Make a forest garden by Community Gardens Australia

Make a forest garden

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a cultivated ecology for home and community garden design THE CULTIVATED ECOLOGY

STACK PLANTS TO MAKE USE OF VERTICAL SPACE

VERTICAL AND HORIZONTAL SPACING OF PLANTS

In designing our home or community garden we can increase the quantity and diversity of food it yields if we include a forest garden, sometimes called a food forest or an orchard.

Stacking mimics the structure of the natural forest. ■ high canopy layer of taller trees ■ mid-layer or understorey of lower trees and tall shrubs ■ ground layer of low shrubs, grasses and creepers.

VERTICAL ARRANGEMENT OF PLANTS:

The size you make your forest garden depends on the space available. It may occupy an area all of its own or it may be the model for your entire garden. The forest garden will be of different structure and appearance in different climates. In cool temperate regions trees will be placed further apart so sunlight can penetrate to the shrubs and ground covers between them. In the tropical, subtropical and warm temperate climates, trees may be closer together. The understorey may be partly shaded, necessitating the planting of shade tolerant plants. We can think of our forest garden as having three vertical layers—the ground layer of herbs, vegetables and low-growing shrubs, an understorey layer of smaller trees and taller shrubs and a canopy layer made up of fruit, nut and other trees. Because it uses the ecology of the natural forest as a model, our forest garden is an example of nature-assisted design, a cultivated ecology.

A root zone, known as the ‘rhizosphere’, makes use of the topsoil immediately below the soil surface. Plants in the understorey and ground layer are selected according to shade tolerance and climate.

Plants occupy different vertical levels in the natural forest depending upon: ■ their sunlight and shade tolerance ■ nutrient and water needs. HORIZONTAL SPACING IS DETERMINED BY: ■

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climatic factors—rainfall, relative humidity biological factors—sunlight requirements, water and soil nutrient availability.

High canopy layer of taller trees

Mid-layer or understorey of lower trees and tall shrubs

Ground layer of low shrubs, grasses and creepers. Cross ssection of a forest garden, Pacific maritime tropics. Illustration: Kastom Garden Association, Solomon Islands.

A root zone makes use of the topsoil

Annual and perennial vegetables merge into a zone of fruit trees in this community garden. Bananas, citrus and other fruit trees have been planted along the fenceline, allowing plenty of sunlight to reach the raised, annual and perennial vegetable beds on the sunward side. In the southern hemisphere we plant vegetables and herbs on the north-facing sunward side and taller shrubs, fruit and nut trees on the southern. This is reversed in the northern hemisphere.

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STARTING OUR FOREST GARDEN A little planning goes a long way. It provides us a set of steps to make our forest garden. We complete each of these before moving on to the next.

1. Start with gardener needs We start creating our forest garden by working out what the people who will make use of it want to have in it and what sorts of experience they want from forest gardening. This is ‘needs analysis’ and it provides the basic information for the design of our forest garden. Some of the needs gardeners might identify include: ■ fresh fruit, nuts and vegetables ■ in a community orchard, social interaction ■ learning ■ providing gardening workshops to the community.

2. Decide how you will manage the forest garden This is something that people starting a community forest garden to be managed by a group would work out.

3. Conduct a site analysis

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To design a garden you must understand the things that influence it from outside and the characteristics of the site itself. This is sector and site analysis and it’s best done as a participatory process with the group.

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First, measure your site and make a plan drawing, marking in the direction of north. ■

In sector analysis we do a little research to find: ■ the direction, strength, temperature and season of the prevailing winds ■ how runoff from heavy rain flows into our site and whether that is likely to be contaminated from nearby roads etc. In site analysis we look for the characteristics of our site itself: ■ what is the aspect of our site; what direction does it face? this will influence sun and shade on the site ■ how sunlight and shadow move across the site during the day and how this would differ in summer and in winter, when the sun is lower in the sky and casts longer shadows including those from neighbouring trees and buildings

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what types of soils do we have? does the site slope and, if so, how steeply and in what direction? this influences summer and winter shading and exposure to seasonal winds how does rainwater runoff move across the site and does it pool anywhere to produce areas of moist soil or temporary puddling? are there existing structures on site, such as paths, and do we want to keep them? is there existing vegetation on site, such as trees, and do we want to retain these in our forest garden?

We plot this information on our plan. With needs analysis, sector and site analysis provides baseline information for designing our forest garden. It indicates how we need to improve our soils; where windbreaks would best by planted to deflect cold, blustery and potentially damaging winds; where we need to establish plants that need plenty of sunlight and a warm microclimate (a small area defined by temperature, shelter from wind and soils); whether we need to drain areas of boggy soil where water pools or, perhaps, plant moisture-loving plants there.

