a well designed forest garden
By zteve t evans
A well designed forest garden can be a productive and important part of a Permaculture, or low-impact living system,providing food or other useful products in an environmentally friendly and sustainable way.
A young natural forest is a highly productive and self-sustaining eco-system so in forest garden design the essential principle are to reproduce those attributes for human benefit. Although a natural wild forest may look tangled and the trees placed randomly and haphazardly there is an inherent structure that helps to give it such great productivity. Because different species of trees and plants grow to different heights a natural vertical structure to the forest evolves.
In forest garden design this is known as ‘layering’ and sometimes these layers are referred to as ‘storeys’ or ‘stacks.’ This layering can often be seen best at the edges of forests where the height of the trees, shrubs, grasses and other plants diminish in size.
Forest garden design
To design a forest garden that is productive and sustainable thought must be given to the creation of these layers. In some well established forest gardens in tropical regions of the world up to 13 layers have been recognised.
Martin Crawford of the Agroforestry Research Trust and author of ‘Creating a Forest Garden’ describes seven layers to a forest garden, but explains that in smaller areas there can be less. This is because on small sites such as back gardens there may not be enough space to accommodate all of the layers especially the canopy so it may be necessary to use smaller trees that are more suitable to the space available. Trees that are coppiced can be regarded as shrubs as can trees that are grown on a dwarfing rootstock, or pruned.
In some parts of the garden these layers may be separate while in other parts they intertwine. Patrick Whitefield in his book ‘How to make a forest garden,’ uses three layers and points out that two layers can be used in smaller gardens.
The seven layers of a forest garden
Starting with the highest storey and working downwards in order the seven layers are the canopy, the under-storey, shrub, herbaceous, ground cover, climbers and vines, and finally, an underground layer.
In forest garden design this is known as ‘layering’ and sometimes these layers are referred to as ‘storeys’ or ‘stacks.’ This layering can often be seen best at the edges of forests where the height of the trees, shrubs, grasses and other plants diminish in size.
Forest garden design
To design a forest garden that is productive and sustainable thought must be given to the creation of these layers. In some well established forest gardens in tropical regions of the world up to 13 layers have been recognised.
Martin Crawford of the Agroforestry Research Trust and author of ‘Creating a Forest Garden’ describes seven layers to a forest garden, but explains that in smaller areas there can be less. This is because on small sites such as back gardens there may not be enough space to accommodate all of the layers especially the canopy so it may be necessary to use smaller trees that are more suitable to the space available. Trees that are coppiced can be regarded as shrubs as can trees that are grown on a dwarfing rootstock, or pruned.
In some parts of the garden these layers may be separate while in other parts they intertwine. Patrick Whitefield in his book ‘How to make a forest garden,’ uses three layers and points out that two layers can be used in smaller gardens.
The seven layers of a forest garden
Starting with the highest storey and working downwards in order the seven layers are the canopy, the under-storey, shrub, herbaceous, ground cover, climbers and vines, and finally, an underground layer.
The canopy layer
The highest layer is the canopy and consists of medium to large trees over 10m (33 feet) in height. Fruit trees are often chosen for this layer as a food crop though trees that yield non-edible crops such as timber can also be utilized to good effect. Also, nitrogen fixing trees such as Italian alder (Alnus cordata) that bring benefit to the other plants in the garden are often chosen for this layer. This layer can be excluded where space is scarce such as in many back gardens.
The highest layer is the canopy and consists of medium to large trees over 10m (33 feet) in height. Fruit trees are often chosen for this layer as a food crop though trees that yield non-edible crops such as timber can also be utilized to good effect. Also, nitrogen fixing trees such as Italian alder (Alnus cordata) that bring benefit to the other plants in the garden are often chosen for this layer. This layer can be excluded where space is scarce such as in many back gardens.
The under storey, or low tree layer
In this layer small trees and large shrubs up to 4-9 metres high (13-30 feet) in height are chosen. Nut and dwarf fruit trees can supply a bountiful food yield and are often utilized here. This layer may be the highest layer on smaller sites.
