Agroforestry encompasses sustainable practices that have the potential to bring environmental and financial benefit to farmers
What is agroforestry?
Agroforestry combines elements of agriculture and forestry in sustainable production systems and can involve rearing livestock or growing trees with agricultural or horticultural crops on the same piece of land. The term encompasses the integration of woody elements that may already be present in agricultural landscapes i.e. shelter breaks, hedgerows, buffer zones, small woodlands and trees in pasture.
Agroforestry systems can also be fully integrated structures where orchard trees, standard trees and / or pollarding and coppice systems are grown in rows between crops and pasture i.e. alley cropping.
Success of agroforestry systems depends on the extent by which individual forest and agricultural components can be integrated to help rather than hinder each other. The choice of tree and crop species combinations is therefore critically important when setting up systems.
Source: Agroforestry (Agroforestry Research Trust)
The overall aim is for all woody components to be fully integrated into the agricultural production system and have a beneficial ecological impact on the land and other system components (i.e. livestock and crops).
It should also be possible to gain an economic profit from the woody components either directly by selling products, or indirectly from the woody components having a beneficial effect on other system components (i.e. the shelterbelt producing higher yielding crops or sheep).
What are the different systems?
Agroforestry systems are classified according to the components present:
- Silvoarable (trees with crops)
- Silvopastoral (trees and animals)
- Agro-silvopastoral (trees with crops and animals)
- Forest farming (cultivating high value products within forested areas)
- Forest gardening (emulating complex forest ecosystems to produce many products)
- Two specialised systems include entomoforestry (trees with insects e.g. honey bees or silk moths) and aquaforestry (trees with fish e.g. trees planted around ponds so that leaf litter enriches the water for fish production).
To read about a forest garden which optimises water and soil use, click here.
For more information on the different systems and tree species, please click here.
Managed properly, trees can be grown to produce timber with little reduction in agricultural production for the same piece of land. In conventional farming, forestry land is allocated separately to the woodland enterprise – resulting in a loss of agricultural area. The return from land for agroforestry is therefore potentially greater with agroforestry.
Crops and livestock
Interactions between trees and crops and /or livestock can bring many benefits including higher productivity than conventional systems and creating opportunities for wildlife and pollinators, attracting more species and a greater abundance of insects and birds than in conventional agriculture.
Agroforestry systems can also provide a wide range of services that can have beneficial effects on crop growth and animal welfare, such as:
- Soil management;
- microclimate modification i.e. temperature, water vapour content and air and wind speed;
- weed control;
- natural fencing;
- carbon sequestration;
- minimising nutrient losses and maximising internal cycling of nutrients;
- enhancing pest and disease control.
Agroforestry systems can support production of a wide range of products that can potentially help contribute to the economic output of a farm, improve the environment, and help improve food and fuel security:
- fodder and forage;
- hedging and thatching materials;
- craft products;
- medicinal products;
- recreation ie. game hunting;
- gums and resins;
- gardening materials.
Taken from http://www.macaulay.ac.uk/agfor_toolbox/try_it.html and Eco-agroforestry and business and Agroforestry: Reconciling Production with Protection of the Environment (Organic Research Centre)
By minimising nutrient losses and maximising internal cycling of nutrients, and by enhancing pest and disease control, agroforestry systems can reduce the need for agrochemical inputs. It can therefore potentially play a further role in protecting the environment and providing a number of ecosystem services, such benefits include:
- Regulation of soil, water and air quality;
- enhancement of biodiversity;
- climate change mitigation and adaptation.
Source: Agroforestry systems (Organic Research Centre).
If you would like to read more click here.
Agroforestry in the UK
There are various trial sites in the UK including a network of six silvopastoral systems set up by the UK Agroforestry Research Forum (now the Farm Woodland Forum). To read about some examples of organic agroforestry farms in the UK click here.
The Eco-Agroforestry Network (integrating agroforestry and biodiversity) aims to bring sustainable agroforestry in to the mainstream of UK food, fuel, timber, and fibre production, through research, dissemination and policy changes.
Agroforestry and animal health
The welfare of an animal can be influenced by trees in the environment; both by using them as a source of food and shelter.
Many breeds used as modern hybrids have been developed for fast growing meat rather than hardiness. Mature trees can reduce wind speed at sheep height by as much as 84%, depending on density and planting. Cattle have been shown to benefit from reduced heat stress due to more time being spent grazing rather than loafing and animals being more evenly spaced.
- A natural environment that includes novel stimuli and physical barriers has been found to help reduce stereotypic behaviour and displace aggression.
- Provision of an outlet for the tendency to explore, root, chew and peck has found that animals such as pigs and hens no longer need to bite each other.
- The flight zone of a pig can be reduced by half if it can find something to hide behind.
- Chickens prefer to range further in a habitat consisting of trees and bushes rather than just short grass.
- If the range provides areas of mottled shade and an area to perch more birds will be encouraged from the house which can also help with foot pad dermatitis caused by wet bedding.
Trees can provide shelter for chickens from aerial predators.
When allowed animals will naturally be drawn to grazing plants with medicinal properties, i.e.cows will graze willow after calving for its pain killing attributes. Tree rubbing by pigs has also been found to help remove skin parasites.
Policies and grants
For information on grants and relevant policies for agricultural systems please click here
To view details of current and completed projects researching agroforestry systems in the UK that could benefit the farming community, please click here.
In the UK, the Organic Research Centre runs agroforestry events.
Some useful websites
Interested in reading a Nuffield Farming Scholarship report on agroforestry and increasing farm production? Stephen Briggs, an organic farmer and advisor who has an agroforestry system on his own farm, wanted to learn more about how commercial agroforestry is practised in other countries and how successful practices can be applied to temperate agriculture in the UK. Click here to access the report.