While a team that starts a community orchard might know each other and get on well, they need to plan for the time when new people will join the garden. A simple governance plan is needed that will define how the group makes decisions, resolves serious disagreement and communicates with each other, the landholder, the media and the local community. Some community managed gardens draw up a gardener’s agreement that new people sign on to. It decribes how decisions are made, disagreement resolved and other things.

A field sketch showing sector and site analysis information. The sketch plan was made while planning a community garden in the Australian coastal subtropics. It locates true north so as to orient the plan, how the sun moves across the site, wind direction, water sources, soil conditions, vehicular access, security needs, storage area and wildlife coming onto the site. The information would be included on a plan drawn to scale to produce a map of conditions affecting the design of the community garden.

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4. Improve your soils

Making compost

With your design completed it’s time to start making your forest garden. The first step—and most important point in an organically-managed forest garden—is to improve your soil to make it suitable for the types of fruits, nuts and vegetables you intend to grow.

Compost need four key imputs: ■ A—aliveness; anything that is or was alive ■ D—diversity; a diverse range of materials ■ A—aeration: air is needed for the decomposition process; aeration is achieved with regular turning of the compost ■ M—moisture; another necessity for the composting process; this can be added, if needed, when turning the compost.

Your first task is to identify the types of soils on your garden site—are they sandy, silt, clay, or a good mix of clay and sandy, a loam? Next, we do a simple chemical test to find out how acid or alkaline our soils are—their pH. We want them around 6.5-7.0, what we call a ‘neutral’ soil. It is in these conditions that our plants will do best. If our soil is too acid or too alkaline it will deprive our plants of a range of nutrients. Making changes

There are options for improving soils: ■ adding compost ■ planting a green manure ■ planting a living mulch after soils have been improved. Loosen your soil

It can be a good idea to take a garden fork, insert it into the soil and move it back and forth. There’s no need to turn the soil. This loosens compacted soils and opens them to air, water and nutrients. If you have some compost already prepared, it’s a good idea to first lay this about 25mm thick over the soil where your forest garden will go, and then loosen the soil. The compost will be incorporated into the root zone of plants.

What our compost does need is a mix of nitrogen-rich (nitrogen is an important plant nutrient) and carbon-rich materials. We can think of these as nitrogen/green—kitchen scraps, garden waste, lawn clippings— and corbon/brown—dry leaves, dried lawn clippings, shredded newspaper etc. To make a fast, hot compost with the right mix of diverse ingredients whether in a bin, open bay or heap, we: ■ place our compost bin or heap in sunny position; the bin or heap should be at least 1 metre x 1 metre x 1 metre in volume (one cubic metre) to achieve a high temperature in the core ■ place a layer of a layer of brown (carbon-rich) material in the bottom

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of the bin; this helps with drainage place a layer of green (nitrogen-rich) mateial over the brown, about ten centimetres thick alternate brown and green layers until the bin or heap is full add water until compost is thoroughly wet cover with a porous material such as hessian turn weekly apply to garden or pots when ready.

The layers will mix when you turn the compost. Layering is a means of ensuring the right mix of nitrogen/carbon materials. For those making a slow, cool compost, it is simply a matter of ensuring that you have a diverse mix of carbon and nitrogen materials as you progressively add them.

Improving your soil: A thick layer of mulch retains soil moisture and degrades into organic matter useful to your forest garden plants. Here straw is being layed over compost. Mulching was done after a succession of seasonal green manure crops which were turned into the soil to enrich it.

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Plant a green manure

Green manures are combinations of annual plants (which go through their lifecycle from seed to seed within a year) that are grown then turned into the soil or slashed and left on the soil surface as a mulch just as the flowers start to appear. Green manures can be used to fertilise nutrient-poor soils in preparation for planting vegetables and herbs. Usually, a legume combined with a grain is planted. The legume decomposes to provide nitrogen and the grain decomposes into organic matter that feeds crops as it decomposes and improves the moisture retention of free draining soils. Green manure mixes are climate and season dependent: ■ a warm season green manure for a temperate climate might be cow pea (a legume) and Japanese millet (a grain) ■ a cool season temperate climate mix may be wooly pod vetch (legume) and oats (grain);

alternatively, broad beans (or lupin) and oats. Viewed as a succession of plant communities following one another over time, your green manure is your first or primary succession. If your soil is nutritionally poor and too freely draining, as sandy soils are, the green manure might be the first of a number you plant to improve your soil. Plant a living mulch

A living mulch is a low-growing groundcover into which fruit and nut trees and shrubs are planted. It is usually planted in the orchard or, sometimes, into the beds of perennial plants (those lasting more than two years), depending on the perennials planted. Living mulches provide the same services as straw and hay mulches. Usually, living mulches are plants of the legume family that set nitrogen in the soil where it is of benefit to our crops. Common living mulches include: ■ alfalfa, also known as lucerne ■ clover.

