Part 3: Structures That Make Patterns and Flow (Elements of Design)
Updated: Mar 23, 2019
ELEMENTS OF DESIGN (cont'd) Section two, General Overview of Structure
To review the last section, we began with some general advice on design. Many of the ideas centred on making informed decisions when forest gardening. We included a discussion of several leading key permaculture designers, innovators and forest gardening figures and their works. Later we introduced Toby Hemenway's Gaia's Garden textbook bestseller. Finally included a discussion on the comprehensive Edible Forest Gardens and the work from Patrick Whitefield. CLICK here to open a slide show of the presentation that accompanies this article (slides references within).
Natural patterns and shapes are an essential aspect of design in permaculture projects, including forest gardens. The edges of walkways, buildings and other pre-existing structures serve as starting points since they set limitations on the plan. Stone materials offer advantages to forest gardens from their unique solar heat storage properties and drainage abilities. Using natural patterns such as leaves and branches, efficiently spaced plants can be organized according to their size and uses. Keyhole beds are one of the common ways to make good use of bed space since they offer more growing bed space similar to how sizeable real estate lots are often at the end of cul-de-sacs in subdivisions.
In this third article in the series, the second section on design structures, we explain zone and sector methods for organizing spaces in the forest garden system. We continue to briefly explore commonalities between city ecology and forest ecology looking at patterns and different needs within a shared area. We will introduce the theory and practice of mounding techniques and discuss the pathway designs for wheelbarrow use. Later, we will explain mounds and depressions (pits) and how they mimic the old growth in a forest. This article will briefly describe the structure of the walkway mosaic design and network geometries that we are using at Turaida forest garden. We explain the need for terracing and mulching of mounded structures. Several organic growers and their works are introduced. Please refer to the accompanying slides for diagram references of these structures.
PERMACULTURE ZONE AND SECTOR METHOD
This seemingly divisive method is also an integrative one. The emphasis should be on organizing and interconnecting functions in forest gardening. The multi-coloured layered shell diagram of the zone (zone zero would be inside the house, extending out) method organizes the space on the future forest garden site (see slide #13). In reality the marked borders and contrast on edges we can see in this shell diagram look much different from the smudged boundaries of an early forest garden. In a developed garden space would blend more into one another since the functional use of land naturally expands over time as the need or desire for production increases. This model splits areas into sectors or zones that extend from the home and other buildings and structures. The zones are designed around commonalities in their functions of space, tools, plants, materials, and perhaps most importantly how people use spaces differently among other considerations.
Toby Hemenway explains how “...the zone and sector method...helps us to decide where to place all the pieces of the garden so that they work with each other... Zones are shaped and squeezed by topography, soil, available sunlight, access from the house, native vegetation and the homeowner's needs.” (see Gaia's Garden, p56-58)
What distinguishes zones and the sectors is where their influences originate. Patrick Whitefield explains with sectors, “This is a matter of placing things concerning influences coming beyond the garden fence. Some of these are climate factors, wind, and frost.” (see Permaculture in a Nutshell, p 24). Whether a sector or a zone, the two function together to create a sense of balance between the particular places (zones) and the specific climate and other outside influences (sector).
The zone methods prioritize places around the home as the zone numbers increases as they radiate from the house or other everyday high traffic work or living areas. Depending on the land size, some zones can differ considerably in their size relative to the land size. For example, it's hard to see a large zone five on any small property where functional, intensified use of space puts land at a premium. Clearings in forests can as microclimates. A practical design improves access to these useful growing conditions. We will discuss later on how ecological succession works in a forest garden and its importance in planning in another article.
TURAIDA'S MOSAIC FLOW DESIGN
City planner and author Richard Florida explains how the mosaics patterns in cities work. One popular option is the Urban Mosaic, where he discusses classic neighbourhood design resembling that of Jane Jacobs (from the bookWho's Your City?) (p 254). We'll get back to this idea later, but it is worth mentioning now since Turaida is a growing space that resembles an urban mosaic design.
At Turaida we are using a networked mosaics to help with wheelbarrow accessible walking paths that surround small pits (to be filled with compost (and forest garden woody debris) and mounds. The narrow gravel lined walkways are often laid out in a branched three-pronged intersection. These centres widen at the edges to prevent wheelbarrows from slowing down, allowing a speedier flow of materials across the forest garden. These intersections act as nodes in a forest garden network that are space according to use across the seasons. They keep up speed and prevent injury from sharp turns as one would do to an on-ramp of a highway. There are typically mounds on either side of the significant walkways creating a twinned berm appearance to the sidewalks. These central walkways with mounded sides take advantage of the edge effect while creating a hierarchy in the pathway structure. Areas being close to the main walkways are a priority. In the microclimates, the mounds offer the tender smaller plants selectively located along the walks, so they are firmly within our grasp. Small depressions are placed on either side of the walkways to divert water.
