Contents
Foreword IX Acknowledgments XI About This Book XIII Prologue XV Chapter 1
WHAT IS SILVOPASTURE?
1
Attitude Determines Success Defining Silvopasture and Agroforestry The Main Components of Silvopasture The Benefits of Silvopasture Challenges to Silvopasture Priorities in Silvopasture
Chapter 4
MANAGING THE WOODS FOR GRAZING
Chapter 2
PERSPECTIVES FROM ECOLOGY AND HISTORY
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Lessons from Forest Ecology Lessons from Grassland Ecology Lessons from Savanna Ecology Traditional/Historical Silvopasture “Turning Livestock into the Woods”: A Disappointing Legacy of American Forest Grazing Chapter 3
TAKING CARE OF GRAZING ANIMALS What Is “Good” Silvopasture Grazing? The Mandate: Rotational Grazing
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The Role of Animal (and Human) Behavior Let’s Get Specific: Choosing an Animal The Problem with Pigs Chickens, Turkeys, Ducks, and Geese: Low-Risk Silvopasture A Rant on Ruminants Choosing a Ruminant Infrastructure: Water, Shelter, and Fencing So Many Choices! The Final Piece: A Grazing Plan
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Climate Change, Woodland Conversion, and Managing Like Old Growth Different Types of Forests Assessing a Woods Determine Stocking Thinning the Woods Abandoned Pasture / Cropland and Hedgerows Understanding Hedgerow Design Methods of Clearing What to Do with All That Brush? Establishing Forage After Thinning or Clearing Regeneration: An Event in the Life of a Forest Summary: Converting Woods to Silvopasture Chapter 5
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BRINGING TREES INTO PASTURE
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Assessing Pasture Making a Pasture Patch Map
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Designing for Trees: When to Add Trees to Pasture, and When Maybe Not Pasture Productivity Tree Spacing and Patterning Selecting Trees for Silvopasture Best Bets for Silvopasture Trees Conifers and Silvopasture: Old Plantations and Timber Production Integrating Silvopasture into Specific Tree Crop Systems Summary: Choosing Trees and Systems Planting Trees Review
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Chapter 6
PUTTING IT ALL TOGETHER
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Key Silvopasture Points Designer’s Checklist The Big Picture: Economics and Marketing Getting Help: Support from Government, Industry, and Private Consultants Looking Ahead: Tenure, Ownership, and the Next Generation Epilogue 263 Notes 267 Index 281
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What Is Silvopasture?
The foundational concepts of silvopasture challenge our notions of modern agriculture and land use as we know it. For centuries European colonizers of North America have engaged in practices that separate the field from the forest, and even the food from the animal. In silvopasture, trees, animals, and forages for those animals are integrated as a whole system that is greater than just the sum of these parts. The word is a combination of the Latin root word silvo- (as in silviculture or forestry) and pasture, which implies grazing. Such a system offers not only the promise of ecological regeneration of the land but also an economic livelihood, and even the ability to farm extensively while adapting to a changing climate. And as we will learn, planted silvopastures rank among the most effective approaches to sequestering carbon while farming the land and soil. Silvopasture is not, however, as simple as allowing animals into the woodlot, or planting trees into the pasture. It is, and must be, intentional, steeped in careful observation skills, and flexible to the dynamics of such a complex ecology. It requires a farmer who is proficient in understanding grassland ecology, forestry, and animal husbandry at once. She or he does not need to be an expert in all of these disciplines, but rather familiar enough to make decisions on a wide variety of timescales. A silvopasture system will inevitably look different from year to year, and careful design, creativity, and visioning for the future are all part of the equation.
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If we travel away from North America, silvopasture is sometimes just called “farming,” whether it’s because in dryland climates animals demand shelter from the hot weather to survive, or because of cultural custom. Though this type of mixed farming is common in Europe, South America, and many other regions worldwide, it never arrived with the colonization of the temperate eastern and midwestern parts of the United States—the regions where the conversation in this book is focused. This lack of transfer was likely because the forest ecotypes found by early settlers were so dense, diverse, and vast. During their imperialism, Europeans spent most of their time clearing trees, opening land to the plow. A well-documented fear of the woods1 meant that harsh lines were drawn between field and forest in the minds of early colonists, as they came to be a dominant force on the American landscape through exploitation of both the land and its longtime inhabitants. Prior to colonization, native peoples had cultivated a wild ecology that included mixed woodlands, forests, and grasslands. They traditionally hunted wild game for food while cultivating a mosaic of gardens and farms for staple crops. Their main tool—fire—created a mixed woodland in many places, where trees were widely spaced and the concepts of “field” and “forest” were blended on a continuum, much more mixed in their composition. Some crops, such as the three sisters of corn, beans, and squash, were widely cultivated on an annual basis,2 while others such as black walnut,
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Silvopasture
Figure 1.1. A honey locust silvopasture at the Virginia Tech research farm. This example shows the potential for animals to forage both grasses and forbs, as well as tree fodders from previously cut trees. Photo by Gabriel Pent.