5. Install piped irrigation If you plan to install drip irrigation or some other type of reticulated irrigation (that delivered through pipes), now is the time to do it.

6. Plant your windbreaks Having done your sector analysis you will know from which direction the damaging, hostile winds come and in what season. This tells us along which edges to plant our windbreak shrubs and trees. Perhaps, though, your site is already sheltered by existing buildings and trees and you don’t need to establish a windbreak. Plants for your windbreak need to be tough, with leaves adapted to exposure to hot sun and strong winds. Just which species you select depends on your climate. In south-eastern Australia, our cold, strong, damaging winds come from the south the south west sector, so it’s along the garden perimeter on those edges that we plant our windbreaks. In the city we probably won’t have a large area of land and so cannot establish a wide windbreak. What we can plant are taller species and a shrub layer made up of close-planted species such as lavendar, rosemary, vetiver grass and the native clumping grass, lomandra.

A number of successive green manure crops were planted to improve the low-nutrient sandy soil in the Permaculture Interpretive Garden at Randwick Sustainability Hub. Different mixes of grain and legumes were used according to the season. The crops were either slashed and composted on site with the finished compost being spread over the garden, slashed and turned into the soil or left on the soil surface and covered with mulch and stable sweepings. This drip irrigation system was laid after a green manure crop, planted to improve the soil, had been slashed and the garden mulched.

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7. Plant your trees and shrubs Soil prepared, irrigation installed, now is the time to plant our fruits and nut seedlings that will over time grow to form our edible crops. To do this and allow sufficient space for the plants to spread their canopies and root systems, and to allow the

necessary amount of light into the garden, the slower growing species are spaced so that their canopies, when mature, will not touch. This leaves a lot of space between the seedlings, which is what we think about next.

8. Your catch crop These slower growing trees and shrubs will eventually form the canopy layer of your forest garden, but between the time you plant the seedlings and the time, years later, when they are fully grown you can grow shorter-lived fruits, the fast fruits, that will make use of the space between your slower-growing fruit and nuts and

PLANTING A TREE OR SHRUB

1. Dig a hole slightly wider than the width of the pot your fruit or nut trees comes from the nursery in, and slightly deeper.

2. Place compost into the hole.

3. Remove seedling gently from pot by inverting and holding the plant and tapping the base of the pot.

4. Place seedling no deeper than the depth it was in the pot. Mound soil slightly around seeding to retain water.

5. Spread compost around seedling on soil surface.

6. Water in well.

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resources such as sunlight, water and nutrients not yet fully used by your still young, slower growing trees. These temporary plants are known as a ‘catch crop’. They catch and make use of the resources that will eventual be used by your fruit and nut trees when mature, and that will eventually shade and claim space from the catch crop.

A WOMAN SITS in a forest... it’s quiet in here, just the sound of insects or the occasional bird... a secluded place of trees and shrubs. But... look closer and you realise that this is no ordinary forest. Even though there are trees with shrubs below them, and there are plants that thrive in the shady conditions of the forest floor, this is a rather special forest because those trees and shrubs the woman sits among are mostly food-bearing plants. We’re in a forest garden, or perhaps we could call it a food forest. Walk the winding path among those trees and notice that this is not a simple ecosystem. The shrubs below the trees... some are low and clinging to the ground, others taller. There’s fruits and nuts and vines twining over the ground and, here and there, there are flowers. There is also the mobile part of the forest—the insects attending the flowers as well as small lizards and, in the shade of the tree canopy, we hear the calls of birds. We can see that an orchard designed and planted according to the principles of forest gardening has, like the natural forest, a ground, understorey and canopy layer of vegetation. This complex arrangment of plants with its vertical structure reflects our climate, rainfall and the fertility of our soils. The forest garden mimics the natural forest in its structure and in the diversity of plants that grow in it, so we can think of the forest garden as an example of ‘biomimicry‘—the mimicing of natural systems. It’s an example of nature-assisted design.

