About Forest GardeningLet's explore the edible forest gardening idea in some detail. The forest gardening vision leads us to explore forest ecology. Forest ecology is the basis for effective design and practice. This synopsis not only explains the fundamentals of forest gardening, but its structure parallels the contents of the two-volume book Edible Forest Gardens by Dave Jacke with Eric Toensmeier.
Picture yourself in a forest where almost everything around you is food. Mature and maturing fruit and nut trees form an open canopy. If you look carefully, you can see fruits swelling on many branches—pears, apples, persimmons, pecans, and chestnuts. Shrubs fill the gaps in the canopy. They bear raspberries, blueberries, currants, hazelnuts, and other lesser-known fruits, flowers, and nuts at different times of the year. Assorted native wildflowers, wild edibles, herbs, and perennial vegetables thickly cover the ground. You use many of these plants for food or medicine. Some attract beneficial insects, birds, and butterflies. Others act as soil builders, or simply help keep out weeds. Here and there vines climb on trees, shrubs, or arbors with fruit hanging through the foliage—hardy kiwis, grapes, and passionflower fruits. In sunnier glades large stands of Jerusalem artichokes grow together with groundnut vines. These plants support one another as they store energy in their roots for later harvest and winter storage. Their bright yellow and deep violet flowers enjoy the radiant warmth from the sky. This is an edible forest garden.
What is Edible Forest Gardening?
Edible forest gardening is the art and science of putting plants together in woodlandlike patterns that forge mutually beneficial relationships, creating a garden ecosystem that is more than the sum of its parts. You can grow fruits, nuts, vegetables, herbs, mushrooms, other useful plants, and animals in a way that mimics natural ecosystems. You can create a beautiful, diverse, high-yield garden. If designed with care and deep understanding of ecosystem function, you can also design a garden that is largely self-maintaining. In many of the world's temperate-climate regions, your garden would soon start reverting to forest if you were to stop managing it. We humans work hard to hold back succession—mowing, weeding, plowing, and spraying. If the successional process were the wind, we would be constantly motoring against it. Why not put up a sail and glide along with the land's natural tendency to grow trees? By mimicking the structure and function of forest ecosystems we can gain a number of benefits.
Why Grow an Edible Forest Garden?
While each forest gardener will have unique design goals, forest gardening in general has three primary practical intentions:
- High yields of diverse products such as food, fuel, fiber, fodder, fertilizer, 'farmaceuticals' and fun;
- A largely self-maintaining garden and;
- A healthy ecosystem.
As Masanobu Fukuoka once said, "The ultimate goal of farming is not the growing of crops, but the cultivation and perfection of human beings." How we garden reflects our worldview. The ultimate goal of forest gardening is not only the growing of crops, but the cultivation and perfection of new ways of seeing, of thinking, and of acting in the world. Forest gardening gives us a visceral experience of ecology in action, teaching us how the planet works and changing our self-perceptions. Forest gardening helps us take our rightful place as part of nature doing nature's work, rather than as separate entities intervening in and dominating the natural world.
Where Can You Grow an Edible Forest Garden?
Anyone with a patch of land can grow a forest garden. They've been created in small urban yards and large parks, on suburban lots, and in small plots of rural farms. The smallest we have seen was a 30 by 50 foot (9 by 15 m) embankment behind an urban housing project, and smaller versions are definitely possible. The largest we have seen spanned 2 acres in a rural research garden. Forest gardeners are doing their thing at 7,000 feet (2,100 m) of elevation in the Rocky Mountains, on the coastal plain of the mid-Atlantic, and in chilly New Hampshire and Vermont. Forest gardening has a long history in the tropics, where there is evidence of the practice extending over 1,500 years. While you can grow a forest garden in almost any climate, it is easiest if you do it in a regions where the native vegetation is forest, especially deciduous forest.
Edible forest gardening is not necessarily gardening in the forest, it is gardening like the forest. You don't need to have an existing woodland if you want to forest garden, though you can certainly work with one. Forest gardeners use the forest as a design metaphor, a model of structure and function, while adapting the design to focus on meeting human needs in a small space. While you can forest garden if you have a shady site, it is best if your garden site has good sun if you want the highest yields of fruits, nuts, berries, and most other products. Edible forest gardening is about expanding the horizons of our food gardening across the full range of the successional sequence, from field to forest, and everything in between.
Edible forest gardens mimic the structure and function of forest ecosystems—this is how we create the high, diverse yields, self-maintenance, and healthy ecosystem we seek for our garden. It is therefore critical to understand forest ecology and its implications for design. Four aspects of forest ecology are key: community architecture, ecosystem social structure, the structures of the underground economy, and how the community changes through time, also known as succession. Brief discussions of each of these aspects and examples of their influence on garden design and management follow.
