Iberian pigs in an oak-studded meadow in Badajoz, Extremadura, Spain; January 2023. Photo by Samuel de Roman/Getty


The return of silvopasture

This ancient practice, nurturing animals and trees in an ecological system, fights climate change and restores the land

by Liz Carlisle & Niki Mazaroli + BIO

Iberian pigs in an oak-studded meadow in Badajoz, Extremadura, Spain; January 2023. Photo by Samuel de Roman/Getty

As a researcher committed to addressing the climate emergency, in 2017 I (Liz Carlisle) was eagerly reading through a new ranked list from Project Drawdown of strategies to reduce emissions, when I came across a word I’d never heard before. Silvopasture. This agricultural practice was the ninth most emissions-reducing climate solution on their list, ahead of rooftop solar panels, electric vehicles, and every other agricultural technique the scientists analysed. It had the potential to reduce more than 31 gigatons of carbon dioxide, more than three times the emissions reductions possible with a transition to electric cars. And yet, despite having written three books about regenerative agriculture and interviewed dozens of environmentally minded farmers across the United States, I had somehow never heard of it. I wasn’t alone in my curiosity.

Another researcher in California was also intrigued by this promising climate solution, wondering why more of her colleagues weren’t talking about it. Following her graduate research in local food systems planning, Niki Mazaroli spent several years working on agriculture and climate projects for various local organisations before starting her own consultancy. The clients for her regional climate strategies and community food security roadmaps never mentioned anything about silvopasture. Yet, prior to California, Mazaroli had worked with sustainable agriculture institutes and demonstration projects in Ecuador, the Virgin Islands and the Pacific Islands, where this practice had a deep history and was relatively common. Overseas, Mazaroli found major international development programmes such as the US Peace Corps recommending silvopasture as a promising strategy for sustainable farming. How come it wasn’t being promoted to farmers and ranchers at home?

In 2020, we both found ourselves teaching in the Environmental Studies programme at the University of California, Santa Barbara, and we resolved to team up and investigate.

Silvopasture is the ancient practice of raising animals, trees and pasture (grasses) on the same piece of land, a form of agriculture that is common in forested parts of the world. There are many forms of agroforestry – farming systems that incorporate trees – but silvopasture is unique among these practices in that trees are integrated with animals. The physical proximity of plants and livestock doesn’t alone make up silvopasture. Rather, the practice and its benefits hinge on careful management by people, who intentionally link up the inputs and outputs of plant and animal systems such that the whole is greater than the sum of its parts. For example, trees provide shade for livestock, and fallen or low-hanging fruits can provide food for the animals too. Meanwhile, animal manure fertilises the trees, and also the animals’ browsing activity can sometimes benefit tree growth, acting as a form of pruning.

Researchers have documented numerous environmental benefits of silvopasture, including increased biological diversity, improved water quality, reduced soil erosion, improved soil water-holding capacity, and enhanced pest management. But none of these benefits have garnered as much attention as silvopasture’s enticing potential to sequester carbon. Soil carbon is primarily built up through carbon-rich substances released by plant roots, which explains why farming systems that include trees can be a climate win: unlike corn, soybeans or lettuce, trees put down roots for decades and centuries at a time, continuously pulling carbon from the atmosphere into the soil. But grazing also plays a role in recycling key nutrients such as carbon and nitrogen, which create climate chaos when released to the atmosphere in excess, but support plant and animal growth when properly integrated into living systems. A recent paper synthesising research on agricultural carbon sequestration found that silvopasture sequestered more carbon than other regenerative agriculture practices.

Equally important in a world already facing the impacts of climate change, silvopasture can help farmers improve resilience to drought, flooding and extreme temperatures. As trees and animals combine to build up soil carbon and improve soil health, one of the happy consequences is better infiltration, meaning soils can better absorb excess rain, which in turn can be handy in case of a prolonged spell of hot, dry weather. Adding trees to a typical pasture can supercharge infiltration quickly: a 2019 study found that soil infiltration rates in silvopasture systems were more than 60 times higher than those in nearby pastures just two years after trees were added to the system. Meanwhile, trees provide critical shade to livestock, a well-known method for increasing overall animal wellbeing and weight gain. Trees can also offer supplemental nutrition when there’s not much to graze over a long summer. Grazing animals, in turn, can lower fire risks by reducing fuel loads.

Why was such a promising climate solution seemingly missing in action in a state famous for its organic farms?

