We all understand – I hope – that Permaculture is NOT a list of techniques or technologies, but rather a design system based on the meticulous observation of many systems (both human and ‘non-human’ natural systems), resulting in a series of principles which can be recognized and applied in all sustainable systems.
We use these as the basis for successful designing, whether of ‘whole systems’, or of sub-systems within whole systems. It includes the design and implementation of highly productive and long-term sustainable Forest Gardens.
Forest Gardens as a term (originally coined by the Englishman, Robert Hart in the 1980s, I believe) only seems to have gained a Big Name for itself in the last ten or fifteen years, but in reality it has always been fundamental to permaculture design, since in designing we are generally aiming at duplicating and accelerating the natural succession process of an evolving ecosystem, and most populated areas of the world exist in successional forest environments.
So, what is the secret to successfully achieving a stable and productive forest garden, and as quickly as possible? And why do we want to accelerate the rate of ‘natural’ succession anyway? Well, the evolution of any system invariably takes the form of a J-curve. Meaning, that the first part of the process is relatively slow, until the project reaches a point of take-off, which occurs only when there is a dynamic of mutual support between the individual plants and associated elements which are involved.
In accelerating this evolutionary process, we are able to leap-frog over the phase in which two systems are effectively in competition with each other, each ‘trying’ to maintain its particular circumstances favorable to its continued existence. Grasslands are structurally different than forests, and in fact most grasses are adapted to physically resist a forest succession through their chemistry, having an allelopathic exudation that is antagonistic to most tree growth.
Beyond the systemic aspect of the forest garden, and general ecological vitality, there are two essential components which need particular attention: water management, and biomass creation, both intrinsically related to creating and maintaining soil health. If we don’t manage the water well, and use it to the maximum, then with every extreme water event – drought or excessive rain – our whole system suffers, either by having not enough water, or by having so much that the soil itself is lost, with the topsoil being carried away by the runoff of water. And the only way to create soil other than in geological time, is through transforming vegetation into soil through decomposition. As Bill Mollison said in relating to biological processes: “If we need it, we grow it.”
Without organic biomass to feed them, all the wonderful organisms and microorganisms, funghi and bacteria and so on, are unable to thrive and multiply, and in doing so create living, active healthy soil. And how else can we expect to have living, active healthy plants and animals in our gardens and land? We can’t! So effectively in our forest garden, we grow our fertility as we develop the site, and grow more to constantly maintain it.
We know both from broad experience and many empirical studies that diversity leads to an enrichening and resilience in an ecosystem, whether ‘natural’ or human-cultivated. It should be born in mind that when we speak of diversity, it is the number of effective relationships that the number of species permits, that is the crucial factor involved, rather than simply the number of species themselves.
In order to support a maximum of bio-diversity, it is desirable to also recognize that it is diversity of distinctly varied ecosystems within a larger ecosystem (such as a forest garden ecosystem) that can support the greatest biodiversity (and therefore also the greatest number of productive species useful to us).
So, how to go about creating an optimum forest garden? I don’t pretend to have a complete and perfect answer to that question, since there probably is no single response, but rather the accumulation of experience of so many people who have been experimenting with the idea since Robert Hart, and no doubt countless people before him, who didn’t bother with a particular name.
They were simply trying to create the most productive system to satisfy all their needs, according to their culture and location. I’ve been experimenting with best fulfilling the concept for the past forty years, in many different climatic contexts, since I started playing and working with Permaculture. Here are some thoughts then, that I’ve arrived at in that time.
Water, of course, is vital to consider right from the start. Too much or too little are both potential problems or solutions to consider, and probably to pay ever more attention to as the extremes of Climate Change become more ‘normal’. Managing water is essential, for water is unforgiving should we ignore it. Basically with water, either you’ve done it right, or you’ve done it wrong. In either case, you will bear the consequences, so it’s better to do it well and wisely.
If your land is flat, a problem can be when there is too much rain, since water will tend to sit. Best therefore to make your access higher than the rest of the land, to ensure that it is always relatively dry. If you are intending to create any ponds (and you should!), then the soil excavated can serve well as the base for these raised access ways. The raised paths or roads also now represent an ideal surface for collecting and directing water wherever you decide it is best needs. Perhaps to the ponds? Or to plants or vegetation systems appreciating more water than other parts of your land.
The best place to store water, is in the soil. There, naturally, it can be held protected from the evaporating strength of the sun. Another quote of Bill’s: “as much as possible, all water entering the land from the sky, should only leave it through the leaves of vegetation.“ Ultimately we want the soil to become so full of organic material and micro/macro-organisms that it behaves like a sponge, in which plants are able to draw moisture and nutrient from it as and when they require it. Here lies another good reason for diversity, since plants have different root systems, through which they draw both moisture and nutrients. More diversity means a better and more complete use of the different depths in the soil profile.