The Turaida design uses a large number of shrubs because of our site-specific conditions, our desire for diversity and the size of our project. We are maintaining a relatively open form while keeping a specific density, pruning for healthy fruit. We use fans, espaliering at 45 degrees and walled structures to support trellised fruit. Smaller, one-foot walking paths allow for improved access around the inner edges of the pit and the far sides of the walkway mounds.
BALANCING FLOW AND DIRECTION ACROSS MOVING SPACES IN THE GARDEN
The fruit producing nature of our forest garden directed us to optimize sun exposure and air when designing pathways. We arranged many of the walkways to extend East-West while being shaded by a series of taller pruned trees to the South of the main sidewalks. Pruning is essential to allow enough light in the lower layers of the forest garden. This design streamlines the plants from strong Westerly wind gusts. Even southerly flowing walkways are curved to capture light that would otherwise be lost to onto walkways during the growing season. Using canopies to close over the top of walkways is another technique that fits in with the forest garden structure. The south-central aspect of the garden has the shape of a small pre-existing valley that opens to the South, twinned on either side with a series of terraced beds. Terraced beds are larger modified raised beds along with a slope.
Similar to the needs of urban dwellers, young plants and many other rare species need the surrounds of a meeting place, the feeding grounds (the workplace), and possible nesting sites (tree lined quiet residential neighbourhoods). Think of how human ecology resembles forest gardens when urban designer Richard Florida reflects: “Older suburbs like Columbia appeal to young people for these reasons. Some are located on subway or mass transit lines (he's talking around Washington DC) that make commuting even easier. All in all, they offer younger residents safety, amenities, and access to a mating market without some of the risks associated with living in the urban core.” (from Who's Your City?, How the Creative Economy Is Making Where You Live the Most Important Decision of Your Life p. 254) As he describes, many cities initially were separate boroughs that eventually amalgamated, forming mosaic patterns where neighbourhoods overlap and species develop like a patchwork of communities in a forest garden.
For all the benefits of mounding, there are drawbacks. For example, their edges are erosion prone, and the soils are more exposed to changing air temperatures above ground. Watering needs during the dry season in the peak Summer heat and cold wind exposure during the Winter are two additional vital considerations that complicate growing on mounds.
SINGLE WHEELED WHEELBARROWS
Eliot Coleman offers a great explanation of the use and design of space conserving wheelbarrows for growing organic vegetables in his classic bestseller The New Organic Grower (1995). Other books of his worth mentioning here include The Four Season Harvest (1999), and The Winter Harvest Handbook (2009). Both of the earlier books include wonderfully illustrated sketches. We were introduced to The New Organic Grower as a sustainable agriculture course text. This book is a core text for vegetable market gardeners, and many of his ideas overlap for managing the vegetative layers of the forest garden.
Fortunately, there are few reasonably spaced gardens where an averagely sized wheelbarrow won't be able to fit in. Tip them upside down when storing outside to conserve their lifespan, or upright in the wind sheltered, dry spot. Try to find the manufacturer that makes a balance of durability and strength with frame choices that are still lightweight. If personal size prevents using larger loads, seek out compact or streamlined designs for ease of use. Smaller sized wheelbarrows prevent lifting injury or fall from overloading, and will quickly turn when balancing over a shorter distance. Broader models have the weight spread over a larger surface on a single wheel, making turns less stable when tilted when turning because of the centre of gravity when unevenly filled.
CREATING EVEN FLOW IN A FOREST GARDEN
Flow and direction are elements to design. As we discussed in section one of this article, the leaf-like pathway shapes change the surface flow. Some designs, such as the network geometry in the pathway design diagram, have a 'directionless' flow since they are so open. Edible Forest Gardens Vol 2 discusses omnidirectional flow (see slide #15 bottom of the picture on the left side) in the network geometry type of design. Be sure to leave adequate room to rotate the wheelbarrow with enough room for the carrier, and being able to angle alongside hedge borders are essential to consider. A single wheel allows for the rotation to turn on one wheel, cutting down space needs compared to larger, multi-wheeled designs in the roundabouts along garden walkways. There are lots of space and loading advantages when running on a single wheel. Tipping is a consequence of a poor balancing act when turning carrying a wheelbarrow. This issue is especially a problem with heavy loads, in wet conditions and on sloped ground.