Silvopasture has been practised for millennia around the globe, particularly in tropical, subtropical and arid areas where the spectre of a devastating drought is never far from farmers’ minds. A popular example is the dehesa (‘grassland’) system of southern Spain, responsible for jamón ibérico (Iberian ham). Pigs graze on grasses and acorns in these ancient tree-studded meadows, and the oaks yield cork and firewood. (Similar landscapes extend into southern Portugal, where they are referred to as the montado.)

Other examples of dryland silvopasture systems include the Espinal of Central Chile and the Galajars across Iran. Across the Pacific Islands, agroforests as diverse as the island nations and cultures themselves have been fine-tuned over millennia to produce an abundance of food on small landmasses. Countless traditional smallholder systems shaped ancient agricultural practices and persist today with little academic documentation or designation. ‘Silvopasture is sometimes just called “farming”,’ says Steve Gabriel, an agroforestry specialist at Cornell University in New York, ‘whether it’s because in dryland climates animals demand shelter from the hot weather to survive, or because of cultural custom.

Recently, though, silvopasture is often part of a larger strategy of ecological and cultural restoration. In Panama and Colombia, silvopasture is helping reverse a damaging history of extractive and poorly managed cattle-ranching by Spanish settlers. And in Sardinia in Italy, traditional oak and goat silvopasture is being revived by young locals looking to stay in the countryside while also remaining connected to the global fight against the climate emergency.

Silvopasture’s prevalence globally does not mean that it has been fully realised. One estimate indicates that silvopasture is currently used on 550 million hectares globally, but could potentially be extended to 823 million hectares, thus greatly reducing the climate footprint of the global food system. Yet it’s rarely mentioned in the US, even among environmentalists and leading sustainable farm groups.

When the California state programme funding farmers to adopt climate-smart practices put out a call in 2021 for grant applications, only two of the 940 proposed projects were submitted under the category ‘silvopasture’. Indeed, the broader category of ‘agroforestry’ is only just making its way into the sustainable agriculture lexicon, following some recent and significant federal funding for climate-smart agriculture.

When we went around surveying farmers in California about their experiences with silvopasture, the most common answer was: ‘Is what I am doing really silvopasture?’ Farmers and ranchers were unsure whether they fit the formal definition of the practice, nor what the term meant in the first place.

Why was such a promising climate solution seemingly missing in action in a state famous for its organic farms and sustainable agriculture movement, especially when it seemed to be so prevalent around the world? Or were we just failing to recognise it?

Just a couple of time zones east, in the Corn Belt, we noticed a small but committed group of farmers talking a lot about silvopasture. Surrounded by monocultures of corn and soybeans, they pointed out all the problems with this dominant cropping system. Lacking biodiversity, their neighbours’ fields were dogged by pest and disease problems. Fields lay bare in the winter, with no plants in the ground to hold the soil. As a result, it often eroded away, and excess nitrogen either ran off into the watershed or escaped to the atmosphere as nitrous oxide. Seeking better ways to produce food and sustain their land, farmers started asking questions about the history of the landscape and how they might better fit into their surroundings.

In 2014, a group of Midwestern farmers, researchers and graduate students gathered for dinner to discuss a radical proposition: planting trees on farms. The next year, they booked a classroom at a food co-operative in Urbana, Illinois, gathered a few others, and called it a conference. By 2016, the group was big enough to fill a farmhouse in Elmwood, Illinois. Attendees listened to the Iowa farmer Tom Wahl describe how he and his wife Kathy Dice created a ‘you-pick’ orchard of chestnuts, persimmons, berry bushes and lesser-known fruit and nut trees on their 86 acres. The Perennial Farm Gathering became an annual event, the flagship initiative of a young and idealistic organisation, an agroforestry research and outreach nonprofit called the Savanna Institute.

‘Savanna’ refers to a curiously in-between sort of landscape, neither forest nor grassland, a diverse transition zone where grasses, trees and animals coexist. Prior to colonisation, this was the character of the Midwestern portion of the North American continent, which was stewarded by dozens of different Indigenous communities. What if, the Savanna Institute founders asked, we were to model 21st-century Midwestern farming on the structure of these ancestral ecosystems? What if food production and environmental restoration could be friends instead of enemies?

