In my last blog I introduced the idea of forest gardening. In tropical and subtropical regions, forest gardens have been used for producing food and a few cash crops for thousands of years. Today, forest gardens can be quite small – you can grow one in a back yard as it is the principles and design that defines them – and they are usually no bigger than 2.5 acres.
In Kerala in south-west India and similarly in areas where traditional agriculture is still practised in Haiti, forest gardening is relatively easy. There is plenty of light and so the multi-dimensional design that exploits all niches below and above ground right up to the top canopy of trees is not difficult to achieve. Here the soil needs to be protected from the fierce sun and so the use of mulch and ground cover is very important.
Temperate forest gardens have an entirely different challenge when stacking trees, vines, shrubs, ground cover and roots in a design because we have far less sunlight and trees can take decades to grow to maturity. A temperate forest garden will change over the years. In early years when the top canopy trees are tiny, we can grow far more ground cover and smaller shrubs and soft fruit. As the top canopy of trees (nuts, top fruit and nitrogen fixers like alder and Siberian pea trees) closes, even the vigour of gooseberries may be compromised. We are therefore not only stacking layers carefully with wider spaces in a temperate garden, we are also stacking time, working to a different rhythm taking into account the process of succession. In others words, the garden will change as it ages and evolves.
Though we do use mulch in cool damp climates, especially to establish trees, it is important not to be too idealistic. Mulch is a haven for slugs and snails. It is important to get the ecology in balance before you set about mulching vast areas with newspaper and straw. Because our land had been an intensive agricultural field, in the early years we were beset with pests and had little biodiversity. We made ponds to attract toads and frogs and habitats to attract common lizards and slowworms. All these creatures ate the plagues of slugs and snails. We also planted wildflowers to attract in beneficial insects. This helped restore the land and cover the ground, reducing the need to mulch as well.
Birds too have been important to establishing biodiversity. They too eat snails and other pests. They also eat some of our fruit but they bring in fertility and add a living dimension to the garden that gives us great pleasure. We feed them in winter and put up nest boxes in autumn and we share a certain amount of our harvest with them too.
The Top Canopy
When planning your forest garden, first select your trees. A common mistake with any tree planting project is to plant the trees too close together. If you do, as they grow to maturity they require intensive pruning, will be prone to disease as the circulation of air will be compromised and they will completely shade out the shrub layer. So the golden rule is to calculate the width and height of the mature canopy of each tree and don’t squash them up together! You can do this on graft paper or plot your design on computer.
Think outside the box too and select nitrogen fixers that will help you build symbiotic relationships between soil and plants. Also consider some exotics suited to your climate. We have all the more common fruit trees you could think of – from mulberries, cherries, figs and medlar to apples and pears, hazelnuts and walnut. We also have the more unusual Chinese quince, Chinese dogwood (yes it is edible) and Nepalese pepper. We squeeze in unusual trees as much as we can. We even have a truffle inoculated hazel – yet to prove its worth but worth a try!
Plant your trees in the late autumn and mulch well around the sapling. Be very careful when you plant them. They are your investment, maybe even part of your edible pension, and so they need tender care. Feed and water when necessary.
Martin Crawford, founder of the Agroforestry Research Trust and author of Creating a Forest Garden recommends for the top canopy of trees:
Chestnuts (Castanea spp), Persimmons (Diospyros virginiana), honey locusts (Gleditsia triacanthos), Strawberry trees (Arbutus spp), Siberian pea trees (Caragana arborescens) Cornelian cherries (Cornus mas), Azeroles and other hawthorn family fruits (Crataegus spp), Quinces (Cydonia oblonga), Apples (Malus spp), Medlars (Mespilus germanica), Mulberries (Morus spp), Plums (Prunus domestica), Pears (Pyrus communis), highbush cranberries (Viburnum trilobum).
You need to check that you have a big enough garden for some of these species. I have mulberry, walnut and Siberian pea. I also have a local apple that is vigorous and some big cherry trees but chestnut would not work for me, partly because our soil is pure chalk and also they are hungry trees that grow huge. Local knowledge and pragmatism is everything here. Leave your trees room to grow and make sure your climate and soil type suits your choice. Look around your neighborhood gardens and see what is working well. Working with nature and not against her and she will grant you bountiful harvests.
Photo (top): A view of the Harland's forest garden. Photo credit Tim Harland
Photo (below): The unusual fruit of the Turkish medlar. Photo credit Tim Harland
Next time: planting the lower storeys – smaller trees and shrubs.
Maddy Harland is the editor and co-founder of Permaculture magazine. To find out more about permaculture please visit www.permaculture.co.uk