Living Fences: Agroforestry in Sub-Saharan Africa





Beginning fence.
Courtesy of http://ppathw3.cals.cornell.edu/mba_project/livefence.html

Background

Pictures

How-To

Africa

Links







For questions, please e-mail kaysa_gabriel@yahoo.com Page created: 3-25-04
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Last Update: 4-23-04





Background
Living fences have a few major differences from hedges. They require less maintenance, are planted further apart, and are usually combined with other materials, such as barbed wire. Used all over the world, these structures are greatly beneficial to the people who use them. (Macklin)
Types:
Though there are two main types of living fences, major distinctions between them will not be made in this article. For reference, live fence posts are widely spaced woody plants in single rows that are pruned regularly and used instead of posts. Barrier hedges are spaced closer together, are thicker, involve multiple species, and usually do not include any other types of fencing material. (Cherry and Fernandes)
Typical Living Fence:
Usually surrounding barbed wire, these trees and shrubs grew in their location from seeds dropped by birds that had perched on the fence. Also common are farmers deliberately planting seeds of species that easily take root. Traditional living fences can be more durable than wooden posts, as they are less susceptible to termites and fungus. It is important that the species that make up the fence have the ability to form a callus rapidly to cover the attachment site of the wire; trees that produce sap should be avoided, as this can be corrosive to metal. An alternative to barbed wire for those who cannot afford it is to use several different species to create a thorny hedge. (Cherry and Fernandes)
Purpose:
The original purpose of living fences was to control basic movement of both people and animals. However, as their benefits were realized, more and more farmers began using them for a broader range of activities. (Cherry and Fernandes)
Advantages:
- fuelwood
- fodder
- sustenance for people (such as fruit)
- wind breaks
- fertilizer
- ownership boundaries
- mulch
- erosion control and a way to stabilize the land
- forage for small mammals
- increase in labor yield
- if leguminous trees are planted, can provide much needed nitrogen into the system
- fibers for cloth
- shade
- construction materials
- medicines
(Cherry and Fernandes) (Martin 1991)

Disadvantages:
- Excessive growth can lead to an increase in labor for pruning
- Competition of the fence with other crops for major resources
(Martin 1991)
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Pictures



Short living fences surrounding a dwelling.
Photo by ICRAF, in Nairobi.
Courtesy http://www.winrock.org/forestry/factpub/Slidesho/Into.htm


Living fence lining a road.
Photo by Bill Macklin
Courtesy of http://www.winrock.org/forestry/factpub/Slidesho/Intro.htm


Photo by Janet Stewart.
Courtesy of http://www.winrock.org/forestry/factpub/Slidesho/Intro.htm

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How-To:

Live-Wattle Fence Method:

- plant developed seedlings at suitable distances apart
- weave branches from one tree into another
- tape the branches together where they meet
- Once the trees begin to increase in diameter the trees should grow together firmly at the contact point.
- Depending on tree species, after 1 or 2 years you should no longer be able to force the branches apart.
- The seedlings have developed into one low tree that has numerous root systems. This makes it hard for an individual tree to die off, due to the support of the roots. This should eliminate gaps as well.
- Barbed wire can be placed at the top of the fence, if desire

- More on live-wattle fences
(Herran 1955).

Small Farm:
- research trees in your area that may already be used for living fences.
- If you do decide to select a new species, look for the following characteristics:
o Cattle resistance
o Rapid growth from seed
o Other uses beside just a fence
o Long lifespan
- use posts with a barbed wire or a wire screen
- spread the plants so that they fill the spaces between the posts rapidly
- fertilization is not necessary, but pruning should be done in the dry season each year
(Martin 1991)

Species:
There are few widely used species, though a few are mentioned here. It is important to remember that using a non-native specie for your fence post may have more negative effects than positive ones on your land and the ecosystem. When possible, use native species that have already been tried and tested as living fences.
Taken directly from Dr. Franklin W. Martin's article The Living Fence: Its Role on the Small Farm.  For more information on each species, click its name.