Animals of all kinds appreciated the shade of trees. In turn, their manure fertilised the trees

Settler agriculture in the US hadn’t completely ignored the promise of silvopasture. Small farmers of the 1800s and early 1900s valued woodlands on their property as key food sources for livestock. But as large-scale plantings of crops like corn, soy and wheat came to dominate the US agricultural landscape – and animals were shuffled off to factory farms – woodlands were largely eliminated. Scientists began questioning the wisdom of separating farm animals from trees as early as the mid-1960s and early ’70s, studying the benefits of pasturing livestock on pine-tree operations. Groups formed in the 1990s for the express purpose of studying and promoting silvopasture and other agroforestry practices to US farmers: the Association for Temperate Agroforestry, the Center for Agroforestry at the University of Missouri, and the National Agroforestry Center of the US Department of Agriculture. But in a country where subsidies for annual crops were ballooning, they were literally going against the grain. In 2012, the US Department of Agriculture asked farmers whether they were practising silvopasture and alley cropping, the first time such a question was included in the agency’s Census of Agriculture. Just 2,725 of a total of 2.1 million farms reported using silvopasture or alley cropping. The practice was so rare, many farmers would have had to travel out of state to find a single example.

Recognising this information gap, the Savanna Institute’s small team of researchers and farmer collaborators began an effort to collect whatever guidance they could find on growing native trees and shrubs – nut trees like pecans and chestnuts, fruit trees like the pawpaw or custard apple – and berries full of antioxidants: elderberries, honeyberries, serviceberries, chokecherries. Simultaneously, they gathered available resources about trees and shrubs that grow well in similar climates in Europe and Asia: hazelnuts, blackcurrants, cider apples and Asian pears. Quirky farmers passionate about their unusual crops and researchers bored of trying to eke out marginal yield gains in row crops contributed to the effort, building up a storehouse of data, experience and ideas.

The next step, for many of the farmers involved in the group, was raising animals in the understory of their growing orchards. They started reaching out to livestock producers, encouraging them to plant trees as well. Farmers had all kinds of reasons for giving silvopasture a try. A dairy cattle operation planted trees in hopes of improving their resilience to floods, which had recently swept away sheds, machinery and fences. A mixed livestock farm planted chestnuts, persimmons and pecans to provide forage for cattle, hogs and poultry. Animals of all kinds appreciated the shade of trees. In turn, their manure fertilised the trees. Mistakes were made but, if farmers choreographed everything right, they could raise two types of crops on one piece of land.

Although the Savanna Institute is steadily accumulating examples of such farms, it would be an overstatement to say that Midwestern farmers are flocking to plant trees and reintegrate animals. It’s not that their current farms are doing well. Corn and soy crops regularly succumb to the floods and droughts that are the new normal in the Midwest, and nutrient runoff from these farming systems creates massive water quality problems. But federal subsidies continue to make corn and soy farmers whole, regardless of whether they bring in a crop, and the agricultural industry has thus far successfully resisted serious regulatory intervention into its water quality impacts. In the perverse economy created by decades of such policy, the easiest path for farmers is to keep doing what they are doing, even though many recognise that their livelihoods rest on the willingness of lawmakers to prop up an increasingly fragile industry.

Meanwhile, the researchers involved with the Savanna Institute continue tracking the environmental advantages associated with agroforestry and silvopasture systems, slowly but steadily welcoming refugees from the commodity crop sector. By pairing animals and perennial crops in mutually beneficial configurations, these farmers are greatly reducing (or wholly eliminating) the three elements of standard Midwestern farming practice with the biggest climate footprint: ploughing, chemicals, and confined animals. At the same time, adding trees and perennial forage to the landscape draws carbon out of the atmosphere and stores it in the soil. Farmers benefit too: they can earn more per acre by stacking multiple enterprises, and diversifying their income streams reduces the risks of relying on just one or two crops. Looking on from several hundred miles to the west, we were struck by the elegance of this group’s vision: by studying the land’s past and restoring the function of the historical ecosystem, they were reversing some of the climate damage caused by industrial agriculture.

As researchers in California, which produces nearly half the nation’s fruits, nuts and vegetables, we wondered if this strategy might work in our state? Rangelands encompass more than 57 million acres in California, and grazing is the state’s most extensive land use. Orchards cover huge swaths of California too: almonds alone cover 1.32 million acres. Surely some farmers and ranchers are already combining animal, forage and tree systems – it’s a no-brainer!

It turned out it wasn’t so simple. Beyond the initial problem of finding any who had heard of silvopasture, those who had tried to establish systems like ones promoted by the Savanna Institute were running into problems.