For all the benefits of mounding, there are drawbacks. As previously mentioned, their edges are erosion prone, and the soils are more exposed to the elements. Watering needs during the dry season are essential considerations. The sloped aspect of mounds makes the flow of water with improved drainage into a problem. Proper air flow keeps the living space open, accessible, visually appealing, and perhaps a most importantly healthy plant. Soil amending and harvesting are more accessible when raised on mounds or terraces.
The goal with pathway flow of the walkways should relate to watering functions that may include drainage, controlling or directing water runoff and surface water to growing areas. Recognise that water could be trapped when in excess each Spring in different regions across the garden, reducing the need for moving water back and forth by draining and irrigating.
MANMADE FORMS IMITATING NATURAL SYSTEMS: PITS AND MOUNDS OF FALLEN TREES IN THE OLD FORESTS
The description of pits and mounds in Edible Forest Gardens Vol. 2, is clear and to the point: (from pgs 97-98)
“Pit and mound topography of old-growth forests is the model for this pattern, Mollison's herb spiral and mulch pit-patterns support the inspiration... Such earthmoving has a place in many contexts for habitat diversification purposes.”
“Essentially flat sites, or those with unvarying soils, have few opportunities for habitat diversity, which is the foundation of other kinds of diversity. On extremely wet or dry sites, the variation of topography means the difference between success and failure with many crops.”
Consequently, most trees and shrubs are on mounds as needed to improve drainage at the Turaida site. As a common practice, raising the plants above water level prevents root rot when ground levels rise during Winter and Spring flooding. As Michael Phillips discusses in his book The Holistic Orchard, by mounding the crown planting heigh to even less than a foot, depending on the rootball, it's possible to grow a broader variety of plants. Without this relatively small amendment, many plants would not otherwise tolerate the drainage conditions of the site.
How tall, broad, steep and flat we make the mound will depend on the specific watering needs, size of the rootball, parent soil and amendment features, areas we are mounding, and other considerations. Practically speaking, smaller mounds for smaller trees and shrubs makes lots of ergonomic sense. Since forest gardens are designed around human use, we need to pay attention to how the forested space connects to the rest of the garden areas and living spaces.
In our case, for the sake of working on and around the limits of the growing season, the pitted depressions are spaced and organized with special consideration placed on walkways. The walkways offer networked access to growing areas of the forest garden. Walkway design is one way that smaller forest gardens differ from ornamental park designs one would find in a city garden space. Forest gardens should be naturally appropriately intensified in their use by design. There is a relentless, persistent demand to access usable growing area. Space needs to work with the natural balance of the system under design. The celebrated gardeners Elliot Coleman and Barbara Damrosch suggest optimal use of timing and spacing in their organic gardening projects. They describe the importance of keeping the garden most productive, efficient and cost-effective as a system.
KEEP THE END GOAL IN MIND
As a site develops, the end goal of the design should be to connect the spread out structures (and functions) of the forest garden. Ideally, aiming to stay focused (while trying to be time sensitive) at the end of the week, month, season, and year. An end goal of the forest gardener is to make use of the spaces purposefully brought together for the intended purposes (that may include a heritage space conserved as a limited use or an existing space devoted to future use). Like strands of a rope, the forest garden is layered and twisted over by design and with the effort by the gardener. Once developed, the structures in the forest garden are designed to minimize effort. The functions are made to create, overlap and become the self-supporting matured ecosystem as the end goal ( see later discussion on ecological succession in forests).
