Martin Crawford is one of the pioneers in edible Forest Gardening in the temperate climate zone of Western Europe. He is director of the Agroforestry Research Trust, has written several books on the matter and is considered a leading expert in this field. We meet Martin in his 2-acre (0.8 hectare), 20-year-old Forest Garden in Dartington, Devon, Southern England, underneath a group of pine trees.
Garnense: Can you describe a Forest Garden?
Martin Crawford: A Forest Garden is a designed garden, using trees, scrubs and lower plants with a very distinctive structure, a little bit like a young woodland, but not quite the same. You could also think of an orchard with additional planting above and below.
All the trees, scrubs and lower plants have a function in the system, they are often edible plants but they have other uses as well. It is all designed so that the plant interactions are as beneficial as possible. The system becomes self-sustaining and needs a very low input.
Garnense: What do you eat from a Forest Garden?
Martin Crawford: The small tree layer is usually fruit trees. Another way of thinking about it is that a Forest Garden is like an orchard, except there is under-planting and over-planting. Underneath the orchard trees there is a mixture of scrubs, that could be bush fruit, lower plants that are often perennial herbs or perennial vegetables. The over planting, that are trees that are higher than the fruit trees, can be fruit or nut trees, alternatively, they can bring fertility into the Forest Garden.
What you eat is what you get of orchard and nut trees and from below them there are a lot of leaf crops, both of trees and perennial plants. There are also more substantial, perennial vegetables, like tubers, roots and direct equivalents of annual vegetables, but mostly perennial.
Garnense: For people who are unfamiliar with perennial crops, what is a good introduction produce from a Forest Garden?
Martin Crawford: There are quite a lot of perennials in the onion family, for example, that have flavors like onion, garlic or leek, or mixtures of those flavors. Everybody knows those flavors anyway from annual vegetables.
Some of those perennial species are very well suited to shade and are easily integrated into Forest Gardens. There are perennial leeks for instance that are very easy to grow. A lot of 'wild' plants can be deliberately integrated, like wild garlic, which a lot of people would know anyway. In fact there is a very interesting overlap between the increasing interest in foraging for wild edible plants and a Forest Garden. You might find a lot of the same wild plants in a Forest Garden that are deliberately introduced.
A lot of the fruits that you might find in a forest garden are the ones people will often grow in their gardens in a more traditional way. Apple or pear trees, black current or blue berries, to name a few. So you can use a lot of the same plants, certainly, that are useful for people who don't have a lot of plant knowledge and are just getting interested. That is probably the most useful way to introduce them to it.
Garnense: To make use of the beneficial interrelationships, is there is a minimum size for a Forest Garden?
Martin Crawford: You can apply the principles to practically any size, but obviously there are some things that you can't do on a small scale. Particularly in terms of tree size, when you have got a small garden you might not even have room for a single walnut tree. When your garden is only a 100 square meters you won't have the space to plant a tree that gets up to a 15-meter diameter in old age. Obviously, you have got room for trees in a 100 square meter garden, probably about 6 small fruit trees of various sorts on dwarfing rootstocks.
On a small scale you have to start from a lower height and work downwards, so there will be more smaller trees, scrubs and herbaceous perennials. You do lose more of the forest like structure and some of the benefits that come with that. Of course, it will become a little bit less efficient, nature will be doing a bit less for you than it would on a bigger scale. A very small forest garden will inevitably be a little more work per square meter, than a bigger forest garden, because you will lose some of the benefits. I do know people with 50-square-meter Forest Gardens, they don't look like my Forest Garden, but you can still use all the same principles, only you exclude the upper layers.
To answer the question: 'Is there a minimum area to grow a fully functional Forest Garden?' Probably about 1000 square meters. With something like that you have got room for some taller trees and enough diversity to have a fully functional system.
Garnense: People often ask: 'What can a Forest Garden yield in relation to agriculture?' In agriculture they try to maximize yields, but what could a given piece of land yield sustainably?
Martin Crawford: I would answer that in several ways. One is that you could think of a Forest Garden as an orchard with extra planting below and above. Nobody regards an orchard as unproductive you know, a commercial orchard yields a huge amount.
The problem with only measuring the output of a system and comparing it with the output of other systems is that you're not comparing like with like. What are you exactly measuring? Do you measure kilograms of carbohydrates, total food? Output is not related to sustainability. In fact, if you look at all the agricultural systems that are used today and you plot the yield against sustainability you will get a line that curves downwards.
The higher the output of a system, the less sustainable it is, in terms of human agriculture. That is because the high yielding systems are the ones that use the most energy, the most chemicals and the most tractors. A sustainable land use has to take all that into account.
Yield is one factor of course, but unless you take into account everything that has gone in to produce that yield you can't get near any measure of sustainability. One way of trying to measure that is to look at energy inputs, that is reasonably easy to measure. Then measure all the energy outputs, so you have to convert all the food to some energy equivalent, which is quite simplistic, because food is much more than energy. Food from a Forest Garden has more vitamins and minerals than food from an annual field of vegetables, but that is a whole other subject.
If you do convert it to energy and look at different agricultural systems, look at the energy in and energy out. One level of sustainability is the ratio of outputs over inputs. You measure the outputs and inputs in energy terms and when you divide the outputs by the inputs you will get a number. For mainstream agriculture that number is usually somewhere between 1 and 5, sometimes it is even below 1, which means you put more energy into it than you get out.
If you look at perennial based systems, the number you get from that is usually much higher. Forest Gardens can go up to about 40 times the energy you get out over what you put in. So that is not measuring yield, it is measuring the ratio of yield over input. You can't look at that just by itself, yield is important as well. But yield is not the only thing, it is not necessarily the most important thing.