Gliricidia sepium, Mother-of-cacao (madre-de-cacao, madera negra, mata raton). This small leguminous tree is so well known to farmers in some countries and so useful that it has been given a medal in Honduras. Common from low to medium elevations, the tree prefers a medium rainfall, and is well adjusted to a periodic dry season. The tree can be propagated from branches. An old living fence post will tend to produce a large number of long, narrow branches, perfect for planting. The branches root readily but the rate of growth is moderate. Gliricidia can also be propagated from seed.
A narrow fence with broad crown is produced. Its lifetime is almost indefinite. The wood of old trunks become black and very hard, and so are useful for many small objects. Animals tend to feed on the foliage, but in fences most is borne out of their reach. The foliage is a useful feed in moderate amounts but there is some question of its toxicity in large amounts. Flowers, buds, and very young leaves are often cooked as a vegetable. The dry seeds are poisonous and are ground and mixed with other grains as a rat poison. Leaf fall occurs during the dry season and the leaves make valuable mulch. The tree was used in the past as a shade tree for cacao and coffee, but now has been replaced by Inga species. On triennial pruning a good quantity of firewood is produced. Pruning also results in root dieback and release of nitrogen to the soil.
Erythrina berteroana, Dwarf immortelle (bucar o bucare enano). This leguminous tree is small to medium in size, and is commonly used as a living fence post or a support tree for vine crops. Other Erythrina species may be substituted it. The tree is covered with dense foliage that is perennial. Because the leaves are not lost during the dry season, this tree is best suited for regions with somewhat more rainfall than is required by Gliricidia. Propagation is from branches, big or little, usually planted where they will be used. However, seeds can also be used. Growth is moderate to rapid. The fence is narrow with a dense crown. The foliage is attractive to animals and frequently used for feeding rabbits, sometimes with ill effects.
The wood is soft and of limited use except for fuel. On pruning the tree a large amount of useful mulch is produced. The seeds are poisonous. This is a favorite shade tree for coffee in Central America.
Yucca elephantipes , Yucca azote. This is one of the most common plants in living fences in Central America. Cuttings of branches large and small are frequently planted close together, and as they grow, make a practically impenetrable wall. The tree is easy to propagate, slow to grow and has a long life. The flowers are edible.
Bursera simaruba, Gumbo limbo (indio desnudo, jinote). Gumbo limbo is especially appropriate for dryer areas where madre-de-cacao is not suited. Planted as large posts, it will root even under fairly dry conditions. This tree has few other uses, for even its wood is soft and short lived.
Moringa oleifera, Horseradish tree. This "vegetable tree" is one of the most successful plants in ECHO's seedbank. It handles dry seasons well and grows especially quickly the first year. The Asian Vegetable Research and Development Center in Taiwan has developed a gardening plan which starts with palisade of moringa grown from closely spaced seed. Trees are pruned at about head height, and the leaves used as a nutritious cooked vegetable or for animal feed.

see more seed species
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Africa

There are many conservation projects currently running in Africa. Most are based on the knowledge that permanent soil is needed to sustain agriculture, especially conservation agriculture. However, biomass availability is limited. (Ashburner et al. 2002) Read more about Conservation Agriculture in Africa.

Living fences are numerous in Africa, and highly diverse. A few of the more well known are listed below.

Kenya:
In Embu, Kenya, it was found that, when fed to cows, new foliage of Calliandra calothyrsus raised the butterfat in milk by roughly 10%. In general, farmers often use the living fence as a source of wood and animal feed. In this particular region it was found that pruning between 2 to 3 months created a higher leafy yield than pruning every 4 to 8 months (higher woody yield). (Cherry and Fernandes)
West African Sahel (subsistance farmers):
In this area, where free animal browsing threatens dry-season gardens, non-living fences were constructed. Made of barbed wire, dead woody material, and crop residues, these fences had to be rebuilt every year. This practice negatively impacted both the soil, from erosion, and living trees, which were harvested regularly to provide the dead wood for these fences.

To help solve this problem, the Institut de Recherche en Biologie et Ecologie Tropicale (IRBET)-ICRAF started a collaborative agroforestry project. They state that the idea was to involve farmers in an exploratory on-farm trial to see how well their technology worked and to see whether live fences appealed to farmers. Their plan had as the potential to raise farm income and productivity while protecting the environment.

Live fences were originally introduced in Burkina Faso in the early 1980s, and were made up of only one species: Acacia nilotica. Sadly, researchers at this time did not work with the farmers, which led to low adoption rates of this procedure. IRBETs new goal in this project was to work with farmers; assessing what they needed and developing a fence that would both protect the farmer, protect the land, and provide by-products as well. (Author unknown)
Read Kabre's story

Jatropha Fences in Mali:
Farmers have been using this plant to make hedges for generations. The physic nut (Jatropha curcas) is a drought-resistant perennial that is not eaten by animals and can grow on marginal soils for up to 50 years Among its uses are the medicinal properties of its oil, a substitute for the gazoil used in diesel engines of that region, and soap making. Malis development is affected in several ways from this plant:

- prevention of erosion
- elevation of women (through soap making)
- reduction of poverty through income generation
- source of renewable energy
- More about Jatropha.
(Henning 2002)
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Links/References


Ashburner, J., Friedrich, T., and Benites, J. (2002). Opportunities and constraints for conservation agriculture in Africa. Leisa Magazine: October. [On-line]. Available: http://www.ileia.org/2/18-3/13-14.PDF.

Author unknown. (date unknown). Burkina Faso: Living fences come alive. ICRAF. [On-line]. Available: http://chemsrv0.pph.univie.ac.at/ska/zifence.htm.

Cherry, S. D., and Fernandes, E. C. M. (date unknown). Live fences. Cornell University. [On-line]. Available: http://ppathw3.cals.cornell.edu/mba_project/livefence.html.

Henning, R. K. (2002). Using the indigenous knowledge of Jatropha. IK Notes: World Bank. [On-line]. Available: http://www.worldbank.org/afr/ik/iknt47.pdf.

Herran, K. (1995). Living fences. Originally published in Permaculture Journal (8). [On-line]. Available: http://www.rainforestinfo.org.au/good_wood/livng_fs.htm.

Macklin, Bill. (date unknown). Agroforestry practices. Slide show. [On-line]. Available: http://www.winrock.org/forestry/factpub/Slidesho/Intro.htm.

Martin, F.W. (1991). The living fence: its role on the small farm. [On-line]. Available: http://www.tropical-seeds.com/tech_forum/growingtech/living_fence.html.

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