So, we must slow the water down as it moves through our site. First choice is to deep-rip the land (not plough) as this opens up the soil without breaking up the structure and causing as much disturbance to the soil and soil organisms. The soil is aerated, but without oxidizing all the soil nutrients as occurs with ploughing. If there is a slope, always try to rip on the contour in the case of a uniform slope, or very slightly downwards from the valley towards the ridges in the case of undulating land.
Swales are another option: horizontal embankments created to slow and accumulate water to be absorbed during heavy rains, when ripping alone may not be sufficient to absorb all the runoff water. These also have to impact of creating much greater diversity in soil moisture content on a uniform slope, and therefore off the opportunity for a much wider range of plant species adapted to the different microclimates created.
Grow the fertility then, and maintain it by growing more, in the form of legumes to fix nitrogen in the soil, and as slashable plants that can constantly be pruned as mulch for the other plants, and to open up the soil for the primary harvest plants. My wife Francesca, a doctor of agronomy, was shocked when she first saw me ‘attacking the rampant vegetation on my overgrown land in India, cutting back the pioneer plants to let in the light, and using the cut material to mulch all the fruit trees, concentrating nutrient and moisture control where it was most needed.
One of the faults most commonly found in forest gardens is to plant the primary trees too close together, preventing sufficient light to all except the top of the trees for flowering and fruiting. So, pre-planning is important for the optimal result in productivity and maintenance. Will you include any water features such as ponds, or forest clearings in the ‘forest’? These can provide greater variety of microclimates for greater biodiversity, and at the same time permit more light to reach the understorey species. Think first, then act! So:
- Best to calculate moreorless the mature diameter of the tree plus around 30% in order to achieve the best spacing. So, first set out the spacings of the primary tree species at this configuration.
- Next, create the access paths/roads (depending on the scale you are working with) to enable the easiest maintenance of the forest garden at maturity. This is a good time lay any water lines for irrigating.
- Then fill in the spaces with shrubs that will ultimately occupy the spaces between the main trees or, in the case of shade-loving shrubs, underneath the matured trees.
- Now, plant densely with pioneer species that can be cut as mulch and biomass to support the fruiting trees. They include a high number of legumes that fix nitrogen in the soil, and their roots open up the soil for the fruit trees. Each time these are cut for mulch, their roots withdraw , leaving space for the roots of the primary species.
- Throughout the forest garden, sow a green manure mixture of legumes and other plant families .
Be aware that in creating a forest garden, we are trying to create a whole system, rather than a great collection of different species. In a mature forest, it has been proven empirically that there is a communication system within that forest, enabling the exchange and distribution of information, moisture, nutrient and probably much else, to wherever it is needed. This is apparently largely facilitated through the sub-soil pathways of funghi and bacteria as conduits. Therefore, we want to plant forests rather than individual plants.
A wonderful structure for multiplying this extraordinary integration capacity, is the ‘sponge’. A sponge is a basin excavated to contain organic material and animal manures which when moistened, form a sponge-like function of holding moisture and nutrient which is available to whatever is planted on the earth rim created from the excavated soil, and by nearby plants beyond the structure which will ‘seek’ the rich source of water and ‘food’ . Apart from the physical support offered to individual plants, ‘sponges’ facilitate perfect circumstances for a broader range of soil micro and macroorganisms that work together to form this communication network, connecting plants otherwise separated by less rich soil profiles. A series of these throughout the forest garden helps to accelerate its development rapidly, as well as creating a significantly greater diversity of microclimates with all the different species supported by them.
Once a forest garden is established, remember to always be inspired by the old Mollisonism: ‘The yield of a system is theoretically unlimited, or, limited only by the information and imagination of the designer.’
Since every system, including a farming system, is necessarily constantly in a dynamic state of change (seasonally, and in maturing and evolving), there are always openings and closings of opportunities, of niches to fill or adapt to in meeting the new circumstances, of sun and shade, rampancy and scarcity, wet and dry, and our challenge as designers of systems, is to recognise and anticipate the consequences of the changes taking place and take advantage of them at the appropriate time.
Composting in wet tropical countries is almost irrelevant, since the whole system is – or should be, a dynamic composting system, although during the dry season composting is a valuable means of preventing the oxidation of the nutrients that takes place if they a left exposed to the heat and strength of direct sunshine. I’ve always found worms to be the best transformers of soft organic material with the least effort. The harder material I just use as mulch.
In our vegetable gardens here in the Italian Alps, the only ‘fertiliser’ we apply is:
- worm compost,
- worm liquid extracted from the organic material which the worms have ‘processed’,
- liquid fertilizer mostly made by the extracting the ‘juice’ from comfrey leaves steeped in water and stirred frequently for 10 days, and
- occasionally a 10:1 dilution of urine.
Nothing from outside our home system. The base soil in our area was almost pure sand, with no structure at all when we started. Now it is rich fertile soil