Over the past few years, I’ve been researching food systems. Not just in the political or economic sense but from an ecology perspective. Most of us have a very set vision of a farm: tilled fields planted every year with annual crops like vegetables and grains. But this isn’t the only option. Many food systems around the world also revolve around plants that live for years in the same place—perennials like shrubs and trees. Through my research, I connected with permaculture teacher and author Tao Orion who lives in Oregon and she frames her understanding of our food systems through a term you might remember from high school biology. It’s called succession.
"So succession is basically a term that describes the process of an ecosystem moving from, say, a big disturbance like a landslide or a volcano where you kind of just like zero everything out all the way into what's called a climax ecosystem," Tao explains.
Someone once described a climax ecosystem to me as the end stage of a plant community — the ecosystem that develops in a place after decades or even centuries without a large disturbance. For instance, in New England, an undisturbed patch of land will usually become an old-growth forest — that’s what Tao means by a climax ecosystem. A pioneer landscape, in contrast, is filled with the plants that first show up when some kind of disturbance brings the land back to bare earth.
"So the first species that come in are called pioneer species, and they kind of often have deep taproots or seeds and fruits that attract animals that come in and eat and poop and bring in seeds from other areas," she says.
Pioneer species by definition are fleeting. If you’ve ever walked by an abandoned city lot or an old farm, you’ve seen succession in action. Bare earth eventually fills in with grasses and flowers, then shrubs and eventually trees start showing up, and after decades, there’s a forest.
"So one of the interesting things about succession and food production is in a kind of conventional European agricultural context the way that succession is managed is by basically setting it back to zero every year."
This is a perspective on agriculture I hadn’t thought of until a few years ago. Most farm plants are pioneer species — plants like tomatoes and potatoes and wheat and corn that like bare earth. Currently, about half of our planet’s habitable land is used for agriculture. Two-thirds is for grazing animals, and the other third grows crops. And 90 percent of this cropland — about 1.4 billion hectares — is disturbed — tilled or ploughed, every year.
"So pioneer type species, like annual grasses like wheat, rye, oats, barley, and beans thrive in that kind of open environment."
This means we’re bring succession back to zero over a huge amount of land every year. This practice has big impacts on soil health and climate change and farm fertility — and the scale of this annual disturbance has grown exponentially in the past hundred years. Obviously, annual agriculture has been practiced all over the world for a long time, but until the past century, most people in most places didn’t rely only on annual agriculture — they managed their land as a mosaic — so that while some foods were grown in fields, many others came from landscapes in later stages of succession.
"Many of these systems are perennial in nature and they rely on longer-term kind of management of ecological characteristics that favor longer-lived species that provide nuts and fruit and habitat for animals, but the basic idea there is that the management rather than relying on setting back succession to zero is kind of like doing this intermediate level of disturbance usually through prescribed fire," Tao says.
In many places, Indigenous food production combines both techniques: on some land succession is brought back to bare earth so that an area can be cleared and planted with annual crops, and bigger tracts are managed with regular fire to promote a mix of perennial shrubs and trees that produce nuts and fruit and create habitat for game species. Cape Cod is a perfect example — Wampanoag oral histories and charcoal sediment layers pulled from local ponds tell us that historically, this kind of mosaic food production has been the norm locally. For me when I first heard this, it was a new way of thinking about the way we produce food — one where we humans aren’t just farmers, but landscape managers with a huge ecological impact.