This is very productive and accessible layer where many fruit trees are grown as are trees that supply medicinal products. Coppiced trees can be regarded as large shrubs and grown here. For example, coppiced limes (Tilia spp.) which have edible leaves can be placed in this layer as can nitrogen fixing trees, or large shrubs.
In this layer small trees and large shrubs up to 4-9 metres high (13-30 feet) in height are chosen. Nut and dwarf fruit trees can supply a bountiful food yield and are often utilized here. This layer may be the highest layer on smaller sites.
This is very productive and accessible layer where many fruit trees are grown as are trees that supply medicinal products. Coppiced trees can be regarded as large shrubs and grown here. For example, coppiced limes (Tilia spp.) which have edible leaves can be placed in this layer as can nitrogen fixing trees, or large shrubs.
The shrubs layer
Shrubs up to 3 metres (10 feet) high can be used here and will need to be able to tolerate shade. The Japanese rose, also known as the Ramanas rose can be situated in this layer. Its flowers are sweetly scented and can be used to make pot pouri.
Other kinds of plants to place in this layer are and blueberries (Vaccinium spp.), redcurrant (Ribes rubrum) and other species of berry and currant, as well as seed, nut and nitrogen fixing plants.
Shrubs up to 3 metres (10 feet) high can be used here and will need to be able to tolerate shade. The Japanese rose, also known as the Ramanas rose can be situated in this layer. Its flowers are sweetly scented and can be used to make pot pouri.
Other kinds of plants to place in this layer are and blueberries (Vaccinium spp.), redcurrant (Ribes rubrum) and other species of berry and currant, as well as seed, nut and nitrogen fixing plants.
The herbaceous layer
In this layer herbaceous perennials and evergreen plants ranging from a couple of centimetres up to a height of 3 metres (10 feet) are placed. Good plants to grow here are mint, sage, comfrey and other herbs and perennial vegetables.
The herbaceous layer often merges and is sometimes part of the ground-cover layer. Often perennial crops that produce food, medicine, dye, or have other uses are grown here. Good examples of edible perennials that can be grown in this layer are globe artichoke (Cynara cardunculus) and sea kale (Crambe maritima).
In this layer herbaceous perennials and evergreen plants ranging from a couple of centimetres up to a height of 3 metres (10 feet) are placed. Good plants to grow here are mint, sage, comfrey and other herbs and perennial vegetables.
The herbaceous layer often merges and is sometimes part of the ground-cover layer. Often perennial crops that produce food, medicine, dye, or have other uses are grown here. Good examples of edible perennials that can be grown in this layer are globe artichoke (Cynara cardunculus) and sea kale (Crambe maritima).
The ground-cover layer
The ground-cover layer consists mainly of a carpet of horizontally creeping plants that cover the floor of the forest garden. Plants in this layer provide living mulch that nourishes the other plants in the forest and can also provide useful crops for food and other products.
The main function of this layer is to protect and nourish the soil and its structure helping all the other plants in the forest garden to grow. Examples of plants used this layer are wild strawberries (Fragaria vesca). Nepalese raspberry (Rubus nepalensis) and apple mint (Mentha suaveolens) and are favoured by Martin Crawford.
Plants grown here need a high tolerance of shade and may include low creeping shrubs and spreading plants that in other types of garden are considered to be weeds.
The ground-cover layer consists mainly of a carpet of horizontally creeping plants that cover the floor of the forest garden. Plants in this layer provide living mulch that nourishes the other plants in the forest and can also provide useful crops for food and other products.
The main function of this layer is to protect and nourish the soil and its structure helping all the other plants in the forest garden to grow. Examples of plants used this layer are wild strawberries (Fragaria vesca). Nepalese raspberry (Rubus nepalensis) and apple mint (Mentha suaveolens) and are favoured by Martin Crawford.
Plants grown here need a high tolerance of shade and may include low creeping shrubs and spreading plants that in other types of garden are considered to be weeds.