apple, and peach orchards were a multigenerational community effort.3 Today we are left with a legacy of not only the choices of early American settlers to extensively clear land, but also the footprint of modern industrial agriculture, which has largely stripped the soil of nutrients and degraded its structure. Trees are all but gone from the pasture, limited to the occasional hedgerow that a farmer happened to keep. Farm woodlots are an afterthought for productive use, only occasionally visited for timber or firewood harvest. Animals are confined and fed predetermined rations of food imported from places far away. Yet despite this being the dominant farm paradigm, we see the slow emergence of a new type of agriculture, one that re-blends the best that field and forest have to offer. This practice is known as
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agroforestry, and silvopasture offers one of the most promising agroforestry practices for this time in history. While silvopasture as a practice is relatively small in the temperate United States, interest and momentum are growing. Examples of specific systems are what really give us a sense of the possibilities. Just a short list of the varied systems includes: • A honey locust plantation for shade, pod production, and leaf fodder combined with sheep grazing in Virginia (see figure 1.1). • Oxen and pigs used to clear forested land in New Hampshire to create space for new market gardens and orchards. • Turkey used for controlling pests and fertilization on an apple cider and asparagus farm in New York.
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What Is Silvopasture?
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There is another big benefit that is not often the first reason for farming in silvopasture but one that will continue to prove critical: climate change mitigation. As described later in this chapter, research shows that mixed systems such as silvopasture sequester significant amounts of carbon from the atmosphere better than forests or grasslands alone—which represents a substantial part of the potential solution to global warming. Equally compelling is the positive aspect of silvopasture to buffer against the unpredictable nature of change: increased rainfall, longer droughts, and more intense storm events that are an inevitable part of our future.
Attitude Determines Success
Figure 1.2. Sheep grazing under four-year-old black locust trees, one of the most useful and versatile of all trees for silvopasture.
• Sheep who graze the understory of hybrid chestnut and hickory plantings to make for an easier harvest for a nut nursery in Minnesota. • Cattle maintaining the understory and providing short-term yields (meat) for southern pine plantations in Alabama. Each of these examples is quite unique and different from the others, yet they all share common goals, components, and philosophies. The systems may take several years to establish, but many farmers see the benefits of this type of production in the longer-term view. Some of these benefits include better support of animal health, more yields off the same acreage, reduced inputs to deal with pests and keep fields mowed, and healthier soil.
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All this sounds very positive, but how do we get there? It’s important to note up front that while we have a lot of knowledge about silvopasture’s parts (pasture management, forestry, animal science, and so on), the combining of systems in the temperate United States is still a bit of a grand experiment. As such, it’s important to identify potential hazards and pitfalls, and proceed with caution as we design and implement. One of the largest challenges is to be thinking in the long term—decades and generations—rather than in just months or years. When a vegetable farmer tries out a new technique, he or she gets feedback if it’s working (or not), usually that same year or maybe the next. Damage to trees can take upward of a decade to show up, however, and by the time we notice the symptoms, it’s often too late to do anything about it. The aim of this book is to articulate the components and design of silvopasture systems and highlight best management practices so that those interested in working silvopasture into their land-use strategy do so in the best possible way. A combination of research into the practice, and the experiences of farmers on the ground, provides readers with a solid list of dos and don’ts as they translate the information to their own context. By no means is this list complete. Each silvopasture plot, even within the same farm, is unique. It expresses itself differently depending on the year, season, weather patterns, animal behavior, and choices the farmer makes. Each element has its role to
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Silvopasture
