Forest Gardens are an idea whose time has come. As a production system they have been utilised around the world by many different cultures. While still extant in some regions of the world we have seen a global shift away from these productive poly-cultures to the mono-culture production that is common-place in global agriculture. As production now moves towards local and resilient systems, the need to design and implement long-term productive poly-cultures is present and Forest Gardening can get us there.
Applicable on many different scales, Forest Gardening can be used in urban and suburban backyards to provide aesthetic areas that produce from a few main-crop trees and provide the habitat and conditions for beneficial associates that meet the needs of the key trees. By incorporating plants and animals that increase the availability of resources to the main trees we build a polyculture that over-yields because it is easier for our crop plants to access the resources that they need. Using these design principles a Forest Garden can scale up to many trees and different polycultures.
A forest is a self-sustaining system. If requires few external inputs once established and is a vast network of inter-connection between all the different elements. When we grow and produce fruit or other forest products we are making it easy for herbivores to make a living. If we can encourage the insects that prey on those herbivores to move into our gardens, we don’t have to do that work controlling pests. Polycultures are not a new idea and there are examples of good ones implemented around the world. However, gardens that have done the design work to supply for the needs of beneficial insects and animals through the year are in the minority. Using Forest Garden design principles we can ensure that our poly-cultures overyeild and improve environmental health.
When a Forest Garden is designed, attention is given to each layer in the forest so that all the different levels of the light and soil can be utilised. The layers of a forest is a concept coming out of Forest Ecology and recognises the following layers: Canopy Trees, Understory Trees, Shrubs, Clumping Herbs, Ground Covers, Roots and the Rhizosphere and Vines. Using an awareness of these different layers within a Forest Garden we can design plantings that produce a yield at each layer and minimise competition because the species in the polyculture are occupying different niches.
To truly mimic a forest and develop a self-renewing and self-maintaining system we focus on four key areas.
Firstly, a Forest Garden is built on Perennial plants and annual plants that self-sow and regrow every year. Perennial plants can take the time to develop deep roots and provide long-term habitat for beneficial insects and animals. Further, work is not required every year re-planting the crop.
Secondly, a Forest Garden develops healthy soil. The bulk of a plants biomass is underground so it follows that developing healthy soil is key for the health of the plant. Healthy soil is developed by minimising compaction using clearly defined pathways and access. This allows the soil to hold more oxygen and water which can feed the soil critters. A Forest Garden also aims to generate soil carbon, which improves the soils nutrient and water holding capacity, regulates pH and supports earthworms. Further, in a Forest Garden we build an environment that is friendly to fungi. Fungi in the soil form associations with the trees that allows the trees to access more nutrients and speeds up nutrient cycles. Conscious design to encourage the development of healthy soil is a corner-stone of Forest Gardening
Thirdly, a Forest Garden is self-maintaining and self-renewing by selecting plants that increase the soil fertility. The ability of leguminous plants (and plants from other families) to take Nitrogen from the atmosphere and make it available in the soil means that by incorporating them into your design you are able to store Nitrogen in the. Effective management can then increase the availability of Nitrogen to other plants in the forest using the soil food web. Nitrogen-fixing plants can be utilised in many different stages of Forest Gardening. Additionally, Forest Gardens utilise plants that are known as dynamic accumulators. These plants are able to rapidly uptake available nutrients which allows them to be cycled in the garden and available to other plants rather than leaching away. Further, many deep-rooted dynamic accumulators can mine minerals from deep down in the soil profile and bring them closer to the surface where the nutrition is available to our tree crops.
Lastly, to ensure that a Forest Garden is self-renewing and self-maintaining we need to make it a place where beneficial birds and insects can make a living. These animals perform a range of key ecosystem functions that we have to fill if they are not present in our gardens. Habitat elements that support birds that eat insects are provided by structures and plants in the garden as are beneficial insects that perform pollination or prey on pest insects. We need to provide for the needs of these animals year round with protection, nectar, pollen and habitat. Consciously providing these needs generates a self-supporting forest ecosystem.
Forest Gardening is taking off around the world as a long-term, high-yielding system that is an enjoyable human habitat as well as a productive polyculture.