Contrary to the prevailing wisdom on forest gardening, vegetation layers are only one of the architectural features important in forest garden design. Soil horizon structure, vegetation patterning, vegetation density, and community diversity are also critical. All five of these elements of community architecture influence yields, plant health, pest and disease dynamics, maintenance requirements, and overall community character. For example, scientific research indicates that structural diversity in forest vegetation, what we call "lumpy texture," appears to increase bird and insect population diversity and to balance insect pest populations—independent of plant species diversity. Learning how and why plants pattern themselves in nature and about the effects of the diverse kinds of diversity on ecosystem function can add great richness to the tool box of the forest gardener.
The unique inherent needs, yields, physical characteristics, behaviors, and adaptive strategies of an organism govern its interactions with its neighbors and its nonliving environment. They also determine the roles each organism plays within its community. The food web is one key community structure that arises from each species' characteristics. Organisms also form various kinds of "guilds" that partition resources to minimize competition or create networks of mutual support.
When we design a forest garden, we select plants and animals that will create a food web and guild structure, whether we know it or not. It behooves us to design these structures consciously so we can maximize our chances of creating a healthy, self-maintaining, high-yield garden. For example, the vast majority of solar energy captured by natural forest food webs ends up going to rot. We can capture some of this energy for our own use by growing edible and medicinal mushrooms, most of which prefer shady conditions. We can design resource-partitioning guilds by including plants with different light tolerances in different vegetation layers, for instance, or mixing taprooted trees such as pecans and other hickories with shallow-rooted species such as apples or pears. We can build mutual-support guilds by ensuring that pollinators and insect predators have nectar sources throughout the growing season. Insights into the guild structure of ecosystems provides clear direction for design as well as research into many aspects of agroecology.
The Underground Economy
The workings of nature's "underground economy" are a mystery, but the dynamics of this ecosystem are fundamental to the workings of all terrestrial communities. What is the anatomy of self-renewing soil fertility? How do plant roots interact with each other and their environment? What roles do microbes and other soil organisms play in our forest gardens, and how should we interact with them?
Plants are critical components of the structure that creates self-renewing fertility in natural ecosystems. They plug the primary nutrient leaks from the soil and energize a networked system of plants, soil organic matter, soil organisms, and soil particles that gathers, concentrates, and cycles nutrients conservatively. Maintaining perennial plant cover greatly aids this process. In addition "dynamic accumulator" plants like comfrey (Symphytum officinale) selectively accumulate mineral nutrients to high levels in their leaf tissues, adding them to the topsoil each fall. As we enter the post-oil age, our understanding of the anatomy of self-renewing fertility will become more and more critical to our success in temperate climates.
Understanding the dynamics of woody and herbaceous plant roots is critical to learning how to design and manage forest gardens. In what patterns do plant roots grow, why, and when? While the majority of tree roots grow in the top two to three feet of soil, it turns out that fruit trees that can get even a small percentage of their roots deep into the soil profile produce more fruit more consistently, resist pests and diseases more effectively, and live longer than those that have only shallow root systems. Good pre-planting site preparation is therefore a highly worthwhile endeavor. Root system understanding provides a solid foundation for plant species selection and polyculture design.
Soil organisms perform numerous critical functions in forest and garden ecosystems, and we can easily disrupt these allies and their work with unthinking actions. Luckily, basic forest gardening principles like using mulch and leaving the soil undisturbed provide just the kind of benign neglect our tiny friends need. However, good soil preparation can make all the difference, as well. For example, compacted or poorly drained soils can severely hamper the development of healthy soil food webs, and hence healthy forest gardens. Understanding the soil food web also provides insight into how to manage for healthy mycorrhizal fungi populations and how to ensure that nitrogen-fixing plants actually do their soil-building work.
Ecosystems are dynamic, and ever-changing. Plant succession used to be thought of as the directional change of a community over time from "immature" stages toward a "mature" "climax" community typical of a given region and environment, such as a field changing to shrubland and then to, say, oak-hickory forest. However, new models of succession have arisen in recent years that articulate the complex reality of plant community change over time without so blatantly projecting human cultural constructs upon natural phenomena. Plant succession is nonlinear and occurs patch by patch within the ecosystem, and rarely do ecosystems ever attain a climax or equilibrium state. Disturbances of various kinds are a natural part of every successional process—windstorms, fires, insect attacks, and human intervention. Nonetheless, linear succession to a "horizon" is a valid model to use when designing forest garden successions, as are various other permutations that mimic garden crop rotations or represent an ever-changing dance responding to the forces, needs, and whims of the moment.
While the practical applications of these new successional theories are of necessity somewhat vague, we do know that the most productive stages of succession are those in the middle—such as shrublands, oldfield mosaics, and woodlands—not necessarily full-fledged forests. In addition, most of our developed tree crops are species adapted to such midsuccession environments. Our highest yielding forest gardens are therefore most likely to contain, not the dense tree canopies of late succession forests, but lush mixtures of trees, shrubs, vines, and herbs all occupying the same space in patches of varying density and character. Succession theory also teaches us many different approaches to directing ecological succession in our gardens.