play: The plants translate sunlight into plant mass, then the animals harvest the green parts and produce foods; the humans harvest wood, food, and materials; and the fungi, bacteria, and other microbes balance the soil. In this great dance, we humans ultimately play the role of determining the fate of each player, a role none of us should take lightly or for granted. The more we as farmers act in response to the clues each element of the farm gives us, the less work we have to do, and the more ecological and sustainable is the system. Rather than thinking of ourselves as “the deciders” or as having dominion, we are better off seeing our role as that of providers and orchestrators: We provide the needs of each living element in the system, so they may thrive. In doing this we orchestrate the type, frequency, and duration of the interactions among organisms. If we wait too long to move our animals, the trees or forage might suffer. If we don’t keep our animals on fresh ground, they might succumb to malnourishment or disease. If we time everything right, and sometimes with some luck, all parties benefit. To some, conducting this symphony of nature is also known as “work.” Many who already raise animals are resistant to rotational management because it’s “too much work.” And in some ways it is more work—especially in the establishment phase of the process. Yet this book will show how the notion of work is relative, and that in the end it isn’t about more or less work, but about what kind of work the farmer does. Silvopasture is not for everyone. It is for someone who reads descriptions of a practice that is part science and part art, and gets excited by it. It is for those farmers who love being part-time ecologists, naturalists, mechanics, and engineers, all wrapped into one. It is for those who are eager to ask questions and not necessarily find out the answer right away. It is for those who find farming to be a lifestyle, and not only a job, though it does need to pay. It is for those who want to grow and change in their thinking and perspective as they form a more intimate understanding of the great wide world we are fortunate enough to inhabit. Ultimately, those who possess a desire to farm in a way that balances practicality with creativity, determination with flexibility, and planning with adaptation
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will succeed not only in farming, but in life. The willingness and eagerness to rise in the morning and seek to make the system more efficient, and to better support ecological good, as well as the positive health and well-being of all creatures involved (human and not), is essential. This is paramount not only to a good life, but to the overall survival of our species in a world that is quickly changing.
Defining Silvopasture and Agroforestry Silva in Latin means “forest” or “woods.” Pasture comes from the Latin pastura, meaning “feeding” or “grazing.” For the purposes of this book, the practice of silvopasture is defined as: The intentional combination of trees, domesticated animals, and forages as a multilayered system where each benefits from its relationship to the others, with multiple yields harvested from the same piece of land. In other words, the presence of these three groups of living organisms, along with the deliberate and intentional design on the part of the farmer, is what defines an active silvopasture system. This leaves the possibilities wide open for its application—there is not a limit to the practice based on tree spacing, on canopy density, on whether the animals are grazing planted grasses or foraging for insects and roots, or on other factors. Silvopasture is considered one of six temperate agroforestry practices, five of which have been recognized by the USDA in an effort to help landowners and farmers understand the possible options. Many consider forest gardening to be an important sixth practice, especially for farmers in urban and peri-urban areas. Each practice relates to another, and you could often argue over exactly which practice is being utilized on a particular site. Often multiple practices are employed simultaneously. The named practices are: Silvopasture. The intentional mixing of trees, animals, and forage.
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What Is Silvopasture?
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AGROFORESTRY SYSTEMS Wellspring Forest Farm
Silvopasture
Windbreak
Forest Gardening
Riparian Buffer
Forest Farming
Figure 1.3. Our farm uses multiple agroforestry practices, many of which overlap in our production systems. Where there are gaps are areas we are actively planning to bring in more trees.
Forest farming. Cultivating non-timber crops under the canopy of an existing forest (for more, see my previous book with Ken Mudge, Farming the Woods). Alley cropping. Growing traditional field or row crops (hay, grain, vegetables) in between rows of trees. Windbreaks. Growing a multistoried hedge of trees to mitigate the effects of wind. Riparian buffers. Tree and woody shrub plantings along a water’s edge. Forest gardening. Growing a diverse set of edible and medicinal plants in a way that mimics forest ecology and evolves into a forest. Each of these practices has its nuances, and it’s easy to see how someone could plant trees in their pasture both to benefit livestock and to act as a windbreak, for example. The designation of these practices is merely to encourage thinking around the main functions of each
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approach. Readers should take note that the lines are thin between each of these, and that there are hundreds of other named agroforestry practices that have been articulated worldwide.
Our Farm— and Further Blurring of Lines At Wellspring Forest Farm & School, my wife and I produce mushrooms, maple syrup, pastured lamb, duck eggs, and elderberry extract, all in agroforestrybased systems. The mushrooms grow underneath the canopy of our sugarbush, which provides maple sap and syrup each season (aka forest farming), while our elderberry plantings are part of the design for riparian buffers on two waterways that flow through the 35-acre property (10 owned and 25 leased). We have planted a windbreak of alder, locust, and willow to help buffer the strong winter winds that visit our land.
