There are many good reasons for growing a forest garden, and no two people who are attracted to it have exactly the same set of reasons. But the main one for most forest gardeners is that it is the most natural way to garden.

A Natural Way of Gardening

Wherever you are on Earth the most sustainable and Earth-friendly way to grow food is the way which is most like the natural vegetation of that area. In each part of the world a different natural vegetation has evolved over the ages to fit perfectly with the climate and other local conditions. In Britain it is woodland.
Fields of crops and grass can be made to work here, but the land is forever trying to get back to woodland. If a field is abandoned it is soon colonised by brambles, blackthorn, gorse or other shrubby plants. Little trees grow up through this protective layer, and if they are left long enough they grow into the tall canopy of a new woodland. It takes a constant input of energy from humans or from our grazing animals to stop this natural process of succession from happening.
By planting a forest garden we are working with the natural inclination of the land rather than struggling against it. This saves us a great deal of energy. But more than that, it takes us closer to the kind of vegetation which the process of evolution has found to be best suited to the conditions here. There is no doubt that this kind of vegetation will be the most healthy for humans, plants, animals and the whole Earth organism, and the easiest to sustain over long periods of time.
In other parts of the world, where the natural vegetation is different, the model for the most natural way to grow food is different. For example, on the Great Plains of North America the natural vegetation is prairie, a mixture of perennial grasses and herbs. There is a movement afoot there to develop domestic prairies , mixtures of these plants which yield human food. This would not only save the enormous amounts of energy involved in growing annual cereals, but would be a cure for the terrible levels of soil erosion which are still common in North America.
It may be that domestic prairies have a place in Britain, and forest gardens on the Great Plains if only so that people living in both places can have a more complete diet from local sources. But each will always be most harmonious when grown in its own home. It is interesting to note that both systems have two important things in common. The first is that they are composed of perennial plants and the soil is rarely, if ever, ploughed or dug. The second is that they are composed of intimate mixtures of plants growing together, not segregated blocks of different crops, as in a conventional garden or farm.

Global Benefits
As well as being suited to its locality, a forest garden has beneficial effects that are global in scale. Possibly the greatest single ecological problem we face is climate change caused by the greenhouse effect. This is no longer a threat but a reality; it has already started to disrupt world weather patterns. As it intensifies, not only will many species become extinct, but much of the world s food-producing capacity will be lost, as many present agricultural areas become semi-desert. Moving production to new areas cannot be done overnight.
The increase of carbon dioxide in the atmosphere is the biggest single cause of the greenhouse effect, and much of the carbon dioxide comes from the destruction and burning of forests around the world, including tropical rain forests. Growing new trees is one way to take carbon dioxide out of the atmosphere, by turning it back into living wood. Indeed Robert Hart s pioneering work was to a great extent inspired by the desire to do something to compensate for global deforestation.
On the first page of his book Forest Gardening he records how the idea of the forest garden first came to him:

Those who are concerned with the full implications of the ecological crisis which we now face generally agree that urgent steps should be taken to plant many millions of trees... It occurred to me that there was no reason why many of the desperately needed new trees should not be fruit-trees planted by the owners of town and suburban gardens, who would gain the bonus of growing nourishing fruit. If one could persuade 100,000 Londoners to plant just ten fruit-trees each, that would be a million trees quite a forest! And if tree-planting programmes were pursued in urban areas around the world, a new worldwide City Forest would arise which would go some way towards compensating for the devastation of the tropical Rainforest.
I had a vision of mini-forests in millions of back-gardens.

His forest garden was started as a demonstration of what could be done in these millions of back-gardens.
The ecological benefits of trees do not stop at being a sink for unwanted greenhouse gasses. They also enable the soil to store more water and then to release it slowly, preventing both flood and drought. They protect soil from wind and water erosion. They give shelter from wind and Sun to us, our buildings and domestic animals, and help to moderate excessive heat and cold.