If you want a sustainable system, then you have to accept that the yields are not going to be as high as yields from conventional agricultural, horticultural or orchards fields that are sprayed with all sorts of chemicals. Your yields aren't going to be as high as that, but your inputs are much and much less. It is sometimes hard to get people to accept that.
The way agriculture has developed over the last 200 years is that yield has become the most important thing. 'To feed the world we need to double the yields', that sort of thinking. This is such a dominant factor in people who talk about agricultural systems. All the agricultural scientists are only interested in yield. If you start with that as your mindset, you will not get to a sustainable system. That is what I think.
Garnense: Your Forest Garden looks like a wondrous and naturally designed system, in which you appear to be a 'Willy Wonka' who knows everything about this wonderland. This made me wonder: what has been your initial spark? How did you go from organic market gardening to Forest Gardening?
Martin Crawford: What happened? Well, I suppose, as you can probably guess, I had a revolution in thinking. For me, most of the time, it wasn't a sudden revelation. It was a period of maybe two or three years when I had been market gardening for a while and I realized that, although organic market gardening is growing organic food, which is great to eat and sell, but in many ways it is not that much different from conventional growing. It is just doing a few things differently, obviously not using chemicals and treating the soil a bit differently. It is actually not so much different.
I come from a fairly scientific background and that makes me wanting to try out new things, you know, experiment. Whilst we were market gardening, well, you know, you will get lots of time to think while you do endless weeding of long, long rows of carrots or whatever. I started to think about different ways food can be grown and I started to research and I found Robert Hart in Shrobshire, in the midlands of England, who started Forest Garden experiments himself in the mid 1970s. He wrote about it and I went to see what he was doing.
Additionally, I found out much more about Agroforestry, not only this sort of Agroforestry but bigger scale systems as well. It is as if lots of pieces of a jigsaw puzzle were gradually being put into place. At some point by what I had seen or researched I had enough of the jigsaw puzzle to think: 'this is fantastic! This is really what I want to do, but can I make it work in our climate? I would love to try!'.
I suppose what intertwined with that is a personal philosophy about how you should live your life. My thinking on that is that if you are working but not enjoying it, you are wasting your life. You will only get one life, well some people might disagree with that, but I think you only get one life. Most people need to work, even if you live frugally, you still need some money. If you can arrange things in such a way that your work is something that you love doing, which feeds you, it is something fantastic to aspire to. So it is not work and home, it is one whole thing.
At some point I had lots of these parts of the jigsaw puzzle fitting together and thought: 'this is really what I want to do'. I worked out how to do it, but I didn't have any money to buy land so we had to get land somehow. I had to persuade somebody to use their land and convince them that it was not just some crazy idea. If you really want something and it really inspires you, anything is possible.
Garnense: Agroforestry has quite a wide range, where does Forest Gardening fit into this range?
Martin Crawford: A general definition of agroforestry is mixing lower trees with annual crops. If you like, there is sort of mainstream agroforestry that might be interesting to large scale farmers, that tend to be lines of trees with gaps in between where you still cultivate the soil and grow wheat, maize or barley, for instance. The lines of trees grow timber or possibly edible crops. That sort of agroforestry is quite simple, it is better than a monoculture but only a little bit. The trees can't give a lot of the benefits to the annual crops that you are growing. So that is the most simplistic form and most applicable to large scale systems.
At the other end of the scale you will find the more intense type of agroforestry, which is Forest Gardening. It is always on a smaller scale, because the diversity is needed to make the system work. It is up to a scale of about 15 acres or 6 hectares and down to small gardens. Mainstream farmers or researchers are not interested in these kinds of systems, they think it is a bit beneath them, partly because they are too complex to easily research in a traditional scientific way. So because of this it is kind of ignored.
Today in Britain there is maybe about 2000 acres of Forest Gardens, compared to the total land size that is a very small amount. If you go to other parts of the world there are thousands of square kilometers of Forest Gardens. Even so, agricultural science ignores them. Even though a lot of people depend on them for their food. They are the most reliable systems the people have got in many parts of the world.
So Forest Gardening is positioned at the intensive end of agroforestry and the smaller scale in terms of land area. In a way it is in a more democratic end, because people tend to be doing it for themselves. It is usually done by families or small groups of people who produce food and materials for themselves, whereas large scale agroforestry is much more suited to large scale ventures and so on.
I'm a big believer of small and beautiful, I like the small scale. Agriculture on a large scale is pretty much unsustainable in the very long term. I would rather like to concentrate on the small scale. Other people can work on a large scale, which is fine, if they want to.
Garnense: Where do you want to be in 15 years' time?
Martin Crawford: By then my Monkey Puzzle trees will just be starting to crop, because right now they are about 15 years old and they take about 30 years before they produce nuts, so I'm really looking forward to that. That is my longest-term crop, but more seriously I suppose, in 15 years' time... I'm not sure. In terms of where I want to be, I haven't looked that far to be honest. The Garden is up and running so I'm sure this will still be here in 15 years' time. There may be one or two things that will look different but I'm sure that largely it will look the same. I imagine I will still be looking after it, mainly, at that time.
What has already happened over the past 10 years is an incredible up search of interest in Forest Gardens and unusual edibles and edible gardens in general. There is already a huge amount of interest in it and it seems to be ever increasing. Where all that will take me in 15 years? I don't know. I have no ambition to be some sort of guru, touring the world, dropping little gems of wisdom to people, which does happen to some in this field. I like to be rooted in one place, yes I might travel now and then, but being rooted here gives me a lot. In 15 years' time, I still expect to be here.
For information about the Agroforestry Research Trust, forest garden plants, shrubs and trees or Martin's courses visit: www.agroforestry.co.uk