At its simplest, forest garden design involves choosing what plants to place in your garden in which locations, at which times. However, these seemingly simple acts must generate the forest-like structures and functions we seek, and they must also achieve your design goals. A forest garden design process, then, must be information intensive if it is to achieve even moderately complex objectives. Therefore, begin by articulating your goals and assessing your garden site. Then you can select and apply design patterns, ecological principles, and plants in such a way that you integrate your goals and the site into a coherent whole. The challenge is to array the available design elements to create a set of ecosystem dynamics that will in turn yield the desired conditions of high yields, maximal self-maintenance, and maximum ecological health as inherent by-products of the ecosystem. You can use design patterns drawn from natural ecosystem examples or invent your own patterns that solve specific problems your design faces to help you do this. Patterns also arise from the requirements of the goals themselves and from a deep understanding of the site's characteristics. The goals guide the site analysis and assessment, and the site assessment discovers the design.
We recommend designing on paper, at least initially, so you can make as many mistakes as possible there, and correct them before putting anything into the ground. On-site design techniques can also work well, especially for those who prefer to avoid the mapping process. Careful design of plant spacing is a critical piece of the puzzle, in any case. Planting too closely together is the most frequent mistake that forest gardeners around the world have made. We hope that a more robust and explicit design process will help us all avoid such common mistakes and make some newer mistakes that are more interesting so we can learn from the experience.
Good site preparation is a critical precursor to planting your forest garden. Your site analysis and assessment should help you understand your site's limitations so that you can decide whether or how to alter the site, or how to adapt to the conditions present. Soil compaction, for example, is exceedingly common in most urban, suburban, and even rural sites, and it can severely restrict root growth, water movement in the soil, and the health of soil organism communities. Double-digging, chisel plowing, radial trenching, and other techniques can help you deal with severe compaction, while the simple act of mulching the soil and planting deep-rooted perennials will eventually address slight compaction. Other common site preparation challenges include poor soil texture, shallow soil depth, road salt, and persistent weeds.
Proper stock selection, planting, and mulching techniques can also have major long-term effects on plant vigor and productivity. Many woody planting specimens have been transplanted multiple times, and these can have kinked, circling, or damaged roots that will result in plant stress and even an untimely death. Carefully examine your specimens before you buy to ensure a quality root system, or purchase bare root stock so you can see the whole root system before planting. In fine-textured soils, the edges of the planting hole often become smeared to a smooth, impenetrable surface as a natural part of the digging process. This can severely restrict root growth and cause water to pool in the planting hole. Breaking up the edges of the hole with a spading fork allows roots and water into the surrounding soil. This needs to become a common planting practice, as do proper planting depth, proper mulch depth, and effective sheet mulching techniques.
Once the garden is in the ground, the longest and most satisfying phase of forest gardening begins: management, harvest, and coevolution. Potentially the hardest part of this phase is learning to do less and let the system take care of itself, as well as knowing when to intervene and how. These questions are, however, part of the process of shifting from a paradigm of command and control to one of cocreative participation as part of a natural system. As we observe ourselves and our gardens through the dance of the seasons, we will learn the most effective ways of guiding the garden ecosystem's evolution, we will select and breed ever more delectable crops for all the niches of the garden ecosystem, and we will begin to realize the full potential of forest gardening as a tool for cultural and personal evolution, not to mention cultural and personal survival in a post oil world. Welcome to the adventure!
Good information on plant, animal, and mushroom species and their ecological characteristics is essential for good forest garden design. You'll need data on the plant's size, form, and habit, its rooting patterns, hardiness and other tolerances and preferences, as well as its native habitat, human uses and ecological functions. Information that helps you design habitat for beneficial wildlife such as insects, frogs, toads, salamanders, and birds is also crucial. Ideally, this information will come in a variety of formats and levels of detail that relate to different parts of the design process. The appendices of Edible Forest Gardens provides this kind of information on over 600 useful plant species and a plethora of beneficial wildlife for your designing and gardening pleasure.
Figure 1: The E.F. Schumacher Forest Garden in Totnes, Devon, England courtesy of Martin Crawford, Agroforestry Research Trust (www.agroforestry.co.uk).
Figure 2: American persimmon (Diospyros virginiana) fruits. Photo by Eric Toensmeier courtesy of Tripple Brook Farm nursery (www.tripplebrookfarm.com).
Figure 3: The front yard at Charlie Headington and Deb Seabrook's home and forest garden, Greensboro, NC. Photo by Dave Jacke.
Figures 4, 6, and 7: Illustrations from Edible Forest Gardens, volume 1 by Elayne Sears.
Figure 5: Illustration from Edible Forest Gardens, volume 1 by Peter Holm, Sterling Hill Productions (www.sterlinghill.com).
Figure 7: Photo by Dave Jacke.
Figure 8: Martin Crawford in front of littleleaf linden (Tilia cordata), from which he eats the leaves. Martin coppices these trees to keep the leaves handy and to maintain continuous fresh green growth. Photo by Dave Jacke.