PITS AND MOUNDS AND DIVERSITY
Here is more of the explanation provided by David Jacke and Eric Toensmeier in Edible Forest Gardens, “The pits and mounds of old-growth forests generate the small-scale structural diversity that makes it possible for these woods to contain up to fourteen species of herbs per square yard and up to 40 species per habitat. Pits and mounds develop in old growth when the root balls of large trees turn on their sides as the trees fall and then decay. This piles up the topsoil in one place and exposes mineral soil elsewhere, raising the elevation of one area and lowering the elevation of the other...in our culture we tend to “make the rough places plain, and the crooked straight,” thereby destroying such foundations of species diversity......Undulating topography is even more critical in extreme soil conditions. A few inches of additional dry soil can make all the difference in survival and production for some species in wet soil... ...One additional advantage of undulating topography is that it increases the surface area available for planting. Mollison uses this idea in his famous herb spiral pattern. These spiralling cone-shaped planting beds generally rise 3 to 4 feet high from a 5-foot diameter. The flat area under the herb spiral area is about twenty feet, while the surface area of the spiral is 30 feet... With mounds and pits, the surface area increases twice as much as that, because the surface area increases down into the pit and up onto the mound. ” (Edible Forest Gardens Vol. 2 p 97)
Hugelbeds offer even more potential to add fertility to the soil. Hugelkultur and wood composting of our felled trees (maple, poplar woods) get mixed nitrogen-rich garden debris. They are hilled and mixed into soil on-top the mound, so there is an adequate soil structure for growing and rooting. The clay soil helps to keep the wood wet, assisting in the process (see a photo of the slide of hugelmounds). Mushrooms are an obvious food to consider adding. Many books are written on the subject. It is mentioned here in passing.
THE IMPORTANCE OF MULCHING AND TERRACING IN THE MOUNDED FOREST GARDEN
Mulching is essential to growing on living mound structures using the forest garden model. Using a small terrace for tall mounds as needed, or placing lips or rims around the rootball will both prevent erosion and improve the quality of growing space. By setting a small back slope to terraces, it is possible to divert the water away from the steep side of a hill. Stone edges and rims around raised areas can improve structurally reinforce small stepped terraces on slopes.
Look for efficient living mulches (green mulch) and other sorts of mulch materials such as adequately prepared garden debris, shells and husks (brown mulch) or stone mulch materials. When used properly, both can be both useful and necessary. Mulch is enough of a priority to be considered an element of design in a forest garden. Dark mulches and thick stone mulches heat up faster and retain more heat when the temperature drops. In many cases, place care on the space made to include small fertility patches in the garden especially around most nutrient demanding, rich fruit and nut trees. Canadian gardener Marjorie Harris covers mulching and composting in detail in her bestseller Ecological Gardening, Your Path to a Healthy Garden (1991). For those interested in forest gardening as productive food forests, fruiting trees and their 'fungal duffs' are covered in detail by Michael Phillips' textbook style guide The Holistic Orchard (2011).
Often the approach towards mulch is a difference of opinion and attitudes. One should initially intend on adding more than less, as the pile will rot as it settles into its place over time. Wind and the elements will chew away at it over time. The depth and composition of the mulch depend on the time of year, and the lifecycle of the plants. The intended use of the mulch, the sun exposure, what you're mulching are among other considerations. It is practical to use shallow slopes and rims to contain water and prevent erosion. Mulching is itself a broad topic covered in a forthcoming article.
STRUCTURES THAT SHAPE PATTERNS AND FLOW SUMMARY
In this article, we explored the flow and patterns created by mounds, pathways and other structures. Various authors and their works were introduced and briefly discussed. Different mosaic patterns at Turaida and mound design and composition were explored. We explained how mounds create solutions by increasing diversity but may present problems of cold wind exposure and watering needs during dry periods. The article discussed how structures shape the patterns that flow. These networks in shared spaces with mounds, walkways, forms and terraces influence flow and are elements of design. In forest gardens, some types of mounding like pits and piles can mimic old growth forests. Briefly, wheelbarrow designs, materials, and storage were reviewed. We discussed the importance of mulch and the uses of mulch as an element of design in mounded forest gardens.
In the next, fourth article in the series "What is Forest Gardening?" we will look at how other simple landscaped structures can add different angles to gardening. Other tips and recommended reads are included.
Coleman, Eliot, and Damrosch, Barbara. The Four Season Harvest (1999) Chelsea Green Publishing
Coleman, Eliot. The New Organic Grower (1995) Chelsea Green Publishing
Coleman, Eliot. The Winter Harvest Handbook (2007) Chelsea Green Publishing
Florida. Richard. Who's Your City? How the Creative Economy is Making Where You Live the Most Important Decision of Your Life.Vintage Canada. (2008)
Jacke, David, and Toensmeier, Eric. Edible Forest Gardens Vol 2. (2005) Chelsea Green Publishing.
Harris, Marjorie. Ecological Gardening, Your Path to A Healthy Garden. Random House Canada. (1991)
Hemenway, Toby. Gaia's Garden: A Homescale Guide to Permaculture,2nd Ed. (2009)Chelsea Green Publishing
Phillips, Michael. The Holistic Orchard, Tree Fruits and Berries the Biological Way. (2011) Chelsea Green Publishing.