartram recorded extensive cultivation of tree crops, in particular, hickory nuts, by Native American tribes in what is now the southeastern U.S.
During the Dust Bowl years, the U.S. government leaned heavily on trees for relief, planting some 220 million trees on the Great Plains between Canada and Texas in an effort to curb erosion. As part of the New Deal, FDR started programs in agricultural areas like Tennessee — degraded by decades of cotton, corn, and tobacco — to restore the land with millions of tree crop seedlings. Pennsylvania author and Columbia University professor J. Russell Smith, born in 1874, studied agriculture at home and around the world. “As plants, the cereals are weaklings,” he advised in the introduction of his 1929 treatise, “Tree Crops: A Permanent Agriculture.” “They must build themselves anew for each harvest […] Trees living from year to year are a permanent institution.”
In 1997, 5,000 miles from Mark Shepard’s farm in Wisconsin, Marcie Mayer arrived on the remote Kea Island in Greece. She’d dropped out of an art history program a decade earlier and started a restaurant in Athens, but now she had a young daughter, and she needed a break. “It was autumn,” she said, “one of those years, like this year, with a lot of acorns. And the acorns from the oak forest on Kea Island were four to five times bigger than what you see in the United States.” Mayer was from northern California, and she remembered doing a unit on traditional foods in fourth grade. “You can eat acorns,” she remembered. “It sparked a memory.”
Mayer moved to Kea Island and started researching acorns. She learned that the nuts are indeed edible, but like olives, they require processing. They have to be dried, then cracked, then leached in cold water to remove bitter tannins, and finally dried again and ground to make flour. She discovered that although no one was eating the nuts on Kea, the large acorn caps had historically been used in traditional leather tanning and until the 1960s had been the mainstay of the island’s agricultural economy. Then the caps were replaced with chemicals. Islanders no longer had a use for the oaks, and huge, 200-year-old trees were being cut to make charcoal and create space for vacation homes.
To save the Kea oaks, Mayer started experimenting with making acorn flour. She helped local farmers begin exporting acorn caps again, and with a market secured, islanders saw a future for their trees for the first time in 50 years. Mayer began buying the nuts and learned to process acorns into flour on a large scale.
She also began cooking with acorn flour. “I started making treats out of acorns, trying to help the farmers understand how many great things could be made from them,” she said. Mayer developed a recipe for an acorn flour cookie — a cookie people told her was good. Really good. She started attending food fairs and winning prizes, and began marketing the cookies under the brand “Oakmeal.”
Currently, buying commercially produced acorn flour is next to impossible. But flours from hazelnuts, almonds, and walnuts are increasingly cropping up in mainstream grocery stores — and talking to Mayer and Shepard, it’s easy to understand why. For farmers, nuts make an excellent staple crop. They grow year after year, sequestering carbon, building soil, and offering resilience in the face of erratic weather. Average yields are competitive — a mature walnut orchard, for example, can produce as much as 6,000 pounds per acre, compared with a world average of roughly 2,700 pounds from an acre of grain.
Nuts store well — acorns, for instance, can keep for over a decade. And for eaters, nuts are what nutritionists call “nutrient-dense” — they have high vitamin and mineral content relative to their weight. They offer a balanced ratio of carbohydrates, proteins, and fats. And perhaps most importantly for human tastes, they can be made into oils and flours.
Today, Shepard and Mayer are both more than 20 years into their experiments. Their work has gone largely unnoticed by large commercial farmers and food processors. But in the past five years, there’s been a sudden uptick of interest in the idea of “restoration agriculture” from the general public. Shepard’s farm has expanded to include ventures into education and design; he’s written two books; he gives talks and workshops all over the world. Mayer’s written a field guide and a cookbook on acorns; travels widely for talks, tastings, and cooking workshops; and hosts people from all over the world on her farm in Greece, where she teaches them about acorn harvesting and processing. And in the policy realm, influential groups like the Food and Agriculture Organization of the United Nations and the Intergovernmental Panel on Climate Change increasingly acknowledge agroforestry as an important component of climate-smart farms.
Shepard and Mayer know of and admire each other’s work — Shepard traveled to Kea Island several years ago to learn about Mayer’s acorn processing operation, and Mayer said Shepard’s farm “is one of the best examples of restoration agriculture in actual practice.”
“For a long time”, says Mayer, “forests were felled for our agriculture.” Mayer and Shepard believe the future can look different.
“Let’s go to the clear cuts, the abandoned farms, and let’s plant it all with food,” Shepard said. “Let’s transform this world using its own playbook, using the species and processes it’s used forever.”
Will acorns and other forest fruits be the future of staple foods?
Mayer said, “I think it would be folly if they weren’t.”