In tropical to warm temperate climates, the catch crop succession might include shorter-lived species such as banana, pawpaw, babaco, tamarillo, pepino as well as crops of pumpkin, squash and melon according to season. These vine crops reduce opportunity for weed infestation because they shade out weeds and occupy the space they would otherwise grow in. You can also include nitrogen fixing (legume) trees and shrubs. The succession we describe here goes through: green manure for soil improvement > catch crops of shorter-lived species that progressively make way for > the suite of slower-growing fruit and nut trees and shrubs. Even that final successional stage can include areas within it for the continued cultivation of the shorter-lived fast fruits, which could otherwise be grown along the edge of the forest garden where there is access to sunlight. Canopy

Understorey

Ground layer

Annual vegetables and herb garden

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9. Maintain your forest garden During its first years your forest garden will need more attention than it later will as it grows and matures. The main things to pay attention to during the first years include: ■ irrigation—ensure the forest garden’s young trees, shrubs, ground covers and vegetables receive all the water they need ■ reducing weed competition—weeds, or spontaneous plants, grow in the wrong place; we need to spend a little time removing them or our garden will lose too many nutrients to them ■ insect pest protection—while we will have planted the flowers that attract pollinators and establish the base of the insect food web, while that gets going (and after) we need to protect our forest garden plants from those vegetarian insects that would eat them.

This home forest garden in Sydney consisting of banana, citrus, mango and other fruit trees growing above a ground cover of herbs and other plants. A nitrogen fixing plant, pidgeon pea, is interplanted between the trees. The garden makes a dramatic and intruiging entrance to the house.

A home garden with a productive difference—the forest garden at the home of the Baileys—a cook and an anthropologist (with a keen interest in ethnobotany—the use of plants by different cultures) produces a range of tropical/subtropical fruits and vegetables used in the kitchen.

Retain water for seedlngs... After planting tree or shrub seedlings, mound the soil around the plant to form a well to retain water and allow it to percolate to the plant roots. Keeping water up to newly-planted seedling trees and shrubs is important to their successful establishment.

The finger lime is a tasty Australian plant for the forest garden.

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NATURE ASSISTED DESIGN How do we make a forest garden that uses the biological principles of nature’s forests? The natural bushland we see around us is a pattern of vegetation that existing soils, climate and water availability can support. In Australia, the bush has evolved to draw sustenance from soils that are often low in nutritional value and subject to long, dry periods and bushfire. The fruits and nuts we plant in our forest garden have evolved elsewhere under different condition. If we want to plant them then we have to provide the conditions they need to grow.

plants evolved with more readily available nutrients and, perhaps, with soils more fertile than many of those found in Australia. We cannot merely copy the ecosystems we find in a region, however we can make use of the principles we find within natural systems, principles such as the vertical layering of forests, the succession of different plant communities over time, soil improvement through the use of

A forest garden at Yandina Community Garden on the Sunshine Coast, south east Queensland, demonstrates a blend of taller trees making up the canopy, smaller fruit trees in the unerstorey and a ground layer of tropical/subtropical species including cardamon, taro, comfrey, nasturtium and other plants adapted to partially shaded conditions.

Community Gardens Australia DESIGN, TEXT & PHOTOS by… Russ Grayson

This is nature assisted design. Doing this, we work with nature rather than against it—and that is the first principle of forest garden design.

THE FOOD FOREST — USING ECOLOGICAL PRINCIPLES IN DESIGN

This means that we augment nature and make its soils more nutritious and, perhaps, deliver greater quantities of water to our fruit and nut trees. Unlike the plants of the bush, our productive

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compost and mulch in biomimicry of the leaf litter of the natural forest, the retention of soil moisture through creating a soil rich in organic matter, diversity in the types of plants we select, plantings that establish the food web we find in nature and that help to manage populations of pest insects.

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NATURAL FOREST - VERTICAL ARRANGEMENT OF PLANTS

CULTIVATED FOOD FOREST — VERTICAL ARRANGEMENT OF PLANTS

Example — Eastern Australia Eucalypt forest

Example — Eastern Australia

Canopy

Uppermost layer — Eucalyptus trees

Tree crops — fruits, nuts, timber, nitrogen fixing (fertiliser/mulch — legumes) trees tropical to warm temperate climates: ■ citrus, avocado, custard apple, sapote, macadamia nut etc cool temperate climate: apple, pear, ■ stone fruits Mediterranean climate: fig, avocado, ■ apples, stone fruit (peach, pear, plum, etc), citrus.

Understory

Occupies space between tree canopy and ground; may consist one or more layers of smaller trees and shrubs and includes saplings of canopy species ; may include legumes

Shorter, shade tolerant fruiting trees depending on climate — bananas, tamarillo, babaco, jaboticaba, pawpaw in tropical, subtropical and warm temperate climates

Ground layer

Below the understorey, closer to soil surface —small shrubs, grasses

Low-growing fruits (eg. pepino), annual and perennial leaf and fruiting vegetables; herbs, legume shrubs, vines

Root zone (rhizosphere):

Plants that produce tubers or bulbs

Potato, sweet potato, taro, galangal, ginger, garlic, oca, jerusalum artichoke, cardamom, depending on climate.

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