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Silvopasture
Interestingly enough, the animals have found their way into almost every inch of the landscape, and thus the practice of silvopasture is both throughout the landscape and intertwined with the other agroforestry systems on the farm. In this way, while silvopasture is a specific practice, it often works well as part of other practices, depending on the timing and season. For instance, we rotate our ducks through the maple grove three to four times a season to reduce slug pressure on the mushrooms. Our sheep rotate through riparian buffer zones during dry times, which minimizes harm to the more sensitive ecosystem while providing good forage during the hotter summer months. So much of what we have found at the farm is that paying attention and being flexible are key. Nature often offers small windows of opportunity for the right conditions to play out, and we need to be ready as farmers to take advantage of all that is occurring at a given point in time.
The Main Components of Silvopasture Since this is a book primarily about the practice of silvopasture, it is useful at the outset to offer an overview of the key principles and approaches that are part of the system, regardless of the specific species or site context at play. Whether you choose to graze sheep in a Christmas tree farm, move cows through a walnut plantation, or graze chickens through an apple orchard, these elements are universal for successful silvopasture.
1. Silvopasture can be established in existing woodlands, or trees can be brought into pasture. One of the nice aspects of silvopasture is that you can establish a system on almost any type of land. Of course, establishing it in existing forest is in many ways a very different process than bringing the trees into open pasture. The similarities and differences of establishment in such different contexts will be discussed in detail in chapters 4 and 5. The only land types on which we might consider avoiding silvopasture are very sensitive areas such as
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wetlands and healthy, maturing hardwood forests that might be best left to their own process of succession. Given that silvopasture has an experimental aspect to it, working first on more marginal lands is the best way to begin, offering the opportunity to learn with lower stakes. In ecological approaches to farming, it’s good to practice precaution, easing into the development of novel systems, all while carefully monitoring for any adverse impacts.
2. Animals are matched to land type and successional stage. It’s critically important from the outset that the appropriate animal is chosen for a given site in order to reduce the potential of inflicting damage on the landscape. Animals are incredible at what they do, but it cannot be overstated that they have just as much potential to do harm as they do good. While we will cover considerations for animals in depth in chapter 3, here is a short list of potential risks for given species: Cows. Excessive stocking/duration with their weight could damage soil and tree roots, as well as cause erosion; also, they can easily destroy young trees. Pigs could root and trample desired vegetation and make a moonscape of your woods or pasture in a very short period of time. Pigs are the most challenging animals to incorporate into silvopasture. Sheep and goats. Depending on forage type, sheep and goats could overgraze the landscape and/or strip the bark off young trees, killing them. Poultry could scratch or root down to bare soil and damage roots and plantings. You can see from the above list that most of the problems can be avoided by doing proper assessment of the land and engaging with the animals to ensure they are moved before they do harm. The key elements of stocking rate, density, and duration in a paddock come into play here; they must be well designed, and redesigned each year, to optimize the system. In addition to choosing the right type of animal for the system, careful selection of the specific breed is an essential task. Some breeds are able to utilize a wider
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What Is Silvopasture?
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Figure 1.4. Silvopasture can be designed from either existing forest or pasture. On the left, cattle graze in an existing woodlot thinned for silvopasture. On the right, cattle graze among established orchard trees. Photos courtesy of Eric Toensmeier (left) and USDA-SARE (right).
range of forage and conditions, whereas others are not as willing to be as flexible. Chapter 3 discusses the role animals play in silvopasture systems in much greater detail.
3. Animals are always on a rotation.
Figure 1.5. Many sheep and goats will eagerly strip the bark of young trees such as this black locust, which can set the trees back or even kill them if the damage is too severe. Still, in many cases such as this, the trees recover even after severe damage so long as the entire bark layer isn’t severed.
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Grasses evolved alongside grazing herbivores, and while it might be surprising, they arguably benefit from being grazed so long as they have a rest period. For wild grazing animals, such rest is achieved when grazing animals need to move on to new places because of the threats predators pose or from seasonal changes to weather and climate. In the context of modern grazing systems, designated paddocks, the farmer, and electric fencing act as the “predator.” When the animal consumes the top of a plant, a proportion of the roots are sloughed off or deposited into the soil, which contributes organic matter content. After plants are grazed, a rest period is critical to their recovery, where the shoots grow back. Overgrazing means these plants take a longer time to recover, while severe overgrazing means the plant might die altogether. Moving animals is also good for them, as they have reduced exposure to disease risks and receive the highest-quality food possible during the season. The rotational process also benefits the farmer’s bottom line, as it’s been shown to improve the quality and quantity of forage on the pasture.4 More intensively
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