What are they?
Food forests are food producing landscapes loosely modeled on natural forests. Fruit tree’s and other useful species replace the trees of a forest and a variety of useful species replace ground covers present in forests.
Like natural forests the ground is constantly covered in a food forest. This is done through the use of living ground covers such as nastirtum and also through the use of dead materials such as straw or chipped wood. As the forest garden matures the trees will increasingly shade out the living ground covers and contribute to mulch from their leaves and pruning.
Because food forests are multileveled diverse landscapes they can be far more useful that conventional orchards or conventional field cropping methods. Food forests have been extensively used in traditional horticultural systems but are relatively new in the western world. As is becoming increasingly clear a well designed food forest requires minimal weeding, watering or fertilization.
Food forests are artificially kept in a state of interrupted succession; trees growing overhead are spaced to allow a lush carpet of greenery to develop. Instead of the thick darkness of a New Zealand native forest we aim to create a relatively open environment conducive to fruit production.
A food forest is typically made up of seven levels; these levels stack plants according to how much light they require.
The principles behind forest gardening can be applied on any scale in any space. On an inner city balcony a dwarf fruit tree may be grown with mint and nasturtium around its base. A suburban backyard may have 10 or 15 trees with passionfruit climbing through them and comfrey across the ground. A rural property may have several acres of useful fruit or nut trees for market.
The edge of a forest is far more productive than the center; on the edge sufficient light is available to support lush vegetation and to support forest species. Creating this rich edge zone is one of the major goals of a design. Trees should be spaced so that light is able to penetrate throughout the forest garden and light wells can be created which herbaceous annuals can be clumped in.
Even a suburban backyard has a wide variety of microclimates, these can be exploited to grow subtropicals like babaco, to help species mature early etc.
On highly exposed sites windbreaks may need to be planted, these can be a mixture of useful species which provide a variety of products.
Wind levels and directions should be carefully observed before planting and trees should be placed according to the levels they can tolerate.
Varying amounts of site preparation will not to be done depending on fertility and soil type. Very poor soils will need proportionately more nitrogen fixing species and species grown for their biomass.
Signs of nutrient deficiencies should be carefully looked for and if necessary soil tests done. It is generally much easier to treat imbalances when the site is being established than when trees are looking sickly down the track.
Wet soils can be used to grow mints, bananas, taro and other water loving plants. Dry spots can be used to grow rosemary, fig or…
Dry sites may require swales to catch rainfall running across slopes and help it infiltrate into the soil and a constant cover of mulch is probably a must.
North facing slopes are ideal for food forests as trees will not shade each other as much as on flat sites. South facing slopes can be used but if deeply shaded trees will have to be further spaced apart. To prevent erosion swales may need to be put in and the ground should be not be unnecessarily cultivated.
Fruit trees should be chosen according to
- How suitable they are for the climate
- When they fruit
- What other functions they might play (medicinal, mulch etc)
- How big they are when mature (dwarf species, full size etc)
Smaller plants should be chosen according to
- Shade tolerance
- Medicinal use
- Whether the attract beneficial insects etc
Other species to include
- Mulch producing species (eg Abyssinian bananas, wild ginger)
- Food for chickens and wildlife (silverbeet etc)
Things to keep in mind
Placing your forest garden is crucial, will the avocado you want to plant eventually shade out your vegetable garden or block crucial winter sun? Through careful placement the same plant can provide welcome winter shade and block cold southerly winds.
When designing your food forest think about how to enhance and maintain fertility, provide habitat for wildlife and grow variety of useful species which can be harvested throughout the year.
Flowers like lavender and wild carrot which attract beneficial insects should be included to improve the overall health of the forest garden.
Nitrogen fixers like tagasate or wattle should be included at planting; these can be eventually thinned and removed for firewood as the rest of the trees mature.
Placing a bathtub in your food forest filled with water and aquatic plants will benefit bird’s insects and lizards.
Establishing the forest
Before you begin a thorough site plan should be developed. The best time to plant trees is in spring or autumn.
Once you have a plan for your site the first step is to remedy any deficiencies or problems with the soil.
Next allow weeds to grow and sheet mulch the site as described in (yet to be written)
In the sheetmulch rough seeds such as potato and broad bean can be grown planted and grown in the first few years. These plants will gradually be shaded out as the forest develops.
Once sheet mulched trees and groundcovers should be planted, around 20% more trees should be planted than you want at the end to make up for plants which do not do well or which die.
In the first few years herbaceous weeds may be a problem; these can be managed through the use of chicken or duck tractors or weeded manually. Many weeds will be shaded out as the food forest grows, useful groundcovers will also suppress weeds.
Pruning of trees in the food forest is primarily done with light in mind and also to remove diseased or unnecessary branches. Trees should be pruned or thinned out as necessary to create light wells for light loving understory plants.
A Japanese farmer Masanobu Fukuoka famous for his so called “natural farming” techniques did no pruning in his orchards and believed this made for much healthier trees. As far as I am aware these techniques have not been trialed in New Zealand.
Ducks and Chickens in the food forest
Chickens can be let into the food forest periodically to eat faller fruit and insects but they love mulch and will scratch up anything that’s loose, soil and seedlings included.
Ducks are very suitable for larger food forests as they do not scratch up mulch. They will however eat green like silverbeet and may need to be managed carefully.
Retrofitting an existing orchard
Conventional orchards are planted in long straight lines or with trees spaced regularly with grass growing between them. One plan for increasing the productivity is to plant nitrogen fixer’s small bushes and plants like borage and comfrey in the rows. Alternately in some agro forestry systems the gap between rows can be used to grow annual vegetables if the trees are sufficiently spaced.
Old trees which are diseased or unproductive should be removed and replaced with desirable species. Small orchards may be sheet mulched whilst in larger orchard living mulches can be planted.