Climbers and vines layer
These plants will need to be introduced when there is something for them to climb up and can grow through the layers even to the canopy in some cases.
Most plants in this layer give an aerial crop and examples of these are hop (Humulus Iupulus), grapes (Vitis spp.) and Kiwi fruit (Actinidia spp.). However, yams (Dioscorea spp.) can also be placed in this layer to provide a root crop.
These plants will need to be introduced when there is something for them to climb up and can grow through the layers even to the canopy in some cases.
Most plants in this layer give an aerial crop and examples of these are hop (Humulus Iupulus), grapes (Vitis spp.) and Kiwi fruit (Actinidia spp.). However, yams (Dioscorea spp.) can also be placed in this layer to provide a root crop.
The root zone, or rhizosphere
This is the underground layer. Here food crops such as beets, carrots and Jerusalem artichokes can be included.
Low-growing carbohydrate food crops and traditional vegetables such as potatoes and cereals need a lot of sunlight and will not grow well in the shade. If these are to be included in the forest garden then a clearing that catches adequate sunlight will need to be provided, but this is not always possible where space is tight. However, the nut of the Sweet chestnut tree can provide a carbohydrate food and can be included in the canopy layer. Most vegetables require good sunlight though some such as Swiss chard are more tolerant of shade.
The importance of fungi
Fungi are crucial components of natural forests and other eco-systems and will usually grow above and underground naturally. In a forest garden design edible mushrooms can be introduced for food crops. It is true some species of fungi are harmful to both cultivated and wild plants but other species play important roles in the health of ecosystems.
Scientists are just beginning to realise the importance of underground fungi to the health of forests. Some of these species of fungi form a symbiotic relationship with plants called mycorriza (plural: mycorrhizae). Other species of fungi breaks dead wood, animals and plants, returning nutrients to the soil for reuse.
Using available space wisely
All of the above examples are just suggestions for plants to use in each layer and the designer will need to consider factors such as geographic location, soil, climate and available resources. In some large plots more than one, or even several species of plant may be used in each layer. In smaller plots such as a back garden it may be necessary to just have three layers, using a plant usually used in the understorey layer as the canopy plant. It may also be necessary to also restrict the number of species in each layer bearting in mind that the more species there are tends to add to the health and productivity of the forest garden. However, sometimes space just is not available and too many plants may choke the system so space needs to be used wisely.
This is the underground layer. Here food crops such as beets, carrots and Jerusalem artichokes can be included.
Low-growing carbohydrate food crops and traditional vegetables such as potatoes and cereals need a lot of sunlight and will not grow well in the shade. If these are to be included in the forest garden then a clearing that catches adequate sunlight will need to be provided, but this is not always possible where space is tight. However, the nut of the Sweet chestnut tree can provide a carbohydrate food and can be included in the canopy layer. Most vegetables require good sunlight though some such as Swiss chard are more tolerant of shade.
The importance of fungi
Fungi are crucial components of natural forests and other eco-systems and will usually grow above and underground naturally. In a forest garden design edible mushrooms can be introduced for food crops. It is true some species of fungi are harmful to both cultivated and wild plants but other species play important roles in the health of ecosystems.
Scientists are just beginning to realise the importance of underground fungi to the health of forests. Some of these species of fungi form a symbiotic relationship with plants called mycorriza (plural: mycorrhizae). Other species of fungi breaks dead wood, animals and plants, returning nutrients to the soil for reuse.
Using available space wisely
All of the above examples are just suggestions for plants to use in each layer and the designer will need to consider factors such as geographic location, soil, climate and available resources. In some large plots more than one, or even several species of plant may be used in each layer. In smaller plots such as a back garden it may be necessary to just have three layers, using a plant usually used in the understorey layer as the canopy plant. It may also be necessary to also restrict the number of species in each layer bearting in mind that the more species there are tends to add to the health and productivity of the forest garden. However, sometimes space just is not available and too many plants may choke the system so space needs to be used wisely.