In many cases, the trees they planted weren’t surviving. While mature trees can be drought tolerant, young ones need water, something that more extreme weather events can withhold. With climate change increasing temperatures and lengthening summer drought periods, getting trees off to a good start in life was hard. Farmers looked wistfully at 100-year-old oak trees, wondering if they could ever successfully raise a baby oak to maturity again.

Livestock were impacted by the lengthening summer droughts too, as forage ran out and the animals were triply stressed: hot, thirsty and lacking sufficient food. Farmers who had planned to buy their own animals and keep them on the land year-round ended up contracting sheep for just a few days, before sending them off to greener pastures. Meanwhile, the ever-present background of worsening wildfires in the Western US was dampening enthusiasm for investing in perennials in fire-prone regions. If a tree takes three to six years to bear marketable fruit and is burned before the costs are recouped, how does a farmer recover financially?

How might we design arid farming systems around adaptive plants again?

Ironically, this promising climate solution of silvopasture was being stymied by the impacts of the climate crisis, which had already come to California in undeniable ways. But something interesting was happening: as farmers adapted to the new climate normal, they were adapting silvopasture too. When we stopped seeing these adaptations as failures and recognised them as climate solutions in their own right, we realised that silvopasture in California was on the verge of something really exciting.

Many of the farmers we spoke to were trialling more drought-tolerant perennial plant species. Squatty carob trees with long brown pods, the source of the chocolatey carob powder and carob chips you might find in a natural food market. Mesquite: another tough, short-statured perennial whose fruits could be ground into a protein-rich flour with a cinnamon flavour. Mulberries of various shapes, sizes and colours, their sweet fruit packed with iron and Vitamin C. As they experimented with these plants, farmers learned about their long history of human use, the food cultures and cuisines that had been built around them. How might we design arid farming systems around adaptive plants again, they asked, eagerly encouraging their friends and neighbours to taste these delicacies. And: could you really count this as silvopasture if the trees were so… short? So what if the trees looked more like bushes, we responded. After all, that’s an adaptive morphology in California’s future climate.

Similarly, the classic definition of silvopasture specifies that animals remain on the same piece of forested land year-round. And yet, seasonal migration is a reasonable way for animals to adapt to drought stress, which is the new normal here. Many of the farmers we spoke with had built partnerships with contract grazers, who brought animals to their orchards during the winter but moved them to other pastures during the hot, dry summer. This made sense. But could we really call it silvopasture?

Ultimately, this semantic issue didn’t matter much to the farmers and ranchers we interviewed. Except that state and federal funding for climate-smart agriculture is tied to specific practices like silvopasture, practices that have precise definitions that agencies need to follow when awarding grants and advising farmers. This too would have to adapt, we realised.

Farming is one of the key axes of humanity’s fate in a warming world. While the current food system is responsible for a quarter to a third of global greenhouse gas emissions, transforming this food system could dramatically reduce these emissions, maybe even suck some of the carbon currently in the atmosphere back into the soil. It’s tempting to think that practices like silvopasture could reverse climate change, returning our planet to some prior Edenic state.

But the notion that humanity could simply annul its relationship with industrial agriculture, as though it never happened, is a dangerous fantasy. Climate change is here. Our planet and the plants and animals we share it with have been indelibly changed by this process. At this advanced stage in the crisis, agriculture is faced with an unprecedented challenge: how do we mimic the ecosystems around us, even as they are changing? Repairing the harm to the planet caused by industrial agriculture may sometimes involve restoring the land to its prior state, but that prior state may not always be possible.

What is possible is restoring the relationships – among plants, animals and people – that not only rebalance the climate cycle but more deeply tie us to places and the people with whom we share them. Instead of looking to static models of how to farm sustainably, we have to deepen our dialogues with the plants and animals in this boat with us, and focus more on dynamic principles rather than prescriptive practices. When we add more perennials to our farms, we decrease the nitrous oxide emissions that come with bare soil. When we plant those perennials in diverse mixtures, they provide ecosystem services like fertility and natural pest control, so we don’t need fossil fuel-based chemicals to accomplish those things. When animals are integrated into cropping systems, instead of cooped up in factory farms, their manure becomes healthy soil, not just methane emissions. Maybe that looks like a pig lolling around in the shade of a carob tree, happily munching on fallen pods. Or a flock of chickens pasturing under a grove of mulberries. Maybe it’s a simple breakfast of eggs, carob-fed sausage and mesquite muffins, shared among people who know in their bodies that they belong to this place, that its healing is their own healing.