In Burkina Faso, a country in West Africa, deforestation and soil erosion are having a disastrous impact on the environment. Reforestation programs have been introduced to reverse the damage. But many of these programs are expensive and the newly planted trees are often destroyed in the first year by village cattle. It is estimated that the plant survival rate is less than 30%. To reduce losses of trees in the reforestation program, researchers from the local Ministry of Environment and Tourism have promoted the use of live fences.
Farmers usually use expensive wire fences to protect their vegetable crops and young plants. Or they make fences from branches or other material that rots quickly. In contrast, live fences are cheap and quickly form permanent barriers that cattle can’t get through.
Researchers first had to identify the best tree species and methods for the local climate. The species were chosen according to the following criteria: the plant’s recovery rate after planting; the plant’s annual growth rate in height and diameter; and the type of branch formation which must be low and full to make a fence that animals can’t get through.
The tree species selected were: Acacia senegal, Acacia nilotica, Acacia seyal, Bauhinia rufescens, Ziziphus mauritiana, and Prosopis juliflora.
The researchers found that there are some important things to remember when establishing a live fence. The trees should be planted in staggered, double rows with 40 centimetres between the rows and 30 to 50 centimetres between trees in the same row. If the trees are planted in trenches, the soil around the trees absorbs water more easily and the roots grow well. The best size for the trenches is 50 centimetres wide for single rows of trees or 80 centimetres wide for double rows of trees, and 60 centimetres deep. The trenches should be dug and refilled before planting.
The fences must be weeded two or three times during the first year after planting, to reduce competition from weeds. During the dry season each plant needs at least 1.5 litres of water per week.
It is best to prune the plants once or twice a year, depending on their height, at the end of the dry season or during winter. At first, pruning should be kept low, about 50 to 80 centimetres from the ground to encourage branches to form at the base of the trees. The next pruning depends on the required height which is generally around 1.2 metres.
Two major drawbacks to this method became apparent during the research stage. First, a lot of work is required to dig the trenches. Second, it is difficult to get enough seedlings at the right time. To solve these problems, the researchers also identified species and methods suitable for direct seeding rather than planting seedlings. Producing live fences using direct seeding is an easy, inexpensive method that does not require growing trees in nurseries. The success of direct seeding depends on regular, frequent watering. The species producing best results using direct seeding are: Acacia nilotica, Acacia seyal and Bauhinia rufescens. The seeds must be planted in early winter in trenches that have been dug and refilled before seeding.
Live fences are popular, especially with farmers who grow vegetables. This method is a significant step forward and will improve reforestation and vegetable farming in the country.
This article was published with the aid of a grant from the International Development Research Centre (IDRC), Ottawa, Canada. It is adapted from 101 Technologies from the South for the South, 1992, IDRC, P.O. Box 8500, Ottawa, Canada, K1G 3H9.
“Living fences,” in Agroforestry Today, volume 2, number 1, January March 1990. ICRAF House, P.O. Box 30677, Nairobi, Kenya
“Living fences help to protect gardens” in Letter No. 67, Summer 1996. Food Gardens Foundation, P.O. Box 41250, Craighall, Johannesburg 2024, South Africa
“The living fence: it’s role on the small farm,” ECHO Technical Note. ECHO (Educational Concerns for Hunger Organization), 17430 Durrance Rd., North Fort Myers, FL 33917, U.S.A. Tree seeds are also available from ECHO.
Ministère de l’Environnement et du Tourisme (Ministry of Environment and Tourism) P.O. Box 7044 Ouagadougou, Burkina Faso
In Burkina Faso the seeds, plants and cuttings of appropriate tree species are available from the Centre National des Semences Forestières (CNSF), P.O. Box 2682, Ouagadougou, Burkina Faso.