The importance of sunlight
No matter how large or small your forest garden is and no matter how many layers it consists of it is of the utmost importance to ensure plants and trees are spaced to allow sufficient light to reach the lower levels. In the tropical regions of the planet sunlight is stronger and can reach to the lower levels but in the temperate zones of the world, in places such as North America, Canada, Northern Europe and Scandinavia, the light is weaker so special consideration needs to be given to spacing to ensure adequate sunlight at all levels.
Designing a self-sustaining system
In a natural forest there are many interactions and relationships that play an important part in the wellbeing of the ecosystem. In forest garden design the aim is to produce a self-sustaining and environmentally friendly system for growing food or other goods, by encouraging and replicating those interactions and relationships. Therefore a good understanding of the different layers that make up a natural forest can help the forest gardener to design a productive and virtually self-sustaining system for growing food, or other beneficial materials.
© 08/10/2013 zteve t evans
No matter how large or small your forest garden is and no matter how many layers it consists of it is of the utmost importance to ensure plants and trees are spaced to allow sufficient light to reach the lower levels. In the tropical regions of the planet sunlight is stronger and can reach to the lower levels but in the temperate zones of the world, in places such as North America, Canada, Northern Europe and Scandinavia, the light is weaker so special consideration needs to be given to spacing to ensure adequate sunlight at all levels.
Designing a self-sustaining system
In a natural forest there are many interactions and relationships that play an important part in the wellbeing of the ecosystem. In forest garden design the aim is to produce a self-sustaining and environmentally friendly system for growing food or other goods, by encouraging and replicating those interactions and relationships. Therefore a good understanding of the different layers that make up a natural forest can help the forest gardener to design a productive and virtually self-sustaining system for growing food, or other beneficial materials.
© 08/10/2013 zteve t evans
References and Attributions
Copyright October 8, 2013 zteve t evans
File:Alnus cordata alder tree.jpg From Wikimedia Commons - An Italian Alder Alnus cordata cultivated in Stevenage, Hertfordshire, England. - Image Author AnemoneProjectors (talk) (Flickr) - Creative Commons Attribution-Share Alike 2.0 Generic licence.
Book References
Robert A de J Hart – ‘Forest Gardening – Rediscovering Nature and Community in a Post Industrial Age’ – Revised Edition first Published by Green Earth Books – Copyright 1991-2009 the estate of Robert A. de J. Harte – ISBN 978 1 900322 02 7
Patrick Whitefield – ‘How to Make a Forest Garden’ – First published 1996, 2nd Edition 1998, 3rd Edition 200, revised 2002, reprinted 2007, 2008, 2009– Published by Permanent Publications – Copyright 2002 Patrick Whitefield – ISBN-13: 978-1-85623-008-7
Martin Crawford – Creating a Forest Garden – Working with Nature to Grow Edible Crops – First published in 2010 by Green Books – Copyright Martin Crawford – ISBN 978 1 900322 62 1
Internet References
Copyright October 8, 2013 zteve t evans
File:Alnus cordata alder tree.jpg From Wikimedia Commons - An Italian Alder Alnus cordata cultivated in Stevenage, Hertfordshire, England. - Image Author AnemoneProjectors (talk) (Flickr) - Creative Commons Attribution-Share Alike 2.0 Generic licence.
Book References
Robert A de J Hart – ‘Forest Gardening – Rediscovering Nature and Community in a Post Industrial Age’ – Revised Edition first Published by Green Earth Books – Copyright 1991-2009 the estate of Robert A. de J. Harte – ISBN 978 1 900322 02 7
Patrick Whitefield – ‘How to Make a Forest Garden’ – First published 1996, 2nd Edition 1998, 3rd Edition 200, revised 2002, reprinted 2007, 2008, 2009– Published by Permanent Publications – Copyright 2002 Patrick Whitefield – ISBN-13: 978-1-85623-008-7
Martin Crawford – Creating a Forest Garden – Working with Nature to Grow Edible Crops – First published in 2010 by Green Books – Copyright Martin Crawford – ISBN 978 1 900322 62 1
Internet References